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UCIENCES
LIBRARY
Digitized by Google
OBIRKELEY,
LIBRARY
U UNIYE.RsITy OF
CALIFORNIA
EXCHANGE
EX L1BRIS
FLORIDA STATE GEOLOGICAL SURVEY
E. H. SELLARDS, Ph. D., State Geologist
FIFTH ANNUAL REPORT
PUBULISBD FOr
THE STATE GEOLOGICAL SURVEY
TALLAHAMSSE, 1913
Digitized by GoOgle
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TuH RicoaD COMPANY
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Digitized by GOOgle
CONTENTS.
Administrative report ............................................ 7
Origin of the Hard Rock Phosphates of Florida, by E. H. Sellards.. 23
List of Elevations in Florida, by E. H. Sellards ................... 81
Artesian Water Supply of Eastern and Southern Florida, by E. H.
Sellards and Herman Gunter ............................. 103
Production of Phosphate in Florida during 1912, by E. H. Sellards... 291
Statistics on Public Roads in Florida, by E. H. Sellards ............ 295
Index ............................................................ 299
Plate
No.
PLATES.
1. Phosphate boulder showing secondary deposition.
2. Laminated phosphate boulder.
3. Phosphate rock.
4. Teeth of mastodon from the phosphate deposits.
5. Teeth and foot bone of horse, and teeth of mastodon.
6. Sharks' teeth from the phosphate deposits.
7. Sharks' teeth from the phosphate deposits.
8. Phosphate washer and prospect drill.
9. Phosphate pit after the removal of the phosphate.
10. Fig. 1. Palmetto flatwoods, Amelia Island.
Fig. 2. Palmetto flatwoods, Ft. Myers.
11. Fig. 1. Scrub, east side of Lake Kingsley, Clay County.
Fig. 2. Sandy pineland, DeLeon Springs.
Fig. 3. Open flatwoods, three miles east of DeLeon Springs.
12. Fig. 1. Everglades west of Ft. Lauderdale.
Fig. 2. Small prairie, four miles west of Sebastian.
Fig. 3. Turnbull Hammock, one mile west of Daytona.
13. Fig. 1. Sand dune near Mayport.
Fig. 2. Ancient sand dune, two miles west of Daytona.
Fig. 3. Exposure at Saw Pit landing, St. Marys River.
14. Fig. 1. Exposure of hardpan at Black Bluff on Clark's Creek eight
miles from Fernandina.
Fig. 2. Artesian well used for power, Melbourne, in Brevard County.
FIGURES.
Fig. 1. Artesian basin.
Fig. 2. Artesian slope.
Fig. 3. Artesian water from unconfined horizontal beds.
Fig. 4. Artesian water from solution passages in limestone.
Fig. 5. Method of measuring flow of artesian well.
Fig. 6. Map showing area of artesian flow in Nassau and Duval Counties.
Fig. 7. Map showing the area of artesian flow in St. Johns County.
282701
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CONTENTS.
Fig. 8. Map showing the areas of artesian flow in Clay and Putnam
Counties.
Fig. 9. Map showing the area of artesian flow in Orange and Seminole
Counties.
Fig. 10. Flowing artesian well.
Fig. 11. Map showing the area of artesian flow in Volusia County.
Fig. 13. Map showing the area of artesian flow in Pinellas and Hillsboro
Counties.
Fig. 14. Map showing the area of artesian flow in Polk County.
Fig. 15. Map showing the area of artesian flow in Osceola County.
Fig. 16. Map showing- the area of artesian flow in Manatee County.
Fig. 17. Map showing the area of artesian flow in DeSoto County.
MAPS.
Map showing the limestone region of Central Florida.
Map showing the location of the hard rock and land pebble phosphates.
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LETTER OF TRANSMITTAL.
To His Excellency, Hon. Park Trammell,
Governor of Florida.
Sir:-In accordance with the Survey law I submit herewith
my Fifth Annual Report as State Geologist of Florida. This
report contaitis the statement of expenditures by the Survey for
the fiscal year ending June 30, 1912, to which I have added a list
of the expenditures of the Survey for the succeeding half year
ending December 31, 1912. The progress of the Survey inves-
tigations during the year are shown by the scientific papers that
will form a part of this report. These include a paper on the
origin of the hard rock phosphates of Florida; a report on the
artesian water supply of southern Florida, and a list of elevations
in the State together with a second edition of the general topo-
graphic map of the State previously published.
I venture to add here a resume of the principal investigations
of the Survey since its organization and to make certain recom-
mendations which I believe to be for the good of the future use-
fulness of the Survey. Permit me to express in this connection
my appreciation of the interest you have shown in the work of
the State Geological Survey.
Very respectfully,
E. H. SELLARDS,
State Geologist.
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ADMINISTRATIVE REPORT.
E. H. SELLARDS, STATE GEOLOGIST.
PRINCIPAL RESULTS OF THE STATE GEOLOGICAL SURVEY
INVESTIGATIONS.
Aside from miscellaneous and routine work, the principal
investigations that have been carried out by the State Geological
Survey since its organization may be grouped under six heads
as follows:
1. Assemblage of the literature on the geology of Florida
and a review of the important publications issued previous to the
organization of the State Survey. This review of the literature
together with the bibliography of publications relating to the
geology of Florida was included in the First Annual Report. The
publications obtained in this connection form a part of the Survey
library.
II. A Report on the Geology and Stratigraphy of Florida.
This report included in the Second Annual Report was prepared
in cooperation with the United States Geological Survey. It
serves as a preliminary account of the geology of the State, and
brings together all the information relating to the geology that
was then available.
III. A General Topographic and Geologic Map of Florida.
With the general report on the geology of Florida referred to
above there was included a topographic and geologic map of Flor-
ida. The topography was shown on this map with as much detail
as the information available regarding elevations would permit,
the contour lines being placed at 50 foot intervals of elevation.
A second edition of this map is included in the report now being
issued.
IV. A very important natural resource of Florida is the
underground or artesian water supply. This subject was one of
the first taken up by the Survey, and with the publication of the
present report the preliminary investigation of the water supply
is completed. The papers published on this subject are as follows:
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FLORIDA STATE GEOLOGICAL SURVEY.
The Underground Water Supply of Central Florida, Bulletin
No. 1; The Artesian Water Supply of Eastern Florida, Third
Annual Report; The Underground Water Supply of West-Cen-
tral and 'West Florida, Fourth Annual Report; The Artesian
Water Supply of Southern Florida, Fifth Annual Report.
V. .The Soils. A general report on the soils of the State
formed a part of the Fourth Annual Report. This paper included
an account of the origin and character of the soils of Florida,
and was intended as a basis for subsequent detailed soil surveys.
VI. The Mineral Resources. Information bearing on the
mineral resources of the State has formed a part of each annual
report issued. An account of the fuller's earth deposits as
complete as the information then at hand would permit was in-
cluded in the Second Annual Report. Papers on the phosphate
deposits formed a part of the Third and the present (Fifth)
Annual Reports. The peat deposits of the State, which are exten-
sive, were described in the Third Annual Report. The clay re-
sources have received general treatment in the First 'and Second
Annual Reports.
RECOMMENDATIONS.
MORE OFFICE SPACE NECESSARY.
The State Survey is at present housed in two small rooms.
Of these one is used as store room, photo room and exhibition
room; the other serves as library, office and work room. These
small rooms including about 1,000 square feet of floor space are
totally inadequate to the requirements of effective work. Fully
10,000 square feet of floor space is necessary to meet the immedi-
ate requirements of the Survey. The library shelves are full, and
it is now and for some time has been quite impossible to care for
the publications that are being received. Many of these new
publications represent the results of investigations by the neigh-
boring State Surveys or by the National Survey, and are very
necessary for comparative purposes to the Florida Survey. Other
publications being received from various sources are for refer-
ence purposes and are necessary to the determination of fossils or
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FIFTH ANNUAL REPORT.
mineral specimens, or of geological formations, or other matters
in connection with the Survey work.
The Survey at present is practically without a work room.
There is no table or desk room available to store or to handle the
maps, charts, and drawings that are constantly being used in the
Survey work. It is impossible from lack of space to properly
open up and study the collection of mineral and fossil specimens
that have been obtained by the Survey. The store room space is
too small to accommodate even the current issues of the Survey's
own publications which must be cared for temporarily awaiting
their distribution.
In connection with the work of the Survey there is a constant
accumulation of notes, records, photographs, manuscripts, plates
and cuts, as well as the general correspondence of the office which
must be cared for. The present limited office space affords no
room for storing, filing or properly caring for these records.
I urgently recommend, -f it meets with your approval, that
the Legislature be asked to provide adequate rooms for the future
work of the State Geological Survey.
A STATE MUSEUM.
The desirability of an adequate museum in which to properly
exhibit the resources of the State is apparent. The State Survey
law makes it the duty of the State Geologist to collect, determine
and label specimens illustrating the geological and mineral fea-
tures of the State and large collections have been made since the
Survey was organized. The small room used for exhibition
purposes has long since been filled and a large amount of material
suitable for exhibition remains unopened in boxes as collected. It
is important that the State provide for the proper preservation
and exhibition of the Survey collections in a State Museum.
DEMAND FOR CLAY TESTING LABORATORY.
There is a very urgent demand on the part of the citizens of
the State for a laboratory in which the various clays may be prop-
erlv tested for brick making and other purposes. It is a well
known fact that the utility of clays is determined not so much by
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FLORIDA STATE GEOLOGICAL SURVEY.
their chemical as by their physical properties. To properly test
a clay it is therefore necessary to install the testing machinery.
Effective clay testing machinery will require for installation more
space than is now available in the Survey rooms.
THE PREPARATION OF A DETAILED TOPOGRAPHIC MAP OF FLORIDA.
While a general topographic map of Florida with contour
lies at 50 foot intervals of elevation has been issued, as already
stated, there is a constant demand for detailed topographic maps
on a scale of about one inch to the mile and with contour lines at
10 foot intervals of elevation. Topographic maps are usually
made in atlas sheets covering unit areas bounded by parallels and
meridians. The unit adopted by the United States Geological
Survey in topographic mapping designated as the quadrangle,
includes when made on the scale of about one inch to the mile an
area of 15' of latitude by 15' of longitude. A separate atlas sheet
is issued for each unit area and when completed the maps so
issued make up a complete map for the State as a whole. The
maps thus made show the land area in relief by means of contour
lines. In this way all hills, valleys, stream channels, sinks, de-
pressions and all changes in elevation are indicated. The actual
elevation above sea, based on exact levels, are also shown by
means of figures printed on the contour lines. Each contour
passes through ,points which have the same altitude. One who
follows the contour on the ground will go neither up hill nor
down hill but on a level. By the use of contours the shapes of
the plains, hills and valleys as well as their elevations are shown.
The line of the sea coast itself is a contour line, the datum or
zero of elevation being mean sea level. The contour line at, say,
20 feet above sea level is a line that would be the sea coast if the
sea were to rise or the land to sink 20 feet. Such a line runs
back up the valleys and forward around the points of hills and
spurs. On a gentle slope this contour line is far from the present
coast line, while on a steep slope it is near it. Thus a succession
of these contour lines far apart on the map indicates a gentle
slope; if close together a steep slope; and if the. contours run
together in one line, as if each were vertically under the one
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FIFTH ANNUAL REPORT.
above it, they indicate a cliff. The heights of many definite points,
such as road corners, railroad crossings, railroad stations, sum-
mits, water surfaces, triangulation stations and bench marks are
also given on the map. The figures in each case are placed close
to the point to which they apply, and express the elevation to
the nearest foot.
In addition to indicating relief and actual elevation above sea
these maps show all other natural features such as lakes, ponds,
rivers, streams, canals, swamps and all cultural features includ-
ing public roads, railroads, towns, cities, county and State
boundaries.
The topographic maps thus prepared find many uses. They
are above all essential to the proper planning of drainage opera-
tions throughout all of the interior of the State. It is a well-
known fact that we have in Florida, particularly in the flatwoods
section, large areas of land that although not actually flooded
yet would be much improved by the more rapid removal of the
heavy summer rains. Other large and valuable tracts of land, but
little used at present, by a proper system of drainage, can
ultimately be made valuable and productive land. The topogra-
phic maps such as are here contemplated are essential to the
proper planning of drainage operations.
The topographic maps are of very great assistance in the
preparation of detailed soil maps. They afford first of all an
exact base map of the area to be surveyed, thereby reducing the
cost of the soil map about one-half. They also facilitate the study
of the soils which bear well known relations to drainage and
moisture conditions. In detailed geologic mapping and in the
study of the mineral resources topographic maps are practically
necessary for the detailed final reports.
Topographic maps find many additional uses. They are of
very great assistance in the laying out and developing a system
of public roads, showing as they do the relief of the land includ-
ing hills, depressions and valleys. In planning the location of
railroads, canals, waterways or other public improvements they
are of great assistance. Finally they afford to the land owners
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FLORIDA STATE GEOLOGICAL SURVEY.
as well as to the citizens in general the manifold conveniences of
a well-made and accurate map on a large scale.
COOPERATION WITH THE UNITED STATES GEOLOGICAL SURVEY IN
THE PREPARATION OF TOPOGRAPHIC MAPS.
Many of the States cooperate with the National Geological
Survey through their respective State Survey organizations in
the preparation of topographic maps. The usual basis of such
cooperation is an equal contribution of funds on the part of the
State and National Survey. The plan of mapping followed is
that already developed and established by the National Survey.
The men employed in the mapping are the expert topographic
mappers already in the employ of the National Survey. The
following States are either now cooperating or have in the past
cooperated with the National Geological Survey in this work:
Alabama, California, Connecticut, Illinois, Iowa, Kentucky, Louis-
iana, Maine, Maryland, Massachusetts, Michigan, Mississippi,
Missouri, New Jersey, New York, North Carolina, Ohio, Okla-
homa, Oregon, Pennsylvania, Rhode Island, Tennessee, Texas,
Virginia and West Virginia.
It is probable that such cooperation can be secured in the
preparanon of the topographic maps of Florida, thus practically
doubling for the State any appropriation made by the Legislature
for this purpose. The Director of the United States Geological
Survey has repeatedly expressed his willingness to cooperate with
the State Geological Survey in the preparation of topographic
maps, meeting any appropriation made by the State with an equal
amount so far as funds permit. An appropriation made for the
preparation of topographic maps may be so framed as to admit
of cooperation with the United States Geological Survey; or may
be made if desired contingent upon such cooperation to be carried
on in accordance with plans approved by the Governor.
SOIL MAPS.
Another very important line of investigation is the prepara-
tion of detailed soil maps. While a general report on the soils of
the State has been issued by the Survey, there is a very great
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F1FTH ANNUAL REPORT.
demand for specific information regarding local soils such as can
be supplied only by detailed soil maps of the several counties. A
limited amount of soil mapping has already been done by the
United States Bureau of Soils. As in the case of topographic
maps many of the, States are cooperating with the National
Bureaus in the preparation of soil maps, and it is probable that
an appropriation made for this purpose would be doubled by the
United States Bureau of Soils. I would urgently recommend
an appropriation of $5,000 per annum for the preparation of topo-
graphic and soil maps. Such an appropriation may be made
contingent upon cooperation with the national bureaus and would
thus result in the expenditure of $10.000 per annum in the State
for this purpose.
EXPOSITIONS.
National Conservation Exposition at Knoxville.-A National
Conservation Exposition will be held at Knoxville, Tennessee,
during September and October of the present year. This exposi-
tion is intended especially to exhibit the natural resources of the
Southern States and to encourage their development. The
opportunity is favorable for making more widely known both the
mineral and agricultural resources of Florida and it is to be
hoped that provision will be made by which the ,State may make
a good showing at this exposition.
Panama Exposition at San Francisco.-A world exposition
will be held at San Francisco in 1915 to commemorate the open-
ing of the Panama Canal. Florida by reason of its extensive
coast line and its nearness to the canal zone is specially interested
in this exposition, and can not afford to lose the opportunity of
making its favorable location with regard to the canal more
widely known. It is none too soon to begin the compilation of
data on the harbors of Florida, and the preparation of maps,
charts and drawings showing their relation to the canal and to
the population and business centers of the United States, as well
as to the lines of transportation within the United States. The
exhibitions of the mineral and agricultural resources made for
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FLORIDA STATE GEOLOGICAL SURVEY.
the exposition at Knoxville may be used subsequently for the
Panama exposition.
MEMBERS OF THE STATE SURVEY.
The members of the State Survey during the past year have
been, in addition to the State Geologist, Mr. Herman Gunter,
and during a part of the year Mr. Emil Gunter. Stenographic
and clerical services were rendered at various times by Ada Moore
and T. C. Alford. The chemical analyses necessary to the work
of the State Survey are made by the State Chemist.
PUBLICATIONS ISSUED DURING 1912.
The Fourth Annual Report of the Geological Survey was
issued during the year. This report contains in addition to
statistics on phosphate rock and fuller's earth, papers on the Soils
and Other Surface Residual Materials of Florida, and on the
Water Supply of West-Central and West Florida.
DISTRIBUTION OF REPORTS.
The reports issued by the State Geological Survey are dis-
tributed upon request, and may be obtained without cost by
addressing the State Geologist, Tallahassee, Florida.
THE PURPOSE AND DUTIES OF THE STATE GEOLOGICAL SURVEY.
Among the specific objects for which the Survey exists, as
stated in the enactment, is that of making known information
regarding the minerals, water supply and other natural resources
of the State. including the occurrence and location of minerals
and other deposits of value, surface and subterranean water
supply and power and mineral waters and the best and most
economic methods of development, together with analysis of soils,
minerals and mineral waters, with maps, charts, and drawings
of the same.
A distinctly educational function of the Survey is indicated
by Section 4 of the law, which makes it the duty of the State
Geologist to make collections of specimens, illustrating the geo-
logical and mineral features of the State, duplicate sets of which
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FIFTH ANNUAL REPORT.
shall be deposited with each of the State colleges. The publica-
tion of annual reports is provided for as a means of disseminating
the information obtained in the progress of the Survey. The
Survey is thus intended to serve on the one hand an economic,
and on the other an educational purpose. In its economic rela-
tions a State Survey touches on very varied interests of the State's
development. In its results it may be expected to contribute to
an intelligent development of the State's natural resources. Its
educational value is of no less immediate concern to the State,
both to the citizens within the State and to prospective citizens
without.
A knowledge of the soil and of the available water supply is
very necessary to successful agriculture, and the Survey's in-
vestigations along these lines are of value to all land owners. A
knowledge of the mineral deposits which may lie beneath the
surface, is likewise necessary to a correct valuation of land.
RELATION OF THE STATE SURVEY TO THE OWNERSHIP OF MINERAL
LANDS.
The relation of the State Geological Survey to the ownership
of mineral lands is specifically defined. The Survey law provides
that it shall be the duty of the State Geologist and his assistants,
when they discover any mineral deposits or substances 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 the
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
are incidental to the regularly planned investigations of the
Survey.
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FLORIDA STATE GEOLOGICAL 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 COLLECTION OF STATISTICAL 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 or company, and will be used
only in making up State and county totals. The cooperation of
the various industries of the State is invited in order that the best
possible showing of the State's products may be made annually.
EXHIBITION OF GEOLOGICAL MATERIAL.
The space available for the exhibition of geological material
is unfortunately as yet very limited. A part of one room is being
used for this purpose. Three cases have been built, designed to
serve the double purpose of storage and exhibition. The lower
parts of the case contain drawers and are used for storage. In
making the collections a definite plan has been followed to secure
a representation of the rocks, minerals and fossils of each forma-
tion in the State. The collection will be added to as rapidly as
space is provided for taking care of the material.
THE SURVEY LIBRARY.
A well equipped reference library is essential to the investiga-
tions of the Survey, and an effort has been and is being made to
bring together those publications which are necessary to the
immediate and future work of the department. The Survey
library now contains more than 1,500 volumes. These include
the reports of the several State Geological Surveys; the reports
of the National Geological Survey; the reports of the Canadian
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FIFTH ANNUAL REPORT.
and a few other foreign Geological Surveys; and many miscel-
laneous volumes and papers on geology and related subjects.
PUBLICATIONS ISSUED BY THE STATE GEOLOGICAL SURVEY.
First Annual Report, 1908, 114 pp., 6 pls.
This 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 published previous to the organ-
ization of the present Geologocial Survey.
Second Annual Report, 1909, 299 pp., 19 pls., 5 text figures,
and one map.
This report contains: (1) a preliminary report on the geology of
Florida, with special reference to stratigraphy, including a topographic and
geologic map of Florida, prepared in cooperation with the United States
Geological Survey; (2) mineral industries; (3) the fuller's earth deposits
of Gadsden County, with notes on similar deposits found elsewhere in the
State.
Third Annual Report, 1910, 397 pp., 28 pls., 30 text figures.
This report contains: (1) a preliminary paper on the Florida phos-
phate deposits; (2) some Florida lakes and lake basins; (3) the artesian
water supply of eastern Florida; (4) a preliminary report on the Florida
peat deposits.
Fourth Annual Report, 1912, 175 pp., 16 pls., 15 text figures,
one map.
This report contains: (1) The soils and other surface residual
materials of Florida, their origin, character and the formation from which
derived; (2) the water supply of west-central and west Florida; (3) the
production of phosphate rock in Florida during 1910 and 1911.
Bulletin No. 1. The Underground Water Supply of Central
Florida, 1908, 103 pp., 6 pls., 6 text figures.
This report contains: (1) Underground water; general discussion;
(2) the underground water of central Florida, deep and shallow wells,
spring and artesian prospects; (3) effects of underground solution, cavities,
sinkholes, disappearing streams and solution basins; (4) drainage of lakes,
ponds and swamp lands and disposal of sewage by bored wells; (5) water
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FLORIDA STATE GEOLOGICAL SURVEY.
analyses and tables giving general water resources, public water supplies,
spring and well records.
Bulletin No. 2. Roads and Road Materials of Florida, 1911,
31 pps., 4 p1s.
This bulletin contains: (1) An account of the road building materials
of Florida; (2) a statistical table showing the amount of improved roads
built by the counties of the State to the close of 1910.
Fifth Annual Report, 1913.
EXPENDITURES OF THE GEOLOGICAL SURVEY FOR THE
YEAR ENDING JUNE 30, 1912, AND FOR THE HALF
YEAR ENDING DECEMBER 31, 1912.
The total appropriation for the State Geological Survey is
$7,500.00 per annum. No part of this fund is handled direct by
the State Geologist, as all Survey accounts are paid upon
warrants issued by the Comptroller of the State as per itemized
statements approved by the Governor. The original of all bills
and the itemized statements of all expense accounts are on file
in the office of the Comptroller. Duplicate copies of the same are
on file in the office of the State Geologist.
LIST OF WARRANTS ISSUED DURING THE YEAR ENDING JUNE 30,
1912.
July, 1911.
E. H. Sellards, State Geologist, expenses, July, 1911 .........$
Herman Gunter, Assistant, expenses, July, 1911..............
Ada Moore, stenographic services..........................
The Record Company, printing............................
John M cDougall, postage ............................ .....
Southern Express Company .................. ...........
August, 1911.
E. H. Sellards, State Geologist, expenses, August, 1911......
Herman Gunter, Assistant, expenses, August, 1911..........
American Peat Society, subscription........................
John McDougall, postage ............... .......... .
30.00
31.05
25.30
7.50
62.75
3.02
48.70
18.50
5.00
20.00
Carried forward ................ ............... $ 251.82
Digitized by GoOgle
FIFTH ANNUAL REPORT.
Brought forward ................................... $
September, 1911.
E. H. Sellards, State Geologist, salary for quarter ending
Septem ber 30, 1911 ...................................
Herman Gunter, Assistant, salary for quarter ending Septem-
ber 30, 1911 ..........................................
Southern Express Company, express for July and August...
October, 1911.
E. H. Sellards, State Geologist, expenses, October, 1911.....
H. & W. B. Drew Company, supplies.......................
P. Blankiston's Son & Company, publications...............
Verlag fuir Fachliteratur, subscription......................
John M cDougall, postage .................................
November, 1911.
E. H. Sellards, State Geologist, expenses, November, 1911..
Herman Gunter, Assistant, expenses, November, 1911.......
Southern Express Company ...............................
December, 1911.
E. H. Sellards, State Geologist, salary for quarter ending
D ecem ber 31, 1911 ....................................
E. H. Sellards, State Geologist, expenses, December, 1911...
Herman Gunter, Assistant, salary for quarter ending Decem-
ber 31, 1911 ..........................................
Herman Gunter, Assistant, expenses, December, 1911........
Emil Gunter, Assistant, salary ($62.50), expenses ($48.05),
D ecem ber, 1911 ..................... ..................
T. C. Alford, stenographic services.........................
H. & W. B. Drew Company, supplies.......................
F. H King, publications ..................................
American Journal of Science, subscription..................
Engineering and Mining Journal, subscription...............
January, 1912.
E. H. Sellards, State Geologist, expenses, January, 1912....
Herman Gunter, Assistant, expenses, January, 1912.........
Emil Gunter, Assistant, salary ($75.00), expenses ($91.92),
January, 1912 ........................................
T. C. Alford, stenographic services ........................
Francis J. Bulask, subscription ............................
251.82
625.00
300.00
5.00
23.70
4.62
2.00
5.76
20.00
38.00
12.60
3.76
625.00
41.10
300.00
68.70
110.55
6.00
2.34
2:50
6.00
5.00
27.20
103.82
166.92
15.00
5.00
Carried forward ................. .................. $2,777.39
Digitized by GoOgle
FLORIDA STATE GEOLOGICAL SURVEY.
Brought forward ..................................... $2,777.39
John McDougall, postage ................................ 20.00
Southern Express Company .............................. 2.72
February, 1912.
E. H. Sellards, State Geologist, expenses, February, 1912.... 37.65
Herman Gunter, Assistant, expenses, February, 1912........ 108.20
Emil Gunter, Assistant, salary ($75.00), expenses ($81.25),
February, 1912 ....................................... 156.25
T. C. Alford, stenographic services ....................... 12.20
Wrigley Engraving Company, engravings ................. 39.78
H. & W. B. Drew Company, supplies ..................... 4.70
Southern Express Company ............................... 8.35
March, 1912.
E. H. Sellards, State Geologist, salary for quarter ending
M arch 31, 1912 ....................................... 625.00
Herman Gunter, Assistant, salary for quarter ending March
31, 1912 .............................................. 300.00
Herman Gunter, Assistant, expenses, March, 1912........... 48.95
Emil Gunter, Assistant, salary ($17.30), expenses ($31.10),
March, 1912 ......................................... 48.40
T. C. Alford, stenographic and clerical services............. 36.00
Economic Geology Publishing Company, subscription........ 3.00
April, 1912.
E. H. Sellards, State Geologist, expenses, March and April,
1912 .................................................. 29.75
T. J. Appleyard, printing ................... ........... 732.20
The Record Company, printing ........................... 18.75
H. & W. B. Drew Company, supplies ....................... 2.21
John McDougall, postage ................................ 125.00
Southern Express Company .............................. 15.70
May, 1912.
E. H. Sellards, State Geologist, expenses, May, 1912........ 70.55
Herman Gunter, Assitant, expenses, May, 1912.............. 78.60
Emil Gunter, services, April and May ..................... 9.00
Alex. McDougall, postage ................................ 25.00
June, 1912.
E. H. Sellards, State Geologist, salary for quarter ending
June 30, 1812 ........................................ 625.00
E. H. Sellards, State Geologist, expenses, June, 1912........ 60.85
Carried forward ............... ................ $ 6,021.20
Digitized by GoOgle
FIFTH ANNUAL REPORT.
Brought forward .....................................$ 6,021.20
Herman Gunter, Assistant, salary for quarter ending June
30, 1912 ................................... ............ 300.00
Herman Gunter, Assistant, expenses, June, 1912............. 23.05
D. R. Cox Furniture Company, supplies ................... 30.00
David S. Woodrow, Agent, subscription ................... 6.00
University of Chicago Press, subscription.................. 4.00
H. & W. B. Drew Company, supplies ...................... 2.78
Total expenditures ................................... $6,387.03
Overdrawn from preceding year ....................... .10
$6,387.13
Balance available ................................. ... 1,112.87
$7,500.00
LIST OF WARRANTS ISSUED DURING THE HALF YEAR ENDING DECEM-
BER 31, 1912.
July, 1912.
T. J. Appleyard, State Printer ............................. $
Southern Express Company ........................ ......
D. R. Cox Furniture Company, supplies....................
August, 1912.
Alex. McDougall, postage .................................
Southern Express Company ...............................
September, 1912.
E. H. Sellards, State Geologist, salary for quarter ending
September 30, 1912 ...................................
Herman Gunter, Assistant, salary for quarter ending Septem-
ber 30, 1912 ..........................................
Southern Express Company ...............................
October, 1912.
E. H. Sellards, State Geologist, expenses, October, 1912.....
Herman Gunter, Assistant, expenses, October, 1912.........
Arthur H. Thomas Company, supplies......................
November, 1012.
E. H. Sellards, State Geologist, expenses, November, 1912...
Herman Gunter, Assistant, expenses, November, 1912........
100.00
13.76
4.13
25.00
3.03
625.00
300.00
1.60
62.80
42.71
19.55
66.47
29.10
Carried forward .................................... $1,293.15
Digitized by Google
FLORIDA STATE GEOLOGICAL SURVEY.
Brought forward .................................... $1,293.15
H. R. Kaufman, repairing typewriter ...................... 5.00
Alex. McDougall, postage ................................ 25.00
Southern Express Company .............................. 3.13
December, 1912.
E. H. Sellards, State Geologist, salary for quarter ending
December 31, 1912 ................................... 625.00
E. H. Sellards, State Geologist, expenses, December, 1912... 72.85
Herman Gunter, Assistant, salary for quarter ending Decem-
ber 31, 1912 .......................................... 300.00
H. & W. B. Drew Company, supplies ...................... 1.79
W. & L. E. Curley, supplies .............................. 3.70
Keuffel & Esser Company, supplies........................ 39.90
Engineering and Mining Journal, subscription .............. 5.00
Southern Express Company .............................. 8.02
Total ......................................... ......... $2,382.54
Digitized by GoOgle
ORIGIN OF THE HARD ROCK PHOSPHATE DEPOSITS
OF FLORIDA.
BY E. H. SELLARDS.
Digitized by GoOgle
CONTENTS.
PAGE.
Introduction ....................................................... 27
Distribution of the hard rock phosphates....................... 27
Distribution of the pebble phosphates........................... :3
Matrix of the hard rock phosphate deposits......................... 28
Gray sands ..................................................... 28
Clay lenses .................................................... 28
Flint boulders ............................................... 29
Limestone inclusions ......................................... 29
Pebble conglomerate ........................................... 29
Vertebrate and invertebrate fossils.............................. 29
Petrified wood ............................................... 29
The phosphate rock........................................... ...... 29
Boulders ....................................................... 29
Soft phosphate .............................................. 29
Fragmentary rock ............................................ ... 29
Plate rock ................................................... 29
Pebble rock .................................................... 29
Thickness of the phosphate bearing formation....................... 30
Amount of hard rock phosphate.......................... ........ 31
Formation name ................................................. 31
Local details ....................................................... 32
Suwannee county ............................................ a2
Columbia county ............................................ 32
Alachua county ....................... ...................... 33
Marion county ............................... ............... 34
Citrus county .................................................. 35
Hernando county ........................ ... .................... so
Problems to be accounted for...................................... 37
Summary of explanation ............................................ 37
Acknowledgments ................................................ 38
Discovery of the Florida phosphate deposits.......................... 40
Beginning of the Florida phosphate mining indusstry................ 42
Investigations of the Florida phosphate deposits..................... 43
Review of theories previously proposed............................. 45
Albert R. Ledoux............................... .............. 45
Francis W yatt .................................................. 45
E. T. Cox...................................................... 46
N. H. Darton................................................... 47
W H. Dall..................................................... 4T
W alter B. M Davidson......................... ................ 47
N. A. Pratt...................................................... .
C. C. H. Millar................................................. 48
George H. Eldridge............................................. 48
L. C. Johnson................................................... 50
Lucius P. Brown .......... ..................................... 50
L. P. Jumeau.................................................... 50
Digitized by GoOgle
26 CONTENTS.
PAGE.
Discussion of theories ............................................ so0
The fossils of the hard rock phosphate deposits...................... 56
Source of the phosphoric acid....................................... 58
Agency by which the phosphate has accumulated..................... 59
Relation of the phosphate to the underground water level............. s
The formation of boulders........................................... 60
Silica boulders .............................................. 60
Phosphate boulders .......................................... 61
Formed by the replacement process......................... 61
Formed by precipitation .................................... 61
Secondary deposition of phosphate.................................. 62
Origin of the plate rock............................................. 62
Localization of the hard rock deposits............................... 63
Limitation of the hard rock phosphates.... .......................... 63
Physiographic types in central Florida........................... 63
The gulf hammock belt..................................... 64
The hard rock phosphate belt.............................. 64
The middle Florida hammock belt........................... 64
The lake region .......................................... 65
Economic relation ................................ ................. 66
Bibliography .................................... .................. 66
PLATES.
Plate No.
1. Phosphate boulder showing secondary deposition.
2. Laminated phosphate boulder.
3. Phosphate rock.
4. Teeth of mastodon from the phosphate deposits.
5. Teeth and foot bone of horse, and teeth of mastodon.
6. Sharks' teeth from the phosphate deposits.
7. Sharks' teeth from the phosphate deposits.
8. Phosphate washer and prospect drill.
9. Phosphate pit after the removal of the phosphate.
MAPS.
Map showing the limestone region of Central Florida.
Map showing the location of the hard rock and land pebble phosphates.
Digitized by GoOgle
ORIGIN OF THE HARD ROCK PHOSPHATES OF
FLORIDA.
E. H. SELLARDS.
Two kinds of phosphate rock are now being mined in Florida,
the land pebble and the hard rock. The deposits which carry the
hard rock phosphate are found over a considerable extent of
country in the western part of central peninsular Florida. The
area includes the southern part of Columbia and Suwannee
Counties, the western part of Alachua and Marion Counties, the
eastern part of Levy, Citrus and Hernando Counties, and the
northern part of Pasco County. From north to south the hard
rock area extends through a distance of about 100 miles. Its
width from east to west is variable. The greatest width is found
in Marion County, almost the whole of the western half of this
county being included in this belt. West of the Suwannee River
a limited amount of hard rock phosphate has been found in
Lafayette, Taylor and Jefferson Counties. The accompanying
map shows approximately the extent of the phosphate-bearing
deposits. The workable deposits are less extensive than the area
here outlined, the mines now operated being confined to a com-
paratively narrow belt reaching from Alachua to Hernando
Counties.
Mining has been carried on continuously in this section for
more than two decades. Seventy-four plants, under the owner-
ship of twenty mining companies, operated" here in 1909, while
forty plants, under the ownership of fourteen mining companies,
were operating at the close of 1912. Each phosphate plant opens
up in the process of mining one to several pits offering excep-
tionally good exposures of the phosphate-bearing formation. The
following paper is based on observations made in the many pits
that have been opened up in this section during the past several
years. The results that are presented in this paper have been
gradually obtained, and have been published in part in the reports
Digitized by GoOgle
FLORIDA STATE GEOLOGICAL SURVEY.
of the Florida Geological Survey during the past few years.
The land pebble phosphates are found in southern Florida in
Polk and Hillsboro Counties. This paper relates to the hard rock
deposits only, the pebble deposits not being included in the dis-
cussion, although their approximate location is indicated on the
map. No attempt is made on this map to show the location of
the low grade phosphates, which occur extensively in central Flor-
ida.
The matrix in which the hard rock phosphate is imbedded is
extremely variable. The formation includes a mixture of
materials from various sources and of the most diverse character,
further complicated by pronounced chemical activity within the
formation itself. The prevailing phase of the formation is feebly
coherent, more or less phosphatic, light gray sands. Aside from
these sands the principal materials of the formation are clays,
phosphate rock, flint boulders, limestone inclusions, pebble
conglomerate, erratic and occasional water-worn .flint pebbles,
vertebrate and invertebrate fossils, and occasional pieces of
silicified tree trunks.
The gray sands may be observed in every pit that has been
excavated in this section. Moreover, from drill and prospect
holes it is known that these sands occur very generally over the
intervening or barren area. The sands are of medium coarse
texture, the grains being roughly angular. The amount of phos-
phate associated with these sands is variable. Upon prolonged
exposure, as seen in numerous abandoned pits, these sands oxidize
at the surface, assuming a pink or purple color. When affected by
slow decay and by water, carrying more or less iron in solution,
they become reddish br ochre yellow in color. Lithologically these
sands resemble closely the gray phosphatic sands of the Alum
Bluff formation as seen at the type locality at Alum Bluff, on the
Apalachicola River.
The clays in this formation occur locally as clay lenses im-
bedded in the sand, or separating the sand from the phosphate
rock, or overlying the phosphate rock. The clays are often of a
light huff or blue color. When lying near the surface, however.
they often oxidize to varying shades of red. The relative amoun:
Digitized by GoOgle
A
ORIGIN OF THE HARD ROCK PHOSPHATES.
of clay in the phosphate-bearing formation increases in a general
way in passing to the south. The exposures in the southern part
of the area show as a rule more clay than do similar exposures in
the northern part of the area. The phosphate boulders seem to
have a tendency to group around and to be associated with local
clay lenses. Frequently the productive pit gives place laterally to
barren gray sands.
Flint boulders occur locally in this formation in some abun-
dance, and occasionally phosphate pits that are otherwise work-
able are abandoned on account of the number of flint boulders
encountered. The flint boulders are usually oval or somewhat
flattened in shape and are of varying size, some weighing several
tons. The exterior is usually of a light color. Some of the
boulders are hollow and occasionally the cavity is filled with
water; other boulders are solid, compact and of a bluish color
throughout. Limestone inclusions are frequent in this formation.
The pebble conglomerate feature is not of frequent occurrence
but may occasionally be observed in the northern part of the hard
rock section. An exposure of flint pebbles may be seen in one
of the pits of plant number 5 of the Cummer Lumber Company,
about one mile southwest of Newberry, in Alachua County. The
matrix at this exposure consists of more or less water-worn frag-
ments of varying size together with round or oval water-worn,
dark colored flint pebbles. This phase of the formation may be
seen through a distance of ten or fifteen feet along the side of the
pit. Water-worn pebbles weighing one or more pounds occur
occasionally in the northern part of the field.
The invertebrate fossils are found in the limestone inclusions.
The vertebrate remains are mixed in with the other materials of
the matrix. The fossil wood is of rare occurrence, but is
occasionally found in this formation.
Phosphate rock, although the constituent of special economic
interest, nevertheless makes up a relatively small part of the
formation. The phosphate in these deposits occurs as fragmentary
rock, boulder rock, plate rock or pebble. The boulders are often
of large size, in some instances weighing several tons, and not
infrequently needing to be broken up by blasting before being
Digitized by GoOgle
FLORIDA STATE GEOLOGICAL SURVEY.
removed from the pit. It is also necessary to operate a rock
crusher in connection with all hard rock phosphate mines to
reduce the larger pieces of rock to a size suitable for shipping.
A certain portion of soft phosphate unavoidably lost in mining
is also present. The relative amount of material that it is neces-
sary to handle to obtain a definite amount of phosphate is always
variable with each pit and with the different parts of any one pit.
The workable deposits of phosphate lying within this formation
occur very irregularly. While at one locality the phosphate may
lie at the surface, elsewhere it may be so deep as not to be
economically worked; while a deposit once located may cover
more or less continuously a tract of land some acres in extent,
elsewhere a deposit appearing equally promising on the surface,
may in reality be found to be of very limited extent. As to loca-
tion, depth from surface, extent into the ground, lateral extent,
quantity and quality, the hard rock phosphate deposits conform
to no rule. The desired information is to be obtained only by
extensive and expensive prospecting and sampling.
The phosphate rock may lie beneath the gray sands, or above
the gray sands or may be entirely surrounded by them. In some
instances the phosphate is interbedded with the sands. Such
interbedding of sand and phosphate was observed by the writer
in the Central Phosphate Company pit number 25, about three
miles west of Clark. This phase of the relation of sand and phos-
phate occurs not infrequently and is confined to no particular part
of the phosphate field. It is frequently stated by the phosphate
miners that there is a relation between the local clay lenses and
the occurrence of phosphate. It is evident, however, that there
are many exceptions to this general statement.
THICKNESS.
The thickness of the phosphate bearing formation is as vari-
able as its other characteristics. It rests upon the Vicksburg
Limestone, the top surface of which owing to solution by under-
ground water, has become extremely irregular. The limestone
projects as peaks into the phosphate formation. In Citrus County
the phosphate bearing formation is known to reach a thickness of
Digitized by GoOgle
ORIGIN OF THE HARD ROCK PHOSPHATES.
from 75 to 100 feet. When of this thickness it is worked to the
permanent ground water level by the dry pit method of mining,
and is then mined from 40 to 50 feet below this level by the float-
ing dredge. In the northern part of the area the formation is as
a rule much thinner, and is worked almost entirely by dry pit
mining.
AMOUNT OF HARD ROCK PHOSPHATE.
It is scarcely possible to give an estimate of the amount of
hard rock phosphate in Florida that yet remains to be mined.
This is due to the fact that the deposits are extremely local and
irregular. While the whole extent of the phosphate bearing
formation can be mapped with a fair degree of accuracy, the
deposits of phosphate within the formation can be located and an
estimate of the amount that is mineable made only after very
exact prospecting. The cost of such prospecting is such that it is
seldom undertaken on a large scale except by the companies
actually interested in producing the rock. It is true that some
estimates as to the total tonnage available have been made, but
these amount to little more than guess work. The amount actually
mined during the twenty-two years since mining operations began
in this field is approximately 9,313,071 tons. The output at
present amounts to about one-half million tons per annum.
FORMATION NAME.
The term Dunnellon formation has been applied by the writer
to the phosphate bearing formation.* These deposits are well
developed in the vicinity of Dunnellon, in Marion County, and have
been extensively mined in that section. It was here also that the
deposits were first discovered and mined. The term Dunnellon is,
therefore, appropriate. The formation is probably of Pliocene age
as indicated by the fauna.
*Florida State Geological Survey, Third Annual Report, p. 32, 1910.
Digitized by GoOgle
FLORIDA STATE GEOLOGICAL SURVEY.
LOCAL DETAILS.
SUWANNEE COUNTY.
The southern and southeastern part of Suwannee County has pro-
duced some phosphate, although no mines are operating in this county at
present. A variable thickness of pale yellow sand occurs in the pits of
this section. At the pits of plant No. 10 of Dutton Phosphate Company,
two miles north of Hildreth, from two to twelve feet of this incoherent
sand rests directly upon the phosphate bearing matrix. In one of the pits
of this plant the phosphate matrix grades at the bottom into a yellow
phosphatic clay overlying the limestone to a depth of 4 or 5 feet. In one
of the pits at this plant are observed, as frequently seen elsewhere in the
hard rock section, many large round elongate siliceous boulders inter-
bedded in the phosphate matrix. The underlying formation here is the
Vicksburg Limestone, which occurs as peaks and as "hog backs" of lime
projecting into or even through the phosphate matrix.
COLUMBIA COUNTY.
The southern part of Columbia County, adjacent to Suwannee County,
has produced considerable phosphate, although only one mine in this
county was in operation at the close of 1912.
At plant No. 2 of the Dutton Phosphate Company, now abandoned,
about one-half mile west of Ichatucknee Springs, the following section
was obtained:
Pale incoherent sand.............................. 10 to 20 feet
Phosphate-bearing matrix ....................... 20 to 25 feet
Buff yellow phosphatic clays...................... 5 to 6 feet
Dark sandy phosphatic clays (exposed) ............ 4 feet
The incoherent sands in this pit, as at Dutton No. 10, rest directly
upon the phosphate stratum, the top of which is exceedingly irregular.
Clay lenses 6 to 12 inches thick are of frequent occurrence, especially near
the tcp. The underlying limestone is reached in places. The buff yellow
phosphatic clay observed in Dutton No. 10 is seen here also and is under-
laid by 4 feet of, dark, sandy phosphatic clay.
The following section was made in one of the pits of the Schilman
& Bene phosphate plant, about two miles northwest of Ft. White:
Pale yellow incoherent sand....................... 3 to 5 feet
Ped clayey sands ................................. 5 to 10 feet
Phosphate matrix .. .......................... 15 to 25 feet
Limestone at the bottom of the pit.
Digitized by GoOgle
ORIGIN OF THE HARD ROCK PHOSPHATES.
This section differs from the preceding chiefly in the presence of the
red clayey sands, which are sufficiently coherent to form a vertical wall
in the pit. This clayey sand stratum when present is referred to by the
miners as "hardpan."
In the pit of the Fort White Hard Rock Company, one-mile south-
east of Ft. White, the foundation rock, as is usual in this section, is the
Vicksburg Limestone. The top of this limestone is exceedingly irregular,
projecting as rounded peaks. Shells, sea urchins, and other fossils are
partly eroded away, the limestone having a comparatively smooth surface.
The phosphate rock consists chiefly of angular fragmental pieces, plates,
pebbles and boulders imbedded in a sandy clayey matrix. This matrix
fills tp the irregularities in the underlying limestone. In several instances
the .phosphate matrix was seen to fill up cavities and solution channels in
the limestone. Slickensides occur, due to the settling of the phosphate
matrix as the underlying limestone dissolved away. Limestone inclusions
and siliceous boulders occur in the phosphate stratum. The following
section is seen in an abandoned pit of this plant:
Pale yellow incoherent sand....................... 1 to 15 feet
Phosphate matrix ................................. 1 to 20 feet
Limestone top surface exceedingly irregular.
The phosphate producing area of southern Columbia and Suwannee
Counties lies adjacent to and in the angle between the Suwannee and
Santa Fe Rivers, including the low lying and intensively eroded parts of
each county. The limestone lies near the surface in this section and as
a rule the phosphate is mined out by dry mining, the limestone being
exposed in the abandoned pits. Dredging, which is applicable in the
southern part of the phosphate area, is not used in this section.
ALACHUA COUNTY.
The west central part of Alachua County is actively producing phos-
phate; fourteen plants were operated in this county at the close of 1912.
Pit No. 25 of the Central Phosphate Company, west of Clark, gave
the following section:
Pale yellow incoherent sands .................... 5 to 10 feet
Red clayey sands................................. 5 to 10 feet
Phosphate-bearing formation ..................... 10 to 25 feet
Limestone at bottom of pit.
The phosphate matrix consists of gray sands, yellow, buff and blue
clays and phosphate rock. At one place in this pit a stratum of gray
sand V3 to 2 feet thick is seen interbedded with the phosphate rock.
Digitized by GoOgle
FLORIDA STATE GEOLOGICAL SURVEY.
The incline leading to a pit belonging to T. A. Thompson, near Neals,
gave the following section:
Pale yellow incoherent sands..................... 5 to 10 feet
Red clayey sands ................................ 7 to 10 feet
Gray phosphate sands (exposed) .................. 15 feet
The gray sands give place laterally to phosphate rock.
Pit No. 2 of the Cummer Lumber Company is, perhaps, the largest
single pit in operation in the hard rock phosphate section. This pit is
reported to include at the present time about thirteen acres. Pit No. 5
of this company, one mile west of Newberry, gives an exposure of the
sandstone and flint pebble conglomerate already referred to as occurring
occasionally in the hard rock deposits. The pebbles are round and more
or less flattened. They vary in size from very small pebbles to pebbles
weighing five to seven pounds.
In the pit of the Union Phosphate Company, at Tioga, a considerable
number of rounded elongate siliceous boulders occur. These vary in size,
the largest approximating a ton in weight. They are embedded in the
phosphate-bearing matrix.
The many other pits which are now being worked, or which have
recently been abandoned, although varying much even within a single
pit in details, are in general much the same as those described.
The limestone in this county, as a rule, lies relatively near the sur-
face. In most instances the limestone is encountered before or very soon
after reaching the water level. The phosphate is thus largely worked out
by dry mining and dredges are rarely used. The limestone is encountered
at varying depths. One pit may show a great deal of limestone projecting
as peaks, while another pit of equal depth near by may scarcely reach the
limestone. Some of the limestone peaks project 15 to 25 'feet above the
general level of the bottom of the pit. The phosphate-bearing matrix here,
as elsewhere, fills up the irregularities in the limestone. The top surface
of the limestone is, as elsewhere, entirely irregular. The red clayey sand
called "hardpan" by the miners may be present or lacking in the pits of
this section. The loose, pale yellow sand is practically always present,
varying in thickness from 1 to 25 feet.
MARION COUNTY.
The plate rock deposit found in the vicinity of Anthony and Sparr,
in the north central part of Marion County, represents an eastward ex-
tension of the phosphate-bearing formation. The relation of the phosphate
matrix to the underlying limestone is the same as previously described.
The limestone projects into the phosphate matrix as rounded peaks. Cir-
cular depressions, similar in appearance to pot holes or to "natural wells,"
Digitized by GoOgle
ORIGIN OF THE HARD ROCK PHOSPHATES.
are frequent in this section. These are filled with the phosphate matrix.
One of these depressions observed by the writer had been cut into, in the
process of mining. This depression was about three and one-half feet
in diameter at the top, fifteen feet deep and narrowed gradually to the
bottom. Other depressions variable in diameter and in depth occur. The
limestone lying near the line of the underground water level has usually
a rough and jagged surface owing to solution by water in contact with
the limestone. Above the water level the limestone has a smooth rounded
surface, the shells and other fossils having been eroded off plane with the
general rock surface. The plate rock beds show evidence of having been
originally faintly stratified. Much of the stratification that originally
existed, however, has been destroyed through repeated local subsidence
as the underlying limestone was moved by solution. The stratification
lines in the plate rock are frequently much curved and distorted owing to
this irregular subsidence.
The chief difference noted between the plate rock and the typical hard
rock region is in the relatively large amount of fragmentary phosphate
rock and the small amount of boulder rock. Flint and limestone boulders
chemically formed are likewise absent or rare.
The deposits at Standard and at Juliette, in the western part of
Marion County, are similar in general character to the hard rock deposits
as previously described. The mines in this section are dry mines and
usually reach to the bottom of the phosphate formation in places en-
countering the limestone.
In the southwestern part of Marion County and in Citrus County the
hard rock phosphate-bearing formation reaches its maximum thickness.
The underlying limestone is ordinarily encountered at a considerable
depth from the surface. Many of the phosphate pits in this section are
worked as dry mines to the underground water level and afterwards as
dredge mines to such depth as the dipper will reach. Some of the pits
on higher lands are mined as dry mines only.
The pit at the Dunnellon Phosphate Company plant No. 10 was one
of the first pits regularly worked in the phosphate section and has been
continuously in operation for the past twenty years. This mine is operated
by a dredge. The bottom of the phosphate is not reached in this pit and
the full thickness of the formation at this place has not been reported.
CITRUS COUNTY.
The conditions in Citrus County are in a general way similar to the
conditions in the vicinity of Dunnellon, in Marion County. The under-
lying limestone is occasionally seen in the pits in this section and is
frequently reached by the dredge. The surface of the limestone wherever
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FLORIDA STATE GEOLOGICAL SURVEY.
seen projects as rounded peaks. There is on an average more clay to be
seen in the phosphate formation in this section than in the northern part
of the field. In a few instances, notably that of the pit in the Istachatta
Phosphate Company, the water level is within a few feet of the surface
and the phosphate formation is entirely submerged. Only the sands of
the overburden are here visible.
HERNANDO COUNTY.
Phosphate is being produced in Hernando County in the vicinity of
Croom. The mine in operation here is a dredge mine. The relation of
the phosphate formation to the underlying limestone, as seen in an aban-
doned pit several miles west of Croom, is the same as that in other parts
of the phosphate section, the limestone projecting' as rounded peaks. The
material above the phosphate stratum consists largely of incoherent sands.
The usual gray phosphatic sands, weathering purple on exposure, are seen
surrounding the phosphate rock. In the mines near Croom a considerable
annunt of clay is associated with the phosphate.
The preceding description of the phosphate-bearing formation
is taken with but slight revision from a paper by the writer
entitled "A Preliminary Report on the Florida Phosphate De-
posits," published in the Third Annual Report of the Florida Geo-
logical Survey, 1910. The present paper, like the earlier one, is to
be regarded as a report of progress in the investigation of the
phosphate deposits and is not in any sense final.
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ORIGIN OF THE HARD ROCK PHOSPHATES.
PROBLEMS TO BE ACCOUNTED FOR.
Among the problems that must be accounted for in connection
with the hard rock phosphate deposits of Florida are the follow-
ing: (1.) The source of the miscellaneous materials that make
up the formation, including sands, clays, flint pebbles, vertebrate
and invertebrate fossils, silicified wood, flint boulders, limestone
inclusions and phosphate rock in its varying forms. (2.) The
intimate admixture in the formation of these diverse materials.
(3.) The processes by which phosphate and flint boulders have
formed. (4.) The limitation of the hard rock phosphate forma-
tion to a characteristic well marked physiographic type of country.
(5.) The localization within the formation of phosphate rock to
such an extent as to form workable deposits. (6.) The forma-
tion of the plate rock deposits.
SUMMARY OF THE EXPLANATION OFFERED.
The explanation offered, briefly summarized, is as follows: It
is believed that the Upper JOligocene and probably some later
formations, now found on the surrounding uplands, formerly
extended directly across the section that is now the hard rock
phosphate fields. The disintegration of these formations supplied
the miscellaneous materials of which the deposits are made up.
The mixing of the materials was brought about in part by stream
action, which has resulted in a reworking and reaccumulation of
the residual material from these formations, and in part by the
local irregular subsidence such as is constantly going on in a lime-
stone country. In some parts of the phosphate fields the lower-
ing and mixing of the materials by solution of the underlying
limestone has been the predominating factor, while elsewhere the
reworking of the materials by stream action has predominated.
It is probable that local bodies of water existed also in which the
materials reaccumulated. The immediate source of the phosphoric
acid is the phosphate, which was widely disseminated through the
overlying formations. The fossils now found in the formation
include those that were residual from the formations that have
disintegrated, and those that were incorporated in connection with
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FLORIDA STATE GEOLOGICAL SURVEY.
'the reworking and reaccumulation of the materials. The phos-
phate and flint boulders are formed chemically through the agency
of ground water. The formation containing the hard rock phos-
phate is limited in its distribution to that section of the State in
which formations carrying more or less phosphate have disinte-
grated, overlying a limestone substratum, thus affording condi-
tions favorable for the downward passage of rain water carrying
phosphoric acid in solution. The phosphate thus removed from
the surface formations is reaccumulated under these conditions in
a concentrated form at a lower level. The phosphate deposits
are localized within the formation because the formation itself is
lacking in uniformity. Local variations, particularly the presence
of clay lenses and other conditions which interfere with the free
circulation of ground waters, favor the formation of phosphate
boulders and thus result in a local deposit of phosphate rock of
sufficient amount and purity to be of commercial value. The plate
rock represents chiefly fragments of disintegrated boulders.
ACKNOWLEDOMENTS.
In presenting this view of the origin of the hard rock phos-
phates the writer takes pleasure in acknowledging his indebted-
ness to the many investigators who have contributed to a knowl-
edge of these deposits. This indebtedness is not alone to those
who have written on the origin of the phosphates, but equally
to those who have contributed to an understanding of the geology
of the State as a whole, and particularly of that part of the State
in which these deposits are found. Only a few of these general
publications can be mentioned at this time, although a full list is
included in the bibliography which forms a part of the First
Annual Report, of the State Geological Survey, 1908.
The monograph on the Tertiary Fauna of Florida by Dr. W.
H. Dall published in the Transactions of the Wagner Free Insti-
tute of Science, 1890 to 1903, includes by far the most extensive
study of the invertebrate fauna of the Florida formations that
has yet been made, and to these investigations we are indebted
for many fundamental facts regarding the succession of forma-
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ORIGIN OF THE HARD ROCK PHOSPHATES.
tions in Florida. In the present discussion the writer is particu-
larly indebted to Dall's observations, recorded in Bulletin 84 of
the United States Geological Survey, pages 109, 110 and 111, of
remnants of the Upper Oligocene formations (then classed as
old Miocene) at Levyville, in Levy County, at Fort White, in
Columbia County, and near Archer, in Alachua County. These
localities lie west, north and east of the northward extension of
the phosphate fields, and Dall, in the map which accompanies this
report, represents the old Miocene as extending directly across
the northern end of the hard rock phosphate area, with local
exposures of the Vicksburg formation. These observations by
Dall are accepted by the writer and form a part of his argument
that the Upper Oligocene (old Miocene) formerly extended
across the phosphate fields as'a whole.
Messrs. George C. Matson and F. G. Clapp, in connection with
cooperative work carried on by the United States Geological
Survey and the Florida State Geological Survey, have added im-
portant observations regarding the former areal extent of the
Upper Oligocene formations in Central Florida, remnants of these
formations having been noted by them at many of the phosphate
mines of Central Florida. Dr. T. W. Vaughai, of the United
States Geological Survey, under whose supervision these co-opera-
tive investigations were carried on, has given material assistance
in determining the stratigraphic succession in Florida both by
directing the field work and by the identification of fossils and
of formations.
Of the many other publications on the phosphates of Florida
all of those of which a record has been obtained are listed in the
bibliography, which follows this paper. In addition, those rela-
ting directly to the origin of the hard rock phosphates are reviewed
in connection with a discussion of the theories previously
advanced; reference to a number of the papers on the Florida
phosphates is included in the notes in regard to the discovery,
investigation and development of the phosphate deposits. In out-
lining, on the accompanying map, the probable extent of the land
pebble phosphates of Southern Florida the writer has utilized,
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FLORIDA STATE GEOLOGICAL SURVEY.
among other sources of information, maps of these deposits by
Geo. H. Eldridge and by C. G. Memminger.
DISCOVERY OF THE FLORIDA PHOSPHATE
DEPOSITS.
The knowledge of, or belief in the existence of phosphatic
material in Florida seems to have been prevalent from an early
date. Thus, in a paper by Pratt (1868) we find a reference to
and an attempted explanation of the coprolite or guano-like
deposits of Florida. The original of Pratt's paper not having
been available to me I have been unable to determine from the
reviews of the paper whether Pratt's reference is to phosphatic
material known to occur in Florida or assumed to occur..
From Professor J. M. Pickel (1890) we have a statement that
"Dr. J. C. Neal, formerly of Archer, now of the Florida Agri-
cultural Experiment Station at Lake City, discovered in Levy and
Alachua Counties, in 1876, and tested chemically phosphatic
rocks, which were in 1885 sent to the Smithsonian and analyzed
quantitatively."
In 1880 Dr. Chas. U. Shepard writing of the phosphate
deposits of South Carolina stated that they certainly extended in-
to North Carolina on the north and probably as far south as
Florida.
Aside from these references the first definite information of
deposits of low grade phosphate rock in Florida seems to have
been obtained incidentally in connection with the investigation
of building stone made for the Tenth United States Census, 1880.
The first samples of the phosphate rock were collected from a
quarry being operated for building stone near Hawthorne, in
Alachua County. This quarry had been opened by Dr. C. A.
Simmons, of Hawthorne, in 1879. -The samples were sent to
Washington probably during the summer of 1880. The paper
which gives the analysis of this rock bears the date, June 29,
1881. It is contained in the Proceedings of the United States
National Museum for 1882, which were issued in 1883. Whether
Dr. Simmons knew or suspected the phosphatic character of this
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ORIGIN OF THE HARD ROCK PHOSPHATES.
rock before the analysis by the Census Bureau is not known.
However, soon after the analyses had been made, and as a result
probably of these analyses, Dr. Simmons began operating a mill
in which this rock was ground for agricultural purposes. These
operations which were carried on during 1883 and 1884 (Mineral
Resources for 1885), were undoubtedly the earliest attempts at
mining and utilizing the phosphate rock of Florida.
In 1881 Captain J. Francis LeBaron, while engaged by the
government in making a preliminary survey for a proposed ship
canal from the head waters of the St. Johns River to Charlotte
Harbor, became interested in the water-worn pebbles and frag-
ments of bones in the bed of Peace River. Samples of this
material were sent to the Smithsonian Institution. Captain
LeBaron obtained leave of absence from the Engineering Depart-
ment in 1882 and 1883, with a view to interesting capital in the
development of the phosphate. Finding many difficulties in
developing this new industry, he subsequently accepted employ-
ment in connection with the proposed Nicaragua Ship Canal.
(Letter of May 23, 1911.) Returning in 1886, Captain LeBaron
made further efforts to interest capital in the development of the
phosphate but without success.
During the early eighties, due probably to these and to other
discoveries, interest became very active in the Florida phosphate,
and new localities for the phosphate rock were reported in rapid
succession. The volume on mineral industry by the United States
Geological Survey for 1882, published in 1883, contains, page 523,
reference to phosphatic marls occurring in Florida, in Clay,
Alachua, Wakulla, Duval and Gadsden Counties. The volume
for 1883 and 1884, page 793, reports that phosphate rock has been
found in Florida, in Clay, Alachua, Duval, Gadsden and Wakulla
Counties. In 1884 and during the early part of 1885 L. C. John-
son made for the United States Geological Survey a somewhat
careful examination of the phosphate deposits in Suwannee,
Columbia, Alachua and Marion Counties. That the existence of
phosphate rock in Florida was generally known at that time is
evident from the fact that Johnson, from his own investigation
and from samples sent to him, and from popular report as to tne
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FLORIDA STATE GEOLOGICAL SURVEY.
occurrence of phosphate, concluded that the phosphate deposits
of Florida extended entirely across the State from the Georgia
line through Hamilton, Suwannee, Alachua, Marion, Sumter,
Polk and Manatee counties to Charlotte Harbor. (Mineral Re-
sources for 1885, pp. 450-453, 1886.)
During 1886 and 1887, owing doubtless to the efforts of
Captain LeBaron and to the general interest in phosphates, care-
ful investigations were made of the Peace Creek section by
private interests. These investigations resulted in the purchase of
lands and the initiation of mining operations in the river pebble
district, the first shipment of Peace River phosphate having been
made in 1888.
The deposits that we now know as the Florida hard rock phos-
phate were discovered in 1888 by Mr. Albertus Vogt. In May
of this year Mr. Vogt, while deepening the well at his place, near
Dunnellon, dug into a rich matrix of gravel, soft phosphate and
sharks' teeth. In June, 1888, a sample of this material was taken
to Ocala and was there analyzed by R. R. Snowden and was
found to be a high grade phosphate.
The time of the discovery of the hard rock phosphate in Flor-
ida has been variously given as spring of 1888, fall of 1888, and
spring and fall of 1889. The dates given above are from a letter
from Mr. Vogt of August 26, 1909. The discrepancies in the
various publications as to the date of discovery probably came
about from the fact that the discovery was not made known to
the public at once.
As soon as the existence of high grade phosphate rock was
made generally known, prospecting became very active and the
hard rock phosphate belt substantially as we now know it was
quickly outlined.
THE BEGINNING OF THE FLORIDA PHOSPHATE
MINING INDUSTRY.
As has been already mentioned the first attempt at mining and
utilizing the phosphates of Florida was made by Dr. C. A.
Simmons, of Hawthorne, in 1883. This plant, however, was not
successful and was closed down in 1884.
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ORIGIN OF THE HARD ROCK PHOSPHATES.
The production of phosphate rock on a commercial scale in
Florida began with the mining of the Peace Creek pebble deposits,
probably in 1887, the first shipments having been made in 1888.
The first company to operate on Peace River was the Arcadia
Phosphate Company, organized by Mr. T. S. Morehead, of
Philadelphia. The first shipments were to the G. W. Scott
Manufacturing Company of Atlanta. (Millar, 1892, page 24.)
Hard rock phosphate mining began one or two years later than
river pebble mining, but developed much more rapidly. Accord-
ing to Millar, the first of the hard rock mining companies to
actually take the field was the Marion Phosphate Company, which
broke ground near Dunnellon in December, 1889, and made a
first shipment to Liverpool in April, 1890. The Dunnellon Phos-
phate Company, which was probably the first company organized,
began mining in February, 1890, and made their first shipment
to London and Hamburg in May, 1890. Following the discovery
of the hard rock phosphate deposits mining companies were
organized in rapid succession. It is said that fully one hundred
hard rock phosphate companies were organized in the United
States, and that forty-one of these actually began operations. -By
the close of 1891 only eighteen companies were operating. At
the present time, 1913, fourteen companies are mining hard rock
phosphate.
INVESTIGATIONS OF THE FLORIDA PHOSPHATE
DEPOSITS.
The chief official investigations that have been made of the
Florida phosphates are those of the United States Geological
Survey, the United States Census Bureau, the United States Com-
missioner of Labor, the United States Department of Agricul-
ture, and the Florida State Geological Survey. In addition, the
reports of the State Chemist of Florida and of the State Experi-
ment Station contain many analyses of Florida phosphate rock.
Dr. J. Kost, during his brief term of office as State Geologist in
1886, also contributed towards the discovery of phosphate and the
development of the industry.
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FLORIDA STATE GEOLOGICAL SURVEY.
The principal investigations made by the United States Geo-
logical Survey are those by Johnson (1885, 1893),* Penrose
(1888), Darton (1891), Dall (1892), Eldridge (1893), Matson
(1909), Clapp (1909), Vaughan (1909). In addition a number
of other members of the National Survey have made notes on the
Florida deposits in connection with the annual statements of the
production of phosphate contained in the volumes on Mineral
Industry.
The Census Bureau investigations are those made by the
Tenth Census in connection with the study of building stone, by
which the low grade phosphates were discovered, and the report
on mineral industries by the Eleventh Census. This latter report
contains a chapter on the Phosphates of Florida by Edward
Willis. The Sixth special report of the Commissioner of Labor,
1893, is devoted to'the phosphate industry of the United States.
A brief review of the Florida phosphate fields was given in 1911
by William H. Waggaman, of the Bureau of Soils of the United
States Department of Agriculture. The investigations of the
phosphate deposits by the Florida State Geological Survey, on
which this paper is based, have been made at occasional intervals
as opportunity was afforded since the organization of the Survey
in 1907.
The discovery of the hard rock phosphate in 1888 resulted in
many private investigations of these deposits. Of these private
investigators a number have made public reports while others
unfortunately have made no permanent record of their investiga-
tions. Among the earliest of these private investigators was Dr.
C. U. Shepard, of Charleston, who examined the phosphates of
the Withlacoochee River section in connection with the organiza-
tion of the Dunnellon Phosphate Company in 1889 and 1890.
Among others who examined the hard rock deposits during the
first few years of mining operations and who have published their
observations are Albert R. Ledoux (1890), Francis Wyatt (1890,
*The numbers in parenthesis refer to the date of publication as listed
*: the bibliography, not necessarily to the year in which the investigations
were made.
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ORIGIN OF THE HARD ROCK PHOSPHATES.
1891), E. T. Cox ( 1890, 1891, 1892, 1896), Walter B. M. David-
son (1891, 1893), N. A. Pratt (1892), C. C. Hoyer Millar (1891,
1892), G. M. Wells (1896), E. W. Coddington (1896), L. P.
Jumeau (1905, 1906).
THEORIES PREVIOUSLY PROPOSED.
The hard rock phosphates of Florida have interested all
who have examined them, and many theories have been advanced
to account for these remarkable deposits. In the following review
these various theories are given as nearly as practicable in the
order in which they are proposed. A strictly chronological order
is, however, often impossible since when several papers appear
during the same year it is difficult to determine which was first
issued. Moreover some of the papers were evidently written
some years before being printed.
The paper by Dr. Albert R. Ledoux read before the meeting
of the New York Academy of Science, January 27, 1890, and
published in the transactions for 1890 is apparently the first
account of the hard rock phosphate deposits that has been
preserved. In this paper Dr. Ledoux offers no specific theory for
the Florida deposits. Speaking of phosphates in general, how-
ever, he notes the fact that within the rain belt, when guano
deposits rest upon limestone the phosphoric acid is leached out
and alters the carbonate of lime to phosphate. An instance is
cited in this connection in which limestone in one of the South
Pacific islands was believed to have been changed to phosphate to
a depth of several feet within the period of twenty years. The
phosphoric acid in this instance was leached by rainwater from
recently deposited guano. The suggestion of the replacement of
the carbonate of limestones under certain favorable conditions by
phosphate is not offered by Ledoux as a new hypothesis, as this
method of formation of certain of the phosphates had been dis-
cussed by various previous writers.
In a paper published in the New York Mining and Engineer-
ing Journal for August 23, 1890, Francis Wyatt proposed the
theory that the hard rock phosphates are due to the evaporation
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FLORIDA STATE GEOLOGICAL SURVEY.
of the Miocene waters which are assumed to have covered this
section of the State. While submerged there was deposited upon
the limestone, according to Wyatt, more especially in the cracks
and fissures, a soft, finely disintegrated calcareous sediment or
mud. As the seas dried up estuaries were formed in which were
found great numbers of fish, mollusks, reptiles and marine plants.
The formation of the phosphate is attributed to the reactions
between the calcareous sediments and the decaying animal and
plant life.
Professor E. T. Cox, in a paper read before the Indianapolis
meeting of the American Association for the Advancement of
Science, August, 1890, expresses the view that the hard rock
phosphates of Florida are derived from the mineralization of an
ancient guano. His argument is that as the peninsula of Florida
was elevated above the ocean the land bordering the sea on the
west coast became the resting place for numerous aquatic birds
and other animals. The humid character of the climate caused
the soluble alkalies to be removed, leaving the less soluble phos-
phate of lime. This accumulation of guano subsequently became
mineralized, thus resulting in the hard rock phosphates. This
theory is restated in papers subsequently published by Cox in
1892 and 1896.
Professor Cox mentions two other views current at that time.
These are stated as follows: "It is a well known fact that phos-
phorous is an element and, like the element of iron, is almost
universally distributed over the globe, and is found in all the living
things thereon. Therefore, it is reasoned that it may, like iron,
be accumulated in large beds by a natural law which governs the
concentration of mineral masses. Again, it is suggested that phos-
phoric acid, derived from mollusca, deposits from. birds, fish and
saurians, has filtered down and replaced the carbonic acid in the
underlying limestone, converting it into phosphate of lime." To
the first of these suggestions Cox offers no objection. Of the
second, however, he says, "Against the latter theory the phos-
phate of lime very rarely contains any trace of organic remains,
while the limestone on which it rests is rich in the casts of mollusca
that are referred to the Eocene age. Then, again, in proximity to
Digitized by GoOgle
ORIGIN OF THE HARD ROCK PHOSPHATES.
the hard rock phosphate is a soft phosphate of lime that has the
consistency of soft, plastic clay. This soft phosphate often under-
lies the hard and is several feet in thickness."
Mr. N. H. Darton, writing in the American Journal of Science
for February, 1891, considers guano as the most probable original
source of the phosphate. The early Miocene is regarded as the
probable time of deposition of the guano which by leaching
supplied the phosphoric acid. Two processes in the formation of
the rock are recognized. The first is the replacement of the car-
bonate of lime by phosphate of lime; the second is a general
stalactitic coating on the massive phosphates and in the cavities.
Whether or not the restricted distribution of the phosphate was
connected with the genesis of the rock Darton regards as undeter-
mined at that time.
Mr. Walter B. M. Davidson contributed a brief paper on the
origin and deposition of the Florida Phosphate, which was
published in the Engineering and Mining Journal, Vol. 51. pp.
628-629, 1891. This paper has not been available to the writer,
but from a reference in a later paper it appears that Davidson at
that time believed that the hard rock phosphate boulders were
deposited in underground caverns and river beds in the Vicksburg
Limestone.
Among important early publications on the Florida phosphates
is a paper by Dr. W. H. Dall, published in 1892. Dall's account
of the phosphate was given in connection with and was incidental
to a general summary of the geology of Florida included in a
monograph on the Neocene of North America by Dall and Harris
(Bull. 84, U. S. Geol. Survey). In this report Dall expresses the
belief that the phosphoric acid of the phosphate deposits was
derived directly from bird guano. The local character of the bird
rookeries determine the local occurrence of phosphate rock. Tht
influence of local clay beds on the accumulation of workable
deposits is also recognized (p. 135).
. Davidson, in a paper read before the American Institute of
Mining Engineers at the Baltimore meeting in February, 1892,
published in the Transactions, 1893, appears to derive the hard
rock phosphates as residual material from the Vicksburg Lime-
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FLORIDA STATE GEI'OLOGICAL SURVEY.
stone. He says, page 12, "The phosphates of Florida, in all
shapes, I derive from the leaching of the Vicksburg limestone, and
in the same way I would account for the phosphates of the West
India Islands. The phosphatic limestone of these islands has been
subject to the leaching action of rains and atmosphere reactions,
and the carbonate of lime has been carried away, leaving on the
surface the more insoluble phosphate, and the iron and alumina.
As in all limestones, the water eats away the rock unevenly, mak-
ing pits and holes, and caves, and the phosphate of lime fills them
up-either in an earthy form, or in the massive variety, which is
described as coating the stalagmites and stalactities in the cave
in Navassa." Davidson believed that after the phosphate had
accumulated in the pits and holes in the limestone, Florida was
again submerged, allowing the sea sand to accumulate over and
around the boulders.
.. Pratt (1892) while conceding that the theory of a pure bird
deposit, in localities favorable to the roosting of water fowl, more
nearly covers the conditions of the problem as presented in all
localities than any other so far advanced, considers that in the case
of the Withlacoochee River deposits the evidence is all opposed to
this theory. In this paper the theory is advanced by Pratt that the
phosphate boulder is a true fossil, the boulder being the phosphatic
skeleton of a gigantic foraminifera, while the soft phosphate is
supposed to be the germ spores or bud of the animals or the com-
minuted debris of the animals themselves.*
Millar (1892) reviews the theories current at that time (pp.
115-117) and favors the view that guano is the most probable
source of the phosphate.
Whether the hard rock phosphates of Florida resulted from a
superficial and heavy deposit of soluble guano, or from the con-
centration of phosphate of lime already widely and uniformly dis-
tributed throughout the mass of the original rock, or from both
*The original of Dr. Pratt's paper not being accessible to the writer
this review is based on the quotation from the paper included in the Phos-
phate Industry of the United States by Carroll D. Wright, 1893, pp. 24-31,
and in the Florida, South Carolina, and Canadian Phosphates by Millar,
1892, pp. 73-77 and 117.
Digitized by GoOgle
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FIFTH ANNUAL REPORT. PL. 3.
Fig. 1.-Sample of phosphate illustrating the formation of phosphate by the
replacement process. The rock was clearly originally limestone of the Vicksburg
formation, the form of the shells being well preserved. The carbonate has been
replaced by phosphate, and the rock as shown by analysis is now a high grade
phosphate. Natural size.
Fig. 2--Piece of phosphate rock showing secondary deposition in cavities and
recementation of broken fragments. Collection of H. Bystra. Natural size.
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FLORIDA GEOLOGICAL SURVEY.
FIFTH ANNUAL REPORT. PL. 4.
Fig. 1.-Mastodon tooth from T. A. Thompson's mine at Neals, Fla.
This tooth has the gray phosphatic sands of the phosphate formation
firmly adhering to it indicating that it came from the phosphate formation.
Natural size.
Fig. 2.-Mastodon tooth from T. A. Thompson's mine, Neals, Fla.
The gray phosphatic sands clinging to the tooth are evident in the photo-
graph. This tooth shows very little wear. Natural size.
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FLORIDA GEOLOCICAL SURVEY.
FIFTH ANNUAL REPORT. PL. 5.
Fig. 1.-A fragment of mastodon jaw with two teeth in place from Neals, Fla.
About one-half natural size.
Fig. 2.-Teeth and foot bone of horse. The light colored tooth on the upper
side at the left is from the Dunnellon Phosphate Company plant No. 5 at Hernando,
in Citrus County. It has the phosphatic sands of the phosphate formation adhering
to it. The lower tooth on the left is from the Franklin Phosphate Company mine,
Newberry, Fla. (No. 1233). The upper tooth in the center is from the Camp Phos-
phate Company, Blue Run mine, near Dunnellon (No. 1366). The lower tooth in the
center is from Cullens River Mine, Dunnellon (No. 1444). The foot bone is from
the Dunnellon Phosphate Company plant No. 6i. near Dunnellon (No. 1302). All
natural size.
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FLORIDA GEOLOGICAL SURVEY.
FLORIDA GEOLOGICAL SURVEY.
FIFTH ANNUAL R*W'ORT. PL. 6.
Sharks' teeth from the hard rock phosphate .deposits.
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FIFTH ANNUAL REPORT. PL. 7.
iA
Sharks' teeth from the bard rock phosphate deposits.
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FLORIDA GEOLOGICAL SURVEY.
FIFTH ANNUAL REPORT. PL. 8.
Fig. 1.-Phosphate washer for hard rock phosphate, Cummer Phosphate
Company, Alachua County.
Fig. 2.-Drill for prospecting for hard rock phosphate, in use by the
Southern Phosphate Development Company. The prospect holes are drilled
through the phosphate formation to the underlying formation, the Vicksburg
Limestone, which is reached at this locality at a depth of 75 to 100 feet.
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FLORIDA GEOLOGICAL SURVEY.
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ORIGIN OF THE HARD ROCK PHOSPHATES.
of these sources is regarded by Eldridge (1893) as a difficult
question. Alteration of the limestone and precipitation of phos-
phate from solution are both regarded as having been active in the
formation of the primary phosphates. Phosphate boulders,
Eldridge suggests, may have been formed by chemical precipita-
tion of layer upon layer of phosphate, either on a surface exposed
to the air or within a cavity in the limestone. By continued growth
in the latter case the cavity would become filled with laminated or
massive rock which upon the solution of the surrounding materials
or the complete breaking down of the formation, as in later times,
would result in a rounded body of phosphate of lime resembling
a sea rolled boulder.
Referring to phosphate of lime in sedimentary rocks Eldridge
says (p. 18), "Its presence in sea-water; its broad distribution in
both plant and animal life; its occurrence in rocks of all ages,
even to the extent of economic value; and its special presence in
limestones, more particularly in Cretaceous and Tertiary lime-
stones, are facts long recognized. Its occurrence in recent time in
the form of leached and soluble guanos on many of the oceanic
islands, and the phosphatization of the underlying strata, have also
been noted by many authorities; the last is by actual observation
a tangible source, but the features first detailed point to some other
and more general origin of phosphate of lime than localized bird-
deposits, or the but little more widely distributed accumulations
of animal remains. Its presence in sea-water, after the manner
of carbonate of lime, though in far smaller amount, is well
established; both materials are of general occurrence, and each
play a prominent part in sea-life. The transfer of a consider-
able percentage of phosphate of lime to localities having condi-
tions favorable for its deposition, either in sediments, then
settling, or on surfaces of rocks already laid down, has doubtless
been accomplished in many cases through the instrumentality
of animals secreting it. Oceanic currents may have assisted this
accumulation. Again, southern waters, swamps, and lands give
evidence of the presence in them of abundant life, secreting
phosphate of lime and afterwards returning it to the beds on
which this life rests."
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FLORIDA STATE GEOLOGICAL SURVEY.
With regard to the plate rock phosphates of Marion County,
Johnson (1893) assumes an original deposition of immense beds
of guano. These beds after the leaching out of their carbonates
and other soluble materials are believed to have become very
compact, yet not entirely impervious to water. Small cavities in
close contiguity became finally separated by mere plates and in
this connection are called laminated rock. By disintegration the
laminated rock is broken up into fragments, thus giving rise to
the so-called plate rock. Still further disintegration, in the opinion
of Johnson, results in the formation of soft phosphate. Johnson's
theory as to the origin of the phosphate as expressed in this papeI
is essentially the same as that advanced by Cox in 1890 to account
for the phosphates as a whole. Johnson's view that the plate rock
results from the disintegration of laminated boulders had not
previously been definitely advanced, although Willis includes a
statement to this effect in his paper published in 1892.
Lucius P. Brown (1904) regards it as possible that guano may
have contributed in a minor degree to the enrichment in phos-
phoric acid of the Florida limestones. The workable deposits of
phosphate of lime, however, he regards as having been gathered
up from miscellaneous sources in sedimentary rocks and concen-
trated through the agency of underground water with more or
less further concentration by mechanical means.
Mr. P. Jumeau (1905) reviews the theories proposed to
account for the origin of the phosphate rock, pp. 68-82. That the
phosphate rock has accumulated chiefly from the leaching of
guano is regarded by him as the most probable theory.
DISCUSSION OF THEORIES.
The theories offered by Wyatt, 1890, and by Pratt, 1892, are
highly speculative and are based on assumptions for which nG
proof is offered. Of this class also are some other theories that
have appeared from time to time in newspaper and magazine
articles.
Davidson assumes that the phosphate rock existed originally
in the Vicksburg Limestone and in its present form is merely
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ORIGIN OF THE HARD ROCK PHOSPHATES.
residual from the decay of that formation. In answer to this
hypothesis it may be noted that while the Vicksburg Limestone
is known by surface exposures throughout a large extent of the
territory in the Gulf States, and by well borings to a considerable
depth in Florida and elsewhere, it is strikingly free from inclu-
sions of phosphate rock, such as would remain upon the disinte-
gration of the limestone to form these phosphate deposits.
Cox, in successive papers, argues that the phosphate rock is
itself mineralized guano. This, likewise, was the view of Johnson
(1893), as applied at least to the plate rock phosphates of Marion
County. The fact that not a few of the phosphate boulders and
pieces of rock have retained more or less well preserved evidence
of their derivation from limestone sufficiently controverts this
hypothesis, which is otherwise improbable.
Darton (1891) and Dall (1892) each assume that guano is
the immediate source of the phosphoric acid. Darton's paper on
this subject is brief and includes merely a statement of the
probable origin of the rock. Dall, however, gives a clear state-
ment of the guano hypothesis in its relation to the hard rock
phosphates of Florida. It is even thought probable by Dall that
each local deposit of hard rock phosphate may represent the loca-
tion of an ancient bird rookery. The hypothesis of the origin of
the phosphate from guano fails entirely to account for the
jumble of materials with which rme phosphate is associated. This,
in the writer's opinion, is the insurmountable objection to the bird
guano theory, as developed by Dall.
Of those who have written on the origin of the hard rock
phosphate deposits of Florida, no one, with the exception of Eld-
ridge, has taken sufficient account of the complexity of this forma-
kton, or has seemed to appreciate that it is as necessary to account
for the associated materials as for the phosphate itself. With
the hypotheses proposed by Eldridge, however, the writer is un-
able to agree.
Whatever the original source of the phosphoric acid, whether
from guano or from phosphate' of lime, originally disseminated
throughout the Vicksburg Limestone, the subsequent process,
according to Eldridge, was the formation of a highly phosphatized
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FLORIDA STATE GEOLOGICAL SURVEY.
zone within and presumably at or near the surface of the Vicks-
burg Limestone. This process Eldridge designates as the first period
during which the primary phosphate was formed. To account for
the condition in which the rock is now found and for the mixture
of materials in the matrix Eldridge assumes that at a late period,
probably at the close of the Pliocene, the peninsula of Florida
was resubmerged and that during this resubmergence this phos-.
phate stratum was broken up, the pieces being removed more or
less from their original location. To account for the associated
sands, clays and other materials mixed with the phosphate rock
he assumes that strong currents were running which washed in
these complex materials. The phosphate that is now present in a
finely divided condition and acts as a cementing substance for the
gray sands was, he assumes, the ground up sediment from the
hard rock which mixed with the sands as they were drifted into
their present location.
The writer's hypothesis is based on observations by himself
and others which lead to the conclusion that formations later than
the Vickburg, formerly extended across the phosphate fields, and
that these have now largely disintegrated. It is shown also that
these formations, where now found intact, or as remnants on the
surrounding uplands, are distinctly phosphatic. From these
observations it is concluded that the matrix of the hard rock phos-
phate deposits is the residue of the formations that have dis-
integrated in situ, and that the phosphate itself is derived from the
phosphate originally widely disseminated through these forma-
tions, circulating waters being the agency by which the phosphate
has been carried to its present location. The gray sands held to-
gether by the finely divided phosphate, referred to by Eldridge,
are a part of the residue from these earlier formations in which
the sands occur under similar conditions.
In the present paper it is not intended to discuss the source of
the phosphate, which is found widely disseminated in the Upper
Oligocene and some later formations, from which by solution and
redeposition it has accumulated to form the workable hard rock
deposits. The writer does not believe, however, that the bird
guano theory will account for these widely disseminated phos-
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ORIGIN OF THE HARD ROCK PHOSPHATES.
phates, any better than for the intensely localized hard rock phos-
phates. Upper Oligocene formations, which are throughout more
or less phosphatic, attain in Florida a thickness of several hundred
feet. Moreover these formations, except where disconnected by
erosion, are continuous from the Apalachicola River, in West Flor-
ida, to an undetermined distance beyond the point at which they
disappear beneath later formations in Central Florida. It is in-
conceivable to the writer that bird guano deposits could have been
so uniformly scattered over so wide an area and through so gr4at
a thickness of sedimentary rocks.
As regards the chemical changes involved in the formation of
the hard rock phosphate there is much less disagreement among
the different writers. Ledoux, Darton, Dall, Eldridge, Brown,
Jumeau and others have recognized that phosphoric acid in solu-
tion in water may and under favorable conditions does replace
the carbonate of limestones thus forming calcium phosphate.
Darton recognized the two processes, the first being the replace-
ment of the carbonate by phosphate, and the second the subsequent
coating over the surface and in cavities by phosphate thrown out
of solution. Eldridge recognized the formation of boulders by
replacement of carbonate by phosphate, and by precipitation from
solution. The evidence of the formation of phosphate by the
replacement of carbonate by phosphate is entirely incontrovertible,
since, as has been previously stated, many of the boulders retain
the original calcareous shells now phosphatized. The evidence of
subsequent secondary deposition in the cavities is likewise obtained
from the structure of the rock itself. The formation of boulders
by precipitation seems probable from the structure of many of the
boulders. Doubtless, as elsewhere stated, the replacement and
precipitation have combined in the formation of many boulders.
The chemical processes involved are more fully discussed else-
where.
Turning again to the explanation of the hard rock phosphate
deposits offered by the writer, the key to the solution of the hard
rock phosphate problems is found, in the writer's opinion, in a
study of the geological history of the State. The foundation rock
in Central Florida is the Vicksburg Limestone of Lower Oligo-
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FLORIDA STATE GEOLOGICAL SURVEY.
cene age. In the hard rock phosphate section there is at present
no formation, other than the phosphate itself, overlying the Vicks-
burg. However, there are good reasons, as already stated, for
believing that the Upper Oligocene and some later formations,
now found on the uplands bordering the phosphate belt, formerly
extended across this area. Upper Oligocene deposits are found
at the present time bordering the phosphate belt on the north, east
and south, while on the west outliers of these formations may
still be found in Levy and in Hernando Counties.* Remnants,
apparently, of these formations have -recently been observed by the
writer on the hills near Morganville, west of the phosphate area
in Marion County.
Further support of the view that the Upper Oligocene deposits
formerly extended across the phosphate belt is found in the topog-
raphy of the area. The phosphate country has been reduced in
elevation more or less by underground solution. The phosphate
deposits of Alachua County are found at an elevation of from 75
to 100 feet above sea, while passing to the east the plateau or
uneroded section of this county rises to an elevation of 200 feet
above sea. In Marion County the phosphates are found at an
elevation of from 40 to 100 feet above sea, while both west and
east of the phosphate belt, hills, the remnants of the former
plateau, rise to an elevation of from 140 to 160 feet above sea.
In Citrus County the hill country west of the phosphate area still
retains a height of from 150 to 220 feet. The Upper Oligocene
formations are found very generally on the east side of the phos-
phate belt, while remnants, as already stated, are found on at least
some of the hills on the west side of the area.
Whether or not marine Miocene formerly extended across the
present phosphate fields is undetermined. The character of the
residue at some localities suggests Miocene material, although no
actual proof of a former extent of the Miocene across this part
of the State has yet been obtained. The marine Pliocene probably
did not reach across this part of the State. Fresh water deposits
of Pliocene and Pleistocene, however, are to be expected since
'Florida Geological Survey, Second Annual Report, Map, 1909.
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ORIGIN OF THE HARD ROCK PHOSPHATES.
fresh water Pliocene deposits, the Alachua clays, containing
remains of land vertebrates are found locally around the border
of the phosphate area. These deposits were formed in small lakes
and sinks, and similar deposits, doubtless, formed in the phos-
phate area. The red sandy clays which form the surface deposits
over practically all of the Northern and Central Florida probably
extended across the phosphate area.
Assuming the former areal extent of these later formations
across what is now the phosphate belt of Florida, the solution of
other problems connected with the hard rock deposits is much
facilitated. As a result of the action of the weathering agencies
these formations have disintegrated, their residue forming the
phosphate matrix. The process of erosion and disintegration has
been long continued, during which time the general surface level
has been gradually lowered by the solution and removal of the
underlying limestone. The lowering of the limestone here as else-
where in limestone countries progresses not uniformly but irregu-
larly, due to the formation of caves, sinks and underground
channels. This irregular subsidence has' resulted in the mixing of
materials originally distinct. Sinks form in the limestone section
of Florida by which material at the surface is lowered by the
sudden caving of the earth. When these sinks are first formed
the walls are vertical or nearly so. As a result of the caving at
the sides together with the wash of surface material they fill up.
By this process long continued the materials of different forma-
tions become intimately mixed.
The mixing of materials by underground solution and sub-
sidence has been supplemented by stream action. While this area;
is at present practically without streams, yet local streams existed
during the earlier stages of physiographic development. These
local streams begin their development as soon as sinks are formed
and when the stratigraphi conditions are favorable a stream
enters each sink; working back from the sink the stream estab-
lished in time a normal drainage system. These streams are
known as disappearing streams since they enter sinks. As has
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FLORIDA STATE GEOLOGICAL SURVEY.
been explained in a previous paper,* the limestone country of
Central Florida is gradually encroaching on the non-limestone
country. These temporary streams make up one of the character-
istic features of the physiography in the transition stage and num-
erous examples of such streams are found in the partially eroded
uplands bordering the phosphate fields. After being formed a
sink is frequently filled up by the materials carried by the stream
which enters it.
In addition to local streams it is probable that considerable
bodies of water existed from time to time in this section into which
streams entered. The Pliocene was probably the time of the most
active reaccumulation of the material which makes up the matrix
of the phosphate deposits. Whether or not this area was partially
submerged during the time of the reworking of the materials of
this formation can possibly be determined by a careful study of
the fossils.
THE FOSSILS OF THE HARD ROCK PHOSPHATE
DEPOSITS.
Two distinct groups or lots of fossils are found in this forma-
tion. The first of these includes those fossils, chiefly sharks' teeth,
that are residual from the formations that have disintegrated. The
second group, of which there is a considerable fauna, chiefly land
animals, includes those fossils that were incorporated in connec-
tion with the reworking of the materials. The invertebrate fossils
of this formation are contained for the most part in loose frag-
ments of rock which represent inclusions from the underlying
Vicksburg Limestone or remnants from later formations that
have disintegrated.
It should be borne in mind in this connection that the residual
fossils do not necessarily all come from formations later than the
Vicksburg. A part, possibly a majority, are residual from the
Vicksburg itself. As already explained, the limestone is being
constantly removed by solution and the fossils that it contained,
if sufficiently resistant, remain as a part of the residue and hence
*Fourth Annual Report Florida Geological Survey, page 33, 1912.
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ORIGIN OF THE HARD ROCK PHOSPHATES.
become incorporated in the phosphate deposits. Among the
residual fossils are sharks' teeth, which are obtained in numbers
from every pit that is operated. It is frequently stated by the
miners that the sharks' teeth become more abundant as the under-
lying limestone is approached near the base of the deposits. This
statement is consistent with the view that many of the teeth are
residual from the underlying limestone. The less resistant parts
of the skeleton can not be expected to have persisted from these
early formations in such abundance and such perfect state of pres-
ervation as have the teeth.
The residual fossils are of value to the geologist since from
them it may be possible to determine from what particular forma-
tions the materials of the matrix have been derived. The fossils
included with the phosphate, not residual, indicate the age or time
during which the reworking of the materials occurred.
The fossils that were incorporated with the materials while
they were being reworked and redeposited are, as would be
expected, of much later date than the residual fossils. Of these
later animals comparatively fragile bones are frequently preserved.
Whole skeletons, however, are rarely found in place. This may
be due to the conditions under which they were entombed, or
possibly to the fact that the parts of the skeleton have been
subsequently more or less dissociated by the subsidence of the
materials due to the solution of the underlying limestone.
From the fact that the formation of caves and sink holes in the
limestone has continued to the present time it is evident that some
comparatively recent fossils are likely to become included with
the phosphate. Moreover local fresh water Pleistocene or recent
surface deposits are likely to occur as a part of the overburden
from which fossils may become mixed with the phosphate. Along
the Withlacoochee River, which cuts through these deposits, also
there has doubtless been more or less shifting of the stream by
which Pleistocene and recent remains are included with the phos-
phate. These are conditions that must be borne in mind in making
and in studying the collections.
Of the fossils that are accepted as contemporaneous with the
phosphate formation the best authenticated is a species of
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FLORIDA STATE GEOLOGICAL SURVEY.
mastodon, probably M. floridanus. This mastodon has been
obtained in the hard rock phosphate section from the following
mines: T. A. Thompson, Neals, Alachua County; Dutton Phos-
phate Company, plant No. 22, Juliette, Marion County; Cullen
River Mine, Dunnellon, and Dunnellon Phosphate Company,
plant No. 5, Hernando, Citrus County. That the mastodon is
actually imbedded in the phosphate bearing formation is not only
vouched for by the miners who have personally taken specimens
from the pits, but is evident from the specimens themselves, some
of which have the gray phosphatic sands of the phosphate forma-
tion adhering to them. Associated with the mastodon is found
the small three-toed horse, Hipparion. The remains of the horse
have been obtained only from the picker belt, but notwithstanding
the fact that they have gone through the washer, some of the teeth
still have bits of the phosphate matrix clinging to them. The
horse remains have been obtained from the following mines:
Franklin Phosphate Company, mine No. 2, Newberry, and T. A.
Thompson, Neals, both in Alachua County; Dunnellon Phosphate
Company, plant No. 6, Dunnellopi, Marion County, and Dunnellon
Phosphate Company, No. 5, Hernando, Citrus County. A number
of other fossils have been obtained, which remain to be deter-
mined. Among these are teeth of an early camel from Dunnellon
Phosphate Company, plant No. 5, Hernando, Citrus County, and
Cullen River Mine, Dunnellon.
From the plants working along and near the bed of the
Withlacoochee River have been obtained a considerable number of
fossils. Among these, in addition to the mastodon, camel and
early horse, is the elephant, rhinoceros and a more recent horse, as
well as a number of other forms, some of which appear to be com-
paratively recent. It is evident that a mixing of fossils has
occurred along the river due, possibly, to the shifting of the
channel.
SOURCE OF THE PHOSPHORIC ACID.
The source of the phosphoric acid is believed to be from the
various formations that have disintegrated in, situ. The Upper
Oligocene deposits are very generally phosphatic throughout their
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ORIGIN OF THE HARD ROCK PHOSPHATES.
entire extent from the Apalachicola River, in West Florida, through
Northern and Central Florida. The red sandy clays forming the
surface deposits over much of Northern Florida and which prob-
ably extended across the phosphate section overlying the
Oligocene deposits, contained fragments from the granitic rocks
and have doubtless contributed in the process of decay more or
less phosphoric acid.
AGENCY.
The agency by means of which the phosphates were accumu-
lated in their present form was ground water. The rainfall, which
in Florida amounts to about 54 inches per annum, in passing
through the surface materials dissolves a limited amount of the
phosphate, which is carried to a lower level and is finally thrown
out of solution in a concentrated form. This process long
continued results in the accumulation of workable phosphate
deposits.
RELATION TO THE UNDERGROUND WATER LEVEL.
It is probable that the ground water level has had an impor-
tant bearing on the formation of the phosphate deposits. There
is, as is well known, a definite relation between the ground water
level and chemical reactions within the earth. The conditions
above and below this level are radically different. Above the
ground water level the movement of water following rains is free
and solution is active; below this level the water stands or has a
scarcely appreciable movement. Above the water level solu-
tion is active, while below this level deposition frequently occurs.
It is important to observe in this connection that the under-
ground water level, in Central Florida, which has such a direct
bearing on chemical deposition has not always remained the same.
In former times when the surface stood at a higher level the water
table was higher above sea than at present. In other words, a
lowering of the general surface level by erosion was accompanied
by a lowering of the water table. It thus happens that a locality
which in one stage of physiographic development is favorable to
the formation of phosphate rock, may in a subsequent stage, when
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FLORIDA STATE GEOLOGICAL SURVEY.
conditions have changed, be favorable to the disintegration of
these deposits. Moreover, any change in levels, either elevation
or depression, affects the water level and hence modifies condi-
tions. Such changes in elevation have undoubtedly occurred. For
instance a rise in elevation of 15 to 25 feet along the east side of
Florida and a similar depression along the west coast as late as
Pleistocene times is fairly well established. This, together with
any further changes that occurred in the elevation of the peninsu-
lar, must be taken into account in its bearing on the change of
water level and the corresponding change in deposition, and dis-
integration. It is not held that the accumulation of the rock in
no case occurs above water level. In fact the secondary stalactitic
deposits seen in many boulders evidently form as in caves above
water level. The earth is a complex chemical laboratory in which
chemical reactions take place in accordance with constantly
changing conditions.
THE FORMATION OF BOULDERS.
The phosphate boulders have evidently been formed chemically
through the agency of ground water. The boulders of silica are
formed by a similar process by which silica taken into solution
near the surface is redeposited at a greater depth.
SILICA BOULDERS.
Most of the flint or silica boulders were originally masses of
limestone and still retain, in recognizable form, the shells and
other fossils of which the limestone was originally composed. In
these boulders the calcium carbonate has been replaced by silica.
This process is common in nature. Petrification, another term
for a similar process, is the slow removal in solution of the sub-
stance of which an object is composed and its replacement by
some other substance. In the case of petrified wood the wood has
been removed and replaced by silica, calcium carbonate, iron car-
bonate or whatever the petrifying agent may be. Silicified wood,
silicified shells, silicified bone all refer to petrification in which
silica was the petrifying agent.
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ORIGIN OF THE HARD ROCK PHOSPHATES.
The boulders of silica are, therefore, masses of silicified lime-
stone, the fossils originally present in the limestone having for
the most part retained their form.
PHOSPHATE BOULDERS.
The phosphate boulders are formed either by replacement of
the limestone or by precipitation from solution.
PHOSPHATE BOULDERS FORMED BY THE REPLACEMENT PROCESS.
Some of the phosphate boulders and pieces of rock are evi-
dently formed by the replacement of the carbonate of the original
limestone by phosphate. That this is true is proven by the fact
that the shells and other fossils that made up the original lime-
stone are sometimes well preserved, and from these shells it is
possible to identify the particular formation from which the
original limestone comes. Among the illustrations which accom-
pany this paper will be found a photograph of a rock, which was
originally pure limestone of the Vicksburg formation but is now
changed, as shown by analysis, to a high grade phosphate. The
shells and other fossils making up the limestone, which were
originally calcareous, were subsequently phosphatized. Other-
wise expressed, they have been petrified, phosphate being the
petrifying agent. The collection of Dr. H. Bystra at Holder
contains a piece of phosphate boulder, in which much larger
shells are equally well preserved. While occasional phosphate
boulders with fossils in a perfect condition of preservation are
found as a rule the preservation of the fossils in the boulders is
imperfect. It is probable, also, that in many boulders formed by
replacement the fossils are entirely obliterated.
PHOSPHATE BOULDERS FORMED BY PRECIPITATION.
Many of the phosphate boulders are formed in part or entirely
by precipitation of calcium phosphate from solution in water.
This is probably the method of formation of the laminated
boulders.
It is probable that replacement and deposition from solution
are both involved in the formation of many boulders.
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FLORIDA STATE GEOLOGICAL SURVEY.
SECONDARY DEPOSITION OF PHOSPHATE FROM
SOLUTION.
In many boulders a secondary deposition from solution may
be recognized. Practically all the laminated boulders show a
rough mamilated or stalactitic undersurface of each lamina, while
the top surface of the lamina next beneath show successive layers,
separated by minute parting planes, indicating successive deposi-
tion of phosphate from solution. This process is similar to that
which takes place in cayes where calcium carbonate is deposited
to form stalactites and stalagmites, and is probably confined to
boulders lying above the permanent ground water level. Many
small pieces of rock were doubtless phosphatized without having
assumed the boulder form.
ORIGIN OF THE PLATE ROCK.
The plate rock deposits represent a peculiar phase of the hard
rock formation. It seems probable that the plate rock represents,
in part at least, fragments of boulders that have disintegrated, as
was suggested by Johnson in 1893. It has also been suggested
that these plates may have been formed by finely divided phos-
phate mud settling as a sediment.
As previously stated many of the boulders have a laminated
structure. When such boulders disintegrate the laminae break
up, giving rise to the flattened pieces to which the term plate
rock is applied. In this connection it is interesting to observe
that the plate rock occurs in those sections of the field in which
the phosphate deposits now lie above the water level, and have
been subjected to disintegrating influences. The plate rock
deposits, as at Anthony and Sparr, form a comparatively thin cov-
ering over the Vicksburg Limestone and represent, in the writer's
interpretation, the disintegrated remnant of an ordinary hard rock
phosphate deposit.
The gravel found mixed with the hard rock very possibly
represents in part small bits of rock that have become phos-
phatized and in part fragments of larger rocks. The soft phos-
phate associated with the hard rock has very generally been
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ORIGIN OF THE HARD ROCK PHOSPHATES.
regarded as resulting from the disintegration of the hard rock,
although a part of the soft phosphate may be merely phosphatic
clays.
LOCALIZATION OF THE HARD ROCK DEPOSITS.
The localized nature of the hard rock deposits within the
formation is with little doubt explained by the variable character
of the materials in which it occurs. As has been previously
stated, the deposits of phosphate boulders are to some extent
associated with local clay lenses. Such an association is a priori
natural since clay interferes with the free circulation of the per-
colating water. On the other hand, when the matrix is chiefly
sands with uniform and open texture, through which the water
moves readily, the conditions are not favorable for the chemical
deposition of phosphate. However, occurrence of the rock can
not be expected to follow too closely the structural conditions as
now observed since, as has already been explained, the whole phos-
phate producing section has been subjected to erosion by solution,
which permitted irregular and intermittent local subsidence, thus
thoroughly mixing the materials and moving them more or less
from their original location.
LIMITATION OF THE HARD ROCK PHOSPHATES.
There yet remains the problem of the limitation of the hard
rock phosphate to a particular and well recognized physiographic
type of country. That the phosphate beds are so confined has
long been apparent to those actively engaged in prospecting for
and mining phosphate as well as to those who have investigated
the deposits from a scientific standpoint. The accompanying map
from the Fourth Annual Report of the Florida Geological Survey
outlines in a general way the several physiographic types of the
limestone section of Central Florida. In the light of what has
previously been written, together with the legend, the map is
largely self-explanatory. Four well defined physiographic types
are recognized as follows: The Gulf Hammock Belt, The Hard
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FLORIDA STATE GEOLOGICAL SURVEY.
Rock Phosphate Belt, The Middle Florida Hammock Belt, and
The Lake Region.
Immediately adjacent to the Gulf coast, in northern Peninsular
Florida and for a few miles inland, the limestone lies at or very
close to the surface. The underground water level is near the
surface, and numerous large springs of limestone water emerge
from the rock and flow to the ocean. This coastal strip contains
numerous extensive calcareous hammocks and is known as the
Gulf Hammock section of Florida. If formations later than the
Oligocene limestones were formerly present over the Gulf Ham-
mock area they have, with the exception of a slight residue of
sand, disappeared. The Gulf Hammock section, west of Suwan-
nee River, is underlaid by the Upper Oligocene limestones, while
east of the Suwannee River the underlying formation is chiefly
the Lower Oligocene limestone.
Inland from the Gulf Hammock area,- in Peninsular Florida, is
found a strip of country over which formations of later age than
the Lower Oligocene were clearly present in former times,
although there now remains of these scarcely more than the
mixed and complex residue. The strip of country of this type
extends in well marked development from the southern part of
Suwannee and Columbia Counties, roughly paralleling the Gulf
coast to Hernando and Pasco Counties. This area includes the
hard rock phosphate deposits, these deposits having accumulated
by the processes elsewhere explained during the period of erosion
through which this section has passed. Few lakes or streams are
found in the hard rock phosphate belt, as the rainfall enters
through the loose surface material and passes directly into the
underlying limestone. The underground water level lies, as a
rule, at a greater depth beneath the surface than in the Gulf
Hammock country. Numerous sinks form, giving evidence of
the continued active erosion by underground solution. The sur-
face contour is rolling, there being no regularity of hills or valleys.
Inland from the hard rock phosphate belt is found areas less
affected by erosion, in which more or less of the formations that
originally overlaid the Vicksburg Limestone may be identified
in position. This type of country is known as the Middle Florida
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ORIGIN OF THE HARD ROCK PHOSPHATES.
Hammock Belt. In this type of country the surface is rolling,
or somewhat hilly and occasionally flat bottomed lakes are found,
which occupy solution basins. The soils on the slopes are pre-
vailingly red with red clay sub-soil. Surface streams occur,
although most of these terminate either in lakes or in sink holes
through which they gain entrance to the underlying limestones,
forming the disappearing streams characteristic of this type of
country. In peninsular Florida two areas of Middle Florida
Hammock lands may be designated. One of these includes a
narrow belt extending in a northwest to southeast direction,
through Columbia and Alachua Counties, into Marion County,
A small part of Suwannee County, east of Houston, along the
Seaboard Air Line Railway, is also included. This belt occupies
the border land between the limestone and non-limestone country
of this part of the State. The second well marked area is that
which extends north and south through Citrus, Hernando and
Pasco Counties, and is surrounded on all sides by more intensely
eroded limestone country. A third large area of this type of
country lies west of the Suwannee River, including the northern
part of Leon, Jefferson and Madison Counties. Temporary lakes,
rolling topography, good drainage, and red clay soils are charac-
teristic features of this stage of topographic development.
The Lake Region of Florida, as a physiographic type, has long
been known and often referred to in the literature of Florida.
This type of topography includes a large area, extending from
Clay County, on the north, to near the middle of DeSoto County,
on the south, its greatest width being found in Lake and Orange
Counties. It is cut into by the St. Johns, Oklawaha and With-
lacoochee Rivers. Aside from these rivers surface streams are
few, the rainfall passing into the soil. Lakes, as implied by the
name, are extremely numerous in this section of the country.
They are of a characteristic type, being usually deep, circular in
outline and bordered by abrupt sloping banks. They are entirely
distinct from the temporary, flat bottomed, shallow lakes of the
Middle Florida Hammock Belt.
The lake region represents, in the writer's interpretation, an
early stage in the degradation of the surface level by under-
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FLORIDA STATE GEOLOGICAL SURVEY.
ground solution. The many basins now occupied by lakes have
been formed by subsidence due to solution. Following the
formation of the basins the surrounding uplands are gradually
lowered, the tendency being to fill up the basins and to reduce
the land surface once more to a common, although lower level.
An examination of the accompanying map, on which the lake
region is separately indicated, bears out the view that this region
represents the further southeastward migration of the limestone
country of the peninsula.
It is not necessary to assume that the hard rock phosphate
belt has passed through a stage of development identical with
that of either the lake region or the Middle Florida Hammock
Belt. Differences in the thickness and character of the forma-
tions, or of the drainage, or other conditions may have modified
the results in this region. Certain it is, however, that the lime-
stone region of Central Florida is encroaching on the non-lime-
stone areas to the east. Whether or not what is now the hard
rock phosphate belt passed through the typical lake region topo-
graphy, it is at least a reasonable inference that lakes more or
less extensive existed in the earlier stages of the development of
this area.
ECONOMIC RELATION.
The economic bearing of the observation that the hard rock
phosphate is confined to a particular physiographic type is im-
portant. Although within the area careful and expensive pros-
pecting is necessary to locate the individual deposits, yet to pros-
pect for hard rock phosphate outside of the particular physio-
graphic type of country with which the hard rock phosphates are
associated is recognized as useless. No hard rock phosphate is
to be expected, for instance, in the lake region nor elsewhere in
the non-limestone areas of Florida, nor in the Middle Florida
Hammock Belt, except possibly in such local areas as have by
more rapid erosion passed into the stage in which hard rock
phosphate accumulates.
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BIBLIOGRAPHY OF PUBLICATIONS ON THE PHOS-
PHATES OF FLORIDA.
The entries in the bibliography are arranged in chronological
order, or as nearly so as is practicable. Those papers not seen
by the writer are indicated by an asterisk. To facilitate reference
an alphabetical index of authors is given, the date of publication
which follows the name indicating the place of the author's paper
in the bibliography.
ALPHABETIC INDEX TO AUTHORS CITED IN THE BIBLI-
OGRAPHY.
Blair, A. W., 1908.
Brown, Lucius P., 1904, 1912.
Carnot, Adolphe, 1896.
Codington, E. W., 1896.
Collison, S. E., 1911.
Cox, E. T., 1890, 1891, 1892, 1896.
Dall, W. H., 1891, 1892, 1896.
Darton, N. H., 1891.
Davidson, Walter B. M., 1891, 1893.
Eldridge, George H., 1893.
Florida State Geological Survey, 1908.
Fuller, Myron L., 1907.
Goldsmith, E., 1890.
Hawes, George W., 1883.
Hovey, Edmund Otis, 1904.
Jackson, Granberry, 1907.
Johnson, Lawrence C., 1885, 1893.
Jumeau, L. P., 1905, 1906.
Kost, J., 1887.
LeBaron, J. Francis, 1893.
Ledoux, Albert R., 1890.
McCallie, S. W., 1896.
Matson, George C., 1909.
Memminger, C. G., 1910.
Mendenhall, H. D., 1908.
Millar, C. C. Hoyer, 1891, 1892.
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FLORIDA STATE GEOLOGICAL SURVEY.
Murray, John, 1886.
Parker, Edward W., 1900.
Penrose, R. A. F., 1888.
Persons, A. A., 1893.
Pickel, J. M., 1890, 1891.
Pratt, N. A., 1868, 1892.
Schrader, Jay, 1890, 1891.
Sellards, E. H., 1909, 1910, 1911.
Shaler, N. S., 1893.
Shepard, Charles Upham, 1893.
Smith, E. A., 1884, 1885.
Struthers, Joseph, 1902.
United States Geological Survey, 1883.
Van Horn, F. B., 1908.
Vaughan, T. Wayland, 1910.
Waggaman, William H., 1911.
Wells, G. M., 1896.
Willis, Edward, 1892.
Wright, Carroll D., 1893.
Wyatt, Francis, 1890, 1891.
LIST OF PAPERS ARRANGED CHRONOLOGICALLY.
1868. Pratt, N. A.:
Ashley River Phosphate. History of the Marls of South
Carolina, and of the Discovery and Development of the
native bone Phosphates of the Charleston Basin. 42
pp., Philadelphia, Pa. 1868.*
In connection with an elaboration of the coral reef
theory of the development of the mainland of Florida in
this report, reference is made to coprolite or guano-like
deposits of birds, reptiles and fishes, from which the soluble
ingredients have been dissolved, leaving the insoluble lime
phosphate.
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BIBLIOGRAPHY OF FLORIDA PHOSPHATES.
1883. Hawes, Geo. W.:
On a Phosphatic Sandstone from Hawthorne, in Florida,
Nat. Mus. Proc. for 1882. Pp. 46-48, 1883.
This paper contains an analysis of phosphatic rock
from the quarry of C. A. Simmons. This was, perhaps, the
first definitely reported analysis of phosphatic rock from
Florida.
1883. United States Geological Survey:
The volume on Mineral Resources of the United States
for 1882, p. 523, published in 1883, reports the occur-
rence of phosphatic marls in Florida, in Clay, Alachua,
Wakulla, Duval and Gadsden Counties.
The volume for 1883-84, pp. 793, published in 1885,
contains a reference to the occurrence of phosphate rock
in Clay, Alachua, Duval, Gadsden and Wakulla Counties.
The volume for 1885, p. 450-453, published in 1886,
contains additional notes based on investigations of Mr.
Lawrence C. Johnson during 1884 and 1885.
The volume for 1886, published in 1887, contains, page
617-618, notes on the examination of phosphate by Dr. J.
Kost in Wakulla County.
The volume for 1887, published in 1888, page 584,
notes the developments which were in progress on the
Peace River, near Arcadia, in DeSoto County, Florida.
The volume on Mineral Resources for 1888 and the
subsequent volumes of the series give the production of
phosphate rock in Florida for each succeeding year, with
occasional notes in regard to the development of the
deposits.
1884. Smith, Eugene A.:
Report on the Cotton Production of the State of Florida,
with an account of the general agricultural features of
the State. U. S. 10th Census, VI, Rept. Cotton Prod.,
pt. 2, pp. 175-258, 1884.
The analysis of the phosphatic rock from Hawthorne
is included in this paper, with comment on the value of the
rock as a fertilizer.
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FLORIDA STATE GEOLOGICAL SURVEY.
1885. Smith, Eugene A.:
Phosphatic Rocks of Florida. Science, V, pp. 395-396.
1885.
In his earlier paper, 1884, Dr. Smith had assumed that
the phosphatic rock at Hawthorne, which he had not seen,
was of Vicksburg age. On the basis of information
supplied to him by L. C. Johnson, and from the examina-
tion of a hand specimen he concludes that the rock is of
Miocene age.
1885. Johnson, Lawrence C.:
(Phosphatic Rocks of Florida.) Science, V, pp. 396, 1885
This publication is in the form of a letter to Dr. E. A.
Smith. In this letter Johnson reports phosphatic rock
from various localities in Florida, among which are Pres-
ton's Sink, Nigger Sink and Live Oak. Evidence is
presented to show that these phosphatic rocks are of later
age than the Vicksburg.
1886. Murray, John:
Report on the Specimens of Bottom Deposits. Report on
results of dredgings under the supervision of Alexander
Agassiz in the Gulf of Mexico, in the Caribbean, and
along the Atlantic Coast of the United States by the
U. S. S. Blake. Mus. Comp. Zool., XII, No. 2, pp. 37-
61, 1885;* abst. Am. Jour. Sci., (3) XXXI, pp. 221-
225, 1886.
Records the occurrence of concretions of phosphate of
lime in the Strait of Florida.
1887. Kost, J.:
First Report of the Geological Survey of Florida, 31 pp..
Tallahassee, 1887. Abst. Science, IX, 446-447, 1887.
In this paper, pp. 21-24, Kost reports the examination
of phosphatic limestone, sandstone and marl in Wakulla,
Alachua, Marion, Hillsboro and Manatee Counties. An
analysis is included of the phosphatic sandstone from near
Sopchoppy in Wakulla County.
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BIBLIOGRAPHY OF FLORIDA PHOSPHATES.
1888. Penrose, R. A. F., Jr.:
Nature and Origin of Deposits of Phosphate of Lime, with
an introduction by N. S. Shaler. U. S. Geol. Surv.
Bull., 46, 143 pp., 3 pls., 1888.
This paper includes a general review of all phosphate
deposits known at that time. The phosphate deposits of
Hawthorne and vicinity were personally examined.and are
described on pages 78 and 79. The report contains a
bibliography of publications on phosphate.
1890. Shrader, Jay:
Florida. The Underground Wealth and Prehistoric
Wonders of Polk and DeSoto Counties, 34 pp. Bartow,
1890.*
An account of the phosphate mining industry as
developed at that time is included in this report.
1890. Ledoux, Albert R.:
The Newly-discovered Phosphate Beds of Florida. New
York Acad. Sci. Trans., IX, pp. 84-94, February, 1890;
Eng. Min. Jour., XLIX, 175-177, 1890; Sci. Am. Supp.,
XXX, 12104-12105, No. 758, 1890. Read before the
New York Academy of Science January 27, 1890.
This paper contains a description of the hard rock
phosphate deposits in Marion, Citrus and Hernando
Counties, based on examination made in 1889 or 1890, and
soon after the hard rock deposits were discovered. Refer-
ence is made to an earlier publication on the hard rock
phosphate at Dunnellon by Professor W. P. Frost, of
Savannah. The place of publication of Prof. Frost's paper,
however, is not given.
1890. Pickel, J. M.:
Florida Phosphate. Fla. Agri. Exp. Station, Bull. 10, pp.
6-11, July, 1890.
A brief account of the Florida phosphates from samples
received for analysis, and brief notes on the discovery of
the deposits.
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FLORIDA STATE GEOLOGICAL SURVEY.
1890. Wyatt, Francis:
Notes on the Florida Phosphate Beds. Eng. Min. Jour.
L, pp. 218-220, August, 1890.* Extract in Florida,
South Carolina and Canadian Phosphates, by C. C.
Hoyer Millar, pp. 85-87, and 116-117, 1892.
Wyatt comments in this paper on the local or pocket
nature of the hard rock phosphate deposits.
1890. Cox, E. T.:
An Extensive Deposit of Phosphate Rock in Florida. Am.
Nat. XXIV, 1185-1186, 1890.*
The term Floridite is proposed in this paper for the
Florida hard rock phosphate.
1890. Goldsmith, E.:
Pea-Like Phosphate from Polk County, Florida. Acad.
Nat. Sci., Phila., Proc. X. (/2 p.), 1890.
Contains a brief description of the microscopic struc-
ture of pebble phosphate from Ft. Meade. Acicular
crystals of apatite were found imbedded in amorphous
silica.
1891. Pickell, J. M.:
Comparative Value of Raw Finely Powdered Phosphate
and of Acidulated Phosphate as a Fertilizer. Fla. Agri.
Exp. Station, Bull. 13, pp. 12-15, April, 1891.
This paper gives a review of experiments in the use of
raw phosphates conducted by other investigators with an
opinion as to the application of the results to the Florida
phosphates.
1891. Millar, C. C. Hoyer:
The Phosphate Fields of Florida. 48 pp.* Eden, Fisher
& Co., London, 1891.
This paper is based on an examination of the Florida
phosphate deposits in 1890.
1891. Wyatt, Francis:
The Phosphates of America,* 187 pages, New York, 1891.
Abst. Eng. Min. Jour., Vol. 53, pp. 202-204, 1892.
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BIBLIOGRAPHY OF FLORIDA PHOSPHATES.
1891. Shrader, Jay:
Hidden Treasures, Bartow, 1891.* Extract included in
The Phosphate Industry of Florida by Carroll D.
Wright, Sixth Special Report of the Commissioner of
Labor, p. 39, 1893.
An account is included in this pamphlet of the discovery
by J. Francis LeBaron of pebble phosphate on Peace
Creek in 1881.
1891. Cox, E. T.:
Floridite: A New Variety of Phosphate of Lime. Am.
Assoc. Adv. Sci. Proc., XXXIX, pp. 260-262, 1891.
Read before the Indianapolis meeting, Amer. Assoc. for
the Advancement of Sci., August, 1890.
In this paper Cox advances the theory that the hard
rock phosphate represents ancient guano which has become
mineralized.
1891. Dall, W. H.:
On the Age of the Peace Creek Beds, Florida. Acad. Nat.
Sci., Phila., Proc. 120, (1-3 p.), 1891; abst. Am. Geol.
VII, 382, 1891.*
1891. Darton, N. H.:
Notes on the Geology of the Florida Phosphate Deposits.
Am. Jour. Sci. (3) XLI, pp. 102-105, February, 1891;
abst. Eng. Min. Jour. LI, p. 210 (1Y2 cols.), 1891.
Guano is regarded by Darton as a probable source of
the rock phosphate. The phosphate of Polk County is
referred to as a conglomerate and is believed to have been
derived from the hard rock phosphates.
1891. Davidson, Walter B. M.:
Suggestions as to the Origin and Deposition of Florida
Phosphate. Eng. Min. Jour. LI, pp. 628-629, 1891.*
Regards the hard rock phosphate boulders as having
been deposited in underground caverns and river beds in
the Vicksburg Limestone.
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FLORIDA STATE GEOLOGICAL SURVEY.
1892. Millar, C. C. Hoyer:
Florida, South Carolina, and Canadian Phosphates. Eden
'Fisher and Company, London, 223 pp, 1892.
The description of the Florida deposits is found on
pages 23 to 122 and includes a general account of the land
pebble, river pebble, hard rock, and plate rock deposits.
1892. Cox, E. T.:
(The Land and River Pebble Phosphate Deposits of Flor-
ida), Amer. Assoc. Adv. Science, Washington meeting
August, 1891.*
In this paper Floridalite is suggested in place of Flor-
idite previously proposed for the Florida hard rock phos-
phates.
1891. Davidson, Walter B. M.:
A Phosphatic Chalk at Taplow, England. Eng. Min. Jour.
LII, p. 502 (2-3 col.), 1891.*
1892. Dall, W. H. and Harris, G. D.:
Correlation Papers: Neocene of North America. U. S.
Geol. Sur. Bull. 84, 1892.
The description of the Florida Phosphate deposits by
Dall is found on pages 134 to 140. The hard rock phos-
phates are regarded as having originated from guano.
1892. Pratt, N. A.:
Florida Phosphates. The Origin of the Boulder Phosphates
of the Withlacoochee River District.* Eng. Min. Jour.
LII1, p. 380, 1892.
In this paper the theory is advanced that the phosphate
boulder is a true fossil, the boulder being the phosphatic
skeleton of a gigantic foraminifera, while the soft phos-
phate is supposed to be the germ spores or bud of the ani-
mals, or the comminuted debris of the animals themselves.
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