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5 1,068,832
Ell
IBRAI1 ,A OF TitE -
97
FLORIDA GEOLOGICAL SURVEY. StCuNil ANNUAL REPORT. FRONTISPIECE. PL. I.
Photo by Sellards.
ALUM BLUFF, APALACHICOLA RIVER, FLA. LOOKING UP STREAM. THE SECTION" N THE TEXT (p. 273) WAS
MADE AT THE h OSUR. I TN THE DISTANCE. 11L t kL 4
FLORIDA STATE GEOLOGICAL SURVEY
E. H. SELLARDS, STATE GEoLczsT
SECOND ANNUAL REPORT 1908-09
ADMINISTRATIVE REPORT
MINERAL INDUSTRIES
STRATIGRAPHIC GEOLOGY
INCLUDING A TOPOGRAPHIC AND GEOLOGIC MAP OF FLORIDA
PREPARED IN CO-OPERATION WITH THE UNITED
STATES GEOLOGICAL SURVEY.
PUBLISI1E FOR
THE STATE GEOLOGICAL SURVEY
TAL.LAHASsEE, 19G0.
*131
THE RECORD COMPANY
ST. AUGUSTINE
FLORIDA 1909
LETTER OF TRANSMITTAL.
To His Excellency, Hon. Albert W. Gilchrist, Governor of Florida.
Sir:-I have the honor to submit herewith a report of the operations of the State Geological Survey for the year ending June 30, 19.09, constituting the second annual report of the State Geologist. In addition to the administrative report and the report on mineral industries, there is included a report on the geology of Florida with special reference to stratigraphy, to which is added a chapter on the topography and geology of Southern Florida. This report on stratigraphy has been prepared in cooperation with the United States Geological Survey carried on in accordance with plans mentioned in my former report. The Florida Survey has derived much benefit from this cooperative work and is fortunate in having the report for publication at this time.
Permit me to express my appreciation of the interest you have taken in the work of the State Geological Survey, and the assistance you have given in the prosecution of that work.
Very respectfully,
E. H. SELLARDS,
State Geologist.
Tallahassee, Florida.
October 1, 1909.
202961
s
xx xx
x x x
x
x x
x x xx x x x xx xx x y x
x x x xx x x x x x x xx x x x x x xx
s xx x x x x x x x x x
s xx xx x x x x xsar x x
xx x x x x x xx
s s xxx xx xx 2xxv
x
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x x
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sa av
CONTENTS.
PAC.
ADMINISTRATIVE REPORT 3Y E. i. SW.ADS_.................. 13
Members of the State Survey force................................. 13
Publications issued ................................................ 13
D istribution of reports............................................. 14
Relation of the State Survey to other organizations.................. 14
The Survey library................................................ 15
Exhibition of geological material................................... 15
The relation of the State Survey to the ownership of mineral hearing lands ........................................................... 15
Samples sent to the Survey for examination......................... 16
Collection of statistical inform ation.............. .................. 16
Financial statem ent ............................................... 17
A PRELIMINARY REPORT ON THE GEOLOGY OF FLORIDA.
with special reference to the Stratigraphy, by GEORGE CHARLTON MATSoN AND FREERicx G. CLAPP. Prepared in cooperation between the United States Geological Survey and the Florida State Geological Survey, under the direction of TftoMAs WAYLAND VAUGHAN
Topography and drainage.......................................... 28
General topographic features..................................... 28
R ivers. ....................................................... :0
Lakes and swam ps .... ........................................ .31
Lake region .....................................................32
Caverns ....................................................... :12
S ink holes ..................................................... 3 4
Natural bridges ................................................ 36
Sand dunes ................................................... 37
Springs ....................................................... 37
N orth and W est Florida.......................................... 38
E rosion features ............................................... 38
Lakes ......................................................... 38
Sand dunes ................................................... 39
Coastal region ................................................... 39
Stream s an.d ponds ............................................. 39
Ridges ........................................................ 39
Terraces ...................................................... 39
S hore lnies ...................................................... 40
Coral reefs .................. .......... ....................... 40
Submerged continental border .................................. 40
Bars ..........................................,. .............. 40
S ounds ........................................................ 4 1
Inlets ............................................................ 41
T idal runw ays ................................................. 41
C apes ........... .............................................. 42
S o ils ....................... .......................... ............. 43
O rig in .......................................................... 43
Classification .................................................... 44
Structure ........................ ............................ 46
Stratigraphic geology .............................................. 50
T ertiary ......................................................... 50
Oligocene .......................................................0
V icksburg group ............................................ . .1
6 CONTENTS.
Stratigraphic geology-Continued. PAGE
Marianna and "Peninsular" limesto nes.................... 52
Stratigraphic position .................................... 52
Lithologic character ..................................... 52
Thickness ................................................ 53
Physiographic expression .................. ................ 53
Paleontologic character ................................. 54
Structure ...... ...................................... 54
Local details ............................................ .54
O cala lim estone ........................................... 59
Stratigraphic position ................................... 60
Lithologic character ...................................... 60
T hickness ............................................... 61
Physiographic expression ................................. 61
Paleontologic character ................................. 61
Structure ................................................ 61
Local details ............................................. 61
M iliolite lim estone .................. .................. 66
Apalachicola group .......................................... 67
Hawthorne formation ...................................... 69
Stratigraphic position ................................... 69
Lithologic character ...................................... 70
T hickness ............................................... 70
Physiographic expression ................................. 71
Paleontologic character .. ................................ 71
Structure ............................................ 71
Local details ............................. ............... 71
Chattahoochee formation ......... ....... ............... 74
Stratigraphic position ................................. 75
Lithologic character ...................................... 75
Thickness .............. ........... ............. 75
Physiographic expression ................. ............... 75
Paleontologic character ....... .. ....................... 77
Structure ................................................ 78
L ocal details ............................................. 78
Tam pa form ation .......................... ................ 84
Stratigraphic position ................................... 86
Lithologic character ................................... 86
Thickness ............................................... 87
Physiographic expression ................................. 87
Paleontologic character .................................. 87
Structure ................................................ 88
Local details ............................................. 88
A lum Bluff form ation ...................................... 91
Stratigraphic position ... ............................... 92
Lithologic character ................................... .02
T hickness ............................................... 94
Physiographic expression ................................. 94
Paleontologic character .................................. 95
Structure ................................................ 95
Local details ............................................. 95
Chipola marl member .............................102
CONTENTS. 7
Stratigraphic geology-Continued. AC.:
Oak Grove sand member........................ ...... 104
Shoal River marl member ...... ....................... 104
M iocene ..................................................... 106
General rem arks ........................................... 106
Jacksonville form ation ..................................... 108
Stratigraphic position .................................... 0I t
Lithologic character ...................................... 109
T hickness ............................................... 110
Physiographic expression ................................. Il
Paleontologic character .................................. III
S tructure ................................................ 111
Local details ..... ................................... 112
Choctawhatchee marl ..................................... 114
Stratigraphic position .................................. 114
Lithologic character ...................................... 115
T hickness ........... ........... ....................... 116
Physiographic expression ...... .......................... 116
Paleontologic character .................................. 116
Structure ............................................ 116
Local details ............................................. 117
P liocene .................................................... 123
Caloosahatchee marl .................... .................. 123
Stratigraphic position .................................... 124
Lithologic character ...................................... 124
T hickness ............................................... 124
Physiographic expression ................................. 124
Paleontologic character .................................. 124
Structure ................................................ 125
Local details ............ ............................... 126
N ashua m arl ............................................. 128
Stratigraphic position .................................... 128
Lithologic .character ..................................... 129
T hickness ............................................... 129
Physiographic expression ................................. 129
Paleontologic character .................................. 129
Structure .............................................. 130
L ocal details ............................................. 130
A lachua clay .............................................. 133
Stratigraphic position .................................... 134
Lithologic character ...................................... 134
T hickness .................... ....... .................. 134
Physiographic expression ................................. 134
Paleontologic character .................................. 135
Structure .................... .......................... 135
L ocal details ............................................. 135
Bone Valley gravel .................................... 138
Stratigraphic position .................................... 139
Lithologic character ..................................... 139
T hickness ............................................... 139
Physiographic expression ................................. 140
Paleontologic character ............................... 140
8 CONTENTS.
Stratigraphic geology-Continued. PAGE
Structure ........................ .................. .... 140
Local details ............................................. 140
Pliocene (?) ................................................ 141
Lafayette formation ....................................... 141
Stratigraphic position ..................................... 141
Lithologic character ...................................... 142
Thickness ............................................ 143
Physiographic expression ................................. 143
Paleontologic character .................................. 143
Structure ................................................ 143
Local details ............................................ 143
Q uatern-ry ................................................... 145
P leistocene .................................................. 146
Fossiliferous. m arls ........................................ 146
General ................................................. 146
Local details ............................................ 148
Gray sand ................................................ 152
P lanorbis rock ............................................. 153
Coquina .................................................. 153
Vermetus rock ............................................ 154
Yellow sand .............................................. 155
Stratigraphic position ............................. 155
Thickness ............................................. 156
Physiographic expression .................................. 157
Paleontologic characters ................................... 157
Structure ................................................. 157
Recent ....................................................... 157
Alluvial d epsits ... ..................................... _.157
Lacustrine dce-n s ts ............................ :............. 1 5S
Vernietus rock .............................................. 158
B each deposits ............................................... 158
Aeolian deposits ............................................. 159
Chem ical deposits ............................................ 149
H um an rem ains ............................................. 160
General Geologic H istory .......................................... 162
TOPOGRAPHY AND GEOLOGY OF SOUTHERN FLORIDA, by
SAMUEL SANFORD.
Introduction ...................................................... 177
Acknowledgments ................................................. 179
O bject of Report ...... ........................................... 179
T opography ....................................................... 179
General features ................................................ 179
Shape of the land mass.......................................... 180
Features of the m ainland......................................... 180
Pinelands ...................................................... 181
Dunes ......................................................... 18
R olling sand plains .............................................. 185
Flat lands ...... ................................................ 186
Rock ridges .. .................................................. 186
S w am ps ......................................................... 188
E verglades .................................................... 189
Elevation ................................................... 190
CONTENTS.
Topography-Continued. PIC
Bedrock surface .. .......................................... 1
Origin ................................................ 193
Cypress sw am ps ............................................... 19 1
Coastal sw am ps ................................... ............ 194
The keys .................. ............................... 195
T he Florida reef ................................................. 19(
Shore line topography ........................................... 19.
Waste and growth of the mainland and keys...................... 200
Recent changes of level........................................... 201
G eology .... ..................................................... 202
General statement ............................................... 202
Pre-Pleistocene formations ....................................... 203
General statement .......................................... 203
Evidence from well records.................................... 203
Palm B each ................................................. 204
Key Vaca .................................................. 204
K ey W est ................................................... 205
B uck K ey ................................................... 206
O ligocene ........................................................ 207
T hickness ....................................................... 207
M iocene and Pliocene .............................................. 207
Lithology ....................................................... 207
T hickness ....................................................... 207
Source of siliceous m aterials...................................... 207
Pleistocene ....................................................... 208
Unexposed beds .............................................. 208
Exposed beds .............................. .................... 209
Palm Beach limestone ............................................ 209
Synonymy ...................................................... 209
Stratigraphic position ........................................... 2 9
Lithologic characteristics ........................................ 210
Thickness ............................ ......................... 210
Physiographic expression .......... ......................... 210
Palcontologic characteristics ................................... 210
A real distribution ........................... .................... 210
Structre ............... ..................................... .211
Miami oolite ..................................................... 211
Synonymy,..... --..2-
Stratigraphic position ............. ............................. 21
Lithologic characteristics ...................................... 212
Thickness ..................................................... 21!
Physiographic expression ................... ....................21
Palcontologic characteristics ..................................... 213
Areal distribution ............................................. .. 213
Structure ............................ ........... ............... 21
Correlation ................ ....... ............................ 214
Key Largo limestone ........................................ ..... 214
Synonymy ...................................................... 214
Stratigraphic position ........................................... 215
Lithologic characteristics ......................................... 21
Thickness ...................................................... 21
Physiographic expression ....................... ............. .
10 CONTENTS.
Key Largo limestone-Continued. PACP
Paleontologic characteristics ...................................... 217
Areal distribution ........................................... ... 217
Exposures ..................................................... 218
K ey W est oolite ................................................. 218
Synonym y ...................................... ............. ... 218
Stratigraphic position ........................................... 219
Lithologic characteristics ......................................... 219
T hickness ............................. ........ ................. 219
Physiographic expression ........................'...... ........ 220
Paleontologic characteristics ........................... .........220
A real distribution .................................. ............. 221
Origin of Florida oolites .................... ................. 221
Lostmans River limestone .......................................... 222
Synonymy ...................................................... 22!
Stratigraphic position ........................................... 223
Lithologic characteristics ......................................... 223
T hickness ............... ....................................... 223
Areal distribution ............................................... 224
Origin ....................... .......................... .24
C oquina ........................................................... 225
Sands ........................................................... 226
Lithology of Pleistocene beds ...................................... 227
Thickness of Pleistocene beds...................................... 227
Recent ..... .................................................... 228
P eat ....... ...... .............................................. 228
M arl .......................................................... 228
Sands ................................... ......... 229
Coral reefs .................................................... 229
Worm rock ................................................. ... 230
Oyster banks .................................. ............ 230
PIcistocene and Recent History of Southern Florida................. 231
MINERAL INDUSTRIES, by E. H. SELLARDS.
P hosphate ... .................... ................................. 235
V arieties ....................................................... 235
L ocation ...................................... .................. 235
Production for 1908 .............................................. 236
Loss of phosphate in m ining ............. ... ... ................ 240
Clay ................................... ...................... 2!2
Plastic kaolin or ball clay ................. ..... ................ 212
Brick m aking clay ................... ..... .................... 243
P eat ........... ................... .................. 243
Diato-maceous carth ............................ ................... 244
Lim- ::nd ground limestonu ..... .... ... ................... 245
5and-lim e brick .............................. ................ 245
Building stone ......................... ........................... 246
Materials for mortar rnd concret"........ ........................ 247
M inerals new to the S:ate.............. ... ....................... 250
M alachite ........................... ......................... 250
THE FULLERS EARTH DEPOSITS OF GADSDEN COUNTY,
with Notes on similar Dleposits found elsewhere in thc State, by
E. H. SELARDS AND HrRMAN GUNT7R.
P reface ..... ......................................... ...... 255
CONTENTS. 11
The fullers earth deposits-Continued. %r .
Introduction ....................................................... 257
Mineral constituents of fullers earth.............................. 257
Physical properties ............................................... 258
T ests .......................................................... 258
U ses ............................................................ 259
M ethods of m ining ......................................,....... 259
Production of fullers earth ....................................... 260
Discovery of fullers earth in.America............................. 260
Fullers earth deposits of Florida................................... 26t
Gadsden County ................................................. 261
Geography and topography ..................................... 261
Geology ...................................................... 263
The Apalachicola River section............................... 20
Section at Chattahoochee Landing and in the vicinity of Chattahoochee and River Junction........................... 257
Section at Aspalaga Bluff.................................. 271
Section at Rock Bluff................................... 273
Section at Alum Bluff...................................... 275
Minor folds in the Chattahoochee limestone................... 277
Dip of the Chattahoochee limestone........................... 277
The Ocklocknee River section................................ 279
Fullers earth outcrops in Gadsden County..................... 280
Section in Owl Commercial Co.'s pit at Quincy.............. 282
Section on public road one mile east of Quincy............. 283
Section on Quincy-Attapulgus road, live miles northeast of
Q uincy ............................. .................. 283
Section one mile west of Gatzlaff on west side of Attapulgus
Creek ................................................ 283
Section at public road crossing on Bear Creek............... 28:1
Section on Crooked Creek................................. 283
Section at N icholson ...................................... 284
Amount of fullers earth in Gadsden County................... 285
Liberty County ...... ........................................... 285
N otes on fullers earth.......................................... 286
Leon County ................................................ 281;
N otes on fullers ,. rch.......................................... 2813
Colum bia County ................................................ 287
N otes on fullers earth.......................................... 287
Alachua County ........... .................................... 287
N otes on fullers earth.......................................... 288
Section at "Devil's Mill Hopper ............................. 288
M arion County .................................................. 288
N otes on fullers earth.......................................... 289
Section at Belleview.................................... 280
Manatee County ................................................ 289
Notes on fullers earth........................................ 289
Sections in pit of Atlantic Refining Company.................. 29
Section at the abandoned pit of the Columbia Fullers Earth
Company .......................................... 291
Amount of fullers earth in Florida.................................. 291
Index ............. ..................................
ILLUSTRATIONS.
PLATES.
PLATE. FACING PAGE.
I. Alum Bluff on Apalachicola River, Florida............... Frontispiece
I. -Fig. 1. Sink hole, southeast of Vernon. Type of topography
of Vicksburg group ............................ 58
Fig. 2. "Falling Water," five miles south of Chipley ...... 58
III. Fig. 1. Ocala limestone. Quarry of Ocala Lime Company. 64
Fig. 2. Ocala limestone ledge in pit of Fort White Hard
Rock Phosphate Company, Fort White.......... 64
IV. Fig. 1. Outcrop of Hawthorne limestone on Suwanee River
opposite Ellaville ........ ..................... 74
Fig. 2. Limestone of Tampa formation, Hillsboro County. 74
V. Fig. 1. Cut on the G. S. and F. R. R., near Kent, Nassau
C ounty ....................................... 100
Fig. 2. Alum Bluff formation, near White Springs on Suw anee R iver ................................... 100
VI. Fig. 1. Land pebble phosphate, showing bzdded deposit.... 140
Fig. 2. Pleistocene terrace, St. Marys River............... 140
VII. Fig. 1. Conglomerate of Lafayette formation. Rock Hill.. 154
Fig. 2. Coquina rock, Anastasia Island. St. Augustine..... 154
VIII. Fig. 1. "Rise" of the Santa Fe. River..................... .. 160
Fig. 2. Ancient shell mound, Indian River...:............ 160
IX. Fig. 1. Quarry in Miami oolite, Keys Station, Dade Count, 212
Fig. 2. Reef rock overlain by-marl.. Knights Key .......... 12
X. Fig. 1. Erosion by spray in Key Largo limestone, Knights
K ey .. ........................................ 2 18
Fig. 2. Beach ridge of calcareous sand. Cape Sable........ 218
XI. Hard rock phosphate mining region...................... 236
XIl. Land and River pebble phosphate mining region........... 238
XIII. Fig. 1. Plate rock phosphate mining, Anthony, Marion
Couny ............................ 240
Fig. 2. Removing overburden, land pebble phosphate, Mulbary.................. ........................ ..240
XIV. Fig. 1. Plast'c Kaolin mine, Edgar, Putnam County....... 244
F:g. 2. Dredge excavating pzat, North Canal, ni'ar Fort
Lauderdale. Photo by Matson.................. 244
XV. Fig. 1-6. Sands for mortar .............................. 248
XVI. Fig. 1. Fullers earth plant at Ellenton, Manatee County ... 25.
Fig. 2. Fullers earth plant at Quincy. Gadsden County... 258
XVIL Fig. 1. Apalachicola River looking south from Alum Bluff. 5
Fig. 2. Exposure of Chattazoochee limestone on A. C. L.
R. R. River function..........................
XVIII. Map of fullers earth exposures in Gadsden and Liberty
C ounties .. ..................................... 2 1
XIX. Fig. 1. Vikw i -it a Owl Commercial Company, Quincy, 2S4
Fig. 2. View in pit of Owl Commercial Company, Quincy, 284
TEXT FIGURES. PCv.
Fig. 1. Map showing sink holes......... ........................ 33
Fig. 2. Solution channel in limestone.............................. 36
Fig. 3. Section along drainage canal.......................... 193
Fig. 4. Section at Chattahoochee Landing....... ................ 269
Fig. 5. Section at Aspalaga Bluff ................................ 272
MAP.
Topographic and Geologic Map of Florida......................... In pocket
FLORIDA -STATE GEOLOGICAL SURVEY.
E. H. SELLARDS, STATE GEOLOGIST.
ADMINISTRATIVE REPORT.
The members of the State Survey force during the past year have been, in addition to the State Geologist, Mr. Herman Gunter, Dr. R. M. Harper, and during a part of the year Professor N. H. Cox. The chemical analyses necessary to the work of the State Survey are made by the State Chemist.
Mr. Gunter has assisted in the preparation of the paper on fullers earth deposits which acconipanies this report. In addition he has had charge of cataloguing and recording the Survey collections.
Dr. Harper's connection with the Survey began in December, 1908, since which time he has been engaged in an investigation of the peat resources of the State. The peat deposits form a natural resource the value of which can not fail to be appreciated as other fuels become exhausted, and Dr. Harper's report will do much to further the development of this industry. The fuel tests of peat samples for this purpose are being made in the fuel testing laboratory of the United States Geological Survey.
Professor N. H. Cox, of the department of civil engineering of the State University, was engaged during the summer of 1908 in an investigation of the roads and road making materials of the State.
In addition to the necessary correspondence and administrativework of the office, the State Geologist has completed the field investigations for a preliminary report on the fullers earth deposits, and has carried on field work with a view to the publication of a report on the phosphate deposits.
PUBIcATIONS ISSUED.
Two publications have been issued during the year as follows: The First Annual Report covering the operations of the State Geological Survey for the year 1908-09, and Bulletin No. 1 of the Survey, on the underground water supply of central Florida.
The annual report contains: (1) A sketch of the geology of Florida; (2) a chapter on mineral industries. including phosphate. kaolin or ball clay, brick-making clays, fullers earth, peat. lime and cement, and road making materials; (3) a bibliography of publications on Florida geology with a review of the more important papers
14 VLORIDA STATI.' G.OLOGICAL SURVEY.
published previous to the organization of the present Geological. Survey.
The bulletin contains: (1) Underground water: general discussion; (2) the -underground water of central Florida, deep and shallow wells, springs and artesian prospects; (3) effects of underground solutioN cavities, sink-holes, disappearing streams, and solution basins; (4) drainage. of lakes, ponds and swamp lands, and disposal of sewage by bored wells. Water analyses are included as well as tables, giving general water resources, public water supplies, spring and* well records.
DISTRIBUTION OF REPORTS.
The reports issued by the Survey are distributed upon request to citizens and to city and to other public libraries. The results of the Survey thus become permanently available to those interested in the geology or mineral resources of the State.
RELATION OF THE STATE SURVEY TO OTHER ORGANIZATIONS.
U. S. Geological Survey:-Cooperation with the National Geological Survey was arranged soon after the organization of the State Survey. During 1907-08 this cooperative work was devoted chiefly to an investigation of the general geology and stratigraphy of the State and the underground water supply. Bulletin No. 1 already referred to formed a part of the results of this cooperative work. A special report on the stratigraphy of the State forming a second part of this cooperative work accompanies this report. During the present year the State Survey has fortunately been able to extend cooperation with the National Survey to include testing of peat samples for fuel purposes. These tests form a part of and will be included in the report on peat deposits.
U. S. Department of Agriculture:-The Director of the Division of Roads and Road Materials of the U. S. Department of Agriculture has very kindly consented to make the necessary tests of samples of road material of Florida taken in connection with the -investigation of roads and road material by the Florida Survey.
Geological Surveys of Neighboring States:- Geological formations are limited by no such lines as State boundaries, and an intelligent study of a formation often necessitates a knowledge of its extent and development in a neighboring State. The relationship of a State Survey is therefore close with neighboring States, and particularly with adjoining States. This relationship in the case of the Florida Survey is especially close with Georgia and Alabama. With more distant States there is a no less real relationship growing out of a similarity of deposits, and of methods of study and development.
SECOND ANNUAL REPORT. 15
Office of State Chemist:-The Survey law provides that analytical work necessary to the investigations of the Survey shall be done by the State Chemist. The Survey is thus brought intp -co-operative, relation with the Division of Chemistry of the Department of Agri-: culture and in so far as the work of the. Survey cortxibutes to agricultural interests, to the Department of Agriculture a a whole.
The State Agricultural Experiment Station:-In its study of the. water supply in relation to agriculture, of soils in their geological. relations, and in other ways, the work of the State Survey may be, expected to supplement certain lines of work of the State Experiment Station, the two organizations being of mutual aid to each other.
State Colleges and Other Educational Institutions: -The State Survey law provides that duplicate suits of specimens obtained by the Survey illustrating the geological and mineral features of the State shall be deposited with the State Colleges. The publications of the State Survey are placed in the libraries of all of the educational institutions desiring them.
THE SURVEY LIBRARY.
A well-equipped reference library is essential to the best results and an effort is being made to bring together those publications which are necessary to.the immediate and future work of the Survey. The Survey library now contains more than 1,500 volumes. These include the reports of the several State Geological Surveys; the Annual Reports, Bulletins, Monographs, Professional Papers, Water Supply and Irrigation Papers, and other publications of the Nalional Geological Survey; the reports of the Canadian, and a few other foreign Geological Surveys; and many miscellaneous volumes and papers on geological subjects. Additions to the Survey library will be appreciated.
EXHIBITION OF GEOLOGICAL MATERIAL.
The Survey law provides for the exhibition of geological material. The space available for this purpose is unfortunately as yet very limited. A part of one room has, however, been used for, this purpose. Three cases have been built, designed to serve the double purpose of storage and exhibition. the lower part of the case being adapted to the purpose of storing material. In making the collections a systematic plan has been followed to secure a representation of the rocks, minerals, and fossils of each formation in the State. The collections will be added to as opportunity permits. THE RELATION OF THE STATE SURVEY TO THE OWNERSHIP OF MINERAl,.
BEARING LANDS.
The relation of the State Survey to the ownership of mineral-bearing lands is specifically defined. The Survey law provides that it shall
16 1AORIDA STATE GEOLOGICAL SURVEY.
be the duty of the State Geologist and his assistants, when they discover any mineral deposits or substance of value, to notify the owners of the land *upon which such deposits occur before disclosing their location to any other person or persons. Failure to do so is punishable by fine and imprisonment. It is not intended by the law, however, that the State Geologist's time shall be devoted to examinations and reports upon the value of private mineral lands. Reports of this character are properly the province of commercial geologists, who may be employed by owners of land for that purpose. To accomplish the best results, the work of the Survey must be in accordance with definite plans by which the State's resources are investigated in an orderly manner. Only such examinations of private lands can be made as constitute a part of the regularly planned operations of the Survey.
SAMPLES SENT TO THE SURVEY FOR EXAMINATION.
Samples of rocks, minerals and fossils will be at all times gladly received, and reported upon. Attention to inquiries and general correspondence are a part of the duties of the office, and afford a means through which the Survey may in many ways be useful to the citizens of the State.
The following suggestions are offered for the guidance of those submitting samples:
1. The exact location of all samples should Lie given. This should be carefully written out in full and placed on the inside of the package.
2. The statement accompanying the sample should give the conditions under which the specimen occurs, whether an isolated fragment or part of a larger mass or deposit.
3. Each package should be addressed to the Florida State Geological Survey, Tallahassee. The name and address of the sender should be plainly written on the outside.
4. Transportation charges, whether by mail, express or freight, should in all cases be prepaid.
THE COLLECTION OF sTATIs'ricAL INFORMATION.
For many purposes the collection and publication of statistical information is helpful, both to the industries concerned and to the general public. Such statistical information is desired from all the mineral industries of the State. Such information will be recognized as strictly confidential in so far as it relates to the private business of any individual cr company, and will be used only in making up State and County totals. The co-operation of the various industries of the State is invited in order that the best possible showing of the State's products may he made annually.
SECOND ANNUAL REPORT.
FINANCIAL STATEMENT.
The total appropriation for the State Geological Survey is $7,500 per annum. With the exception of the salary of the State Geologist the amount of which is fixed by statute, all Survey accounts are paid upon warrant issued by the Comptroller as per itemized vouchers approved by the Governor. The following is a list of the expenses of the Survey for the year ending June 30, 1909. The original of all bills and the itemized statements of all expense accounts are on file in the office of the Comptroller. Carbon copies of the same are on file in the office of the State Geologist:
July, 1908.
E. H. Sellards, salary for the quarter ending June 30, 1908, chargeable to funds of the year covered by this report............... $ 189.46
Herman Gunter, Assistant, salary, June, 1908...................... 75.00
Nellie Mathes, stenographer, salary, June, (half month)............ 30.00
E. H. Sellards, State Geologist, expenses, May and June, 1908...... 57.65 Herman Gunter, traveling expenses, June, 1908.................... 36.35
John M cDougall, postage ...................... .................. 13.49
Herrick and Cowell, peat testers.................................. 24.00
E. P. Greene, Arcadia, Fla., tripod................. ............... 3.00
Eimer and Amend, supplies...................................... 8.90
American Peat Society, journal.................................. 2.00
W. H. Lowdermilk, Washington, publications...................... 1.87
Hill Publishing Company, publications............................ 8.20
University of Chicago Press, Journal of Geology................... 3.00
S. H. Coleman, Tallahassee, painting sign.......................... 4.10
G. E. Stechert and Company, publications.......................... 14.25
Iowa Geological Survey, publications.....................4..... 13.75
Economic Geology Publishing Company, Economic Geology........ 3.00
Capital Publishing Company, printing............................. 40.25
N. H. Cox, Assistant, salary ($58) and expenses ($67.35), July 1-18 125.35 Nellie Mathes, stenographer, salary, July (two-thirds month)...... 40.00 Capital City Livery Stables, drayage............................... 1.80
August, 1908.
E. H. Sellards, State Geologist, traveling expenses, July and August 46.94 Nellie Mathes, stenographer, salary, August....................... 60.00
Geological Society of America, publications ........................ 1.40
The H. & W B. Drew Co., supplies............................... 6.60
September, 1908.
E. H. Sellards. salary for the quarter ending Sept. 30, 1008......... 625.00
Herman Gunter, Assistant, salary, July to September............... 225.00
Nellie Mathes, stenographer, salary, September..................... 60.00
N. H. Cox, Assistant, salary ($30) and expenses ($30), August 3-13 60.00 Minnie M illigan, stenographic work............................... 9.18
Capital Publishing Co., printing................................... 573.60
Maurice-Joyce Engraving Co., engravings ......................... 62.98
Carried forward ......................... ........ ..... .. $2, 312
18 FLORIDA STATE GEOLOGICAL SURVEY.
Brought forward ....................................... $2,426.12
October, 1908.
E. H. Sellards, State Geologist, traveling expenses, Sept.-Oct......... 60.01
Nellie Mathes, stenographer, salary, October ...................... 60.00
Gilmore and Davis, office supplies................................. 13.45
W. H. Lowdermilk & Co., publications............................. 21.25
Capital Publishing Co., printing ................................... 512.00
Capital Publishing Co., printing ................................... .2.50
John McDougal, Postmaster, postage ............................. 150.00
November, 1908.
E. H. Sellards, State Geologist, traveling expenses, November...... 62.94 Nellie Mathes, stenographer, November ........................... 60.00
Munson Supply Co., typewriter keys.............................. 3.50
December, 1908.
E. H. Sellards, State Geologist, traveling expenses, December...... 61.90 E. H. Sellards, salary for the quarter ending Dec. 31, 1908.......... 525.00
Herman Gunter, Assistant, salary, October-December.............. 225.00
R. M. Harper, Assistant, salary ($100.00), expenses ($72.24)....... 172.24
The D. R. Cox Furniture Co., supplies ............................ 5.03
Engineering and Mining Journal, publications...................... 1.00
J. K. Sm all, publications ......................................... 4.12
Board of Managers, City Water and Light Plants, supplies......... 13.10 January, 1909.
E. H. Sellards, State Geologist, traveling expenses January........ 41.50
R. M. Harper, Assistant, traveling expenses ($39.81), salary ($100). 139.81 Herman Gunter, Assistant, traveling expenses ($8.65), salary ($75). 83.65 February, 1909.
E. H. Sellards, State Geologist, traveling expenses, February....... 96.89 R. M. Hagr, Assistant, traveling expenses ($60.25), salary ($100). 160.25 Herman Gunter, Assistant, traveling expenses ($34.89), salary ($75) 109.89 Nellie M athes, stenographer ..................................... 12.50
The H. & W. B. Drew Co., supplies ........ ................... 5.00
March, 1909.
E. H. Sellards, State Geologist, traveling expenses, March.......... 81.44
E. H. Sellards, salary for the quarter ending March 31, 1909........ 625.00
R. M. Harper, Assistant, traveling expenses ($2.25), salary (half
m onth, $50.00) ..................... ........................ 52.25
Herman Gunter. Assistant, traveling expenses ($12.71), salary ($75) 87.71 John McDougal, Postmaster, postage ............................. 10.00
April, 1909.
E. H. Sellards, State Geologist, traveling expenses, April.......... 46.90
R. M. Harper, Assistant, traveling expenses ($60.05), salary ($70).. 130.05 Herman Gunter, Assistant, traveling expenses ($67.35), salary ($75) 142.35 May, 1909.
E. H. Sellards, State Geologist, traveling expenses, May, 1909...... 70.25 R. M. Harper, Assistant, salary ($100), traveling expenses ($56.35) 156.35 H. Gunter, Assistant, salary, May, 1909............................ 75.00
Carried forward .......................................
SECOND ANNUAL REPORT. 19
Brought forward ............................................$6,605.95
Keuffel, Esser & Company, one Abney level..................... 13.93
H. & W. B. Drew Company, supplies.............................. 32.56
Alpha Photo Engraving Company, engravings..................... 28.90
American Journal of Science, subscription for 1909.................. 6.00
June, 1909.
E. H. Sellards, State Geologist, salary for the quarter, ending June
30, 1909 ...................................................... 625.00
R. M. Harper, Assistant, salary ($100), traveling expenses (33.04). 133.04 H. Gunter, Assistant, salary ($75.00) ............................. 75.00
E. H. Sellards, State Geologist, traveling expenses.................. 45.15
Maurice Joyce Engraving Co., engravings......................... 19.17
W are Bros. Co., publications...................................... 6.00
Hill Publishing Co., publications................................... 10.00
Economic Publishing Co., Economic Geology...................... 3.00
The Macmillan Co., publications................................... 8.52
The University of Chicago Press, Journal of Geology.............. 3.00
Frances J. Bulask, publications.................................... 2.00
Total expenditures ..........................................$7,617.22
Overcharge ................................................ 117.22
$7,500.0O
t
=
A PRELIMINARY REPORT ON THE GEOLOGY or FLORIDA
WITH SPECIAL REFERENCE TO THE STRATIGRAPHY BY GEORGf CHARLTON MATSON AND FREDERICK G. CLAPP.
INCLUDING A CHAPTER ON THE
TOPOGRAPHY AND GEOLOGY OF SOUTHERN FLORIDA
BY SAMUEL SANFORD.
PREPARE!) IN COOPERATION BETWEEN THE UNITED STATES GEOLOGICAL
SURVEY AND THE FLORIDA STATE GEOLOGICAL SURVEY, UNDER
TIE DIRECTION OF THOMAS WAYLAND VAUGHAN.
G
DEPARTMENT OF THE INTERIOR
UNITED STATES GEOLOGICAL SURVEY WASHINGTON.
OFFICE OF THE DIRECTOR.
Dr. E. H. Sellards, State Geologist of Florida,
Geological Survey of Florida, Tallahassee, Florida.
Dear Sir: I herewith transmit the manuscript and illustrations of a Preliminary Report on the Geology of Florida, with especial reference to the Stratigraphy. By George Charlton Matson and Frederick G. Clapp. Including a chapter on the Topography and Geology of Southern Florida. By Samuel Sanford. Prepared in cooperation between the United States Geological Survey and the Florida State Geological Survey, under the direction of Thomas Wayland Vaughan.
This report has been prepared in accordance with the agreement entered into by the Florida State Geological Survey and the United States Geological Survey on the first day of August, 1907, and is transmitted to you for publication by the Florida State Geological Survey.
Very respectfully yours,
GEO. OTIS SMITH,
DIRECTOR.
1
*
A PRELIMINARY REPORT OF THE GEOLOGY OF FLORIDA
WITH SPECIAL REFERENCE TO THE STRATIGRAPHY
GEORGE CHARLTON MATSON AND FREDERICK G. cLAPP.
INTRODUCTION.
OBJECT AND SCOPE OF REPORT.
Previous Information Regarding the State:-Although Florida was settled early in the history of colonization, various natural causes have cooperated to retard the development of the State's resources. At the present time Florida contains the largest unsettled area in the eastern part of the United States.
Various papers containing information relating to the geology of the State have appeared in scientific journals at intervals, especially during the last twenty years of the nineteenth century.' Such institutions as the Wagner Free Institute of Science of Philadelphia have published the results of extensive investigations, and the U. S. Geological Survey has at various times sent parties into the State. Numerous scientists, attracted to the South by the delightful climate during the winter months, have attempted, with varying degrees of success, to solve some of the geologic problems; but prior to 1907 no State Geological Survey had been authorized by the legislature and no stratigraphic report, published by the State, of a popular and comprehensive nature has appeared. A prominent object of the present report is to fulfill this important task.
Insufficiency of Knowledge:-It is a fact that, in many States, the geologic conditions are so complicated and diverse that few persons other than geologists and parties engaged in prospecting or developing the mineral resources have even a fair idea of the character, sequence, and significance of the strata, and this is true particularly in Florida. Indeed, this characteristic is more striking in Florida than in many other States, because the greater part of the State is low, and the older geological formations are obscured by a thick mantle of sand. An incorrect belief, still held by many, and unfortunately taught until recently, is that' the Florida peninsula is entirely a coral formation. Few people who have not made the sub'For a bibliography of.the geology of Florida see First Annual Report, E. H. Sellards, 1908.
26 FLORIDA STATE GEOLOGICAL SURVEY.
ject a study realize that the geologic formations and structure in Florida are in reality very diversified. It is to throw some light on these that the present report is published. An effort has been made to bring together information relating to the geology of Florida and to supplement the knowledge already available with such observations as were possible in the time allotted to the work. However, this report is to be regarded as preliminary, and it is expected that further work will not only add new facts, but will also lead to some revision and modification of the views now held. In the body of the report several unsolved problems are indicated, but it should be borne in mind that not all of them are enumerated.
Sources of Information:-As is usually true of reports covering large areas, the data incorporated here are derived from many different sources. All previous literature has been carefully studied and the different views compared and brought up to date, giving credit to the respective investigators. Particularly helpful has been the work of Dr. W. H. DalI, of the U. S. Geological Survey, who has made extensive investigations of the paleontology of the State, and, in 1892, published a treatise of nearly a hundred pages, incorporated in Bulletin 84, of the U. S. Geological Survey, in which he outlined the stratigraphic geology of the State as well as it could then be done. A later report by Dr. Dall was published in the transactions of the Wagner Free Institute of Science. This publication is primarily paleontologic, but it also contains a r6sum6 of the geology and the stratigraphy of the State. These papers have furnished much valuable information which has been incorporated in this report and is specifically acknowledged elsewhere. The work has been carried on under the immediate supervision of Dr. T. Wayland Vaughan, of the U. S. Geological Survey. In addition to exercising general oversight of the work, Dr. Vaughan has examined and identified the fossils collected during the progress of the investigation. He has very generously placed his own extensive notes-accumulated during a series of years-at the disposal of the writers, and has aided both by advice and assistance in the field and in the office. The investigations of Drs. Dal] and Vaughan have been of great value because they have formed a basis for all subsequent work. Other geologists, prominent among whom are Dr. E. A. Smith, Prof. Angelo Heilprin, and Prof. Louis and Dr. Alexander Agassiz. have added much to the knowledge of the geology of Florida.
After the first discovery of phosphate in Florida Mr. George H. Eldridge was sent by the National Survey to make detailed investigations of the deposits of that material. He obtained much valuable data, but, unfortunately, did not live to prepare his final report. His
SECOND ANNUAL REPORT. 27
notebooks have been available and were occasionally drawn upon by the writers.
The investigations leading to the present report were enabled primarily through the passage of the act incorporating the new State Survey. At the same time the National Survey was engaged in a comprehensive investigation of the geology of the Atlantic and Gulf Coastal Plain of the United States, and hence cooperation between the two bureaus enabled a more thorough study than could have been carried out in a single season by either bureau alone.
In October, 1907, Mr. Clapp began a field study of the stratigraphy and underground water resources of Florida. In November he was joined by Mr. Matson, and together they remained in the field continuously until May 1, 1908, visiting nearly every town in the State and gathering as many data as time would permit.
Having exhausted the funds available for field expenses, the writers repaired to the office about May 1, 1908. On July 1, 1908, Mr. Clapp resigned from the U. S. Geological Survey, and the work of preparing the manuscript for the report was entrusted to the senior author. The base map which accompanies the report was prepared by the Topographic Branch of the U. S. Geological Survey.
ACKNOWLEDGMENTS.
The interest and cooperation of the people of Florida have rendered this work a pleasure, and the authors wish to make public acknowledgment of the numerous favors and courtesies extended to them while in the field and office. Several persons deserve particular mention, among them being Dr. J. N. MacGonigle, of Miami, and Mr. Goff, J. C. Meredith, Constructing Engineer, Key West Extension, and other officials of the Florida East Coast Railway, for affording opportunity to visit the extension of the railroad during process of construction.
Hon. Frank Clark, of Gainesville, furnished introductions which greatly facilitated the work. Dr. De Witt Webb, of St. Augustine, and Dr. E. S. Crill, of Palatka, have interested themselves in the work. Many well drillers have furnished logs and records which added valuable data to our knowledge of the underground stratigraphy, and it is a pleasure to mention particularly Capt. Alexander Near, of Eau Gallie; Mr. H. C. Haven, of DeLand; Mr. W. D. Holcomb and Mr. Edward Pettigrew, of Ianatee; Mr. H. W. Pearce, of Arcadia; Mr. H. Walker, of St. Augustine, and Mr. Win. E. Hughes, of Charleston, S. C. All these and many others, who can not be mentioned on account of lack of space, have given substantial assistance. Many citizens have interested themselves in acting as guides and in furnishing specimens and samples from wells. The officials of
28 FLORIDA STATE GEoLoGICAL SURVEY.
the Atlantic Coast Line Railroad, the Seaboard Air Line Railway, the Florida East Coast Railway and the Louisville and Nashville Railroad, in Jacksonville, Wilmington, Norfolk and Louisville, have allowed access to their profiles and other records, which gave valuable information for use in the construction of the topographic map of the State.
At the time when the field work for this report was begun Mr. Samuel Sanford was engaged in geologic work for the Florida East Coast Railway. The task of investigating the geology of the Keys and the southern end of the State was entrusted to him. The results of Mr. Sanford's work are incorporated in a subsequent chapter.
TOPOGRAPHY AND DRAINAGE.
General Topographic Features :-While Florida is a region of coinparative slight relief, its surface configuration presents considerable diversity, ranging from the nearly level plain in the coastal region and the Everglades to the deeply dissected upland in the northern part of the State, where much of the surface is trenched by steep walled valleys, and the highlands of the peninsula where the surface often consists of a series of more or less rounded depressions separated by narrow divides. The range in altitude varies from sea level along the coast to over '200 feet ahove tide at various points on the ridge which forms the center of the peninsula and to about 300 feet above the same datum near the northern boundaries of Gadsden, Valton, Santa Rosa and Escambia Counties.
The accompanying topographic map (in pocket) is intended to show the approximate areas of land which lie above and below certain altitudes. The datum plane is mean sea level, and the contour lilies show the variations in altitude for each fifty feet. This map embodies the results of the earlier topographic surveys, the river surveys of the U. S. Army engineers, and the various railroad surveys, together with a large number of barometric determinations which were made during the progress of the field work. While the exact location of the contours is sometimes more or less uncertain, it is believed that tile) are sufficiently accurate to give a good idea of the relative areas of different altitudes, and to present a general plan of the broader topographic features of the State. Owing to tile small scale of the map, it was necessary to omit such minor details as sink-holes, valleys of small streams, narrow ridges and siall, more or less, isolated elevations. The U. S. Geological Survey has already published detailed maps of certain parts of the peninsula, and to these the reader is referred for local information.'
'Arredondo, Citra, Dunnellon. Ocala, Panasoffkee, Tsala Apopka and Williston sheets.
SECOND ANNUAL RLPORT-TOPOGRAPIHY AND DRAINAGE. 29
An examination of the map will show that the southern part of the peninsula, comprising an area about 150 miles long and averaging over 100 miles in width, has an altitude of less than fifty feet above sea level. In addition to this large area, there are narrow strips of lowland along the Atlantic and Gulf coasts. It is also apparent that the valleys of the streams do not rise above the 50-foot contour for a considerable distance from the coast, and in one case-the St. Johns River-the stream is nowhere more than thirty feet above tide.
The uplands of the peninsula and adjacent part of north Florida are separated into two more or less distinct parts by the Ocklawaha River. Beginning southeast of Arcadia, a belt of high land extends northward to Summit, in Marion County. This area, which is very irregular in shape, separates the Kissimmee River drainage from the various streams to the westward. In this upland at Lakeland, Brooksville, and several other points, the surface is known to rise more than 200 feet above sea level.
Another broad irregular upland extends from just north of the Ocklawaha River to the Georgia-Florida line. This area forms the divide between the Atlantic and Gulf drainage basins, and includes a considerable tract which rises above 150 feet. Its narrowest part is along the western boundaries of Clay and Duval Counties where it forms the long north-south divide known as "Trail Ridge." This upland includes Lake City with a altitude of 201 feet above tide and Highland on the "Trail Ridge" with an altitude of 210 feet above the same datum place. Near the Georgia line the upland broadens into the Okefinokee swamp which occupies a large area in Georgia, but extends only a short distance into Florida. The western slope of this highland is cut by the Santa Fe River and its tributaries, while its eastern slope is deeply dissected by the tributaries of the St. Johns and St. Marys Rivers.
Near the State line in the northern and western parts of Florida there is a narrow upland which has been deeply eroded by the various streams which cross it. On its seaward side this highland often descends rather abruptly to the low coastal region. The highest points in this region are near the northern line of the State where considerable areas rise above the 250-foot contour. Notable examples of this upland are seen in Gadsden County and in the counties west of the Choctawhatchee River; and Tallahassee, the capital of the State, with an altitude of about 200 feet above tide, is situated upon a remnant which has been isolated by erosion. East of the Apalachicola River, the railroad stations at Monticello, Midway and Quincy are all reported to be over 200 feet above sea level. West of the Apalachicola River, between Argyle and Holt, on the Louisville and Nashville Railroad, and at various points on the Yellow River Rail
30 FLORIDA STATE GEOLOGICAL SURVEY.
road, the profiles show that there are considerable tracts of land which rise above the 200-foot contour, while Argyle, De Funiak Springs and Mossyhead are all above 250 feet-the last named being 264 feet above tide. It appears probable that at some localities near the Alabama line the surface may rise somewhat higher and small areas may exceed 300 feet.
Rivers:-The drainage history of Florida has been somewhat complex, and the changes in relative positions of land and sea which have affected the stream are so closely interwoven with the general geologic and physiographic history that their full discussion is left for a subsequent report. At this time it is only necessary to note the general character of the streams and state briefly the factors which have produced the existing conditions. Some of the rivers are confined to the coastal lowlands where they assumed their courses in consequence of the initial slope of the land as it emerged from beneath the sea, and they are therefore known as consequent streams. Their positions are dependent upon the original slope of the surficial sand, and their channels are frequently winding. Wherever there were depressions in the sands, lakes were formed and some of the consequent streams consist of a chain of such lakes joined by more or less well defined channels. To this class belongs the Kissimmee-Caloosahatchee system with its numerous lakes.
Wherever the consequent streams have removed the thin mantle of surficial sand and cut into the older formations they belong to the class known as superimposed streams. Thus the Caloosahatchee River which in parts of its course has eroded a channel through the surface formations and into the underlying Pliocene and possibly Miocene marls. is superimposed upon the older formations. In like manner the St. Johns River north of Sanford has been superimposed upon the Pliocene and probably the Miocene rocks. The Manatee and Aucilla Rivers have in parts of their courses been superimposed upon the Oligocene formations. There are in Florida many other examples of consequent and superimposed streams and many of the rivers such as the St. Johns are in part consequent and in part superimposed.
The rivers which cross both the older and younger geological formations existed before the deposition of the sands which form the surface of the lowlands. At that time they entered the sea at the edge of the present highland belt. Where they cross the highland these streams have broad, deep valleys floored with a deposit of alluvium and are often bordered by prominent bluffs. In their courses across the uplands, they take a direction which was determined by the slope of the surface; but they have usually removed the surficial formations and cut deeply into the older rocks upon which they are superimposed.
SECOND ANNUAL HEPORT-TOPOGRAPHY AND DRAINAGE. 31
As the coastal belt emerged from the sea by successive additions to its landward margin these streams gradually extended their channels across this new land and hence became in part what is commonly known as extended streams. On the coastal belt they flow in broad. shallow trenches bordered by low banks of sand, and in some cases they have removed the Pleistocene sand and eroded channels in the underlying limestones and marls. The most important extended streams of the State are the Escambia, Black Water, Yellow, Choctawhatchee, Apalachicola, Ocklocknee. Aucilla, Withlacoochee, Hillsboro, Peace and St. Marys Rivers. With the possible exception of the Escambia River all of these streams are in part superimposed upon the Pliocene or older geological formations.
After the deposition of the younger geological formations and the extension of the streams across the newly emerged land there came a slight submergence which caused a shortening of the streams and permitted the sea water to enter the river channels for a distance of several miles from the coast. In this way the lower parts of the stream valleys have been transformed into estuaries which contain brackish water and are affected by the tides. The length of these estuaries or tidal portions of the rivers varies in the different streams, and even in a single river it may vary with the strength and direction of the wind. Strong on-shore winds raise the height of the water and force the sea water farther up-stream, while off-shore winds have an opposite effect.
Lakes and Swamps:-Although the State of Florida is crossed by many large rivers there are numerous tracts of land which are very imperfectly drained and are occupied by lakes or swamps. The lake region will be more fully discussed on subsequent pages, and it is sufficient to note that lakes are very numerous, some of them being of considerable size. The swamps are of varying size, from a few rods to many miles in diameter. The most notable undrained area is in the southern part of the peninsula where the Everglades and adjacent lowlands form a nearly impenetrable wilderness. In this low-. land tract lies Lake Okeechobee, which is one of the largest and most interesting lakes in the South Atlantic States. According to the measurements cited by Sanford the Everglades nowhere rise more than 22.4 feet above sea level, and the surface has such a gentle slope that the water which falls during the rainy season forms broad shallow ponds and marshes which afford excellent opportunity for the growth of saw-grass and other aquatic plants. These plants by their partial decay under water have formed peat and muck deposits several feet in thickness.
The smaller swamps and marshes occur in all parts of the State, but they are especially numerous in the belt of lowland which borders
32 FLORIDA STATE GEOLOGICAL SURVEY.
the coast, and they become smaller and less numerous in the highlands which border the north line of the State. In the coastal belt there are many small lakes and ponds, some of them permanent, but most of them lasting only during the rainy season. They seldom exceed two or three feet in depth and appear to occupy shallow depressions in the surface of the sand.
In the central part of the peninsula and in some localities near the northern boundary of the State there are lakes and swamps which appear to be the result either of unequal deposition of the surface sands or of solution of the subjacent limestone and consequent lowering of the surface in the manner described under Caverns. Some of these lakes are shallow and resemble those of the coastal belt, but others are deep basins partially or wholly enclosed by a rim of rock. The smaller swamps often contain considerable deposits of peat or muck.
LAKE REGION.
The lake region occupies a large part of the highland in the central part of the peninsula, but similar topography is to be found in both North and West Florida. The southern boundary of the lake region is not sharply defined and it comprises two more or less distinct areas consisting of the lakes in the elevated portion of the peninsula which usually have rock basins and those of the coastal and southern lowlands which occupy shallow depressions in the sand. While the areas characterized by these two types are more or less distinct, there are many lakes in the highlands which may be due to depressions in the sand and there are small lakes in the lowlands which are known to occupy rock basins. The highland area of the peninsula where rock basins predominate has commonly been known as the Lake Region, and for convenience this meaning is retained.
The Lake Region comprises a type of topography common to all limestone areas which have been sufficiently elevated to permit the formation of large underground streams. The character of the surface is well shown by the Williston topographic sheet of the U. S. Geological Survey. The numerous depressions shown in the accompanying text figure, which is taken from this map, are known as sink-holes and, in order to understand their origin, it is necessary to consider the development of the underground drainage.
Caverns:-This region is underlain, at no great depth. by several hundred feet of porous limestones of Vicksburg age. Where surface water F-earing carbonic acid, derived from decaying organic matter, enters this rock, it gradually dissolves the limestone and thus forms underground channels.
SECOND -ANNUAL REPORT-TOPOGRAPIJY AND DRAINAGE. 33
A large part of the mineral matter which is thus removed by the underground water is carried to the surface; and, entering the rivers, is transported to the sea. In an earlier report by this Survey,1 there is an estimate of the amount of solid matter removed in this manner. The quantities given were based upon a consideration of the amount
VI
IMZ
Contour Intervn 0 feet Scale _W-i petwhn im men eed7~
0 2 3 iles
Fig. 1. Map showing sink holes.
of mineral matter removed in solution in eight of the large springs of the State. These springs emerge from caverns in the underlying limestone and they are fed by the rainfall upon the surrounding area. The percentage of mineral matter in solution was determined by analysis and the volume of flow was estimated. By this method Dr. Sellards estimated that Silver Spring brought to .the surface 340 pounds of mineral matter per minute. While the quantity of matter in solution in the water of the other springs varied it was in all cases
Sellards, E. H., A Preliminary Report on the Underground Water Supply of Central Florida, Fla. State Geol. Survey, Bull. 1, 1908, pp. 47-48.
2g
34 FLORIDA STATE GEOLOGICAL SURVEY.
large. With a conservative estimate of the average mineral content of the spring water (219 parts per million) and the assumption that about one-half' the rainfall of Florida entered the earth and removed this amount of material, Dr. Sellards reached the conclusion that the rate of solution was sufficient to remove, in the limestone section of Florida, about 400 tons per square mile annually. If evenly distributed, this would lower the surface of the limestone about one foot in five or six thousand years. The concentration of this solution along certain beds oi channels of active circulation would permit the formation of large underground passages in a comparatively short period of geological time. These channels, known as caverns, are sometimes hundreds of feet in diameter and several miles in length. A level surface and a porous soil favor the development of caverns because most of the rainfall sinks into the earth instead of flowing off over the surface. In the past the region under discussion appears to have furnished an excellent opportunity for the formation of caverns because its surface was comparatively level and covered by a mantle of porous material.
Sink Holes:- As solution progressed the cavern roofs became weakened at various points and collapsed, forming the depressions known as sink-holes. In some areas these depressions are so numerous that they occupy a large part of the surface and give the region its characteristic topography. Splendid examples of ancient sinks such as the Devil's Mill Hopper are to be found in various parts of the State, and instances where sinks have been formed by the collapse of cavern roofs within the memory of persons now living are known in different parts of the Lake Region. A good example of a recently formed sink is to be seen on the road between High Springs and the "Sink" of the Santa Fe River. In the phosphate region a large quantity of water, which has been used in mining operations, is allowed to enter the ground. That this water frequently has a noticeable effect in weakening the roofs of the underground drainage channels is shown by the following quotation from the unpublished notes of Geo. H. Eldridge:
Sinks have frequently been formed since the mining of phosphate has been undertaken in the vicinities of the settling ponds, or in the line of drainage from the mine washers. The writer has passed over an apparently solid road in the morning to return at night to find in his way a chasm fully 40 feet across, earth, shrubs and trees engulfed, and with the water pouring down to an underground passage in the weirdest way. Again, at one of the Southampton mines, the floor of the old pit, together with an adjoining area of the sand overburden, has sunk several feet with a rift in the earth 4 or 5 feet across in which is shown on the one side the smooth walls of lime spires and connecting ridge; on the
'Ibid. p. 16.
SECOND ANNUAL REPORT-TOPOGRAPHY AND DRAINAGE. 35
other the materials that slipped away, no longer being able to retain their purchase on the walls, their support below having been. removed.
If the bottom of the sink does not contain an opening, the water which accumulates after a rainfall will usually escape to the underground stream by seepage; but where the amount of rainfall is too great to be carried away in this manner, lakes or ponds accumulate. The level of the standing water in such cases fluctuates, rising after each rainfall and gradually sinking during dry weather. There are hundreds of lakes in Florida which appear to belong to this class. Some of the sinks have an opening in the bottom which connects directly with the underground stream. Into these openings the surface streams plunge, carrying their loads of sediment and other debris. This sediment probably aids the underground stream in enlarging its channel by mechanical wear, but sometimes it accumulates in such quantities as partially or even wholly to close the passage*. In such cases the surface water remains in the sink to form a lake. Examples of open sinks receiving the discharge of surface streams are common, conspicuous among them being the sink of the Santa Fe River, the sink of the Chipola River, the Lake sink in Jefferson County and Alachua sink near Gainesville. Alachua sink is important because it illustrates some of the changes through which sinkholes may pass. This sink receives the drainage of a large stream which crosses a prairie (Payne's Prairie). In the early history of the State this region appears to have been in about the same condition as it is today.' Later, owing to the outlet becoming closed,2 perhaps by logs and other rubbish thrown into the stream, a large lake formed in the depression. About 1891, the sink reopened and the basin was drained, effectually ending the steamboat traffic which had developed on the lake.
In some parts of the caverns the water which enters through the openings in the limestone evaporates, leaving a deposit of calcium carbonate. By gradual accretion these deposits may form large pendants-stalactites-hanging from the roof or walls. When the water falls to the floor of the cavern and evaporates, it often forms projections known as stalagmites. The deposits in caverns are frequently highly ornamental and form the chief attraction for visitors.
Sometimes the underground streams form new passages and abandon portions of their old channels. The abandoned channels are the caverns which are visited by travelers. In Florida, only a few caverns have been explored and none are reported to be highly ornamented. The most important caverns which were noted during the
'Bartram, William, Travels, 1791, pp. 187 et seq.
'Dal, Win. H., Neocene of North America, U. S. Geol. Survey Bull. 84, 1892, pp. 94-96.
36 FLORIDA STATE GEOLOGICAL SURVEY.
field work are located near Marianna, Ocala and Alachua. The one near Alachua is known as Warren cave and is said to be well worth visiting.
Natural Bridges: -Where the underground stream emerges it forms a spring and as the roof of the cavern falls it leaves an open channel through which the spring drains to some surface stream. By a continuation of this process the underground stream is transformed into a surface stream. Where a segment of the roof of the underground channel remains after the parts above and below have fallen, a natural bridge results. In Florida natural bridges may also be
Fig. 2. A D represents the bed of a stream flowing across limestone. The development of an underground channel from X to Y caused the stream to abandon its surface channel.
formed in another manner. In text figure 2 A D represents a longitudinal section of a surface stream flowing toward D and having for its bed the limestone A B C D. A passage, X Y, formed by solution, may permit some of the river water to take a course through the underlying limestone. As this channel is gradually enlarged by solution and mechanical wear, more river water passes through it. Finally, the surface channel may be unoccupied except during high water, or if the underground passage is large enough the surface channel may be entirely abandoned. A surface channel may also be produced across a natural bridge whenever the underground passage is partially obstructed.
There are many natural bridges in Florida, small ones being reported near Homosassa, north of Clarksville, in northern Walton County, and in many other localities. Large natural bridges occur on the Chipola River above Marianna, on the St. Marks River, southeast of Tallahassee, on the Santa Fe River, northeast of High Springs,' and on several other rivers. The natural bridge on the Chipola River is submerged (luring high water, and a broad shallow surface channel which crosses the one near High Springs is said to carry a portion of the flood waters of the Santa Fe River. The breadth of the surface channel near Hiigh Springs suggests that the natural bridge of the Santa Fe River may have been formed by the second method outlined
'See Fig. 1, Plate viii.
SECOND ANNUAL REPORT-TOPOGRAPHY AND DRAINAGE. 31
above. The natural bridge of the Chipola River was submerged at the time the field work was (lone in that vicinity, so that no observations could be made. However, the broad valley of the river above the bridge indicates that the upper part of the Chipola River has been a surface stream for a long period. Since natural bridges in such rocks are not apt to endure for long periods it appears probable that this one may also have been formed by the second method.
Sand Dunes:-A large part of the surface of Florida is covered by a few feet of Pleistocene sand. In the Lake Region this sand has sometimes reduced the original inequalities of the surface. In other cases the formation of sand dunes and ridges has increAsed the topographic irregularities. However, the dunes and ridges are seldom more than a few feet in height, and hence their effect on the topography is not very marked.
Springs:-The great development of underground drainage in many parts of the State has already been mentioned. Where the streams emerge from their subterranean channels they form springs. It is impossible to make any exact estimate of the number of springs in the State, and it is perhaps sufficient to say that they are exceedingly numerous. They vary in size from mere seeps to springs which give rise to creeks and rivers large enough to float good-sized passenger and freight steamers. The best known and largest of these springs is the Silver Spring in Marion County, which gives rise to a large stream of remarkable clearness and beauty. The water emerges from the basin which probably attains a depth of at least thirty-five feet, and the stream, Silver Spring Run, that flows from this basin, has an average width of about fifty feet and a minimum depth in the center of the channel of more than nine feet. The water is so clear that it is possible to discern objects lying on the bottom and to observe the fish and other aquatic animals. Among the other large springs of the region are Wekiva Spring, in Orange County, the source of the river-of the same name: Sulphur Spring, near Tampa; Suwanee Sulphur Spring, White Sulphur Spring, Blue Spring, near Juliette Station; Blue Spring, near Orange City Junction; Green Cove Spring, on the St. Johns; Wakulla Spring. near Tallahassee; Itchetucknee Spring, near Fort White; Poe Spring near High Springs; Crystal River Springs which give rise to the Crystal River; Weekiwachee Spring, near Bayport, and Newland Spring, near Falmouth. All of these springs are well known and many of them are very large. They are supplied with water by the underlying limestone which is everywhere so porous and cavernous that it yields large supplies.
A spring at Tarpon Springs is worthy of special mention because it appears to be in part supplied with water from a small lake. The
38 FLoRIDA STATE GEOLOGICAL SURVEY.
water emerges at the bottom of the bay a few feet below mean tide level. On the opposite side of the town is a small lake with no surface outlet and apparently occupying a sinkhole. Usually the flow of this spring is comparatively insignificant, but at times the discharge is enormous. Observations made upon the lake just before and after one of these outbursts of the spring appear to show that the lake discharges water into the spring through some underground channel, for the surface of the lake is said to have been lowered several inches while the spring was flowing rapidly.
Aside from the large springs mentioned above there are many others which yield quantities of water, and springs of moderate size are to be found in nearly all parts of the State. Some of the smaller springs are supplied with water from the superficial sands, but many of them derive their supplies from the limestones.
NORTH AND WEST FLORIDA.
In West Florida and in parts of peninsular and northern Florida, the surface configuration has been largely determined by the erosion of surface streams. However, sink-hole topography is common as far west as Walton County, and many of the depressions are occupied by small lakes.
Erosion Features: From Leon County westward the major streams cross the upland in wide level-floored valleys bordered by well-defined bluffs. The depth of these valleys is due to the erosive action and the width to the meandering of the streams. The valleys usually contain a deposit of sand and mud, which rises but little above the level of the streams and is partially overflowed when the rivers are high.
The small streams of the uplands flow in narrow valleys having steep walls and high gradients. In most cases erosion has not extended far from the main streams, and hence there are many comparatively level areas which form the divides between the principal rivers. On approaching the rivers, the areas of level land become smaller and the number and depth of the valleys increase until the surface is largely reduced to steep slopes. It is also worthy of note that the amount of dissection which the upland has suffered increases toward the south. Thus the largest level tracts of upland are usually found near the northern line of the State. At its southern edge, the upland sometimes descends abruptly to the coastal belt which borders the Gulf of Mexico. In some cases, however, the transition to the coastal lowlands is by a gradual slope.
Lakes:-The uplands are usually covered by a few feet of white Pleistocene sand which masks the minor inequalities of the erosion
SECOND ANNUAL REPORT-TOPOGRAPHY AND DRAINAGE. 3)
topography. Moreover, it is frequently difficult to determine whether shallow depressions are sink-holes or are merely due to irregularities in the surface of the sand. However, in the case of such deep depressions as the lake at De Funiak Springs, the sink-hole origin of the basin appears to be unquestionable.
Sand Dunes: Sand dunes and ridges are common, especially along the southern edge of the uplands, but they are seldom more than a few feet in height. Wind blown sands are probably much more widespread than is indicated by the surface topography. However, at the present time, the heavy precipitation, together with abundant vegetation, prevents the development of an extensive dune topography.
COASTAL REGION.
Streams and Ponds:-The coastal region of Florida comprises a belt of lowland which seldom rises above the 50-foot contour, and over large areas its surface is only a few feet above high tide. Its emergence from the sea took place after the drainage of the uplands had been well developed, and the rivers gradually extended their channels across it as new areas were added to the land. The Pleistocene sand which forms a large part of the surface has a gentle slope toward the sea and is occasionally crossed by small streams which flow- in shallow valleys. Minor irregularities in the surface of the sand have given rise to shallow lakes and ponds which cover large areas during the rainy season. The difference in elevation between the bottoms of some of these ponds and the surrounding areas is frequently less than two feet.
Ridges :-Scattered throughout the coastal region are small areas of higher land which in some places resemble sand ridges and in other places are very irregular in shape. In some places they are found to contain a core of rock which is covered by a thin mantle of sand, but frequently they appear to Le entirely composed of sand. These areas represent the higher parts of the original sea floor, and their position was determined by the inequalities in the surface of the underlying rock or by unequal deposition of the sands.
Terraces: -In the valley of the St. Johns River and at various points along the coast, the sands form a well defined terrace which rises twenty to thirty feet above tide. This terrace was observed at several localities and it appears to be the result of wave action during the Pleistocene. Similar terraces occur along the other streams of Florida and there is some evidence that there are others at higher levels; but their satisfactory discrimination will require a more detailed study than could be made in the time allotted to the field work.
40 FLORIDA STATE GEOLOGICAL SURVEY.
SHORE LINES.
The State of Florida has an extensive coast line, presenting a great variety of topographic forms. The various agents which have been important in producing the coastal forms are: the waves, the tides, the shore currents, and the growth of organisms, chiefly corals. The configuration of the shore lines is dependent upon the relative importance of these agents.
Coral Reefs:-The coral reefs are restricted to an area near the southern end of the peninsula; and it was to this area that much of the earlier geological work was devoted. In a subsequent chapter Mr. Samuel Sanford will discuss the formation of the keys and the adjacent portion of the mainland in the light of his recent studies in that region. At present it is only necessary to call attention to the fact that coral reefs have been of minor importance in the development of the peninsula of Florida; in fact, there appears to be no reason to suppose that reefs have existed on the west coast or north of the north line of Palm Beach County on the east coast.
Submerged Continental Border:-Reference to the charts of the U. S. Coast and Geodetic Survey shows that the depth of the water along the Florida coast is seldom more than a few feet. As the distance from the land increases, the water gradually deepens over this submerged continental border and there is an abrupt descent to deep sea bottom at a considerable distance from the land. This marginal shelf is to be regarded as a part of the continent now covered by the sea, and it has probably been in part, if not wholly, above water during some period of geological history.
Bars:-In the shallow water at some distance from the shore, the waves gradually build bars which rise nearly to the surface of the water. The material for the construction of these bars is derived from the sea bottom, and hence they vary with the character of the shore. At the present time the prevailing materials on both the east and west coasts is sand, though there is often a considerable admixture of shells. For this reason the bars which are now forming consist largely of sand with a small proportion of shell fragments. In comparatively recent geologic time the beach materials on some parts of the coast appear to have been largely shells and these were built into bars which were afterward cemented to form coquina. 'Occasional layers of sand and a considerable percentage of silica in the coquina show that terrigenous material was never entirely absent, though it was often of minor importance. In the shallow water along the exposed shores, either of the mainland or islands, currents are formed which transport the beach materials and build them into a variety of forms. One of the common types to be found on the Florida coast is
SECOND ANNUAL REPORT-TOPOGRAPHY AND DRAINAGE. 41
the bar which is built across the entrance to a bay. Such bars are to be found at the entrance of all the bays, and their removal is one of the important problems which confronts the army engineers in their endeavor to nake the rivers and harbors accessible to shipping.
On the east coast where the prevailing currents move southward, the bars are commcnly extended by additions to their southern ends. On the Gulf coast of the peninsula the dominant currents appear to be in the opposite direction and the bars are usually built by extensive additions to their northern ends. The dominant current on the coast of West Florida appears to move toward the west, though an eastward current of some importance may be inferred from the position of the bar at the entrance to St. Andrews Bay. Bars of the kind described above are to be seen along the entire coast of Florida wherever there are large bays.
Sounds: Behind the shore bars on the east coast are narrow bodies of shallow water which are commonly known as rivers, though they might more appropriately be termed sounds. To this class belong such bodies of water as the Halifax and Indian Rivers. As the sounds become more nearly surrounded by the growing bars they are changed into lagoons which are in turn gradually filled with silt and thus transformed into marshes. Mosquito lagoon and Lake Worth on the east coast are excellent examples of lagoons, and there are numerous marshes along both the east and west coasts.
About twenty years ago an attempt was made to open a passage for steamship navigation by deepening the sounds and lagoons. This plan was successful, but in recent years the channels have been allowed to become obstructed by sand bars and oyster reefs. In the last few years interest in this "inside" channel has been revived, and it is now proposed to extend the passage northward to New Jersey.
Inlets: -Where drainage from the land enters a sound or partially enclosed bay, the water escapes through a narrow passage in the bar known as an inlet. As the bars are built under the influence of a prevailing current, the inlet is gradually shifted in the direction of growth. After a. time the opening becomes so obstructed that a new inlet is formed by the action of high water. Usually the inlets are formed near the head of the bar and their direction of movement on the Atlantic coast is southward and on the Gulf coast northward or westward. At Jupiter on the east coast an opening is sometimes dredged near the north end of the bar and this opening is gradually shifted toward the south. It has been found that the inlet remains open much longer when the opening is made toward the northern end of the bar than when it is located farther south.
Tidal Runways:-At ordinary high tide the level of the water in the bays and sounds is raised from one to two feet above the normal
42 rLORIDA STATE GEOLOGICAL SURVEY.
low water level. If, at the same time, a strong wind is blowing toward the land the water rises much higher. When the tide recedes, a seaward current is formed which scours the bottom and sides of the channels. Frequently the water pours through some low gap in a shore bar, thus helping to form a passage. Many of the inlets across the Florida bars are formed in this way. To the erosive action described above, Mr. F. P. Gulliver' has given the name of "tidal scour," and he thinks that the channels near Cedar Keys present an example of tidal runways produced by tidal scour, and he designates these runways as the "Western Florida Type." At the mouth of the St. Johns River and elsewhere along the South Atlantic and Gulf coasts the army engineers have constructed dams to narrow the runway so that
- the effect of the tidal scour will keep open a channel deep enough to permit the entrance of large vessels. Examples of tidal scour along the keys and the southern part of the Florida peninsula will be discussed by Mr. Sanford.
Capes:-Many of the important capes of Florida appear to have L:een built of sand deposited by the currents moving along the shore. Cape Canaveral on the east coast was formed where the easterly trend of the coast caused the southward moving current to move outward from the coast into the deeper water which checked its velocity and caused it to deposit some of its load of sand. From the outward end of the cape there projects a long, narrow spit of sand which rises nearly to the surface of the water. The seaward end of the spit is often bent into a hook by the action of the current.
On the west coast the northward moving current encounters the islands near the west end of St. Vincent Sound, and turning westward forms Cape San Bias. Cape St. George at the western end of the island of the same name, and Southwest Cape, west of Apalachee Bay, appear to have been formed in a similar manner. All of these capes are gradually being extended seaward by the continual addition of more material transported along shore by the currents. In addition to the capes mentioned above, there are many minor projections usually known as points, which originated in practically the same manner as the larger capes. In 18.I8 Dr. F. P. Gulliver2 studied the origin of Capes Canaveral and San Bias and designated them ".current cuspate forelands."
Shoreline topography, Proc. Amer. Acad. of Arts and Sciences, Vol. 24.
'Gulliver. F. P. Shoreline topography. Proc. Arn. Acad. of Arts and Sciences, vol. 24. pp. 180-181.
SECOND ANNUAL REPORT-SOILS. 43
SOILS.
ORIGIN.
The soils of Florida are almost all based upon the sandy formations of Pliocene and Pleistocene age; and, since the gray Pleistocene sand is the most widespread of the surface deposits, it naturally forms the soils over the greater portion of the State. The Lafayette soils occupy considerable areas in northern and western Florida and they often form the subsoil where the Pleistocene sands are thin. The Alachra clay and the Pleistocene marls are so thinly covered in some parts of Peninsular and West Florida that they form a part of the subsoil. In some areas, where erosion has been especially active toth Pliocene and Pleistocene deposits have been removed, leaving the older geological formation exposed to form the soils; but such areas are of limited extent, and are comparatively unimportant. In a few localities residual materials formed by the weathering of the Oligocene fornrations lie so near the surface that they form a more or less important part of the soil or subsoil.
Other types of soil occupy a large area in the southern part of the peninsula and smaller areas in various other parts of the State. These are the peat and muck soils which have their greatest development in the Everglades, but are found in many other localities where swamps exist. They consist of organic matter mixed with more or less inorganic material, such as sand and clay. These soils are of recent origin and are still being formed, especially over a large area south of Lake Okeechobee where the surface is very low and flat and the drainage imperfect.
The Pleistocene sands form the soil in nearly all of peninsular Florida and extend over a part of the uplands in northern and western Florida. Their occurrence in detail may be gathered from the description of the distribution of the Pleistocene formations. The soils of the Lafayette formation are largely confined to the upland areas near the northern boundary of the State. They do not form large, unbroken tracts, but occur in more or less isolated areas where the postPliocene sands are absent. In many localities the overlying sands are so thin that the Lafayette deposits form an essential part of either the soil or the subsoil, even where the surface materials are younger. This is the condition in a part of the important tobacco producing area in Gadsden County.
Pleistocene marls and coquina, in a more or less decomposed state, form the subsoil at various places along the east coast and along the west coast south of Bradentown. These marl and coquina beds are discussed under the head of geology, and their distribution, so far as
44 FLORIDA STATE GEOLOGICAL SURVEY.
it is now known, is given. However, it should be remembered that the areas where these Pleistocene beds lie near enough to be considered part of the soil are much more restricted than is their geological distribution.
In the central part of the peninsula, especially. northwest of Gainesville, the Alachua clay is so near the surface that it forms a part of the subsoil, but does not enter into the formation of the surface soil. Over much of the area where this formation occurs, it is too deeply buried to be considered a part of the soil.
On the norlh bank of the Manatee River, in the vicinity of Ellenton, there are some areas of land, valuable for truck gardening, where the residual clays left by the solution of the limestone of the Tampa formation form very good soils. In some places, these clays contain more or less .Pleistocene sand, and angular or sub-angular fragments of flint are -common. There are doubtless other localities where the residual products of this limestone are near enough to the surface to form part of the soils, but their distribution is not vet known. The limestones of the Chattahoochee formation and the Vicksburg group may form parts of the soils in a few localities, but they are usually too deeply buried beneath the younger geological formations to be important in soil formation. It is the proximity to the surface of marls or residual products of the \'icksburg group which is regarded as the source of the fertility of many of the "hammock" lands near the west coast. It is doubtless the presence of such materials near the surface which accounts for the excellent growth of timer in places where the surface soil is very poor.
CLASSIFICATION.
In 1897, Prof. Milton Whitney made a general examination of the Florida soils and classified them as follows:
The principal types of soils examined were the first, second and third quality of high pine land; the pine flats or so-called "flat woods"; the light hammock, the gray or heavy hammock, the mixed land, the heavy marl hammock; the pineapple land; the Etonia scrub, the spruce-pine scrub; and the Lafayette formation.
Since the publication of Prof. Whitney's report detailed soil surveys have been made in the vicinity of Gainesville, and in Jefferson, Leon, Gadsden and Escambia Counties. In the detailed work, the soils were classified by their physical properties, origin and topography. In this classification texture is the most important characteristic. In Florida, the principal types of soils recognized are sands, fine sands, sandy loam, and fine sandy loams. Subordinate types are loams, silt loams, clays, muck and meadow. These types have. with
SECOND ANNUAL REPORT-SOILS. 45
some exceptions, been grouped into three series and correlated with similar soils elsewhere in the coastal plain. Since a detailed description of the soils cannot be given in this report, no attempt will be made to discuss the various series represented in the State. Aside from the general types of soils which have been grouped into series and correlated with similar soils outside of the State, there are the Gainesville sand, the Gadsden sand' and some other types which have not yet been correlated.
The clay and loam soils of Florida cover a very limited area, and are not of great importance. The clay soils are largely restricted to small tracts in the neighborhood of streams and are not tilled. In this connection, it should be borne in mind that much of what is commonly called clay in northern and western Florida is to be classified as a sandy loam, because, while it is more or less plastic, sand is the most important constituent. The greater part of Florida has either a sandy or sandy loam soil, and while these soils may be subdivided into a large number of types, they possess, as a whole, certain general characteristics. When brought under cultivation, they commonly have a low natural productivity, but they respond quickly to proper treatment, and can be made to produce large crops which grow rapidly and mature early. These characteristics, when linked with a subtropical climate, make the production of early fruits and vegetables very profitable. In order to procure the best results, it is necessary to exercise skill and judgment in the treatment of the soils, and, in some instances, considerable money must be expended for fertilizers. There is apt to be a deficiency of moisture on some of the sands and sandy loams, and hence irrigation is sometimes practiced.
Fertilizers are used in nearly all parts of the State, the amount and kind of fertilizer required in the different localities being governed by the nature of the crops grown and the experience of the most successful farmers. A striking example of the productivity of a sandy soil properly tilled is furnished by the yield of pineapples which are grown upon the ridge of sand near Fort Pierce. The value of barnyard refuse and legumes as fertilizers is recognized in sonic localities, but their use should be much more extensive. Some recent experiments of the Department of Agriculture2 are of interest, since they show that lime, which is not generally used on Florida soils, may add greatly
'Names applied by Bureau of Soils, of the Department of Agriculture, to certain -soils in this region; not geologic subdivision. Soil survey of the Gainesville area, Florida; soil survey of Gadsden county, Florida, U. S. Dept. Agriculture Field Operations Bureau of Soils, 1904, pp. 269-286.
'Soil survey of Escambia county, Florida, Field Operations of the Bureau of Soils, U. S. Department of Agriculture, 1906, pp. 348. See also "Soil Studies" by the Florida State Experiment Station, Bulletins 87 and 93.
46 FLORIDA STATE GEOLOGICAL SURVEY.
to the productiveness of certain types of the sand and sandy loam soils.
The peat and muck soils of Florida have not been extensively used because they are in swampy areas which require drainage. Extensive drainage operations are in progress in the Everglades, and, if these are continued, large areas of peat soil will be available for cultivation. The natural productivity of the peat and muck soils of Florida has seldom been determined, but, judging from the experience of farmers in other States, it is safe to predict that the Everglade soils are destined to take rank among the best lands of the State for the production of certain crops. Moreover, experience in several other States has shown that such soils seldom require the addition of complete fertilizers such as are used on sandy soils. In fact, the addition of small quantities of salts of potassium should usually be sufficient to cause a peat or muck soil to produce good crops, though possibly, in some cases, the addition of phosphates would be necessary. These facts are important because it will cost much less to fertilize the peat and muck soils than is now being expended on the sandy soils.
STRUCTURE.
One of earliest discussions of the structure of Florida was written by Johnson,1 in 1888. Though he was hampered by lack of detailed knowledge of the stratigraphy of the State, Johnson presented considerable evidence to show that the peninsula is a broad anticline. The conclusion reached by him was, in a general way, the same as that of several subsequent writers. His paper is accompanied by a section of the strata across the northern end of the peninsula showing a broad arch with the apex in the vicinity of Gainesville. The location of the crest of the arch was recognized by the sink-hole topography which was thought to indicate the presence of "Eocene" limestone (Oligocene, Vicksburg group) within less than 100 feet of the surface, and the dips away from the central part of the peninsula were determined by noting the presence of younger formations at the surface and by the altitude of the Oligocene beds in wells at various points.
About two years after the appearance of Johnson's paper, Prof. Shaler2 published a brief discussion of the topography of Florida, and in the same article stated his ideas of the structure of the State. Prof. Shaler appears to have regarded the peninsula as a broad arch which he likened to the Cincinnati anticline:
The first question before us concerns the origin of the Florida uplift. It will be observed that we have in the peninsula of Florida a very remarkable
'Johnson, L. C., Amer. Jour. Sci.. 3d series, Vol. 36, 188S, pp. 230-236.
'Shaler, N. S., Topography of Florida, Bull. Mus. Comp. Zool., Vol. 16, No. 7, 1890, pp. 139-156.
SECOND ANNUAL REPORT-STRUCTURE OF FLORIDA.
ridge, which has grown up from the sea-floor to the altitude of about five thousand feet; and a somewhat similar elevation in the archipelago of the Bahama Islands. Neither of these ridges has a mountainous character. Indeed, it is at first sight difficult to find the analogues of these great anticlinal-like folds in the existing structures of the land. They can hardly be classed with any of our known table-lands, for the reason that such elevations are in all cases more or less associated with definite mountain folding. The only similar structure which is known to me is that exhibited in the "Cincinnati anticlinal," that well-known ridge extending from near Columbus, Ohio, to Northern Alabama. This elevation in length and breadth may be compared to that of Florida, though it never had more than one-half the height of the Floridian peninsula.
It should be remembered that there is to be included with the peninsula the submerged plateau which borders it on either side and extends out to the abysmal depths of the ocean, and when Prof. Shaler speaks of a broad earth arch he includes in it not only the land but this submarine plateau which in places extends over 150 miles beyond the coast and which descends steeply to profound depths. In a later paper, Prof. Shalert reiterates the same view and states that he regards Florida as a broad submarine fold, approximately 600 miles in length which has risen from a depth of about 5,000 feet.
In commenting on the hypothesis advanced by Prof. Shaler, Dr. Dali2 says:
In considering the topography of Florida, it has been customary among geologists and others to speak of the "central ridge," "elevated axis," and in the latest contribution to the subject Prof. Shaler regards Florida as "formed of lowlands rising as a broad fold from the deep water on either side to a vast ridge, the top of which is relatively very flat, there being no indication of true mountain folding in any part of the area." In an extremely wide and general sense, it is, of course, true that the peninsula forms a great fold, but in the ordinary and literal meaning of the words this description conveys an inaccurate idea of the structure of the region.
Dr. Dali regards the structure of Florida as characterized by low folds approximately parallel to the general trend of the peninsula. By means of railroad profiles he finds indications of two well'defined ridges, one near the Atlantic coast and another near the Gulf coast. A third ridge is noted in the vicinity of Brooksville and Plant City. The eastern ridge which forms the eastern boundary of the central "lake basin" includes the well known Trail Ridge and was thought to be composed of "Miocene" rocks. In this connection "Miocene" is probably intended to include the Oligocene rocks belonging to tlie Apalachicola group which were then known as Miocene. The western ridge forms the western boundary of the central "lake basin" and
Shaler, N. S., Relation of Mountain Growth to Formation of Continents. Bull. Geol. Soc. Amer., Vol. 5, 1804, pp. 206.
Dall, Wm. H,, Neocene of North America, Bull. U. S. Geol. Survey N-. 84, 1892, pp. 87.
48 FLORIDA STATE GEOLOGICAL SURVEY.
passes through Lakeland. The theories advanced by Dali and Johnson differ in one important point. Dali believes that the central lake basin is a synclinal valley; Johnson holds that this region which he designates as "high hammocks" or "lake region" represents the eroded apex of a broad arch.
Considering the State of Florida as a whole, it is merely the southern extension of the coastal plain, and its history has in general been the same. Broadly speaking there are two distinct axes of uplift which appear to extend in a general north-south direction. The outline of the Vicksburgian limestone west of the Apalachicola River indicates a gentle uplift, and field observations show that this limestone has there an altitude of about 75 to 100 feet over a considerable area. From this uplift, the rock dips rapidly to the south and west, and more gently, but still perceptibly, towards the southeast. Towards the north and northeast it rises to form the basis of the highlands of southern Georgia and Alabama, and then gives place to the underlying Jackson, which outcrops farther north. The exact trend of the uplift which brought the Vicksburg to its present altitude in west Florida is not known, but it is probably to the east of north. The peninsular portion of Florida represents a broad uplift such as was postulated by Johnson and Shaler, and the comparison with the Cincinnati arch appears to be quite appropriate. The objection to the use of the term "anticline" in connection with these broad uplifts is due to the fact that most geologists are inclined to associate the word with narrower archings of the strata, such as are common in the Appalachian or other closely folded regions. By the use of the term "arch" it is hoped that this objection will be removed. In the peninsula of Florida, the arching of the beds has raised the lower Oligocene to an altitude of more than 100 feet above tide over considerable areas from the vicinity of Brooksville and Croom northward to and beyond Gainesville. Live Oak and Lake City. Around the outcrops of the rocks belonging to the Vicksburg group which have been exposed on account of the erosion of this arch, are the exposures of the formations which comprise the Apalachicola group and younger beds. The rocks belonging to the Apalachicola group occupy a broad belt from Sarasota northward to the Georgia-Florida line, and extend vwestward to where they are overlapped by the beds of Miocene age. On the eastern side of the central uplift the Apalachicola group occupies a much narrower area and is soon buried beneath younger beds. Since there is little difference in the thickness of the beds belonging to this group on the east and west sides of the arch, it may be readily inferred that the easterly dips are more steep than the westerly.
The northern end of the arch which forms the peninsula pitches gently downward, so that the limestones of the Vicksburg group dip
SECOND ANNUAL REPORT-STRUCTURE OF FLORIDA. 49
below the surface north of Live Oak and Lake City and the formations comprising the Apalachicola group appear in the valley of the Suwanee River. The southern end of the arch sinks gently beneath the younger formations so that the limestones of the Vicksburg group lie several hundred feet below the surface in Lee County and at Key West, where they were encountered in drilling wells.
The varying depths to rocks of Oligocene age along the east coast of Florida are probably due, in part, to local variations in the rate of dip and to various minor folds. There appears to be little doubt that any upheaval which produced the broad arch which forms the peninsula of Florida would also produce minor arches or folds parallel to the direction of the main uplift, as well as minor folds transverse to the main arch. The satisfactory discrimination of these minor folds calls for a large amount of detailed stratigraphic work based upon a knowledge of the fossils representing different horizons. It is possible that the ridges mentioned by Dr. Dall are really minor folds, but he does not appear to have eliminated the possibility of their being due to circumdenudation. That there are many minor folds in Florida cannot be denied. Good examples of such folds are those which Dal' mentioned on the Caloosahatchee River. These small folds are not more than ten to twelve feet in height and are usually not more than one-quarter of a mile wide. They are of more than usual interest because they involve marls of Pliocene age and hence are probably of Pleistocene or even of Recent age.2
'DalI, Wm. H., Notes on the geology of Florida. Am. Jour. Sci., 3d series, vol. 34, 1887, p. 168.
DalI, Wm. H., Tertiary fauna of Florida. Trans. Wag. Free Inst. of Sci., vol. 3, pt. 6, 1903, p. 1604.
Dali, Wm. H., Neocene of North America, Bull. U. S. Geol. Survey No. 84, 1892, p. 143.
'For evidence of minor folds in the Chattahoochee limestone and in the Alum Bluff formation, see paper on "Fuller's Earth Deposits," by E. H. Sellards and Herman Gunter (pp. 277-284).
50 FLORIDA STATE GEOLOGICAL SURVEY.
STRATIGRAPHIC GEOLOGY.
TERTIARY.
OLIGOCENE.
The oldest rocks which have been recognized in Florida belong to the Oligocene series. They may be separated into two divisions, called here the Vicksburg group and the Apalachicola group. These two subdivisions were formerly regarded as Eocene and Miocene, respectively. One of the earliest attempts to fix the age of the rocks of Florida was made by Conrad1 in 1846. In his paper Conrad referred both the "silex beds" and the limestone of the Tampa formation, together with the prevalent rock of the peninsula, to the upper division of the Eocene. For many years the rocks here included in the Vicksburg group continued to be called Eocene by various writers, including Bailey,2 Tuomeya Smith,4 Dall, and others. The deposits here called Apalachicola group were first differentiated from the "Vicksburg" in 1887, when Langdon examined these formations along the Apalachicola River and classified them as probably "Miocene. This name was retained for some time, but it was modified by the use of "Old Miocene" or "Subtropical Miocene" to distinguish it from the later Miocene. In 1896, Dall7 published a brief statement of the reason for regarding the so-called Eocene and the so-called Old Miocene of Florida as Oligocene. This usage has since prevailed in many, but not in all, of the publications dealing with southern coastal plain geology.
VICKSBURG GROUP.
After the recognition of the "Old Miocene" there remained a considerable thickness of rock which was still regarded as Eocene and
'Conrad, T. A., Observations on the Geology of a part of East Florida, with a catalogue of recent shells of the coast. Am. Jour. Sci. 2d ser., Vol. 2, 1846, pp. 36-48.
'Bailey, Prof. J. W., Am. Jour. Sci., 2d ser., vol. x, 1849, p. 292.
'Tuomey, Prof. M., A notice of the Geology of the Florida Keys, Am. Jour. Sci., 2nd ser., vol xi, 1850, pp. 390 et seq.
'Smith. E. A., On the geology of Florida, Am. Jour. Sci., 3rd ser., vol xxi, 1881, pp. 292-309.
'Dal, Wm. H., Neocene of North America, U. S. Geol. Surv., Bull. 84, 1892, pp. 101-105.
*Langdon, Dani. W., Jr., Some Florida Miocene, Am. Jour. Sci., 3rd ser., vol. xxxviii, 1889, pp. 322-324.
'DalI, Wm. H. Descriptions of Tertiary fossils from the Antillean region, U. S. Nat. Mus. Proc., vol. xix, No. 1110, 1896, pp. 303-305.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 51
was known as the "Vicksburg limestone."1 This name had been used to include all the older Tertiary rocks of the peninsula, comprising both the Vicksburg and the deposits here called Apalachicola group; but with the increased knowledge of the geology of the State it was gradually restricted to the older limestones. Subsequent study indicated that this group of older limestones, while presenting but slight lithologic variation, was divisible upon paleontologic grounds into two parts, the lower division (here called "Peninsular") being designated the Vicksburg "limestone" and the upper division being named the Ocala limestone. Still later, DalI3 proposed the abandonment of the name Vicksburg as applied to limestones of the peninsula of Florida, and the substitution of the term "Peninsular" for the lower division above described. He states:
From the observations on the typical Vicksburgian by Coloney Casey it seems probable that the Orbitoidal limestone which forms the mass of the Floridian plateau, and which has been, in this work and in the literature generally called the Vicksburg limestone, may really form a different horizon altogether from the typical Vicksburgian and be intermediate between the latter and the nummulitic Ocala limestone. In order to promote clearness and avoid confusion, it is probably advisable to adopt a distinct name for the Orbitoidal phase or formation, for which I would suggest the term Peninsular limestone. This is intended, not as a permanent formation-name, but as a general term for the fundamental plateau limestone of Florida, in which a close and thorough study may result in the discrimination of more than one horizon or zone.
The reason for the change suggested by DalI4 is the fact that the fossils which have long been regarded as characteristic of the Vicksburg have been found to occur in other horizons, and hence their occurrence in the limestones which underlie the nummulitic rock of the peninsula cannot be regarded as proof of equivalence of that limestone with the limestone at the type locality at Vicksburg, Miss. The question of the correlation of the Florida formations has been further complicated by the fact that there are two horizons represented in the bluff at Vicksburg. To avoid further confusion, however, the Oligocene rocks in Florida which were originally known as the Vicksburg "limestone" are here designated the Vicksburg group. They are thought to comprise three formations, here called the Ocala limestone, the "Peninsular" limestone and the Marianna limestone.
The "Peninsular" and Ocala limestones have already been recognized by Dall. The name Marianna limestone is here given to the soft, porous, light-gray to white limes'ones of western Florida, which
'Dall, Wm. H. Neocene of North America, U. S. Geol. Survey, Bull. 84, 1893, pp. 101-104.
2Smith, E. A. On the Geology of Florida, Am. Jour. Sci., 3rd ser., vol. xxi, 1881, pp. 292-309.
'Wagner Free Inst. of Sci., vol. iii, pt. 6, p. 1554.
*Loc. Cit.
52 FLORIDA STATE GEOLOGICAL SURVEY.
are characterized by an abundance of Orbitoides mantelli and other foraminifera associated with many other fossils, prominent among which are Pecten poulsoni and P. perplanus. At the type locality, (Marianna, Jackson County) this limestone is so soft that it can be cut into blocks with a saw. It contains some beds of chert and many of the fossils are silicified. Lithologically, the rock at Marianna resembles the Ocala limestone at Ocala and the "Peninsular" limestone; but it differs from the former in the character of its fauna, especially in the absence of nummulites, and it is believed that it may represent a horizon below the "Peninsular" limestone of Dall. The close lithologic resemblance between the Marianna limestone and the "Peninsular" limestone, however, makes it possible to combine much of the discussion concerning these two formations.
MARL\NNA AND "PENINSULAR" LIMESTONES.
Stratigraphic Position:-The base of the "Peninsular" limestone is not exposed in Florida and there is no satisfactory evidence that it has been reached in drilling wells; hence the character of the subjacent formation is not known. Reference has already been made to the uncertainty concerning the exact correlation of the "Peninsular" limestone of Florida. It will thus be seen that no satisfactory conclusions can be drawn concerning the relation which the "Peninsular" limestone bears to the underlying beds. The relation of the Peninsular limestone to the overlying formations will be discussed in connection with those formations.
The Marianna limestone is thought to be the stratigraphic equivalent of the upper part of the bluff at Vicksburg, Miss., and some of the wells in west Florida enter beds of sand and clay which probably represent older horizons; but the stratigraphic relation of the formation to these older beds cannot be determined. In west Florida, where this formation is recognized, it is unconformably overlain by beds belonging to the Apalachicola group or by post-Pliocene formations.
Lithologic Character: -The Marianna and "Peninsular" formations consist of soft, porous, white or light-gray limestone, sometimes resembling marl, especially when partiallVy decomposed. Some bands of darker-colored, dense limestone are reported at various localities where these formations have been penetrated by drilling, and nodules and layers of chert are common throughout them, but chert beds are especially prominent in certain horizons. The chert beds are usually darker in color than the limestone and range in thickness from a fraction of an inch to twelve or fifteen feet. In some localities as many as six or seven successive beds of chert have been encountered in a single well. In general, the heavier layers are more persistent,; and it
SECOND ANNUAL REPORT-STRATIGRAPHIC GEoi9GY. 53
is usually the chert which forms a nearly water-tight cap to the artesian water beds in these formations. Certain horizons are abundantly fossiliferous, containing innumerable specimens of Orbitoides and shells of mollusks such as Pecten poulsoni, etc. At several localities the rock is so soft that it can be cut into blocks with a saw; and upon exposure to the weather these blocks harden rapidly, making a very fair quality of building stone. Beds of sand, sometimes ten feet or more in thickness, are reported in some of the wells which penetrate this formation. In general, these sands appear to be most numerous in the northwestern part of the State.
Thickness:-The thickness of the "Peninsular" limestone and the Marianna limestone appears to be exceedingly variable. The thickness given by Foerste,1 from his investigations of the Vicksburgian limestones in southwestern Georgia and the adjacent part of Florida, is 220 feet, and probably this may be regarded as the approximate measure of the thickness of the Marianna. At Salt Mountain, Alabama, the rocks of the Vicksburg group are reported by Dr. Dall2 to have a thickness of 140 feet, and on the basis of well borings the same writer estimates the thickness to be over 350 feet at Gainesville, 212 feet at Lake Worth, and 1,068 feet at St. Augustine. From recent examinations of well borings by Drs. Vaughan and Bassler, limestone of Vicksburg age is known to have a thickness of over 225 feet at Quincy, 250 feet at Alachua, and 325 feet at Bartow. Apparently there is a marked thickening of these limestones from the exposures of Georgia and Alabama southward. It is hard to tell just how much reliance can be placed on well records, because the drill may penetrate some distance into a formation before characteristic fossils are obtained; and it is possible for fossils to drop from the side of the bore and thus continue to appear in the drillings far below the base of the formation to which they belong. Of all the estimates given above the one at Gainesville is probably the most reliable because the well is cased to the bottom.
Physiographic Expression:-The "Peninsular" and Marianna
limestones are characterized by a topography produced by solution with numerous underground streams, natural bridges, sink-holes and large irregular depressions. The underground streams of these formations attain considerable size as is shown by a number of large springs which emerge, apparently from definite channels. The most noted natural bridge of the Marianna limestone is on the Chipola River near Marianna; but there are many of smaller size, both in
'Foerste, Aug. F., Am. Jour. Sci., 3rd ser., vol xlviii, 1890, p. 46.
'Dall, Wm. H., Neocene of North America, U. S. Geol. Survey, Bull. 84, 1892, p. 103.
54 FLORIDA STATE GEOLOGICAL SURVEY.
this formation and in the "Peninsular" limestone. Wherever the limestone rises near the surface, sink-holes characterize the topography, and the sinks form many lake basins in the central part of the peninsula. (See Fig. I, pl. II, p. 58.)
Paleontologic Characters :-Both the "Peninsular" limestone and the Marianna limestone are characterized by an abundant fauna, the most prominent fossil being Orbitoides mantelli, associated with Pecten potlsoni and P. perplanus. DalI' says that the fauna of the "Peninsular" limestone includes about two hundred and twentytwo species, of which one hundred and two are restricted to it. With the imperfectly known fauna of the Ocala limestone, it has fifteen species in common, while nine species continue into the "silex beds" and limestone of the Tampa formation and two species continue into the Miocene and on down to the recent fauna.
Structure:-The "Peninsular" and Marianna limestones have been affected by the various earth movements which have produced the present structure of the State. The major structural features consist of broad anticlinals, such as are described under the general discussion of the structural features of the State. The dips are low and are generally seaward. Local variations in altitude of the surface of these limestones are so pronounced as to suggest that there has been considerable local warping as well as a general arching. Toward the southern end of the peninsula the "Peninsular" limestone dips southward beneath the Everglades where it is probably buried under hundreds of feet of younger sediments. Along the east coast there are marked variations in depth to this formation: but it probably does not rise within less than about 200 feet of the surface, and at Jacksonville it is not less than about 525 feet from the surface.
At Tampa, on the west coast, the "Peninsular" limestone probably lies somewhat more than 100 feet below the surface, but farther north along the coast it may be exposed. Apparently the dip of the Marianna limestone toward the southwest in the long western extension of the State is very rapid, for at Pensacola this limestone is buried to a depth of more than 1,100 feet beneath younger sediments.
Local Details:-As early as 1849 limestone of Vicksburg age was noted in Florida by J. XV. Bailey2 who obtained some "Orbitulites" from a chert at Pyles Plantation, about forty miles west of Palatka. The exact location of the settlement where these specimens were obtained is not known. The same writer mentions the occurrence of similar rock at several points between Palatka and Tampa, but in no case does he give the exact localities.
'Wagner Free Inst. Sci. Trans., pp. 1553.
"Bailey, J. W., Amer. Jour. Sci.. second series, 1m51, vol. ii, p. 86.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 55
While collecting statistics for the Tenth Census Dr. Smith1 gathered much valuable information relating to the geology of Florida. The results of these geological investigations were published in 1881. After summarizing the previous literature Dr. Smith presented evidence to show that limestone of Vicksburgian age underlies nearly the entire peninsula of Florida. He gave in part its areal outcrop and noted the occurrence of Orbitoides mantelli and Pecten poulsoni, and other characteristic fossils in exposures of the limestone here called Marianna a few miles southeast of Campbellton, at the Big Spring, east of Marianna, and at other localities which he does not name. From a limestone collected by him six miles from St. Marks, in Wakulla County, Heilprin identified Orbitoides mantelli and pronounced the rock to be "Vicksburg," but the rock at St. Marks is now known to belong to the Apalachicola group instead of the Vicksburg. Dr. Smith examined a marl which occurs at various points along the Gulf coast and decided that it also was of Vicksburg age. He states that this marl forms the basis of the "Gulf Hammock" land in the coastal counties from Wakulla County nearly to Tampa Bay in Hillsboro County. In describing the areal extent of the "Vicksburg," Smith included in it large areas of rock which is now known to belong to the upper Oligocene or Apalachicola group: for example, the limestone extending along the Suwanee River for many miles, and the limestone at Tampa were, on the observations of others, wrongly included in the Vicksburg. He called attention to the fact that the Vicksburgian limestone is the prevailing rock in the vicinity of Gainesville and that it is often composed largely of Orbitoides mantelli. Other localities included in the Vicksburg were Payne's Prairie and Ocala.
In addition to the localities mentioned above, Smith reports limestone of Vicksburg age at Live Oak and Lake City in the northern part of the peninsula. At these localities, as in many other parts of the peninsula, the formation is overlain by a few feet of younger rock. Dr. DalI2 gives the following summary of localities where the "Vicksburg" limestone has been observed:
It is impracticable with the data yet printed to determine exactly at how many of Smith's localities the country rock belongs to the Orbitoides horizon. Some of them, doubtless, will eventually be shown to be of later age, as will be indicated later in this summary. Only those where no doubt seems to exist will be specified here. In Alachua County it is widespread, having been observed by Smith and Dall at Gainesville and westward to and about Archer, though in many places overlain by solutionary residium, remnants or even beds of later age but moderate thickness. It had been identified at Silver Spring, 6 miles east
'Am. Jour. Sci. (3) xxi, 292-309, 1881.
2 Op. cit. pp. 102-103.
56 FLORIDA STATE GEOLOGICAL SURVEY.
from Ocala, by Le Conte, as early as 1861,' and subsequently the observation has been confirmed by Smith. Specimens of this rock have been collected by Willcox at Martin station, Marion County, about 8 miles north of Ocala, where the rock is very cherty; and at Jarves' Spring, on the southern border of Pasco County; at Fort Foster, on the North fork of the Hillsboro River, where, as in many other places, relics of the old Miocene beds overlie it. Several-of the localities referred to by Heilprin must remain for the present on the doubtful list, but among them should hardly be counted the islet at the mouth of the Homosassa River, from which Mr. Willcox obtained the Pygorhynchus (Ravenelia) gouldii Bouv6, a small echinoderm originally described from the buhrstone (ante-Claibornian) of Georgia.
It will be seen from this quotation that later investigations indicate that the limestone at some of the localities mentioned by Smith is not all of Vicksburgian age. However, this should not be regarded as detracting from. the value of the earlier work, for with. the increase of knowledge it is inevitable that formation lines should be shifted and that new formations should be discriminated.
Miss Maury's2 summary of the Vicksburgian indicates that it forms a large part of the country rock in north central Florida, and she cites many of the localities mentioned by Dall and Bailey. She mentions especially the exposures seen in the vicinity of Gainesville, which are surrounded by rocks belonging to the subdivision here called Apalachicola group. Attention is also called to the occurrence of gypsum, which is regarded as the result of the action of sulphur on calcium carbonate, and the occurrence of phosphate rock resulting from an analogous chemical action,
During the progress of recent field work the occurrence of the Marianna limestone was noted at Natural Bridge in north central Walton County, but there is no indication that it reaches the surface west of this county; indeed, from well records and exposures of other formations, there is every reason to believe that in Escambia and Santa Rosa Counties, this formation lies some hundreds of feet below the surface of the upland.
East of Marianna the formation is exposed at several localities where it presents considerable variation in its lithologic characteristics. At some of these localities it is a soft, porous, white limestone, while in other places it is a tough, dense, gray limestone. However, sonic of this difference in texture may be accounted for by the fact that the rock hardens upon exposure to the air, and it is perhaps a significant fact that the hard, gray limestone usually occurs at natural exposures while the soft, porous rock is seen in the quarries.
Am. jour. Sci., 2nd ser., 1861. vol. xxi, pp. 1-12.
2 Maury, Carlotta joaquina. The Oligocene of western Europe and southern United States. Bull. Amer. Paleont., vol. iii, No. 15, 1902, pp. 45-46.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 57
Near the east edge of the town of Marianna there is a small exposure which affords the following section: SECTION No. 1.
Red, sandy clay, with some beds of sand and gravel, Lafayette.......... 25 ft.
Marianna limestone:
W hite, m arly clay ............................................... 5 ft.
Hard, earthy, gray limestone ..................................... 2 ft.
Blue marl with many Pectens .................................... 8 ft.
Hard gray limestone ............................................. 4 ft.
Approximately twenty feet below this is section No. 2.
SECTION No. 2.
Hard, gray limestone, very fossiliferous, Orbitoides mantelli, Pecten
poulsoni, etc. ................................................... .5 ft.
Dark gray chert ..................................................... 4 in.
Soft, porous, white limestone, with a few Orbitoides and other fossils... 30 ft.
The white limestone of this section is exposed in a quarry where it is obtained by sawing. It is used locally for building purposes, especially in the construction of chimneys; upon exposure to the weather the rock hardens until it resembles the hard member at the top of the section.
A well drilled at Marianna penetrated limestone, marl and clay to the depth of 265 feet, where a bed of quicksand was encountered. An incomplete log of this well is given below: Sand and sandy loam, Pleistocene ................................... 1V ft.
Red and yellow sandy clay and sand, Lafayette....................... 20 ft.
Alternating beds of hard limestone and marl.......................... 45 ft.
(This doubtless includes section No. 1 at the east end of the town.) Hard rock (chert) followed by alternating beds of marl and limestone
with some chert, Marianna (?).................................. 200 ft.
The log of this well does not afford any means of judging at what depth the base of the Marianna limestone was reached, but it is possible that an underlying formation was penetrated some distance above the quicksand.
At a locality two and a half miles southeast of Chipley, the Marianna limestone outcrops in the edge of a sink; and about six miles southwest of Chipley and one mile north of Duncan it is exposed in some small quarries where it had been obtained for building purposes. At one of these quarries belonging to Mr. F. G. Owens, the rock has also been burned for lime, which was reported to be of good quality. This quarry shows about twenty feet of porous, white limestone, resembling the rock in section No. 2 at Marianna. Near the surface it is very hard and durable, but at greater depth it becomes much softer.
Fossils occur throughout the entire section, but are especially numerous in the upper five feet, where the rock appears to be largely
58 FLORIDA STATE GEOLOGICAL SURVEY.
composed of Orbitoides mantelli. The rock, where it is quarried at this locality, appears to form a well defined ridge covered by a few feet of white Pleistocene sand and sandy loam, but its presence is indicated at various points by numerous boulders containing characteristic organic remains.
A few miles northeast of Duncan at Falling Water, a large sink exposes several feet of light gray limestone, probably belonging to the same formation. At this locality there appears to be a well defined system of underground drainage, which is indicated at the surface by numerous sink-holes. The best exposure is seen where a small stream plunges into one of these sink-holes. The stream is reported to have a fall of over seventy feet. The rock here forms a nearly perpendicular cliff and hence the section is not easily accessible.
At Natural Bridge near the north line of Walton County, a lightgray to yellowish-gray marl forms the arch which spans a small stream. The width of the channel is probably twenty feet and the length of the bridge about one-fifth of a mile. The height of the exposure was estimated by Vaughan' to be about thirty-five to forty feet above the level of the water in the creek. When fresh, this rock is soft and crumbles readily in the fingers, but when exposed to the weather it hardens rapidly and assumes the yellowish color mentioned above. It is quarried by sawing and is locally known as chimney rock, because it is used in the construction of chimneys. A considerable percentage of clay, which occurs in fine particles distributed through the rock, indicates that the material is a marl rather than a limestone. Pecten poulsoni is the most abundant fossil. From the lithologic character of the rock, together with the occurrence of numerous specimens of the species mentioned above. the rock is considered to belong to the Marianna limestone.
A quarter of a mile south of the Bridge near a turpentine still a similar marl is exposed in the bed of a small stream. The outcrop at this locality has a thickness of about twenty feet and it differs lithologically from the marl of the Bridge in being slightly more compact and of a distinctly grayish or bluish color. However, these differences are probably (lue to the fact that this exposure has not suffered so much weathering as the one at the Natural Bridge, and the substantial equivalence of the rock at the two localities can hardly be questioned. Numerous concretions of nearly pure carbonate of lime are scattered throughout this marl, but they do not appear to have any relation to the occurrence of the fossils.
About seven miles southwest of Marianna and nearly one mile from Kvnesville, a number of fragments of limestone were obtained
'Vaughan, T. Wayland, unpublished notes.
FLORIDA GEOLOGICAL SURVEY. SECOND ANNUAL REPORT. PL. II.
4~t:
FIG. 1.-SINK HOLE CONTAINING POND, TEN MILES SOUTHWEST OF
VERNON, WASHINGTON COUNTY, FLORIDA. TYPE OF TOPOGGRAPHY OF THE VICKSBURG GROUP.
FIG. 2.-"FALLING WATER," FIVE MILES SOUTH OF CHIPLEY, FLA. THE
SMALL STREAM FALLS INTO A SINK ABOUT SEVENTY FEET DEEP.
SECOND ANNUAL REPORT-TRATIGRAPHIC GEOLOGY. 59
from a field where they were said to have been turned up by the plow. They represent a very cherty phase of the Marianna, and are probably the residual products of weathering. They consist of boulders up to two or three feet in diameter containing innumerable specimens of Orbitoides mantelli and Pecten poulsoni.
At the phosphate mines in the vicinity of Croom, a number of specimens of Orbitoides mantelli were collected and the rock here has the lithologic characteristics of the "Peninsular" limestone. The collection was made from boulders dredged from a mine, and hence may not be sufficiently characteristic to decide whether this is "Peninsular" or Ocala limestone. The presence also of a number of specimens of Cassidulus suggests that limestone belonging to the Apalachicola group is also represented. In the absence of characteristic nummulites in the collections, it appears not unlikely that the limestones of the Apalachicola group may here rest upon the "Peninsular" limestone. However, this conclusion is made subject to revision in case future collections from this locality should reveal the presence of fossils belonging to the Ocala limestone.
The "Peninsular" limestone is known to occur throughout the central part of the peninsula, where it may be observed in numerous natural and artificial exposures. It has been encountered in many of the hard rock phosphate mines from Croom northward nearly to the north line of the State. It is also known to underlie a large part of the central lake basin of the peninsula. This limestone is encountered in wells along the east coast from Fernandina southward beyond Palm Beach, and along the west coast south of Tampa.
OCALA LIMESTONE (NUMMULITIC ROCK.)
The Ocala limestone was formerly regarded as part of the "Orbitoides" limestone, but in 1882 nummulites derived from waste products of the Ocala limestone were described by Heilprin. The specimens were obtained by Willcox1 on the Chassahowitzka River, and their association with fresh-water forms of recent shells was rightly interpreted to mean that the nummulites had been transported from some other locality and re-deposited with the younger shells. In 1884, Willcox2 announced the occurrence of the nummulitic rock in place some distance above the original locality on the Chassahowitzka River and Heilprin, in commenting upon the announcement. stated that the beds belonged to the Oligocene.
'Heilprin, Angelo. On the occurrence of nummulitic deposits in Florida, and the association of nummulites with a fresh water fauna. Acad. of Nat. Sci., Phila., Proc., 1882, pp. 189-193.
Science, N. S., vol. iii, 1884, p. 607.
60 FLORIDA STATE GEOLOGICAL SURVEY.
In subsequent publications by the same author this rock was called the "Nummulitic" limestone, but, in 1892, Dali' proposed the name Ocala limestone.
Stratigraphic Position:-The Ocala limestone lies stratigraphically between the "Peninsular" and the beds here designated Apalachicola group. Lithologically, it bears a strong resemblance to the underlying "Peninsular" limestone, with which it also has a close faunal relation. These facts have led to the conclusion that the two formations are conformable, and it has also been suspected that the Ocala limestone represented a local phase of the "Peninsular." While the two formations are probably conformable, the extensive distribution of the nummulites of the Ocala limestone shows that it represents a widespread change in conditions and is not to be classed as a mere local phase of the underlying beds.
The Ocala limestone, as already noted by Johnson,2 is sometimes wanting, so that the overlying formations rest directly upon the "Peninsular." This relation was noted at several localities which will be mentioned in discussing the younger formations. At present it is sufficient to note its absence and to suggest that since the Ocala limestone does not appear to be a local phase of the "Peninsular," there is probably a stratigraphic break between the rocks belonging to the Vicksburg and Apalachicola groups in the central part of the peninsula.
Lithologic Character: The Ocala limestone consists of a soft, porous, light-gray to white limestone which bears a strong lithologic resemblance to the underlying "Peninsular" limestone, but is distinguished from it by the included fossils. When slightly weathered, the rock becomes light yellow, and owing to its granular appearance is often regarded as sandstone. The removal of the calcareous material by the leaching action of underground water leaves a pale yellow, more or less incoherent sand, containing a small percentage of calcium carbonate. When fresh, the Ocala limestone is so soft that it is easily broken, but exposed surfaces often become hardened by the deposition of calcium carLonate from the waters which emerge along the outcrop. For this reason the rock frequently appears to be hard and firm. Its porosity and ready solubility permit the formation of numerous underground channels which are sometimes seen at the outcrop and are inferred from the presence of numerous sink-holes. The rock contains an abundance of organic remains which are commonly preserved as casts. Nodules and large masses of chert are also common and in some localities a large part of the rock has been silicified.
'Dali, Wm. H. Neocene of North America. U. S. Geol. Surv., Bull. 84, 1892, pp. 103-104.
'Johnson, Lawrence C. Op. cit.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 61
Thickness:-No definite determination of the maximum thickness of the Ocala limestone has been made, and as yet no exposures have been observed which show the contact with the underlying "Peninsular" limestone. All the information now available indicates that the thickness may be variable, and that the variation is in considerable measure due to subsequent erosion rather than inequalities of deposition. In the Transactions of the Wagner Free Institute of Science, Dr. DallI' states that at the type locality the Ocala limestone has been quarried to a depth of twenty feet without reaching its contact with the underlying "Peninsular" limestone. The greatest thickness noted during the recent field investigation was in a sink-hole near Ocala where the formation is exposed to a depth of about forty feet without reaching its base. This locality is described in a subsequent part of the discussion.
Physiographic Expression:-As in the case of the "Peninsular" limestone, the Ocala limestone is soft and porous, and hence gives rise to a topography which is characterized by underground channels, sink-holes, sinking streams, natural bridges, and large springs. The limestone has an important influence in the formation of many of the lake basins, and it forms the natural bridge of the Santa Fe River near High Springs. Large springs from the Ocala limestone are numerous in the central part of the peninsula.
Paleontologic Characters:-The Ocala limestone, like the underlying "Peninsular," is characterized by a great number of foraminifera, but it differs from the latter in the presence of nummulites. A few mollusks are said to be restricted to this formation, but as -yet the fauna is very imperfectly known, and future study may add to the number of fossils which are peculiar to it.
Structure:-The Ocala limestone shows the same structural feattires as the underlying "Peninsular," and there is little reason to doubt that both have been subjected to the same movements since their deposition.
Local Details:-One of the earliest statements relating to the type locality of the Ocala limestone was made by Prof. LeConte in his description of the Silver Spring.2 He says (p. 11):
As in some measure related to the peculiar system of subterranean drainage above indicated, it may not be deemed inappropriate to conclude this communication with a few general remarks in relation to the physical causes which have produced the several qualities of surface soil which are found in the neighborhood of Ocala and the Silver Spring. The whole of this portion of the Penin' Dall, Wm. H., Trans. Wagner Free Inst. Sci., vol. iii, pt. 6, 1903, p. 1556.
'Le Conte, Prof. John. On the optical phenomena presented by the "Silver Spring" in Marion County, Florida. Am. Jour. Sci., 2nd series, vol. xxxi, 1861. pp. 1-12.
62 FLORIDA STATE GEOLOGICAL SURVEY.
sular appears to have been originally composed of a mixture of sand and shelllimestone; probably of the Eocene period. The lime-rock comes to the surface almost everywhere; in some cases it is composed of nearly pure carbonate of lime; in others silicification, to a greater or less extent, has taken place by the displacement of the lime by silex. But in all cases where its structure can be made out, it 'consists of a mass of conglomerated shells.
A later paper by Conrad' mentions some of the fossils found in the Ocala limestone, and correlates it with the Shark River Eocene of New Jersey. However, neither Prof. Le Conte nor Conrad made any special study of the Ocala limestone, and it remained for later workers to recognize its distinctive characteristics.
The Ocala limestone was for a long time regarded as a part of the Vicksburg "limestone," as it was then known; but it was later separated from the Vicksburg. It was in 1882 that Mr. Joseph Willcox discovered a rock from the vicinity of Chassahowitzka River which he submitted to Heilprin2 for identification. Heilprin recognized some of the fossils as nummulites, and to a new species belonging to this genus he gave the name X. willcoxii. In 1886 Prof. Heilprin3 added another to the published list of localities where the nummulitic fauna is known to occur. This new determination was based upon the presence of Nunimaulites floridanus which was obtained near Arredondo about six miles southwest of Gainesville. The specimens were collected by Prof. G. A. Wetherby and Mr. Joseph Willcox.
In his paper on the Neocene of North America, Dr. Dal4 mentions Prof. Heilprin's discovery of nummulitic rock in Florida and suggests the name Ocala limestone from the locality where it is best exposed. He states (p. 103):
Among the rocks which until recently were not discriminated from the Orbitoides limestone, and which' appear in central Florida directly and conformably to overlie the latter, though no one has described their contact, is a yellowish friable rock containing many foraminifera, conspicuous among which are two species of nummulites, N. willcorii and N. floridana Hp. This rock was first brought to notice by Mr. Joseph Willcox, and to Prof. Heilprin we owe a description of it which discriminates between it and the Vicksburg or Orbitoides rock. The rock was early recognized as Eocene, though not discriminated from the earlier beds. It is best displayed at Ocala, Florida, where it forms the country rock, and has been quarried to a depth of 20 feet without coming to the bottom of the beds.
'Conrad, T. A. Observations on American fossils with descriptions of two new species. Proc. Acad. of Natural Sciences, Philadelphia, 1865, p. 184.
Heilprin, Angelo. Proc. Acad. of Nat. Sci., Philadelphia, 1882. pp. 189193. Abstract of same, Am. Jour. Sci., 3rd ser., vol. xxiv, 1882, p. 294.
Heilprin, Angelo. Notes on the Tertiary geology and paleontology of the southern United States. Am. Jour. Sci., 3rd series, vol. xxix, 1885, p. 69.
'DalI, Wm. H. Neocene of North America, U. S. Geol. Survey, Bull. 84, 1892, pp. 103-104.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 63
After summarizing the results of previous investigations, Dall mentions the following new localities where the Ocala limestone is exposed:
Since then Mr. Willcox has obtained the rock in place 15 miles northeast of the original locality, from the shore of Wacassassa Bay, near Cedar Key, and also from the banks of the Wacassassa River, Levy County; from a "sinkhole" at Pemberton's Ferry' on the Withlacoochee River; about 10 miles eastward from Brooksville and also at Bayport, Hernando County, and at various places about Ocala. Prof. Wetherby has also sent specimens from a well 5 miles southwest of Gainesville, Alachua County, and Mr. L. C. Johnson reports it from an old Confederate iron furnace, 3 miles north of Levyville, Levy County, where it is only 20 feet thick and is covered with a bed of bog-iron ore formerly worked. Pemberton's Ferry is the most southern point at which it has been recognized at the surface, but at Bartow, Polk County, it occurs covered by about 6 feet of later strata.
From the character of its included organic remains the exposure at Martin Station3 is regarded as equivalent to the Ocala limestone. At this locality, the rock is more or less silicified and hence has been found useful for railroad ballast, road metal and other purposes where durable material is needed.
To the rock at the old Confederate iron works in Levy County, Mr. Johnson4 gave the name "Levyville formation," and states that it consists of about twenty feet of soft, porous building stone. He believed that it has been partially removed by erosion in the western part of the peninsula where it is much thinner than farther east. He also expressed doubt as to its ever having been deposited over the entire surface of the underlying Vicksburg.
Several other localities were mentioned where this formation was recognized, among them being Payne's Prairie. At a quarry on the Newnanville road near the Santa Fe River, Johnson reports that the Neocene formations rest directly upon the limestone of Vicksburg age the nummulitic rock (Ocala) being absent. Johnson's Levyville formation has usually been regarded as the substantial equivalent of the Ocala limestone; but it is not possible at the present time to verify the determination of the nummulites, and the rocks at Levyville may really belong to some other formation.
In 1902 Miss Maury5 summarized the known distribution of the Ocala limestone, but did not give any new information relating to it.
Ibid. p. 104.
Now called Croom.
'DalI, Wni. H., Trans. Wagner Free Inst. Sci., vol. iii, pt. 6, 1903, pp. 1156-1157.
'Johnson, Lawrence C. Op. cit.
Maury, Carlotte Joaquina. A comparison of the Oligocene of western Europe and southern United States. Bull. of Am. Paleon., vol. iii, No. 15, 1902, p. 47.
64 FLORIDA STATE GEOLOGICAL SURVEY.
She appears to have obtained her facts relating to the formation from some of the publications already mentioned.
The Ocala limestone is extensively exposed at the type locality where it has been quarried for the construction of roads and the manufacture of lime. Exposures are occasionally seen in the walls of sinks and its presence ma"' also be inferred by the appearance of numerous boulders containing nummulites. These scattered fragments are frequently found resting upon the surface sands and are usually rather firmly cemented, probably by an accumulation of silica and iron. A thin deposit of sand is commonly found resting upon the uneven surface of the limestone. In such cases the sand appears to be largely the result of disintegration of the country rock, and it is therefore residual. While this statement concerning the origin of such sands may seem improbable. it is explained by the fact that the soil formed from the limestone is the insoluble material left after solution has removed the calcium carbonate. Consequently the residual sands constitute the impurities of the original rock and may in some cases have formed only a small percentage of the whole. Since the publication of Dall's report, quarrying at Ocala has been carried to a somewhat greater depth. The quarry of the Florida Lime Company, situated near the southwest corner of the city, now shows: Sandy loam with more or less organic matter Pleistocene........... I ft.
Sand, pale yellow, residual ........................................ 1-4 ft.
Light gray to white nummulitic limestone (Ocala).................. 25-30 ft.
In this quarry the fossils occur throughout the greater portion of the limestone, but are especially numerous near the top where the removal of the calcium carbonate has loosened the casts of the organic remains. In addition, the quarry presents certain other points of interest in the arrangement of the cherty portions of the rock. Chert nodules occur in various parts of the section and in places two sets of vertical silicified bands were noted. These cherty bands are at approximately right angles to each other and probably represent planes of silicification along vertical joints.
A good section of this limestone is exposed in another quarry situated on the north side of the road to Silver Spring about a half mile east of the town. At this locality, the rock, which is considerably decomposed, has been quarried to a depth of forty feet and contains an abundance of nummulites.
About twenty feet of Ocala limestone is exposed in a third quarry situated a quarter mile north of Ocala, and about fifteen feet of the same rock was seen in a quarry two and a half miles southwest of the city. One of the most important sections may be seen in a sink-hole about three miles southwest of Ocala. This sink-hole is approximately forty feet deep and affords entrance to a small cavern which may be
FLORIDA GEOLOGICAL SURVEY. SECOND ANNUAL REPORT. PL. III.
0
I0 IK
Fic. 1.-QUARRY OF OCALA LIME CO. (OLD PHILLIPS QUARRY) Fic. 2.-OCALA LIMESTONE LEDGES IN PIT OF FORT WHITE
ONE MILE SOUTHEAST OF OCALA, FLA., SHOWING DE- HARD ROCK COMPANY, FORT WHITE, FLA.
COMPOSED ZONES AND SOLUTION CHANNELS IN OCALA
LIMESTONE.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOCY. 65
penetrated a short distance. Mr. Clapp reports that nummulites occur down to the base of this exposure, but are not so numerous as at some of the other localities. Lithologically this rock is essentially the same as that exposed at the quarry of the Ocala Limestone Company, and the section shows the maximum observed thickness of the formation.
At the old "Phillips" quarry, one mile southeast of Ocala, there is a section which shows about twenty-five feet of soft, porous, lightgray limestone which contains an abundance of chert throughout the entire section. Since this rock contains many nummulites, its identification as the Ocala limestone can scarely be questioned. Solution cavities are common and along certain vertical crevices the rock has been removed, forming passages two or three feet in width. These have been filled by the settling of the overlying sandy clay.
On the Anclote River, about one mile from Tarpon Springs, there is an exposure showing from two to three feet of nummulitic limestone which extends some distance up the stream. The rock here lies near the surface over a considerable area and boulders containing nummulites are common. A similar exposure of Ocala limestone was noted near Port Richey on the Pithlachascotee River where the rock is said to outcrop over a considerable area. At the mine of the Fort White Hard Rock Company, one-half mile southwest of Fort White, the Ocala limestone is well exposed. In the north pit belonging to this company, the following section was observed:
Light-gray sandy loam, Pleistocene ................................ 4-8 ft.
Fine, even-grained, yellow sand, residual............................ 20 ft.
Limestone and phosphate rock, Ocala limestone..................... 25-30 ft.
In this pit the Ocala limestone occurs in irregular ledges separating the.phosphate rock which appears to be in part the result of replacement of the country rock. The limestone ledges commonly form two discontinuous series at approximately right angles to each other, the intervening space being occupied by the irregular bodies of phosphate rock. In general, the limestone bands thicken toward the base of the pit, and the phosphate deposits become smaller. Both the limestone and phosphate are more or less cherty, but the silicification appears to be in the form of nodules and small boulders rather than extensive replacement. Fossils are very abundant in the limestone, prominent among them being the characteristic Nummulites of this formation. At the mine of the Cummer Lumber Company, four miles west of High Springs, there is a similar exposure of the Ocala limestone. At this locality the rock lies much nearer the surface, the total thickness of overlying sand being seldom greater than ten feet. There is the same characteristic arrangement of the limestone and phosphate rock as at Fort White.
3g
66 FLORIDA STATE GEOLOGICAL SURVEY.
Similar relations between the Ocala limestone and the phosphate were observed at the mine of the Union Phosphate Company, seven miles east of Newberry. The Alachua sink was visited by Mr. Clapp, who reported an exposure of about ten feet of soft, white limestone containing many flint nodules. From the collections made at this locality it is evident that the Ocala limestone forms part of the walls of the.sink and it also appears probable that the overlying Hawthorne formation is present. On the island across the Indian River from Melbourne, Dr. Sellards reports the occurrence of the Ocala limestone at a depth of 221 feet. This determination was made from fragments of the rock obtained by Mr. Oliver Gibbs in drilling a well. The rock was found to contain nummulites, and although the specimens were not specifically determined. the occurrence of the genus appears to warrant its correlation with the Ocala limestone. This is a point of special interest because it shows the Ocala limestone to be nearer the surface in that part of the State than would naturally have been inferred from previous publications.
The Ocala limestone is known to be well exposed at various points in the region where rock phosphate is being mined. Nummulites have been collected from various mines in the vicinity of Hernando, Citrus County. In a pit Sec. 10, T. 18, S. R. 19 E, the following section was observed:
Yellow sand, with phosphatic gravel and brown and yellow clays;
also phosphatic white and gray sand, sometimes greenish........ 2-3 ft. Phosphatic bluish-gray clays, some hard sandstone with boulders of
hard rock phosphate containing nummulites.
The entire section probably represents altered and weathered phosphatic Ocala limestone.
Nummulites were also obtained by Eldridge from a stone.quarry on the Burns place one and a half miles southwest of Owensboro, Citrus County, and on Mr. Clement's mine No. 8, on the east- side of Blue Springs, T. 16 S., R 19 E.
Miliolite Limestone:-In 1887 Heilprin' noted at Wheeler's, on the Homosassa River, the occurrence of a porous and cavernous limestone,'which he called Miliolite limestone because of the presence of many foraminifera belonging to the Miliolidae. DalI2 reports similar rock six miles southwest of Lake City, and thinks the "Miliolite" limestone belongs with the other foraminiferal limestones; but he does not express an opinion as to whether it belongs with the "Peninsular" or Ocala limestone. The "Miliolite" limestone is here placed with
'Heilprin, Angelo. Explorations on the West Coast of Florida, Wag. Free Inst. Sci., Trans., vol. i, 1887, p. 57.
Dall, Win. H., Neocene of North America, U. S. Geol. Survey, Bull. 84, 1692, pp. 104-105.
SECOND ANNUAL 'REPORT-STRATIGRAPHIC GEOLOGY. 67
the Vicksburg group, and is tentatively referred to the Ocala limestone, to which it probably belongs.
APALACHICOLA GROUP.
Prior to 1887 the rocks belonging to the group here designated Apalachicola group from the exposures along Apalachicola River, in western Florida, were included with the Eocene and were regarded as part of the "Vicksburg" ("Orbitoides") limestone. In that year Langdon' observed a group of beds occurring on the Apalachicola River which he referred tentatively to the lower Miocene, designating them the Chattahoochee group. With the Miocene beds Dall,2 in 1892, included not only the Chattahoochee group of Langdon, but the Hawthorne formation, the so-called "Waldo formation," the "Tampa limestone," the "Tampa silex bed," the Chipola marl, the Alum Bluff formation and certain sands, gravels and clays, which he did not specifically name
The use of the name Miocene to designate the group here called Apalachicola continued for a number of years, the Oligocene beds being often called "Old Miocene" or "Sub-tropical Miocene," to distinguish them from the "new" or "cold-water" Miocene. In 1896 Dalls discussed the faunal reasons for regarding the "Old Miocene" as Oligocene, and in his publications since that date he has restricted the term Miocene to later beds (here called Jacksonville limestone and Choctawhatchee marl). However, the Chattahoochee formation is still included in the Miocene by both Smith4 and McCallie.5
The Apalachicola group was formerly designated the Chipolan stage6 and the Chipola group,7 but these names are abandoned because the name Chipola has been used to designate a marl belonging to the group.
The Apalachicola group includes a number of beds differing widely in lithological character; though they are recognized by their fossils
'Langdon, Danl. W., Jr., Some Florida Miocene; Amer. Jour. Sci., 3rd ser., vol. xxxviii, 1889, pp. 322-324.
'DalI, Wm. H., Neocene of North America, U. S. Geol. Surv. Bull. i4, 1892, pp. 105-123.
'Dall, Wm. H., Descriptions of Tertiary Fossils From the Antillean Region, U. S. Nat. Mus. Proc., vol. xix, No. 1110, 1896, pp. 303-305.
'Smith, E. A., The Underground Water Resources of Alabama; Geol. Survey of Alabama, 1907, p. 81.
'McCallie, S. W., The Preliminary Report on the Underground Waters of Georgia, Geol. Surv., of Georgia, 1908, pp. 31 and 32.
"Dal], Wm. H., North American Tertiary Horizon, U. S. Geol. Surv., 18th Ann. Report, 1896-1897, p. 334.
'Foerste, A. F., Studies on the Chipola Miocene of Bainbridge, Ga.; and of Alum Bluff, Fla., Am. Jour. Sci., 3rd ser., vol. xlvi, 1893, p. 244.
68 FLORIDA STATE GEOLOGICAL SURVEY.
as integral parts of a single group. While limestones and mars predominate, the group also includes beds of nearly pure sand and clay. The entire period of deposition appears to have been characterized by the accumulation of more or less terrigenous materials, and hence the limestones are usually rendered somewhat impure by an admixture of clay and sand. At certain times the conditions appear to have been especially favorable for the development of organic life and some horizons, such as the Chipola marl member of the Alum Bluff formation, and the "silex bed" of the Tampa formation contain very large faunas.
Owing to the lithologic variations and widely separated exposures, the exact correlation of the formations of this group is dependent upon their organic remains. While the paleontological studies, especially those made by Dali, have shed much light upon the stratigraphic relations of the different beds, there are still many points which cannot as yet be fully decided. For this reason it seems best to retain the names of various beds and to indicate as far as possible their known relationships. The Apalachicola group is separated into four formations-the Chattahoochee, the Hawthorne, the Tampa and the Alum Bluff. There is, however, some reason for believing that the first three are, in part at least, synchronous, though exact equivalence is difficult to determine where outcrops are widely scattered and faunal variations are slight. The Alum Bluff formation is clearly younger than the Chattahoochee formation, upon which it rests.
The name Chattahoochee group was first applied by Langdon1 to the beds occurring at a series of exposures along the Chattahoochee and Apalachicola Rivers. The localities examined by Langdon extend from the final disappearance of the Vicksburg, nine miles by water above River Junction (Chattahoochee) to the point where the Oligocene exposures give place to the overlying sands and mars of younger formations. The exposures examined are at Alum Bluff, Rock Bluff, Ocheesee and River Junction.
In 1893 the section along the Apalachicola River was examined by Foerste2 who recognized the presence of three dissimilar groups to which he gave the names Chattahoochee, Chipola and Chesapeake. His paper gives considerable attention to the character of the materials comprising his Chipola and Chesapeake groups, with a view to correlating them with the non-marine deposits grouped under the names of
'Langdon, Daniel W., Jr., Some Florida Miocene. Amer. Jour. Sci., 3rd ser., vol. xxxviii, 1889, p. .122.
2Foerste, A. F. Studies on the Chipola Miocene of Bainbridge, Ga., and Alum Bluff, Fla., with an attempt at correlation of certain Grand Gulf Group beds with marine Miocene beds eastward. Amer. Jour. Sci., 3rd ser., vol. xlvi, 1893, pp. 244-254.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 69
"Grand Gulf and Lafayette formation." The major portion of the discussion, however, deals with the conditions of sedimentation during the deposition of the rocks belonging to the various groups.
In 1892 Dal' divided the formations here called Apalachicola group into two groups, retaining the name Chattahoochee group for the limestones and marls which are extensively developed in the northcentral part of the peninsula, and employing the name Tampa group to include the beds which he called Chipola marl, Alum Bluff sands, Sopchoppy limestone, Tampa limestone and Tampa silex bed. In his later paper on the Tertiary faunas of Florida, DalI places the "silex bed" at Tampa in his Chattahoochee group. The discovery of the characteristic species of the genus Orthaulax in the basal portion of the Chattahoochee formation led to this change in the correlation.
HAWTHORNE FORMATION.
In 1892 DalI2 described, under the name of Hawthorne beds, some limestones, sands and clays, extensively exposed in the interior of Florida, which had been observed by L. C. Johnson. These beds are here designated the Hawthorne formation. At the time of the publication of DalI's report the Hawthorne formation was being quarried and had aroused considerable interest because of the presence of phosphoric acid in the rock. The formation consists of clays, sands and phosphatic limestones and lies stratigraphically between the limestones of the Vicksburg group and the Alum Bluff formation.
Stratigraphic Position:-The stratigraphic relation of the Hawthorne formation to the underlying rocks of the Vicksburg group has been observed at several localities in the interior of the peninsula. From what is said concerning the geologic history, it is apparent that the deposition of the Vicksburg group was followed by a widespread emergence of the land which permitted extensive erosion and the formation of hills and valleys. There is no doubt that this emergence and consequent erosion affected the central part of the peninsula, where the Hawthorne formation is well exposed, for this formation rests uncomformably upon either the Ocala or the "Peninsular" limestone at many localities. This relation is emphasized by the lithologic character of the beds, for there is an abrupt change from the soft finegrained limestones of the Vicksburg group to the clays, sands and phosphatic limestones of the Hawthorne formation. The relation of the Hawthorne formation to the Alum Bluff formation has not yet been accurately determined, though, at De Leon Springs, Chipola
'Dall, Wm. H., The Neocene of North America, Bull. U. S. Geol. Survey No. 84, 1892, pp. 105-123.
'Dal], Wm. H. Neocene of North America, U. S. Geol. Survey. Bull, 84, 1892, pp. 107, et seq.
10 FLORIDA STATE GEOLOGICAL SURVEY.
fossils have been found in a marl overlying phosphate rock which belongs to this formation. At various points in the peninsula of Florida the Hawthorne formation is found resting unconformably upon limestone of Vicksburg age, and in the vicinity of Hawthorne thin beds of conglomerate occur in the base of the formation. At many of the phosphate mines in central Florida the limestones of the Hawthorne formation are found overlying either the Ocala limestone or the "Peninsular" limestone with an apparent unconformity, which has permitted the deposition of sands and some limestone beds along channels developed in the upper surface of the Vicksburg formations. It should be said, however, that in many of these cases the materials belonging to the Hawthorne formation appear to have been more or less disturbed since their deposition, and it is possible that at some localities the apparent unconformity may be due to the falling of the roofs of caverns developed near the contact of the two formations. The relation of the Hawthorne formation to the other members of the Apalachicola group has not been determined, but there is no doubt that its deposition was in part contemporaneous with the Tampa and Chattahoochee formations. In fact, while the absence of paleontologic information makes it impossible to correlate these formations on biologic grounds there is little doubt that they were all deposited during an extensive submergence which succeeded the emergence of the rocks belonging to the Vicksburg group. On physical grounds, therefore, there is good reason for regarding these formations as synchronous.
Lithologic Character:-According to Dr. E. H. Sellards the rock at the type locality at Hawthorne is a light-colored, soft, porous limestone. The original building stone quarry, which is located near the station of Grove Park, about three miles west of Hawthorne, is now abandoned and is badly overgrown, so that the thickness of this limestone cannot well be determined. At the old phosphate mine, which is at least a mile southwest of the stone quarry, the rock is a phosphatic conglomerate. At many localities the limestones of the Hawthorne formation are silicified, forming bowlders and beds of chert. This is a very common condition in the rock phosphate region where these limestones rest directly on those belonging to the Vicksburg group.
Beneath the phosphatic limestones of the Hawthorne formation are beds of sand, sandstone, or gravel, which are underlain by several feet of clay. The sand beds at some localities contain iron oxide which forms a coating on the grains of silica. The clays are greenish and locally sufficiently calcareous to be called a marl.
Thickness.-The thickness of the Hawthorne formation varies greatly, the maximum amounting to approximately ninety-five feet. The three members of this formation with their maximum observed
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 71
thicknesses, according to Dall,' consists of greenish clay'seventy feet, ferruginous yellow sandstone four feet and phosphate rock twenty feet. The maximum thickness of the Hawthorne formation, as given by the same author, is 125 feet.2 However, over a large part of the peninsula, where the sole representative of the Hawtho'rne formation is the phosphatic or siliceous rock, the thickness is but a few feet.
Physiographic Expression: The Hawthorne formation seldom has much influence upon the surface configuration in the region which it underlies. Locally, however, the cherty beds protect the underlying rock from erosion and thus give rise to ridges; and where the clays lie near the surface they are characterized by an erosion surface of moderate relief. The chert-capped ridges are usually inconspicuous,
-but in some parts of the phosphate region they are sufficiently marked to form well defined topographic features.
Paleontologic Character:-The fauna of the Hawthorne formation has received but little attention and is practically unknown. The green clay and sands are reported to contain many oyster shells which are thoroughly silicified, and the phosphatic limestones and the chert beds are characterized by numerous specimens of an echinoid belonging to the genus Cassidulus. Molluscan remains are associated with this echinoid, but they have not yet been investigated.
Structure:-The Hawthorne formation has been affected by broad earth movements similar to those which produced the peninsula of Florida. There is a gentle seaward dip which is seldom noticeable in single exposures, but may be determined by means of well records which show that the formation sinks below sea level on the east coast. There are probably dips both northward and southward from the central part of the peninsula, but the determination of their amount requires detailed study. The general easterly dips are known to be irregular in amount, but probably do not average more than 75-100 feet to the mile.
Local Details: -While the Hawthorne formation is well known, information concerning the detailed sections is comparatively meager. The most complete sections which have been recognized as belonging to this formation are those described by Dall.? At the type locality near Hawthorne the rock is phosphatic and has been mined and crushed for use as a fertilizer and at many other places the formation contains more or less phosphate. One of these localities is at the Devil's Mill Hopper northwest of Gainesville, where the rock is ex'Dal, William H., Neocene of North America; U. S. Geol. Surv. Bull. 84, 1892, p. 109.
'Ibid. p. i5s.
'Dali, Wm. H., Neocene of North America, U. S. Geol. Survey Bull. 84, 1892, pp. 107-112.
FLORIDA STATE GEOLOGICAL SURVEY.
posed in the walls of the sink, which has a depth of about 115 feet. Here the greater portion of the section belongs to the Vicksburg group, but a phosphatic rock near the top probably represents the Hawthorne formation. Another sink which exposes this formation is located in section 18, T. 7 S., R. 18 E. At this locality the section given by Dal' is:
This place is locally known as "Nigger sink," and the Vicksburg limestone has been reached by a well hole in the center of it. Above the well the lower 10 feet of the wall of the sink is hidden by talus, but is believed to be clay of a greenish-yellow color, 30 feet of which rises above the talus, covered by a four-foot layer of firm, hard sand, almost a sandstone, and this by a sandy ferruginous layer of clay and gravel containing an oyster, like 0. virginica, reproduced in chalcedony. This ferruginous layer, which will be referred to here under the term ferruginous gravel, seems to appear in many different sections, with its oyster and silicified corals. It also occurs in Georgia. Above it is a layer 2 feet thick of soft sandstone resembling the phosphatic rock in appearance. Covering this is a bed of sand and clay 8 feet thick containing fragments of all sizes, from a few pounds to a ton in weight, of the phosphatic rock and its large, silicified coral heads. These last, when they appear on the surface as around Archer, from the solution of the phosphatic matrix are popularly known as "fossil stumps" or "nigger heads." They are large masses of chert or chalcedony, often hollow, retaining on the surface more or less obscure indications of the original coral structure. Above this stratum come the surface sand and loam, here about 20 feet thick.
In this sink the well was drilled to limestone of the Vicksburg group, but the depth and character of the material penetrated are not given. The same writer gives more or less complete descriptions. of several other sections.2 One of these is in Newnansville, where the clay which immediately overlies the limestones of the Vicksburg group has a thickness of seventy feet and is overlain by two feet of ferruginous sand, three feet of undescribed material, and eight to twenty feet of phosphatic rock. About five miles east of Mixon's the ferruginous sand rests on the Vicksburg group and is overlain by the phosphatic bed, and nearer Archer the remnants of the phosphatic rock are found resting directly upon the Vicksburg. Occurrences of similar phosphatic rock are reported where the railroad crosses the Hillsboro River and at Jarves Springs; while at De Leon Springs a phosphatic rock is said to be overlain by beds containing Chipola fossils. The same phosphatic rock is also reported from Live Oak and Lake City, and the ferruginous bed with its silicified oysters is known to occur at Levyville and at Magnesia Springs. The following sections are given by Dall:3
'Loc. cit. p. 109.
Op. cit.
'Dall, Wm. H., Neocene of North America, U. S. Geol. Survey Bull. 84, 1892, pp. 110-111.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 7 3
At White Springs on the Suwanee, the following section was obtained:
1. Gray soil, sand, and humus.......... ....................... 2 ft.
II. W hite sand ................................................ 4 ft.
III. Clay with silicified corals and oyster (Hawthorne beds)...... 6-8 ft.
IV. Indurated clayey rock (Hawthorne beds?)................... 2 ft.
V. Clayey sand-rock, rather fine grained and soft................ 4 ft.
VI. The same, somewhat coarser and harder..................... 8-10 ft.
VII. Sand rock of coarser sharp grains, coated and cemented together with white limy matter........................... 4-6 ft.
VIII. Foraminiferal Eocene top-rock (Vicksburg) indefinitely below.
The silicified corals of bed III are sometimes 20-60 pounds in weight and along the river when dislodged from the clay often wear immense pot holes in the softer lime rocks. Miocene sharks' teeth and fragments of bone also occur in the clay. Under bed VIII, when it is tilted up, as occurs in various places along the river, is found the older Orbitoides limestone of the Vicksburg group.
In a sink 4 miles north of Lake City, the following section was observed: I, II. Sand and sandy soil ...................................... 5 ft.
IV. Indurated clayey rock ...................................... 2 ft.
VII. Lime cemented sand-rock ................................... 8 ft.
VIII. Foraminiferal Eocene (indefinitely down).
At White Springs numerous specimens of Cassidulus were obtained from a cherty rock which has been used in constructing a foundation for the spring house. According to reports, which were obtained from well-informed residents of the town, this rock was quarried from the river channel. At the time of the field investigations for this report the river was too high to permit an examination of the outcrop in the river channel; but a subsequent examination by Mr. Stephenson1 resulted in finding the cherty beds of the Hawthorne formation in close proximity to exposures of the Alum Bluff formation. This strengthens the conclusion that was formed at the time of the earlier field work, that the Cassidutus-bearing zone lies near the top of the Hawthorne formation.
Two miles south of Lake City:
1. Sandy soil ............. .......... ........................ 2 ft.
III. Clay, with corals and oysters ............................. 20 ft.
VII. Lime cemented sand-rock ................................... I ft.
VIII. Foraminiferal Eocene (indefinitely below).
Near the southern boundary of Columbia County, at Fort White, the rocks are gently folded and the surface has been more or less worn into basins containing phosphatic breccia of the older lime rocks, which are themselves under these basins of phosphate slightly phosphatized in their upper portions. Here, ow ing to the fact that the Miocene and Foraminiferal Eocene (Miliolite) beds have been more or less broken up by the action of water dissolving or wearing away the softer parts, the Orbitoides limestone sometimes immediately underlies the breccia in the basins and in other places the basins are composed of the Miliolite limestone. Beds VI, VII and VIII, of the above series are more or
'Stephenson, L. W., Unpublished notes.
74 FLORIDA STATE GEOLOGICAL SURVEY.
less silicified, or when broken up the resulting breccia contains numerous angular fragments of chert.
In the north-central part of the peninsula and extending as far south as Croom, there are many exposures of chert and cherty limestone which rest on the limestones of the Vicksburg group. This rock usually contains many casts and molds of an Echinoid, which Vaughan has identified as a Cassidulus. The rock appears to be very persistent but seldom attains any great thickness. At Bass Station, about six miles southwest of Lake City, it was quarried to a depth of twelve or fifteen feet without reaching the underlying Vicksburg group. About six miles west of Gainesville on the Newberry road, it appears to have a thickness of more than fifteen feet and to rest directly on the Ocala limestone, which forms the country rock of that region. The same Echinoid is found in cherty beds in many localities between Bass Station and High Springs and at Alachua sink, White Springs, Ellaville and Croom. It is also known at various localities in the hard rock phosphate region. At the railroad trestle just west of White Springs, there is an exposure of sands, marls and clay which is probably the local equivalent of the limestones belonging to the Hawthorne formation. At this locality the beds pass under the Chipola marl member. A section at the railroad trestle shows the following materials:
1. Sandy loam .................................................. 20+ ft.
2. Soft friable marl containing some bands of chert and numerous
Echinoids ................................................ 10-15 ft.
3. Soft marl containing oyster shells.
4. Light green thinly laminated siliceous clay..................... 4 ft.
5. Light green sand to water..................................... 4+ ft.
T otal .................................................... 44+ ft.
CHATTAII(XCIEE FORMATION.
The limestones and marls exposed along the Apalachicola River have been grouped in various ways by different writers. In this paper tile name Chattahoochee formation is restricted to those limestones and marls of northern and western Florida which lie stratigraphically between the limestones of the Vicksburg group and the Chipola marl member of the Alum Bluff formation. Beds of chert occur in this formation and thin layers of sand and clay are not uncommon. The type locality is at Chattahoochee Landing, where there is an exposure of light gray marl and impure limestone. This formation forms Langdon's' Chattahoochee group. and it -is apparently the Chattahoochee group of Foerste2
'Op cit.
Op cit.
FLORIDA GEOLOGICAL SURVEY. SECOND ANNUAL REPORT. IL. IV.
FIG. 1.-OUTCROP OF LIMESTONE OF HAWTHORNE FORMATION ON
SUWANEE RIVER. OPPOSITE ELLAVILLE, FLA.
FIG. 2.-LIMESTONE OF TAMPA FORMATION EXPOSED ALONG SIX-MILE
CREEK. ONE-FOURTH MILE BELOW A. C. L. R. R. BRIDGE, IIILLSBORO COUNTY, FLORIDA.
JU LIv
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY.
In 1892 DalI' called this formation "Ocheesee beds." but in a subsequent paper he notes the absence of exposures at Ocheesee2 and uses the names Chattahoochee formation and Chattahoochee limestone.4 As the formation contains considerable marl, the use of Chattahoochee limestone is not entirely satisfactory, and hence the name Chattahoochee formation is retained.
Stratigraphic Position:-The Chattahoochee formation is known to rest unconformatly on the underlying limestone of the Vicksburg group in southern Georgia. The evidence upon which this unconformity exists was summarized by Pumpelly in 1893.- According to this writer, there is usually a limestone conglomerate at the base of the .Chattahoochee formation in southwestern Georgia, and the altitude of the contact between the two limestones varies considerably within short distances. The variations in altitude given by Pumpelly might, if considered alone, Le, regarded as due to deformation rather than to an erosional unconformity, but the evidence of erosion is strongly supported by the conglomerate which in some places resembles breccia, but in other localities contains rounded pebbles of the underlying rock. The difference in lithologic character between the limestones of the Vicksburg group and the Chattahoochee limestones is so marked that it would hardly be possible to mistake the source of these pebbles. The argument in favor of the inequalities of the surface of the limestones of the Vicksburg group being due to erosion is strengthened by the paleontologic evidence. On evidence furnished by Foerste, Pumpelly states that the Chattahoochee at Griffins Creek contains a fauna characteristic of the upper part of the Vicksburg group, while the other localities examined contain faunas belonging to the lower part of that group. It thus appears that at Griffins Creek the deposition did not begin until after the formation of the beds exposed in the immediate neighborhood, or, in other words, that an island consisting of the underlying limestones of the Vicksburg group was not submerged until after the deposition of the lower part of the Chattahoochee formation.
Tuomey also collected corals at the contact between the Chattahoochee and the underlying limestones, and Dr. DalI identified these
'Dal, Wm. If.. Neocene of North America, U. S. Ceoi. Surv. Bull. 84. 1892, pp. 105-107.
'Dali, Wm. H., and Stanley-Brown, Joseph, Cenezoic Geology along the Apalachicola River, Geol. Soc. Am., vol. v, p. 154, 1894.
lIbid, p. 152.
'Ibid, p. 155.
'Pumpelly, Raphael. An apparent time break between the Eocene and Chattahoochee Miocene in southwestern Georgia. Am. Jour. Sci., 3rd ser., vol. xlvi, 1893, pp. 445-448.
16 FLORIDA STATE GEOLOGICAL SURVEY.
as belonging to the base of the Miocene, to which the members of the Apalachicola group were formerly assigned.
In Florida the base of the Chattahoochee formation was not seen, but there is little doubt that the pronounced unconformity observed farther north extends southward into that State. This view is strengthened by what is already known of the physical history of the State; and by the fact that both the Hawthorne and Tampa formations, which appear to have been deposited at about the same time as the Chattahoochee, rest upon an eroded surface of the limestones of the Vicksburg group.
Lithologic Character:-The Chattahoochee formation consists of light-colored limestones and marls, containing some thin beds of chert, clay and sand. The colors vary from creamy white to light gray or green on recently exposed surfaces to light yellow, brown or more rarely, pink, on weathered outcrops. Lithologically, there is a gradation from nearly pure limestone to sands and clays, but, in general, the argillaceous and siliceous limestones predominate, forming impure limestones or marls. The formation is in part composed of semi-crystalline limestone; but soft, loosely coherent rock resembling an impure chalk is more common. While chert beds occur at various horizons, they are much thinner and less persistent than those of the underlying group. At times, organic life appears to have been abundant, and hence some layers are very fossiliferous, though the fossils are usually preserved in the form of imperfect casts and molds which have been left by the solution of the shells.
Thickness:- Vaughan's' observations along the Apalachicola River show that the Chattahoochee attains a considerable thickness near the type locality.
The Chattahoochee limestone at the Old Landing has a thickness of at least 95 feet and probably is greater because the basal 20 feet of the two sections measured on the roads to the water's edge at the river are not exposed. However, in all probability the alluvium bottom accompanying the river is underlain by this formation, giving it a total thickness of slightly more than 100 feet.
Well borings from Quincy indicate that the thickness of the Chattahoochee formation at that locality is slightly greater than 100 feet; but here, as elsewhere, it is difficult to determine the exact thickness of formations from well samples. The maximum thickness of the formation is probably double the figure given above and it may even be as great as 250 feet.
Physiographic Expression::-In general. the region underlain by the Chattahoochee formation is one of high relief and well developed surface drainage. However, this is not always due to the character of the rocks of this group, for in the northern part of the State the
Vaughan, T. Wayland. Unpublished notes.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 77
surface configuration is often determined, in part, by the character of the superficial sands and clays of post-Oligocene age. The limestones of the Chattahoochee formation are less soluble than those of the underlying Vicksburg group; and, hence, they contain fewer underground streams, which give a characteristic sink-hole topography. However, underground streams, sink-holes and natural bridges are by no means rare. Where the limestones belonging to the Chattahoochee formation are thin the topography is often the combined result of solution of the Lower Oligocene limestones and the protection of the ridges and hills by the more durable Upper Oligocene limestones.
Paleontologic Characters:-At some localities in southern Georgia the basal layers of the Chattahoochee formation supply many corals1 and the lower part of this formation contains Orthaulax pugnax, a gastropod which is characteristic of the "silex bed" at Tampa. This locality has been studied by Vaughan, whose description emphasizes the existence of an erosion interval between the deposition of the VicksbUrg and Apalachicola groups, and shows the existence of a fossil coral reef. Of this coral reef, Vaughan says:
My estimate is that there are between twenty-five and thirty species.
This is the richest fossil coral fauna known from any one locality of the Continental North American Tertiaries. However, the state of preservation of the specimens is not always satisfactory, and it may not be possible specifically !o describe all of them.
The particular interest of this fauna does not lie in its richness, but in its geologic import. The Tertiary coral faunas of the United States below the Chipola horizon were very isolated, no species from the continent, excepting the Orbicella mentioned, being found in any other area. This fauna is distinctly Antiguan in types. Besides the Orbicella referred to, there is a very large-celled Orbicella, very close to 0. crassilamellata (Duncan), if not identical with that species, found abundantly at Russell Spring. An Astrocoenia is extremely close to A. ornata of Duncan from Antigua. The same remark will apply to the Stylophora and Alveopora.
From this field examination it appears that the reef corals of the Antiguan marls and cherts can be correlated with the base of the Chattahoochee limestone, the base of Dall's tipper Oligocene. It is also quite probable that the Oligocene reefs in the vicinity of Lares. Porto Rico, and of Serro Colorado, Curacao, represent the same horizon. The Bowden, Jamaica, fauna would be slightly higher, to be correlated with the Chipola fauna.
It is evident that this coral fauna from Russell Spring, besides filling a gap in the faunal succession on the continent, furnishes a basis for correlating many of the West Indian fossil reefs with the continental Tertiary section, and we may confidently expect more light upon the correlation of American and European horizons.
Pumpelly, Raphael. An apparent time break between the Eocene and Chattahoochee Miocene in southwestern Georgia; Amer. Jour. Sci., 3rd ser., vol. xlvi, 1893, pp. 445-447. See Vaughan, Science 1900.
'Vaughan, T. Wayland. A Tertiary Coral Reef near Bainbridge, Georgia. Science, N. S., vol. xii, 1900, pp. 873-875.
78 FLORIDA STATE GEOLOGICAL SURVEY.
One interesting feature of these corals, not already mentioned, is that they apparently bring the fauna of Vicksburg, Mississippi, into closer relation with the succeeding faunas. A great deal is shown regarding the succession and interrelations of the faunas of the continent itself.
A bed in the lower part of the Chattahoochee formation usually contains an abundance of Echinoids, and several different genera belonging to this group are known to occur in other horizons. At a horizon about twenty feet above the echinoid bed there is a layer containing an abundance of gastropods belonging to the genus Helix, and a slightly higher horizon is characterized by numerous specimens of Cerithium. Among the fossils collected from this limestone are:'
Pyraiisinus cornutus. 1'. cancellata.
Cerithium hillsboroensis. V. penita.
Potamides transecta. Cytherea nuciformis.
Conus planiceps. Cyrena vesica.
Natica amphora. Orbitolites floridanus.
Lucina hillsboroensis. Tagecls undet.
Cardita serricosta. Solen undet.
Venus staminea.
Structure:-In northwestern Florida the limestones of the Chattahoochee formation dip toward the south. The exact amount of this dip is difficult to determine, but careful estimates by Miss Maury, based on sections made by Harris, places the average descent at twenty-three feet per mile. The same writer has noted a variation in the rate of dip, as will be seen from the following quotation:
That this dip is steeper toward the north is shown by the following rate of slope :
Aspalaga to ravine ..........................1-8 mile, 10 feet, or 80 feet per mile.
Aspalaga to Camp Scott .................. 2 miles, 70 feet, or 35 feet per mile.
Camp Scott to Rock Bluff .............. 3 miles, 48 feet. or 16 feet per mile.
Local Details:-The Chattahoochee formation, which is best exposed along the Apalachicola River, has been described by a number of writers. At Chattahoochee, according to Dall, the major portion of the rock exposed belongs to the Alum Bluff formation. His most complete section, which was wade on the road running north from Chattahoochee Landing, is given below.2
'DalI, Wm. H., and Stanley-Brown, Joseph; Cenozoic geology along the Apalachicola River; Bull. Geol. Society of Amer., vol. v, p. 153, 1894.
'Dali, Wm. H. and Stanley-Brown, Joseph. Cenozoic geology along the Apalachicola River, Bull. Geol. Soc. of Amer., vol. v, 1894, p. 152.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 79
Sections at Old Chattahoochee Landing.
Feet.
1. Reddish sand and gravel, with streaks of clay................... 20 to 40
2. Grayish yellow friable marl, with harder layers ................. 20
3. Greenish clayey marl, very adhesive........................... 2%
4. Chattahoochee limestone, with fossil casts...................... 4
5. Talus to water's edge, about ..... ..... .................. ..... 3
Total thickness ........................................... 49/ to 69%
This section was taken on the road running northeast from the landing.
Feet.
1. Reddish sands, gravel and clays................................ 15 to 20
2. Grayish yellow marl, friable ................................... 20
3. Greenish clayey marl, sticky ................................... 2%
4. Talus to Water's edge, about .............. ................ 3
Total thickness ...........................................303 to 45Y2
Section number 2 was taken on the road which runs about southeast from the landing. The exposures are mostly in the gullies.
The fossil-bearing bed is number 4, and contains, among other fossils, echinoids, Pecten (Chipola sp.), Arca (like transversa), large solitary coral, Venus penita, Lima (like scabra), Hemicardium, Ostrea, Loripes, Scala, Plicatula, Divaricella, Pyrazisinus, Phorus, all as poor casts; fish bones and ribs of some mammal resembling those of the Manatee. No orbitolites were seen.
From the correlations made by Dall it is apparent that he regarded No. 1 of the above section as Lafayette and Nos. 2 and 3 as Alum Bluff. A generalized section made by Vaughan1 from Chattahoochee Landing to Chattahoochee postoffice, is given below: Thickness.
Feet. Inches.
3. Red sands with some gravel. Toward the base becoming more
argillaceous sometimes composed of mottled red sands and bluish or purplish clays. The basal portion forms a mantle following quite closely the contact with the Alum
Bluff formation ....................................... 50
The mottled basal portion extends through a vertical
distance of about 40 feet.
2. White chalk and clays sometimes greenish or bluish. The
greater portion of these clays are calcareous and a considerable portion is argillaceous limestone in harder and softer ledges. A calcareous specimen (chalky) was taken 70 feet above the water's edge of the river. The clays are jointed and show conchoidal exfoliation. The lower portion of this exposure does not appear to be calcareous.
Some fine sands at the bottom. Thickness.............. 50
Rocks of the same character, either clay or limestone, as
that described above, occur 100 feet above the river. The
'Vaughan, T. Wayland. Unpublished notes,
80 FLORIDA STATE GEOLOGICAL SURVEY.
total thickness of the Chattahoochee formation here exposed is 80 feet.
1. Alluvium of river bottom composed of reddish sands along
the river, thickness .................................... 20
No exposure of beds beneath the river alluvium was seen.
Total ........................................,............. 120
In commenting upon this section, Vaughan says:
It is evident that I did not examine the specific locality described by Dall, for I did not see his Chattahoochee limestone. The upper part of his No. 2 is the lower part of my No. 2. From Dall's description the whole of my No. 2 would be referable to the Alum Bluff. The combination of his section and mine gives a thickness of over 80 feet. His maximum thickness is 67 feet
The following more detailed section by Vaughan shows the character of the rocks exposed in the lower part of the section given above.
Feet. Inches.
3. White argillaceous chalk in harder and softer layers......... 46 2. Very calcareous blue clay............................. 2
1. Indurated calcareous clay stained yellow in places............ 15 3
Six feet 6 inches above the base is a fine-grained, very calcareous marl white or slightly tinged with yellow in spots. This stratum contains casts of many shells, etc.
T otal ..................................................... 63 3
At Wiley's Landing on the Chattahoochee River, about seven miles above River Junction, Vaughan obtained the section given below, but it has not been correlated with the other sections farther down the river.
Section of bluff at Wiley's Landing. Thickness.
Feet. Inches.
7. Red clay ....... .......................................5 or 6
6. Lim estone ................................................. 25
5. Not definitely exposed, clay or limestone, probably limestone
or calcareous clay ..................................... 5 6
4. Limestone containing a large oyster, Isocardia, Venus,
Pyrula, etc. ........................................... 5 6
3. Unexposed surface red clay, apparently underlain by limestone ................................................. 11
2. Bluish sticky clay .......................................... 5 6
1. From water's edge to 5 feet 6 inches not definitely exposed,
but apparently bluish sticky clay. There is much limestone detritus over the surface, it having rolled down
from the upper part of the bluff. Thickness............. 5 6
The surface of this bluff is so covered by red clay and talus from above (limestone pebbles and boulders) that it is not possible to discover the details of the section. The basal 11 feet are argillaceous while the succeeding 47 feet are for the most part limestone. But the rock is so indurated that the fossils
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 81
can scarcely be freed from the matrix. In one portion of the limestone horizon, the lower 25 feet, very large oyster shells are abundant. These weather out in good condition, probably because their matrix is argillaceous or because the limestone is softer. The greater portion of the limestone is hard and rings under blows of the hammer.
No fossils were found in the basal argillaceous layers. These lower layers would, according to the literature, probably be referred to the Vicksburg. The limestone belongs to the Chattahoochee. The lithologic specimen of it was taken from the top of the exposure and a fair number of fossils were collected. The exposure was also photographed. This section was measured by a hand-level.
The following descriptions were also furnished by Vaughan:
Section, Aspalaga Landing. Thickness.
Feet. Inches.
5. Sand ...................................................... 27 6
4. White lime rock. The surface appearance and color are those
of chalk. This rock is indurated in thick, massive ledges and fragments show concentric exfoliation. Its color is
originally bluish and becomes white upon drying......... 39 6
3. Chalky limestone more calcareous in the basal portion.......18-20
2. Friable limestone containing patchesof blue clay and very
peor remains of fossil mollusks......................... 1 4
1. Whitish tinged yellowish chalk which when kneaded in the
water forms a whitish sticky paste. The stratum is sufficiently indurated to form a ledge and extends at least
1 foot below the surface of the water. Thickness........ 7 8
The argillaceous basal portion of stratum No. 3 is about 2 feet, then follows a chalky stratum and bluish clays at the base of No. 4.
At the extreme upper end of the bluff the exposure is more satisfactory. The bluff face (Nos. 1, 2, and 3, and the lower 10 feet, 8 inches of No. 4, total thickness 30 feet 5 inches) is white chalk with layers of more or less friable and argillaceous marl. Fossils are very numerous and several layers of the chalk especially in stratum No. 2 and at the top of the bluff face, but all are miserably preserved, there being no shell substance left, only casts. Nucula, Pecten, Venericardia, Lucina, Isocardia, Meretrix, Turritella, Stylophora solitary corals, etc., were observed.
A resume of the exposure at Aspalaga excluding the surface sands, is as follows:
Feet. Inches.
4 .................... ........................................ 39 6
3 ......................................... ................... 11
2 ....................... ..................................... 1 4
.............................................................. 7 8
Total thickness ........................................... 50 6
(Or roughly, 60 feet.)
The whole of these 60 feet (perhaps excepting some marl beds near the top) is chalky limestone. This section was-measured with a hand-level.
I could not find the marl bed described by DalI and think it must have been simply a disintegrated chalky stratum or weathered chalk as the weathered chalk is frequently a clay marl. The limestone was sectioned at two places, one near
82 FLORIDA STATE GEOLOGICAL SURVEY.
the lower end of the bluff; the measurements were by hand level and steel tape; the uppermost exposure was a ledge and the thickness as has already been stated was 59 feet 6 inches, or roughly, 60 feet.
Near the upper end of the bluff an aneroid section was made and 55 feet was the thickness by that measurement, practically the same as the preceding.
Coming down the road to Aspalaga Landing is an exposure just before passing to the river bottom. To the right of the road is a small branch that empties into the Apalachicola at Aspalaga Landing. The Chattahoochee formation forms an escarpment a few feet high along the northern side of the branch. An aneroid measurement from the water's edge to the highest exposure on the road gave a thickness of 35 feet, that is, only a portion of the limestone is there exposed.
At the crossing of the River Junction-Bristol Road, over (Flat Creek?) is an exposure of limestone of small extent, probably the Chattahoochee.
Tests with acid of specimens from Aspalaga Bluff.
Stratum 4. Specimens from highest exposure effervesces.
Specimen from chalk ledge in face of bluff effervesces.
Stratum 3. Clay, just beneath base of No. 4, considerable effervescence. Very
calcareous, stiff blue clay effervesces strongly. Stratum 2. A friable limestone, containing considerable clay. Stratum 1. Is an argillaceous limestone, chalk.
Section western end of trestle cast of River Junction, Mile-post 206.
Thickness.
Feet. Inches
(7.) 4. Soil and humus ...................................... 1 6
(6.) 3. Gray sands ............ ...................... 3
(5.) 2. Stiff, mottled sandy clay .............. ............. 3
(4.) 1. Stiff, non-calcareous blue clay........................ 3 2
T otal .............................................. 10 8
(Section measured with steel tape.) Immediately below (4) 1, of the preceding section and nearer the Creek.
Thickness,
Feet. Inches.
3. Sandy, ferruginous clays containing black, apparently carbonaceous particles. Stratum mottled yellowish or brown, .
and bluish white with black spots....................... 3
2. Stiff blue clay with lumps or seams of white clay .......... 1
1. White, sandy, non-calcareous clay oxidizing yellowish or brown
on surface ............................................ 3 6
The barometer readings correlate these clays in altitude with those immediately back of the station house at River Junction and as they are similiar in character this correlation is apparently trustworthy.
One telegraph pole west of milepost 205 is an exposure of the argillaceous chalk of the Chattahoochee 2.7 feet in thickness. It is overlain by the dump from the railroad excavation. The material was tested with acid and found to be calcareous. It has the appearance of the usual limestone of the Chattahooche.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 83
The surface shows irregular joints and conchoidal or concentric exfoliation. One imperfect fossil was found, a surface cast, probably a Lucina.
This locality is about 23/ miles east of River Junction railroad station on the Seaboard Air Line Railway. River Junction is at mile-post 208, 208 miles from Jacksonville.
From looking along the railroad this exposure seems to be topographically lower than the two preceding exposures.
Excepting the two exposures described, there are none between this locality and River Junction excepting surficial sands and may be some red sands or clays and sands. There are no deep cuttings along the railroad track.
Section at Station House, River Junction. Thickness.
Feet. Inches.
Chocolate or brownish soil ..............*.......................: 1
Sandy whitish clay ............................................ 1 6
Sandy whitish clay slightly calcareous in ledges.................. 8
T otal ..................................................... 10 6
Section near lower end of train yard.
Feet. Inches.
7. Humus and blackish or dark brown soil, about................ 1
6. Yellow sandy clay or marl, estimated........................ 3
5. Whitish sandy clay, very slightly calcareous.................. 4 7
4. Whitish sandy clay (very slightly or not at all calcareous).... 4 3. More calcareous white sandy clay............................ 1
2. Very calcareous sandy clay.................................. 1 5
1. Sandy chalk very argillaceous, sand grains fine................ 6 5
T otal ................................................. 21 7
1, at edge of sand flat of small branch. This last bed is the one from which DalI mentioned fossils. I found as poor casts, Isocardia, Hemicardium, Venericardium, Tagelus, Turritella (very large species) cast of inside of large gastropod (Orthaulax?), smaller gastropods, etc. There were many specimens and many species but all poorly preserved.
Between River Junction and the railroad bridge over the Apalachicola River, there are no rock exposures except the one already mentioned.
Ditch running east from back of Station House at River Junction.
A few yards east of the wagon road crossing the railroad there is a small fall in this ditch and here a number of fossils were obtained:
Mammalian ribs, fragments. (These Pecten.
ribs are probably of the manatee.) Venus.
Large Chelepod crustacean claws, Lucina.
the animal apparently the size of Astarte.
a large lobster. Natica (very large species).
Cardium, several species. Orthaulax?
Hemicardium. Fusus.
Venericardia. Cerithium or Turritella.
The shells are all casts, internal or external, but the fauna is evidently typical Chattahoochee. One fine regular Echinoid was collected.
84 FLORIDA STATE GEOLOGICAL SURVEY.
Cement Quarry one-half mile south of River Junction. Thickness.
Feet. Inches.
8. Superficial coating of black humus and some gray sand......
7. Friable chalky limestone forming slope of hill............... 13+
6. Harder chalky layer ............. ............. 5
5. Softer chalky layer ....................................... 1 5
4. Harder, somewhat saccharoidal limestone................... 9
3. Softer fossiliferous chalk ....................... ......... 1 7
2. Harder limestone with numerous fossils, the commonest the
Hemicardium and an orbitoid foraminifer. This material when weathered turns reddish and forms a residual red clay. No original molluscan tests were observed, but they
are sometimes replaced by crystalline calcite............ 1 3
1. Soft white chalk, indurating upon exposure, used in making
cem ent brick .......................................... 4
According to the barometer, the base of No. 1 is 50 feet above the railroad at River Junction.
Some twelve to fifteen feet of limestone belonging to the Chattahoochee formation is exposed at Rock Bluff, and it doubtless underlies the Chipola marl member at Alum Bluff. On the Chipola River the same limestone is exposed at intervals from near the mouth of Ten-mile Creek northward to beyond the Peacock Bridge. These exposures seldom exceed four or five feet in thickness and the rock is a chalky limestone similar to that exposed on Apalachicola River. The outcrops at Peacock and Willis bridges on the Chipola River were visited, but they proved to be nearly destitute of organic remains. This limestone, doubtless, forms the natural bridges over Ten-mile and Sinking Creeks, tributaries of the Chipola River, but high water prevented a close examination of these localities. Similar limestone occurs in the form of loose bowlders in the vicinity of Knoxhill, Walton County, and outcrops of it are reported on the Choctawhatchee River, south of the Louisville and Nashville Railroad bridge. At Caryville, the well of the Wood Lumber Company penetrated eight feet of pinkish limestone, which doubtless belongs to the Chattahoochee formation. The limestone at St. Marks and at some localities farther north and east is also tentatively referred to this formation.
TAMPA FORMATION.
The Tampa formation consists of greenish clays, light gray to yellow limestones, and a very fossiliferous bed of "silex." Hitherto, the "silex" and a portion of the limestone have been all that was known of the formation. The "silex beds" and limestone of the Tampa formation were first examined by Conrad' over sixty years ago. In the
'Conrad, T. A., Observations on Eocene formations and descriptions of 105 new fossils of that period from the vicinity of Vicksburg, Miss.; Phila. Acad. Science Proc., vol. iii, p. 28.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 85
same year Professor Allen' described both the limestone and "silex bed" at Tampa, and his account of these beds has been generally accepted as correct. The same locality was subsequently visited by Tuomey.2 In 1884, Kerr and Mitchell3 visited Tampa and noted the replacement of fossiliferous limestone by chalcedony in what has since been called the "silex bed." Ballast Point, near Tampa, where the "silex bed" is best exposed, is the locality where Bailey4 found, what he regarded as infusorial earth, resting on the "silex bed." Later investigations have shown that this material is merely a residual material produced by the action of the weather upon the silicified limestone.
In 1887, Heilprin- published an account of the explorations near Tampa and called attention to the fact that the fossil which Conrad regarded as a nummulite is really an orbitulite. Heilprin gave a brief description of Ballast Point and other exposures near Tampa, but does not appear to have recognized the relations between the limestone and the "silex bed." Later publications by Dall give more complete descriptions of the Tampa exposures and show clearly that there are two horizons represented which he has called respectively "Tampa silex bed" and "Tampa limestone." Because the "silex bed" is characterized by the presence of Orthaulax pugnax, Dall has called it the "Orthaulax bed" and the limestone has been designated "Cerithium6 rock," on acount of the presence of many specimens belonging to that genus.
In his bulletin on the Neocene of North America, Dali 'described the "Tampa group," including what he designates the Tampa, Chipola and Alum Bluff beds. But the subsequent discovery of Orthaulax pugnax in the Chattahoochee led him to place the "silex beds" in his "Chattahoochee group."'
While engaged in the field work for this report, additional information concerning the rocks at Tampa was obtained. Stated briefly, the observations showed the presence of a limestone below the "silex bed"
'Allen, Prof. John H1. Amer. Jour. Sci., 2nd ser., vol. ii, 1846, pp. 36-48.
'Tuomey, M. Notice on the geology of the Florida Keys and the southern coast of Florida. Am. Jour. Sci., 2nd ser., vol. ii, 1851, pp. 390-394.
'Kerr, W. C., and Mitchell, Elisha. Scientific Society, 1884-5, p. 87.
'Bailey, J. W. Microscopic Observations, Smithsonian contributions to knowledge, vol. ii, No. 8, 1850, p. 10.
'Heilprin, Angelo. Explorations on west coast of Florida; Wagner Free Institute of Science Trans., vol. i, 1887, pp. 10 and I].
'Dall, Wm. H. Neocene of North America, U. S. Geol. Survey,. Bull. 84, 1892, pp. 112-113.
'Loc. cit.
"Dall, Wm. H. Tertiary fauna of Florida; Wagner Free Institute of Science Trans., vol. 3, pt. 6, 1893, pp. 1564 and 1565.
86 FLORIDA STATE GEOLOGICAL SURVEY.
and the existence of clay beds at both the base and top of the formation. The limestone below the "silex bed" is similar to what Dal1 has called "Cerithium rock," and in this connection it is interesting to note what he has said concerning its existence:
From these observations it appears that, while the existence of a Cerithiums rock under the Orthaulax bed is a priori probable, sufficient evidence of its existence is still to be collected, and the rock identified as such by Heilprin may very possibly have been a portion of the Tampa limestone.
Since the publication of the report from which this quotation is taken, a series of wells have been drilled, and the samples which were preserved show the presence of the limestone below the silex.
Stratigraphic Position :-Evidence of an unconformity at the base of the Tampa formation was obtained in drilling wells for the city of Tampa. The log of one of these wells is given on page 89, and it will be noted that after passing through thirty feet of limestone and chert the drill encountered a blue clay forty-one feet in thickness. The limestone and chert represent the limestone and "silex bed" of the Tampa formation and the clay appears to belong at the base of that formation. At a distance of 200 feet from the well mentioned above, the clay was encountered at about the same depth and was said to have a thickness of sixty-four feet. This variation shows that the underlying limestones of the Vicksburg group have an irregular surface which was doubtless produced by erosion.
The relation of the Tampa formation to the Hawthorne and Chattahoochee formations has already been discussed, and its stratigraphic relation to the Alum Bluff formation is probably similar to that of the other two formations mentioned. The post-Oligocene formations, which occur in the area where the Tampa formation is known, rest unconformably upon it.
Lithologic Character:-The upper member of the Tampa formation comprises a well stratified greenish clay containing some calcareous nodules and thin beds of limestone near the base. Scattered throughout the clay are many silicified corals, some of them having a diameter of two or three feet. The clay is very plastic and hence is valuable for the manufacture of brick. Beneath this clay is the light-gray to yellow limestone which was formerly called the "Tampa limestone." The "silex bed" represents a silicified zone in this limestone and is, therefore, a zone of replacement. This is well shown by some of the fossils which have been only partially silicified; and by the presence of more or less unaltered carbonate of lime in the original rock. Small nodules of chert occur at other horizons in the
'Dall, Wm. H., Neocene of North America, U. S. Geol. Survey, Bull. 84, 1892, p. 119.
SECOND ANNUAL REPORT-TRATIGRAPHIC GEOLOGY. 87
limestone, and outcrops of the rock are often denser and harder than exposures in quarries. Locally the limestone is hard enough to make a durable building stone which might be useful in the construction of foundations for buildings. Fossils are abundant in some parts of the limestone, but they are largely represented by casts and molds, which have been left by the solution of the original shells. The "silex bed" contains numerous fossils which have been wholly or partially replaced by chalcedony. Resting upon the "silex" at some localities is a siliceous residual material which was formerly thought to be infusorial earth, but is now known to be weathered material derived from the underlying rock. In such cases the action of the percolating water has removed the matrix, leaving many beautifully preserved pseudomorps and casts of shells. These fossils are commonly composed of chalcedony which frequently exhibit the characteristic markings of the original shells. (See Fig. 2, Plate IV.)
Beneath the limestone beds is a greenish clay which commonly contains a considerable admixture of sand. This clay is very plastic and resembles the clay which overlies the limestone. Judging from well records, the deposit is homogeneous, but there is a possibility that the sand contained in the well samples may be derived from thin sand partings in the clay bed.
Thickness:-The information concerning the thickness of the Tampa formation is meager, but it is sufficient to fix the maximum thickness at more than 130 feet. The clay bed at the top of the fornation has a known thickness of fifteen feet. The limestone between the "silex bed" and the upper clay is about forty feet thick. The thickness of the "silex bed" varies considerably, ranging from about four feet to more than ten feet. Beneath the "silex bed" is a limestone which has a known thickness of six feet. The clay bed at the base of the formation has been penetrated by two wells within 200 feet of each other, and the thickness varied from forty-one feet to sixty-four feet.
Physiographic Expression:-The area underlain by the Tampa formation is so near sea level that no marked physiographic features can be discerned. The influence of the limestone of this formation is seen in the rapids of the Hillsboro River; and it may be the solution of these limestones which gives rise to some of the depressions northeast of Tampa. Aside from these minor features. the surface of the formation is not very diversified.
Paleontologic Characters:-In addition to the characteristic Orthaulax pugnax, the "silex bed" of the Tampa formation has furnished a very large number of species, including some corals, many species of gastropods, pelecypods and a few specimens of Orbitolites floridanus which becomes abundant in the overlying limestone. At
88 FLORIDA STATE GEOLOGICAL SURVEY.
Ballast Point the fauna of the "silex bed," though largely marine, contains many fresh water shells which were probably supplied from some lakes or lagoons situated near the shore. The complete list of the fossils from the "silex bed" is given by Dall, who says:'
About forty-nine per cent of the species in the Orthaulax bed are peculiar to it, and very few of the more minute forms which should be present in such a fauna are known. The relations of the fauna are most intimate with that of the Oligocene beds above it, the Orbitolite or Tampa limestone, the Chipola, and the Oak Grove sands. With either of these the percentage of species common to both is more than twice as great as with any of the beds below, such as the nummulitic, the Peninsular limestone, or the Vicksburg. But it must be admitted that the faunas of all these, except the last, are very imperfectly known. With the faunas of the horizons above the Oak Grove sands, there is little in common, though in the tropical waters of the Antilles, about eight per cent of the species are believed to survive to the present day. Only about 2.6 per cent survive except in tropical waters.
One of the most interesting features of the fauna is the assembly of land shells, which are southern immigrants and have left no survivors on the American continent at the present day, though representative species occur to the southward.
The fauna of the limestone in the Tampa formation contains fewer species than that of the "silex bed," but the faunas are closely related, as will be seen by the following quotation which' contains Dall's comments on the list of fossils from these two beds:2
Total, ninety-five species, of which thirty-six are uncertain specifically, leaving fifty-nine identified, of which thirty-seven are common to the silex beds, ten are peculiar to the Tampa limestone horizon, four are known from the Ocala nummulitic limestone, and two appear in the Vicksburgian, the Jacksonian, and the Claibornian. One species (and probably more not yet discriminated) survives into the Chipola and two are believed to persist to the recent fauna.
Structure:-The Tampa formation lies near sea level and hence it is difficult to get sections which show the structure of the beds. Apparently the formation is nearly horizontal with a slight seaward dip. While the formation may be affected by gentle flexures, the evidence is still too meager to show their existence.
Local Details:-The "silex bed" of the Tampa formation is best exposed at Ballast Point where it rises only a few feet above tide. At this locality the maximum thickness of the bed is not shown. Dall's" section at Tampa is:
'Dal, Win. H., Geological results of the study of the Tertiary fauna of Florida; Ex. from Trans. Wagner Free Institute of Science, Phila., vol. iii, Part vi, p. 1565, 1903.
2 Ibid, p. 1572.
'Dal], Win. H. Neocene of North America, U. S. Geol. Survey, Bull. 84, 1892, p. 113.
SECOND ANNUAL REPORT-STRATIGRAPHIc GEOLOGY. 89
White sand ..................... ....................... 6 to 24 inches.
Yellow sand ................................................ 6 to 36 inches.
Pliocene breccia ............................................. traces.
Tampa limestone ............................................ 10 to 15 feet.
Tampa silex bed ............................................ 6 to 10 feet.
In drilling wells at the Tampa water works, between Sixth and Seventh avenues, the "silex bed" was found to have a thickness of only four feet. Beneath the "silex bed" there was a thin bed of limestone underlain by greenish clay, which varied in thickness from forty-one to sixty-four feet. The log of one of these wells follows:
1. W hite Pleistocene sand ........................................ 2 feet.
2. Tough yellow clay with no sand, residual clay.................... 10 feet.
3. Soft limestone which disintegrates readily-"Tampa limestone".. 14 feet. 4. Chert, "Tampa silex bed".......... ............................. 4 feet.
5. Soft limestone closely resembling No. 3......................... 6 feet.
6. Tough plastic greenish sandy clay .............................. 41 feet.
Base of the Tampa formation:
7. C hert ......................................................... 2 feet.
8. White m arl .................................................. 6 feet.
9. Soft lim estone ................................................. 6 feet.
10. Very light colored hard rock.................................... 15 feet.
11. Very hard dark yellow limestone................................ -6 feet.
12. Gray porous limestone with some water.... .................. 15 feet.
13. Cherty beds ................................................... 14 feet.
14. Darker limestone.
15. Gray plastic clay.
16. Hard yellow rock with chert.
17. Gray porous rock, water-bearing.
18. Like preceding.
Nos. 3-6 inclusive represent the Tampa formation, but at this locality the upper clay and a portion of the limestone have been removed by erosion.
Another well 200 feet away encountered sixty-four feet of No. 6, which suggests an unconformity at base of this bed, and this hypothesis is strengthened by the fact that the rock immediately below the clay differed in the two wells.
The upper clay bed of the Tampa formation is best exposed at the pit of the Tampa Brick Company on the bank of the Hillsboro River five miles northeast of the city. At this locality there is an exposure of from ten to fourteen feet of light green siliceous clay which is unconformably overlain by from two to four feet of light-gray Pleistocene sand. The clay is very plastic and is said to make excellent brick. Scattered throughout the deposit are numerous cobbles and boulders of chert which represent silicified corals. While the major portion of the exposure is of a light greenish color toward. the bottom
90 FLORIDA STATE GEOLOGICAL SURVEY.
of the pit, the clay becomes gray and is interbedded with thin nodular layers of limestone.
A light green siliceous clay similar to that described above was seen on the west side of Old Tampa Bay, near Safety Harbor (Espiritu Santo Springs). Here the section shows four to six feet of white Pleistocene sand resting unconformably upon six feet of greenish clay. On the beach, near this exposure are several large chert boulders which were probably derived from beds beneath the clay. About one mile north of the postoffice the following section was observed: W hite Pleistocene sand ............................................ 2-4 feet.
Dark brown sand, partially indurated............................... 1-6 feet.
Light greenish clay, thinly laminated............................... 5 feet
On the Gulf coast, near Clearwater, are numerous exposures of cherty limestone which are probably to be correlated with the rocks at Tampa, but in the absence of paleontologic evidence, this correlation must be regarded as merely tentative. A generalized section at this locality was obtained from well records and observations along the beach.
I. W hite Pleistocene sand ..................................... 12 feet.
2. Light colored clay .................. ............. 14 feet.
3. Light colored limestone with chert concretions ............... 1 ft. to 6 in.
4. Bluish laminated marly clay with chert concretions............ 2-4 feet.
5. Light gray limestone wjth chert concretions................... 2-3 feet.
A generalized section near Laporitieres Spring is given by Dall:' Humus, yellow sand, etc. .................................... 6 to 36 inches.
Tampa limestone ............................................ 10 to 15 feet.
O rthaulax bed .............................................. 7 in. to 10 ft.
The limestone of the Tampa formation is exposed near the pumping station, where it has been quarried to a depth of over fifteen feet, and other exposures occur at intervals along the Hillsboro River for a distance of over fifteen miles inland. Probably the best exposures are in the excavations near the Sulphur Spring, northeast of Tampa, and at the rapids about a mile above the spring. The same limestone was observed resting on the "silex bed" at the railroad crossing over Six-Mile Creek. Here the limestone is immediately overlain by fossilifepous Pleistocene shell marl which grades upward into coarse white sand.
Section one-eighth mile below railroad bridge-Orient (Tampa).
4. Soft white marl ................................................. 6 feet.
3. Light gray to buff fine grained quartz sand........................ 3 feet.
2. Gray shell marl Pleistocene ..................................... 1-2 feet.
1. White soft limestone with some gastropods and other fossils....... 5 feet.
'Dal, Wm. H., Neocene of North America, U. S. Geol. Survey, Bull. 84, 1892, p. 108.
SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 91
No. 2 rests unconformably upon No. 1 and is a thin but persistent bed.
Section at railroad bridge-Orient (Tampa).
5. Fossiliferous white sand ......................................... 2 feet.
4. W hite m arl .................................................... 6 feet.
3. Light gray sand .................................... ....... I foot
2. Gray shell marl ................................................ 0-1 foot
1. Gray to yellow limestone, very fossiliferous in places ........... 6 feet.
No. 2 rests unconformably upon No. 1 and is evidently the same horizon as No. 2 in the preceding section. The limestone in both of these sections is what has commonly been called "Tampa limestone." In the section at the railroad bridge, there is some "silex" near the base and this evidently represents the same horizon as the "silex bed" at Ballast Point.
ALUM BLUFF FORMATION.
The name Alum Bluff formation as here used includes those beds which belong stratigraphically between either the Chattahoochee forination or the Hawthorne formation and the marls and limestones of Miocene age. This usage differs from that of Dall,1 who appears to have regarded the Chipola marl and the Alum Bluff as distinct formations. The Alum Bluff formation includes two different, though closely related, members which have been known respectively as the Chipola marl and the Oak Grove sands. To these is added a third member, recently discovered by Vaughan2 in west Florida, and called the Shoal River marl member, from the stream where it is best exposed. The Chipola marl member and- the sands of the type locality at Alum Bluff were first described by Langdon, who referred them to the Miocene.3
The type locality of the Chipola4 marl member is at McClelland's farm, near Bailey's Ferry, on the Chipola River, and the Alum Bluff formation is named from a bluff on the Apalachicola River, where it was first examined. The fullers earth deposits which represent the Alum Bluff formation east of the Apalachicola River, have been mentioned by a number of writers, but the first comprehensive description of
DalI, Wm. H., Cenozoic Geology Along the Apalachicola River; Geol. Soc. Am. Bull., vol. v, 1893, p. 167.
'Vaughan, T. Wayland. Unpublished notes.
"Langdon, Daniel W., Jr. Some Florida Miocene; Am. Jour. Sci., 2nd ser., vol. xxxviii, 1889, p. 32.
'DalI, Wm. H., Neocene of North America, U. S. Geol. Survey Bull. No. 84, 1893, p. 122.
92 FLORIDA STATE GEOLOGICAL SURVEY.
them was given by Vaughan' in 1901. The Oak Grove sand member was described by Dal2 in 1893.
Exposures of limestone on the Sopchoppy and Ocklocknee Rivers, some five or six miles from the town of Sopchoppy, have been called the "Sopchoppy limestone." This rock was first described by bal who assigned it to about the horizon of the Chipola marl member. In this report it is tentatively included with the Alum Bluff formation. Further investigation is needed to determine its exact stratigraphic relations.
The limestones and marls on the Manatee River near Ellenton were thought by Heilprin4 to belong to the Miocene, but are probably somewhat older. They are here referred tentatively to the Oak Grove sand member of the Alum Bluff formation, but this correlation is subject to revision, if subsequent investigations should show that the fauna is characteristic of some other horizon.
Stratigraphic Position:-The Alum Bluff formation is conformable upon both the Chattahoochee and the Hawthorne formations. This is inferred from the facts that no distinct evidence of a stratigraphic break between the two groups has been noted, and their faunas are closely related. At Alum Bluff, on the Apalachicola River, and Jackson's Bluff, on the Ocklocknee River, the marls of Miocene age rest upon an eroded surface of the Alum Bluff formation, but farther west, in Walton County, it is possible that they may be conformable.
Lithologic Character: The, Alum Bluff formation consists of marl, sand and clay, which are sometimes fairly distinct, but more often interbedded. Limestones also occur in the formation, but they are not extensively developed and usually contain enough earthy material mixed with the carbonate of lime to form marls. Shell marls with a calcareous or sandy matrix are common and they often occur interbedded with nearly pure sand. In general, the beds belonging to this formation are light gray, but occasionally shades of green or yellow prevail.
At Alum Bluff, on the Apalachicola River, Dal-- gives the following section:
'Vaughan, T. Wayland. Fuller's earth; U. S. Geol. Survey, Mineral Resources of the United States. 1901, pp. 921-934.
'Dal, Wm. H. Cenozoic Geology Along the Apalachicola River, Geol. Soc. Am. Bull., vol. v, 1893, pp. 166-167.
'Dal, Wm. H., Neocene of North America, U. S. Geol. Survey, Bull. No. 84, 1892, pp. 119-120.
Heilprin. Angelo. Explorations on the west coast of Florida. Wagner Free Inst., Trans., vol. 1, p. 13.
'Dal, Win. If., Geol. Soc. Am.. vol. v, 1893, p. 157.
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