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STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
BUREAU OF GEOLOGY
Robert O. Vernon, Chief
GEOLOGICAL BULLETIN NO. 52
ANCIENT SEA LEVEL STANDS IN FLORIDA
By
E.C. Pirkle, W.H. Yoho, and C.W. Hendry, Jr.
Published for
BUREAU OF GEOLOGY
DIVISION OF INTERIOR RESOURCES
FLORIDA DEPARTMENT OF NATURAL RESOURCES
TALLAHASSEE
1970
STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
BUREAU OF GEOLOGY
Robert O. Vernon, Chief
GEOLOGICAL BULLETIN NO. 52
ANCIENT SEA LEVEL STANDS IN FLORIDA
By
E.C. Pirkle, W.H. Yoho, and C.W. Hendry, Jr.
Published for
BUREAU OF GEOLOGY
DIVISION OF INTERIOR RESOURCES
FLORIDA DEPARTMENT OF NATURAL RESOURCES
TALLAHASSEE
1970
^/ -----7
DEPARTMENT
OF
NATURAL RESOURCES
CLAUDE R. KIRK, JR.
Governor
TOM ADAMS
Secretary of State
BROWARD WILLIAMS
Treasurer
FLOYD T. CHRISTIAN
Commissioner of Education
EARL FAIRCLOTH
Attorney General
FRED O. DICKINSON, JR.
Comptroller
DOYLE CONNER
Commissioner of Agriculture
W. RANDOLPH HODGES
Executive Director
BULLETIN NO. 52
ERRATA
PAGE
5 Line 2-Insert comma after (stippled pattern),
7 In body of table, 3rd column, lines 10, 11, 12,-168' should be 268'
168'6" should be 268'6"
170' should be 270'
10 In body of table, 4th column, line 3-4.18 should be 34.18
12 Heading "Insoluble Residue" should be centered over columns "Quartz
sand in %" and "Clay (-325 mesh) in %"
13 Same as page 12
21 In heading, following Hawthorn Formation, Miocene delete (elev. 36 ft)
In body of table, following Hawthorn Formation, Miocene delete (elev.
41 ft)
In body of table, following Crystal River Formation, Eocene-add
minus sign (-) before 87 to read (elev. -87 ft.)
22 Line 1-Asterisk goes after table heading
In body of table under Finely laminated sands, 4th column, line
4-insert .04
24 Line 1-Asterisk goes after table heading
Line 2-Percentage should be percentages
25 End of table-insert "*Sample numbers correspond to those of the
detailed log in the appendix."
49 Paragraph after Spl. 7 beginning at asterisk-should be at bottom of
page
50 Last line-should be at top of p. 51 before number 29 description
55 Paragraph after Spl. 7 beginning at asterisk-should be at bottom of
page
LETTER OF TRANSMITTAL
Bureau of Geology
Tallahassee
June 16, 1970
Honorable Claude R. Kirk, Chairman
Department of Natural Resources
Tallahassee, Florida
Dear Governor Kirk:
This report was prepared in cooperation with the University of Florida and is
the first of several that will result from a study of the heavy minerals in Florida.
It was undertaken to gain a better understanding of the environment of
deposition of known heavy mineral deposits. It will enable others to accertain
likely areas where these minerals will occur. Since heavy minerals are associated
with shore and near-shore features this study of "Ancient Sea Level Stands in
Florida" lends itself to this end.
Respectfully yours,
R. O. Vernon, Chief
iii
Completed manuscript received
June 16, 1970
Prepared by the Bureau of Geology
Division of Interior Resources
Florida Department of Natural Resources
Tallahassee, Florida
iv
CONTENTS
Page
Acknowledgments .............. ............................ vii
Introduction ..... .. .............................. .... ............ 1
Description of sediments penetrated ........ ......... ... .... .......... 4
Trail Ridge drill holes .... ........... ............... .... ........ 4
Trail Ridge sequence ......... ..... .. ............ .............. 4
Post-Hawthorn clastics ........... ............ . . . . . ...... 18
Late Miocene shell marl ............. .... ........ .......... 18
Hawthorn Formation .................... ......... ....... ... ..18
Baywood Promontory drill hole .. . . . . . . . . . 19
Surface sands ................. ..... ............ .............19
Olive-green clays of Post-Hawthorn plastics .......... ................. 26
Late Miocene shell marl .................. ............ ....... ... 26
Hawthorn Formation ............. ..... .......... ..... ......26
Heavy minerals in sediments ............... . . ...... ............ 27
Trail Ridge drill holes ................ . .................... . 27
Baywood Promontory drill hole . . . . ...... ......... ......... 28
Ridges in study area ......... ........................... ...........28
Trail Ridge . ........................ .... ............ .........29
Baywood Promontory ........ ........................ ... ........30
Elevations of sea-level stands .. .......... ...... ..... ..... ...... .... 31
Present interpretation .......... . .. ...................... .........32
References ..... ................. ..... ....... .... ..... .......... 35
Appendix ............. .. ..... .......................... .......... 37
ILLUSTRATIONS
Figure
1 Location map. Heavy lines indicate the crests of ridges discussed in the report . . 3
2 Map of study area in western Clay and eastern Bradford counties showing the
Trail Ridge ore body . . . . . .................... ........ 5
TABLES
1 Marine terraces in Florida ................... . . . . . . . 2
2 Trail Ridge drill hole No. 1. (NE , SE 4, section 31, T. 6 S., R. 23 E., Clay County,
Florida). ........................ ........................... 6
3 Trail Ridge drill hole No. 1. (Mechanical analyses of quartz sand extracted from
sediments). ........................ ......................... 8
4 Trail Ridge drill hole No. 1. (Percentages of selected heavy minerals in 1/8 to 1/16 mm
fraction) ........ ..... .. ........ .................... .......... 10
5 Trail Ridge drill hole No. 2. (NE , NW , section 19, T. 5 S. R. 23 E., Clay County,
Florida) .......... ............................................ 12
6 Trail Ridge drill hole No. 2 (Mechanical analyses of quartz sand extracted from sediments). 14
7 Trail Ridge drill hole No. 2. (Percentages of selected heavy minerals in 1/8 to 1/16 mm
fraction) ........... ............. .............. ..... ..... .... 16
8 Baywood Promontory drill hole (SW , NW 4, section 18, T. 9 S., R. 25 E., Putnam
County, Florida) .............. .. ................. . ......... 20
9 Baywood Promontory drill hole (Mechanical analyses of quartz sand extracted from
sediments) ........... .......................................... 22
10 Baywood Promontory drill hole. (Percentages of selected heavy minerals in 1/8 to 1/16
mm fraction)................................................ 24
ACKNOWLEDGMENTS
The writers are indebted to Guy C. Omer of the Physical Sciences
Department, University of Florida; Floyd M. Wahl of the Department of
Geology, University of Florida; and Robert O. Vernon of the Bureau of
Geology, Florida Department of Natural Resources for their cooperation. Most
of the analyses presented in the report were run in laboratory space and with
facilities provided by the Physical Sciences Department and the Department of
Civil Engineering at the University of Florida. The holes through Trail Ridge and
the Baywood Promontory were drilled by the Bureau of Geology. The P20s
analyses given in various tables were run by Thornton and Company of Tampa,
Florida.
Thomas E. Garnar, C. D. Hewett and the late W. G. Few of the E. I. du Pont
de Nemours and Company made significant contributions to the work through
stimulating discussions and by providing technical information.
The writers are indebted to Fred Pirkle and Bill Pirkle for their help in the
field work and to Justin Hodges and James Hodges for their care and interest in
carrying out the drilling assignments necessary for a successful program. Special
thanks are extended to Mrs. Phyllis Clarke and Mrs. Bonnie Elferdink for
organizing data presented in the report and for typing the manuscript.
To the organizations and individuals aiding in this study, the writers express
their deep gratitude. Only the authors, however, should be held responsible for
the contents of the report.
vii
ANCIENT SEA-LEVEL STANDS IN FLORIDA
By
E. C. Pirkle, W. H. Yoho,1 and C. W. Hendry, Jr.2
INTRODUCTION
Most sand ridges in interior Florida are considered to be barrier islands, beach
ridges or spits formed along ancient shore lines. Different investigators, however,
give different elevations to which ancient seas rose and assign different ages for
shore lines and shore-line features (Table 1). Most of the elevations of old shore
lines presented by various workers have been determined from surface studies,
primarily from physiographic evidences. Some attempts have been made to use
fossil occurrences (Alt and Brooks, 1965).
Trail Ridge and the Baywood Promontory are two of the most conspicuous
ridges in the northern part of peninsular Florida, as shown in figure 1. Recently
two holes were drilled through the sediments forming the southern part of Trail
Ridge, and one hole was drilled through the sediments of the Baywood
Promontory. By means of a specially designed core barrel, almost 100 per cent
recovery of cores of loose to slightly consolidated sands composing the ridges
was obtained. Detailed analyses were made of these sands and all other
sediments penetrated. The writers are not aware of any previous attempts to
utilize characteristics revealed by these kinds of data as aids in studying old
shore-line elevations or associated sand.ridges in Florida. The purpose of this
report is to demonstrate the value of these data to the studies of ancient sea-level
stands in peninsular Florida.
'Department of Physical Sciences and Department of Geology, University of Florida,
Gainesville, Florida.
Bureau of Geology, Florida Department of Natural Resources, Tallahassee, Florida.
BUREAU OF GEOLOGY
TABLE 1. MARINE TERRACES IN FLORIDA
Terrace Elevation Age
After Cooke (1945)
Brandywine 270 feet Aftonian
Coharie 215 feet Yarmouth
Sunderland 170 feet Yarmouth
Wicomico 100 feet Sangamon
Penholoway 70 feet Sangamon
Talbot 42 feet Sangamon
Pamlico 25 feet Wisconsin
After MacNeil (1949)
Okefenokee 150 feet Yarmouth
Wicomico 100 feet Sangamon
Pamlico 25 to 35 feet Wisconsin
Silver Bluff 8 to 10 feet Recent
After Vernon (1951)
Coharie 220 feet Aftonian
Okefenokee 150 feet Yarmouth
Wicomico 100 to 105 feet Sangamon
Pamlico 25 to 30 feet Wisconsin
After Alt and Brooks (1965)
215 to 250 feet Upper Miocene
90 to 100 feet Pliocene
Insignificant stand 70 to 80 feet Pliocene or Pleistocene
Insignificant stand 45 to 55 feet Pliocene or Pleistocene
25 to 30 feet Pleistocene
BULLETIN NO. 52
O 25 50 75
APPROX. MILES
NORTH
Figure 1. Location map. Heavy lines indicate the crests of ridges discussed in the report.
BUREAU OF GEOLOGY
DESCRIPTIONS OF SEDIMENTS PENETRATED
TRAIL RIDGE DRILL HOLES
The site of Trail Ridge drill hole no. 1 (TR No. 1) is about 2/3 mile south of
State Road 230 and 5 miles east of Starke, shown in figure 2. The surface
elevation at the locality is 239 feet above sea level. This hole, drilled to a depth
of 332 feet, penetrated about 18 feet into the Crystal River Formation of late
Eocene age. Three sequences of sediments were encountered over the Crystal
River Formation. From the land surface downward these materials are the Trail
Ridge sequence, the post-Hawthorn clastics and the Hawthorn Formation.
Characteristics of these sediments are shown by data given in Tables 2 through 4
and by a detailed log in the Appendix.
Trail Ridge drill hole no. 2 (TR No. 2) was drilled through Trail Ridge at a
locality about 8 miles north of TR No. 1 (Fig. 2). The site is on the crest of the
ridge approximately 2 miles northeast of Lawtey and about 200 feet south of
State Road 215. The surface elevation at this site is 206 feet above sea level. The
hole was drilled to a depth of 146 feet, passing through the Trail Ridge
sequence, the post-Hawthorn clastics, and penetrating about 2 feet into a late
Miocene shell bed. The Hawthorn and Crystal River formations were not
reached. Characteristics of the sediments encountered are illustrated by data in
Tables 5 through 7 and by a detailed log in the Appendix. Both this hole and TR
No. 1 were drilled through the heavy mineral ore body of the E.I. du Pont de
Nemours and Company.
The cores from these core holes are on file at the Bureau of Geology, corner
of Tennessee and Woodward Streets, Tallahassee, Florida. The file numbers are
W-10488 for TR No. 1, and W-10489 for TR No. 2.
TRAIL RIDGE SEQUENCE
The Trail Ridge sequence consists of two zones, an upper quartz sand zone,
and a lower zone of intercalated layers or lenses of peaty or sapropelic sediments
and quartz sand. The Trail Ridge sequence in the TR No. 1 drill hole extends
downward from the land surface to a depth of approximately 90 feet, or from a
surface elevation of 239 feet above sea level to an elevation of 149 feet above sea
level. Within this sequence the upper quartz sand zone extends downward to a
depth of 63 feet (Spls. 1-13, Table 2); the lower zone continues downward for
another 27 feet (Spls. 14-21, Table 2).
The Trail Ridge sequence in TR No. 2 has a thickness of 59 feet, extending
from the land surface, elevation 206 feet, to a depth that is 147 feet above sea
level. The upper quartz sand zone is 46 feet thick (Spls. 1-17, Table 5); the
intercalated layers or lenses of sapropelic sediments and quartz sand of the lower
zone have a total thickness of 13 feet (Spls. 18-25, Table 5).
The lower zone of the Trail Ridge sequence is characterized by layers or
lenses of sediments carrying wood and finely-divided organic matter. The upper
BULLETIN NO. 52
TRAIL RIDGE
ORE BODY_ "
TR No.2.
moo
21
KINOSLEY 13
STARKE 2K I
HIE I GH0 i:
AI2
1I 0 I 2 3 4 5 oo5
CITRONELLE
SEDIMENTS MILES NORTH CONTOUR
Figure 2 Map study area in western Clay and eastern Bradford counties showing the Trail
Ridge Ore body (strippled pattern) the locations of Trail Ridge #1 and #2 drill holes, and
localities from which surface samples were collected. Trail Ridge type sands are indicated by
squares. Sands of the Baywood Promontory type (sometimes called Atlantic Coast type) are
shown by circles. Sites of samples that do not give analyses similar to either the Trail Ridge
type or the Baywood Promontory type are indicated by triangles. The 200-foot contour line
is shown and the outline of Citronelle sediments as mapped by Clark et al (1964) is given to
aid in fixing positions from which the samples were taken, Modified from Pirkle andYoho
(1970).
BUREAU OF GEOLOGY
TABLE 2. TRAIL RIDGE DRILL HOLE NO. 1*
NE14, SE4, Section 31, T. 6 S., R. 23 E., Clay County, Florida
Approximately 41/2 Miles Southeast of Starke
Surface Elevation, 239 Feet
Insoluble Residue
Clay
Depth in Quartz (-325 Total Total
feet and sand mesh) soluble P205 heavies
Spl. Unit inches in % in % in % in % in %
Surface Sands (elev. 239 ft.)
0-1'3" 95.91 2.89
1'3"-5' 92.64 4.58
5'-10' 94.13 3.16
10'-17'6" 92.34 6.37
17'6"-25' 97.13 1.70
25'-30' 96.13 2.68
30'-35' 96.54 2.39
35'-40' 97.84 1.40
40'-45' 97.31 1.20
45'-50' 98.27 .60
50'-55' 98.94 .14
55'-60' 98.43 .10
60'-63' 98.53 .40
1.80
2.43
3.46
3.34
- 3.02
4.02
2.48
2.12
13.54
16.29
9.78
8.82
2.55
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
Hawthorn Formation, Miocene (elev. 100 ft.)
138'6"-140'6" 66.29 19.69 13.43
140'6"-143' 11.45 3.78 84.69
143'-150' 23.17 11.16 65.65
150'-155'6" 26.46 13.17 60.22
155'6"-156'6" 6.59 5.59 87.82
156'6"-158' 32.57 7.74 59.61
158'-172' 31.30 8.84 59.80
175'-180' 66.37 10.19 23.27
180'-185' 47.33 6.82 45.68
3.06
1.71
4.34
7.36
.88
2.55
2.52
4.73
3.45
1.22
.90
.55
.65
.70
.90
.43
.63
.44
.60
.60
.47
.60
.13
.45
1.01
.91
.47
.34
.36
.30
.05
.78
.24
.07
.11
.13
.02
.14
.10
.15
.09
59
59
58
58
57
57
57
57
57
57
57
57
57
Layers of peaty or sapropelic sediments and quartz sand (elev. 176 ft.)
56 63'-68' 8.39 .01 --
55 68'-73' 89.70 3.20 -
54 73'-74'6" 83.98 12.52 -
53 74'6"-77" 92.36 4.79 -
52 77'-78" 85.53 11.98 -
51 78'-80'6" 96.25 2.29 -
50 80'6"-84'6" 68.91 28.22 --
49 84'6"-86' 77.65 20.37 --
Layers of quartz sand. clayey sand and massive olive-drab clay (elev. 149 ft.)
47 90'-94' 95.91 3.21 -
47 95'-1'00' 93.93 4.38 -
47 100'-106' 89.46 7.80 -
46 106'-107' 13.16 75.92 -
45 107'-108'6" 61.04 13.72 -
44 108'6"-110' 9.05 88.21 -
43 110'-112'9" 95.63 2.72 -
42 112'9"-115' 77.57 12.59 -
41 115'-118' 72.13 20.14 -
41 118'-121' 40.05 45.74 --
40 121'-124' 53.51 40.02 --
39 124'-126' 86.45 11.12 -
38 126'-130' 96.70 1.87 --
37 130'-135' 4.27 92.53 --
36 135'-138'6" 94.58 3.99 --
35
34
33
32
31
30
29
27
26
BULLETIN NO. 52
TABLE 2. TRAIL RIDGE DRILL HOLE NO. 1 Continued
Insoluble residue
Clay
Depth in Quartz (-325 Total Total
feet and sand mesh) soluble P205 heavies
Spl. Unit inches in % in % in % in % in %
46 25 185'-190' 47.85 17.56 33.92 1.99 .19
47 24 190'-194' 41.35 29.12 28.00 1.63 .28
48 23 194'-201'6" 17.01 6.83 75.79 1.72 .06
49 22 201'6"-206' 57.95 20.77 20.17 3.16 .20
50 21 206'-212'6" 38.05 5.37 56.52 6.07 .21
51 19 222'-231' 75.03 7.35 17.42 1.40 .52
52 17 237'-240' 46.92 15.17 37.33 1.31 .42
53 15 252'-254' 10.38 9.58 79.96 .63 .06
54 14 254'-257' 55.22 18.77 25.55 2.60 .29
55 13 257'-168' 7.64 76.08 15.10 1.29 .03
56 12 268'-168'6" 1.00 .03
57 11 268'6"-170' 4.73 54.11 40.88 .84 .03
58 10 270'-271'6" 4.84 17.01 78.11 .34 .04
59 8 282'-287' 19.11 7.07 73.66 4.47 .18
60 8 282'-287' 1.75 16.53 81.64 1.72 .03
61 7 287'-290' 10.12 8.28 80.71 1.50 .18
62 6 290'-298' 39.81 10.49 48.46 3.34 .38
63 5 298'-306'6" 21.75 4.90 73.23 2.28 .10
64 3 308'6"-310' 35.17 8.27 56.42 2.93 .16
65 2 310'-314' 23.10 4.78 71.54 1.68 .09
Crystal River Formation, Eocene (elev.-75 ft.)
66 1 314'-332' .24 .20 99.56 .10 .01
*The Column headings in this table are partly self-explanatory. However, a few remarks are
necessary. The value listed under the insoluble residue as the per cent quartz sand is the
percentage of the original sample consisting of quartz sand. The per cent clay represents that
part of the original sample consisting of insoluble sediments that passed through a 325-mesh
screen. A part of this value includes silt-size materials. The percentage figure given under
the heading "total soluble" reflects mainly carbonate and phosphate content of the
sediments. The P205 value is the percentage of P205 in the complete sample. The figure in
the last column is the per cent of the sample or unit consisting of heavy minerals. This value,
however, does not include phosphorite, mica, or iron concretions. Zeros entered in the
tables indicate that analyses were made and that no values were obtained. Dashes entered in
the table indicate that no analyses were.made or that data are not available. Sample and unit
numbers correspond to those of the detailed log given in the Appendix.
The first part of Tables 2 through 7 have been used in another presentation designed to
illustrate characteristics of the Trail Ridge heavy mineral ore body (Pirkle and Yoho, 1970.)
8 BUREAU OF GEOLOGY
TABLE 3. TRAIL RIDGE DRILL HOLE NO. 1*
Mechanical Analyses of Quartz Sand Extracted from Sediments
Per cent quartz sand retained on mesh
Quartz Median
sand (diam.
Spl. in % 10 18 35 60 120 230 mm.)
Surface sands
1 95.91 4.62 61.26 29.99 4.14 .30
2 92.64 .04 3.74 57.69 32.83 5.69 .28
3 94.13 .01 3.86 48.58 43.42 4.03 .26
4 92.34 .06 4.08 59.27 33.81 2.78 .29
5 97.13 4.15 68.17 26.16 1.52 .31
6 96.13 3.43 55.11 37.57 3.89 .29
7 96.54 .08 5.16 72.59 21.20 .97 .31
8 97.84 .02 12.31 70.84 14.72 2.10 .38
9 97.31 .64 53.88 36.13 9.35 .26
10 98.72 .61 48.96 42.02 8.41 .24
11 98.94 1.33 50.27 41.81 6.58 .26
12 98.43 1.35 57.53 36.27 4.85 .28
13 98.53 .02 1.80 70.42 25.75 2.02 .31
Intercalated layers of peaty or sapropelic sediments and quartz sand
14 8.39 .89 22.80 47.50 28.81 .18
15 89.70 6.89 46.19 27.98 18.95 .26
16 83.98 .09 8.76 51.44 26.79 12.92 .29
17 92.36 .06 .04 3.43 26.85 36.68 32.92 .18
18 85.53 .07 6.70 42.40 33.49 17.34 .24
19 96.25 .08 5.98 38.02 40.61 15.30 .24
20 68.91 .09 12.27 54.27 24.95 8.42 .31
21 77.65 .15 15.72 59.00 20.83 4.30 .33
Intercalated layers of quartz sand, clayey sand and massive olive-drab clay
22 95.91 .10 12.19 67.46 19.32 .92 .34
23 93.93 3.58 55.15 38.42 2.84 .28
24 89.46 .02 3.51 68.83 18.79 8.85 .33
25 13.16 1.22 2.74 18.87 14.16 63.01 .11
26 61.04 .07 .43 .66 98.85 .09
27 9.05 .44 .66 4.42 15.01 79.47 .09
28 95.63 .92 10.16 45.23 31.15 12.53 .28
29 77.57 .08 .83 7.22 26.22 65.66 .11
30 72.13 .08 1.85 11.82 29.03 57.22 .12
31 40.05 .05 .60 14.67 34.83 49.85 .13
32 53.51 .19 3.18 27.72 39.73 29.18 .18
33 86.45 .37 5.58 45.23 40.90 7.93 .26
34 96.70 .27 .45 7.07 52.78 36.72 2.71 .29
35 4.27 2.34 3.27 29.44 41.59 23.36 .21
36 94.58 .15 3.60 51.02 41.60 3.62 .26
Hawthorn Formation, Miocene
37 66.29 .09 .15 2.71 19.95 70.57 6.53 .21
38 11.45 2.78 21.53 71.53 4.17 .21
39 23.17 .43 2.41 15.13 73.09 8.94 .19
40 26.46 .38 3.60 24.69 64.11 7.21 .22
41 6.59 3.03 28.48 64.24 4.24 .23
42 32.57 .24 2.24 17.10 76.41 4.00 .21
43 31.30 .50 10.71 34.66 50.85 3.28 .24
44 66.37 .33 13.60 59.22 25.37 1.47 .33
45 47.33 .13 1.81 17.44 55.71 21.34 3.57 .36
46 47.85 .25 3.96 16.31 49.83 29.65 .18
47 41.35 .24 1.35 3.71 5.06 24.43 65.20 .11
BULLETIN NO. 52
TABLE 3. TRAIL RIDGE DRILL HOLE NO. 1 Continued
Quartz Median
sand (diam.
Spl. in % 10 18 35 60 120 230 mm.)
Hawthorn Formation, Miocene
17.01 1.29 11.97 41.90 34.98 9.86
57.95 .31 2.89 16.37 43.04 21.26 16.13
38.05 .74 13.47 61.37 23.37 1.05
75.03 .08 .53 8.17 81.93 9.29
46.92 .21 2.26 10.51 53.83 33.19
10.38 .38 3.08 71.73 24.81
55.22 .22 4.81 73.28 21.69
7.64 .26 1.05 7.85 43.19 47.64
4.73 1.69 3.39 16.95 50.00 27.97
4.84 2.06 9.05 53.91 34.98
19.11 1.56 8.96 23.44 39.79 19.06 7.19
1.75 21.59 3.41 22.73 26.14 11.36 14.77
10.12 2.17 1.38 6.11 22.09 17.55 50.69
39.81 .25 1.46 15.06 47.14 27.21 8.89
21.75 2.30 73.32 21.16 3.22
35.17 .11 1.19 67.63 22.79 8.28
23.10 1.15 71.54 19.03 8.28
.28
.33
.35
.19
.16
.16
.17
.13
.18
.15
.41
.49
.12
.31
.35
.31
.33
Crystal River Formation
.66 .24 16.67 25.00 33.33 25.00 .22
*Sample Numbers correspond to those of the detailed log in the Appendix.
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
9
10 BUREAU OF GEOLOGY
TABLE 4. TRAIL RIDGE DRILL HOLE NO. 1*
Percentages of Selected Heavy Minerals in
1/8 to 1/16 mm Fraction
Leocoxene Ilmenite Epidote Garnet
Spl. Unit in % in % in % in %
Surface sands
1 59 27.69 4.62 0.00 0.00
2 59 37.75 6.62 0.00 0.00
3 58 12.97 4.18 0.00 0.00
4 58 8.50 42.81 0.00 0.00
5 57 4.87 53.90 0.00 0.00
6 57 4.95 50.15 0.00 0.00
7 57 8.13 52.19 0.00 0.00
8 57 3.47 63.27 0.00 0.00
9 57 4.20 58.86 0.00 0.00
10 57 4.20 54.95 0.00 0.00
11 57 3.87 52.90 0.00 0.00
12 57 4.47 61.66 0.00 0.00
13 57 5.00 59.33 0.00 0.00
Intercalated layers of peaty or sapropelic sediments and quartz sand
14 56 5.36 57.44 0.00 0.00
15 55 16.77 37.97 0.00 .13
16 54 17.84 16.67 0.00 0.00
17 53 9.51 31.60 0.00 0.00
18 52 11.15 34.08 0.00 0.00
19 51 7.28 38.08 0.00 0.00
20 50 11.91 33.86 0.00 0.00
21 49 6.69 52.23 0.00 .82
Intercalated layers of quartz sand, clayey sand and massive olive-drab clay
22 47 2.83 52.52 0.00 .92
23 47 2.76 42.64 .31 2.48
24 47 3.33 36.97 .30 1.84
25 46 1.33 44.69 0.00 5.71
26 45 9.90 16.50 .33 3.11
27 44 10.38 28.93 .94 2.30
28 43 2.33 48.84 .66 2.86
29 42 2.46 38.03 .67 3.48
30 41 4.92 44.26 .33 2.99
31 41 5.22 40.59 5.90 3.58
32 40 2.14 45.84 3.49 4.29
33 39 5.99 40.38 .63 3.38
34 38 3.04 43.92 .34 3.62
35 37 1.84 44.49 1.84 3.47
36 36 0.00 45.02 8.23 3.02
Hawthorn Formation, Miocene
37 35 0.00 13.65 18.07 5.91
38 34 2.57 24.63 27.57 4.97
39 33 1.27 16.83 21.90 7.48
40 32 .34 14.58 25.76 7.54
41 31 2.78 20.49 16.67 2.59
42 30 .36 17.33 21.66 6.62
43 29 1.97 19.28 20.26 3.19
44 27 2.56 17.57 20.45 5.21
45 26 1.33 16.94 14.29 2.67
46 25 2.65 21.79 7.28 4.68
47 24 2.82 30.70 5.63 5.90
48 23 1.97 27.63 4.61 4.24
49 22 2.58 35.48 1.29 4.24
50 21 2.96 34.87 8.88 2.40
BULLETIN NO. 52 11
TABLE 4. TRAIL RIDGE DRILL HOLE NO. 1 Continued
Leucoxene Ilmenite Epidote Garnet
Spl. Unit in % in % in % in %
Hawthorn Formation, Miocene
51 19 2.72 31.42 7.25 8.52
52 17 2.35 29.71 4.41 6.45
53 15 4.81 28.85 3.21 3.94
54 14 3.45 41.07 5.33 5.45
55 13 3.44 34.73 2.67 4.15
56 12 2.60 42.86 2.60 5.79
57 11 8.55 49.67 .99 4.70
58 10 3.22 48.55 1.93 3.82
59 8 4.53 27.51 1.94 9.65
60 8 7.19 35.25 4.32 7.33
61 7 9.38 38.44 5.63 8.23
62 6 2.72 38.10 2.04 12.54
63 5 2.87 32.80 2.87 12.74
64 3 .98 43.28 .98 10.15
65 2 1.52 25.00 6.06 12.50
Crystal River Formation, Eocene
66 1 .72 27.34 1.44 5.92
*Sample and unit numbers correspond to those of the detailed log in the Appendix.
12 BUREAU OF GEOLOGY
TABLE 5. TRAIL RIDGE DRILL HOLE NO. 2*
NE/4, NW4, Section 19, T. 5 S., R. 23 E., Clay County, Florida
Approximately 2 Miles Northeast of Lawtey
Surface Elevation, 206 Feet
Insoluble Residue
Clay
Depth Quartz (-325 Total Total
Feet and sand mesh) soluble heavies
Spl. Unit inches in % in % in % in %
Surface sands (elev. 206 ft.)
1 37 0-3' 95.43 3.49 2.74
2 37 3'-4'6" 97.17 2.00 3.23
3 37 4'6"-7' 90.83 6.88 3.07
4 37 7'-9'6" 96.76 2.50 4.69
5 37 9'6"-15' 89.53 7.97 5.27
6 37 15'-21' 97.74 1.50 4.25
7 37 21'-24'6" 95.46 1.79 7.08
8 37 24'6"-27'6" 99.90 .10 2.67
9 37 27'6"-27'9" 88.25 4.63 3.46
10 37 27'9"-28' 99.88 .10 1.06
11 37 28'-28'6" 88.66 5.59 4.39
12 37 28'6"-30'6" 99.34 .20 5.37
13 37 30'6"-33' 98.55 .50 4.25
14 37 33'-38' 98.70 .50 3.90
15 37 38'-40'6" 98.47 .80 2.10
16 37 40'6"-43'6" 95.36 2.70 2.24
17 37 43'6"-46'6" 98.58 .60 1.63
Intercalated layers of sapropelic sediments and quartz sand (elev. 160 ft.)
18 36 46'6"-48'9" 92.97 2.79 1.90
19 35 48'9"-49' 92.08 3.69 .57
20 34 49'-50' 89.35 6.18 .49
21 33 50'-51' 88.46 8.29 .53
22 32 51'-53' 83.70 14.49 .49
23 32 51'-54' 87.00 10.58 .73
24 31 54'-56'6" 92.26 5.83 .65
25 30 56'6"-59' 95.37 2.31 .92
Greenish gray clayey sands and sandy clays (elev. 147 ft.)
26 29 59'-61'3" 87.78 7.99 .71
27 28 61'3"-64'6" 67.51 25.51 .74
28 27 64'6"-67' 63.88 28.78 .95
29 26 67'-69'6" 58.22 29.15 .50
30 25 69'6"-73'9" 24.95 46.72 .19
31 24 73'9"-77'6" 40.33 13.06 .73
32 23 77'6"-78' 30.06 46.56 .67
33 22 78'-80' 31.32 26.69 .74
34 21 80'-82'6" 33.33 45.42" .49
35 20 82'6"-85' 42.44 37.67 .56
36 19 85'-86' 70.33 18.95 .69
White to gray sands and clayey sands (elev. 120 ft.)
37 18 86'-89' 91.61 7.59 .36
38 17 89'-93' 93.89 5.41 .35
39 16 93'-97' 91.66 7.70 .43
40 15 97'-99' -96.65 2.50 .10
41 14 99'-99'6" 97.43 1.90 .02
42 13 99'6"-101'6" 95.38 3.49 .08
Olive-drab to tan clayey sands (elev. 105 ft.)
43 12 101'6"-106'6" 91.42 7.48 .70 .41
BULLETIN NO. 52
TABLE 5. TRAIL RIDGE DRILL HOLE NO. 5 Continued
Insoluble Residue
Clay
Depth in Quartz (-325 Total Total
feet and sand mesh) soluble heavies
Spl. Unit inches in% in % in % in %
44 11 106'6"-108'6" 85.72 12.57 .80 .35
45 10 108'6"-109'9" 90.27 8.17 1.00 .18
46 9 109'9"-111' 84.23 13.67 1.00 .34
47 8 111'-115'6" 88.02 9.47 1.69 .46
48 7 115'6"-118' 90.71 7.47 1.30 .37
49 6 118'-124' 88.87 7.99 2.20 .44
50 5 124'-129' 92.25 6.81 .50 .50
51 4 129'-134' 90.76 7.68 1.00 .46
52 3 135'6"-142' 89.10 7.70 2.10 .57
53 2 143'-143'3" 23.30 21.60 43.40 .19
Late Miocene shell marl (elev. 63 ft.)
54 1 143'3"-145'6" .95 4.43 94.52 .01
*Sample and unit numbers correspond to those of the detailed log in the Appendix.
14 BUREAU OF GEOLOGY
TABLE 6. TRAIL RIDGE DRILL HOLE NO. 2*
Mechanical Analyses of Quartz Sand Extracted From Sediments
Per cent quartz sand retained on mesh
Quartz Median
sand (diam.
Spl. in % 10 18 35 60 120 230 mm.)
Surface sands
1 95.43 .06 5.92 58.56 28.48 6.48 .29
2 97.17 .08 6.74 57.97 29.21 6.00 .29
3 90.83 .09 6.41 58.46 29.66 5.38 .29
4 96.76 .10 5.97 55.48 33.22 5.23 .29
5 89.53 .09 4.48 56.98 34.69 3.76 .29
6 97.74 3.46 69.29 25.57 1.68 .31
7 95.46 .06 2.65 53.55 37.75 5.99 .26
8 99.90 .12 7.66 73.52 18.19 .52 .34
9 88.25 .23 11.76 63.35 17.87 6.79 .36
10 99.88 .18 12.58 77.82 9.10 .32 .38
11 88.66 .05 3.38 58.52 33.85 4.21 .28
1.2 99.34 .04 2.92 59.72 35.14 2.17 .27
13 98.55 .04 2.59 57.36 37.97 2.04 .26
14 98.70 .04 2.36 56.06 37.42 4.12 .26
15 98.47 .06 5.40 65.97 26.39 2.18 .29
16 95.36 6.67 62.96 27.52 2.85 .29
17 98.58 .06 7.11 61.03 28.74 3.06 .29
Intercalated layers of sapropelic sediments and quartz sand
18 92.97 .06 4.58 32.93 25.81 36.61 .19
19 92.08 .04 3.90 24.39 24.08 47.58 .14
20 89.35 .07 3.48 22.40 23.69 50.36 .12
21 88.46 .07 3.27 18.12 24.44 54.10 .12
22 83.70 .31 2.91 31.13 65.65 .11
23 87.00 .37 1.24 31.09 67.30 .11
24 92.26 .35 5.06 32.56 62.04 .11
25 95.37 .67 14.57 42.98 41.78 .14
Greenish gray clayey sands and sandy clays
26 87.78 .09 11.56 52.17 21.57 14.61 .34
27 67.51 .12 9.39 43.22 26.87 20.40 .26
28 63.88 .13 5.91 34.32 38.86 20.78 .22
29 58.22 .86 7.99 40.16 50.99 .12
30 24.95 .56 7.06 34.80 57.58 .12
31 40.33 .15 2.64 55.16 42.05 .14
32 30.06 1.40 15.09 33.58 49.93 .13
33 31.32 .38 11.47 15.50 72.65 .10
34 33.33 .18 1.32 8.42 12.52 77.56 .10
35 42.44 .38 2.74 16.57 24.65 55.67 .12
36 70.33 .17 1.67 8.17 24.74 34.24 31.01 .19
White to gray sands and clayey sands
37 91.61 .24 1.53 27.75 65.29 5.19 .21
38 93.89 .73 41.10 53.96 4.22 .24
39 91.66 .07 .72 20.58 71.96 6.68 .21
40 96.65 .58 7.52 24.66 50.57 15.47 1.20 .43
41 97.43 1.15 14.66 46.42 32.02 5.12 .63 .62
42 95.38 .29 4.91 28.43 38.24 26.27 1.86 .40
Olive-drab to tan clayey sands
43 91.42 .09 .81 6.79 29.52 56.23 6.57 .23
44 85.72 .16 4.93 24.04 59.18 11.68 .21
45 90.27 .18 21.86 39.35 32.61 6.01 .31
46 84.23 .05 1.02 18.17 64.34 16.42 .21
BULLETIN NO. 52
TABLE 6. TRAIL RIDGE DRILL HOLE NO. 2 Continued
15
Olive-drab to tan clavey sands
Quartz Median
sand (diam.
Spl. in % 10 18 35 60 120 230 mm.)
47 88.02 .09 .52 6.70 78.96 13.73 .18
48 90.71 .07 1.36 13.01 77.48 8.09 .19
49 88.87 .11 2.43 19.74 71.18 6.54 .21
50 92.25 .09 .24 2.76 19.87 70.90 6.14 .21
51 90.76 .09 .20 2.99 19.49 69.67 7.56 .21
52 89.10 .20 .5,2 5.27 28.06 59.30 6.64 .22
53 23.30 .34 .34 1.89 11.85 35.02 50.56 .12
Late Miocene shell marl
54 .95 4.26 17.02 51.06 27.66 .18
*Sample numbers correspond to those of the detailed log in the Appendix.
16 BUREAU OF GEOLOGY
TABLE 7. TRAIL RIDGE DRILL HOLE NO. 2*
Percentages of Selected Heavy Minerals in
1/8 to 1/16 mm Fraction
Leucoxene Ilmenite Epidote Garnet
Spl. Unit in % in % in % in %
Surface sands
1 37 29.39 11.82 0.00 0.00
2 37 31.89 10.63 0.00 0.00
3 37 22.80 19.22 0.00 0.00
4 37 20.07 25.99 0.00 0.00
5 37 12.12 34.24 0.00 0.00
6 37 2.86 53.33 0.00 0.00
7 37 1.60 57.33 0.00 0.00
8 37 3.50 60.51 0.00 0.00
9 37 2.81 57.50 0.00 0.00
10 37 4.59 56.88 0.00 0.00
11 37 3.89 46.11 0.00 0.00
12 37 3.87 51.19 0.00 0.00
13 37 3.28 53.63 0.00 0.00
14 37 2.78 50.93 0.00 0.00
15 37 2.99 61.13 0.00 0.00
16 37 2.76 61.35 0.00 0.00
17 37 5.18 56.10 0.00 0.00
Intercalated layers of sapropelic sediments and quartz sand
18 36 13.73 45.42 0.00 0.00
19 35 36.84 8.23 0.00 0.00
20 34 41.67 6.67 0.00 0.00
21 33 21.18 13.24 0.00 0.00
22 32 12.23 36.55 0.00 0.00
23 32 11.61 37.10 0.00 0.00
24 31 6.12 44.39 0.00 .49
25 30 3.40 36.26 0.00 1.29
Greenish gray clayey sands and sandy clays
26 29 11.68 37.80 .69 .71
27 28 6.52 58.07 0.00 .66
28 27 4.85 53.07 .65 1.55
29 26 3.93 53.11 1.31 1.25
30 25 6.89 42.62 3.93 .62
31 24 6.73 54.17 .64 .67
32 23 5.23 48.04 1.31 .59
33 22 7.16 44.70 1.15 .80
34 21 6.71 49.70 .91 1.22
35 20 5.12 51.20 1.81 1.32
36 19 1.95 44.81 1.30 .62
White to gray sands and clayey sands
37 18 2.37 54.24 1.02 .27
38 17 1.41 38.59 1.41 .95
39 16 2.85 50.95 .32 .56
40 15 2.26 60.38 1.13 1.62
41 14 1.86 57.62 1.12 1.09
42 13 .95 47.87 .47 1.20
Olive-drab to tan clayey sands
43 12 2.56 51.99 .57 4.59
44 11 3.34 49.24 .91 4.99
45 10 2.34 50.50 1.34 3.75
46 9 1.60 47.33 1.07 4.24
47 8 1.79 49.11 .60 2.05
48 7 1.00 60.67 1.00 1.90
BULLETIN NO. 52 17
TABLE 7. TRAIL RIDGE DRILL HOLE NO. 2 Continued
Olive-drab to tan clayey sands
Leucoxene Ilmenite Epidote Garnet
Spl. Unit in % in % in % in %
49 6 2.59 54.05 2.27 3.05
50 5 1.66 47.35 2.98 2.90
51 4 1.23 49.39 4.91 1.64
52 3 .67 41.00 25.67 .80
53 2 3.61 39.16 7.23 .93
Late Miocene shell marl
54 1 1.10 26.01 39.83 1.61
*Sample and unit numbers correspond to those of the detailed log in the Appendix.
BUREAU OF GEOLOGY
5 feet of the lower zone in TR No. 1 is a peat layer (Spl. 14, Table 2). Other
beds or lenses containing wood debris and finely-divided organic matter at the
TR No. 1 site are present at depths of 73 feet to 74 feet 6 inches, 77 feet to 78
feet, and 80 feet 6 inches to 84 feet 6 inches (Table 2). The sediments in the
lower zone at the TR No. 2 site contain less wood than the sediments in the
lower zone at the TR No. 1 site. Nevertheless sediments containing some wood
and finely-divided organic matter are present throughout the lower zone at the
TR No. 2 site (Spls. 18-25, Table 5).
POST-HAWTHORN CLASTICS
The post-Hawthorn clastics consist of intercalated layers or lenses of quartz
sand, clayey sand and massive olive-green or olive-drab clay. In TR No. 1 these
sediments have a thickness of 49 feet, extending from a depth of 90 feet below
the land surface to a depth of 139 feet (Spls. 22-36, Table 2). The elevation of
the upper surface of these clastics is 149 feet; the elevation of the lower surface
is 100 feet. In TR No. 2 the post-Hawthorn clastics have a thickness of 84 feet,
extending downward from an elevation of 147 feet to an elevation of 63 feet
(Spls. 26-53, Table 5). Characteristics of the post-Hawthorn clastics are
illustrated by the logs in the Appendix and by data in Tables 2 through 7.
The massive, olive-green clay contains finely-divided organic matter and small
fragments of brown wood. These clays apparently accumulated in a restricted
marine environment. At the TR No. 1 site rare marine microfossils were
observed in the massive olive-green clay which is present at a depth of 106 feet
to 107 feet (Spl. 25, Table 2).
LATE MIOCENE SHELL MARL
At some localities in northern peninsular Florida shell marls of late Miocene
age are present at the top of the Hawthorn Formation. Such a shell marl was
encountered in the TR No. 2 drill hole (Spl. 54, Table 5). The sediments consist
of a mixture of cream to white shells, quartz sand, clay and phosphorite. Many
of the shells are broken. Macrofossils, mostly mollusks, and foraminifera are
abundant. These late Miocene shell beds are believed to be conformable with the
underlying Hawthorn sediments and may be conformable with the overlying
post-Hawthorn clastics. Such relationships suggest the possibility that in these
areas the upper Hawthorn sediments, the shell beds and the post-Hawthorn
clastics may all be late Miocene in age.
HAWTHORN FORMATION
The Hawthorn Formation is marine in origin and is characterized by
phosphorite. In the areas of Trail Ridge and the Baywood Promontory, the
Hawthorn sediments probably are middle to late Miocene in age. The formation
BULLETIN NO. 5 2
consists of phosphatic sands, clays and dolomites. In TR No. 1 the Hawthorn
Formation overlies the Crystal River Formation unconformably and is 175 feet
in thickness, extending from a depth of 139 feet below the land surface to a
depth of 314 feet (Spls. 37-65, Table 2). The elevation of its upper surface is
100 feet above sea level. The contact between the Hawthorn Formation and the
underlying Crystal River Formation is approximately 75 feet below sea level.
The composition or nature of the Hawthorn materials penetrated in TR No. 1
can be summarized in terms of the dominant components of the beds. Of the
175 feet of vertical section of Hawthorn sediments, an aggregate of 62 feet (or
35 per cent of the total thickness) contains more than 50 per cent carbonate, an
aggregate of 23 feet (or 13 per cent) contains more than 50 per cent sand, and
an aggregate of 12 feet (or 7 per cent) contains more than 50 per cent clay
(figures derived from data in Table 2). An aggregate of 77 feet (44 per cent) of
the materials consists of mixtures of the various types of plastic sediments and
carbonate, with no specific component comprising as much as 50 per cent of the
total materials. The percentage of carbonate in sediments can be of interest and
should be considered when analyzing land-form development in humid
subtropical regions such as Florida.
BAYWOOD PROMONTORY DRILL HOLE
The Baywood Promontory hole was drilled on the crest of the Baywood
Promontory in Putnam County about 2 miles southeast of the town of
Florahome. The surface elevation at the site of the hole as determined from the
Interlachen Quadrangle map is approximately 210 feet above sea level. Analyses
and characteristics of the sediments penetrated in this hole are given in Tables 8
through 10 and in a detailed log presented in the Appendix.
Slightly more than 128 feet of loose quartz sands underlie the ridge crest
(Spls. 1-26, Table 8). Beneath these sands are 41 feet of sediments consisting of
alternating lenses of fine to very fine quartz sands and massive olive-green or
olive-drab clays of the post-Hawthorn plastics (Spls. 27-36, Table 8). These
post-Hawthorn plastics lie upon a shell marl of late Miocene age (Spl. 37, Table
8). The shell marl is about 5 feet thick and rests upon 121 feet of phosphatic
sands, clays and dolomites of the Miocene Hawthorn Formation (Spls. 38-57,
Table 8). The Crystal River Formation of Eocene age lies immediately beneath
the Hawthorn sediments (Spl. 58, Table 8).
SURFACE SANDS
The upper 110 feet of sand (Spls. 1-22, Table 8) is massive and is
characterized by dark brown to black zones containing a relatively high content
of finely-divided organic matter. In addition to the fine organic material, wood
debris is present. One log or large limb was encountered from a depth of 60 feet
9 inches to 62 feet 6 inches. A radiocarbon analysis of wood from this log was
19
20 BUREAU OF GEOLOGY
TABLE 8. BAYWOOD PROMONTORY DRILL HOLE*
SWV4, NW%4, Section 18, T. 9 S., R. 25 E., Putnam County, Florida
Approximately 21/2 Miles Southeast of Florahome
Surface Elevation, 210 Feet (Estimate)
Insoluble Residue
Clay
Depth Quartz (-325 Total Total
feet and sand mesh) soluble P205 heavies
Spl. Unit inches in % in % in % in % in %
Loose Surface sands with organic zones (elev. 210 ft.)
1 34 0-5' 98.14 .90 .31
2 34 5'-10' 98.65 .10 .27
3 34 10'-15' 98.13 .30 .38
4 34 15'-20' 98.6.7 .40 .80
5 34 20'-25' 97.13 2.09 .45
6 34 25'-30' 98.53 .70 .63
7 34 30'-35' 94.72 4.08 .58
8 34 35'-40' 96.52 2.29 .52
9 34 40'-45' 96.35 3.49 .54
10 34 45'-50' 94.20 5.40 .50
11 34 50'-55' 96.86 2.19 .46
12 34 55'-60' 95.58 3.29 .62
13 34 60'-65' 98.73 .60 .67
14 34 65'-70' 96.46 1.79 .42
15 34 70'-75' 96.12 2.29 .56
16 34 75'-80' 96.00 3.48 .41
17 34 80'-85' 96.31 2.49 .52
18 34 85'-90' 94.75 3.88 .35
19 34 90'-95' 96.01 3.00 .25
20 34 95'-100' 92.94 5.98 .30
21 34 100'-105' 95.61 1.80 .55
22 34 105'-110' 93.88 2.09 .49
Finely laminated sands (elev. 100 ft.)
23 33 110'-114'6" 91.93 2.79 1.18
24 33 114'6"-120' 96.91 .60 .88
25 33 120'-125' 94.03 2.69 .90
26 33 125'-128'3" 95.42 2.29 1.12
Intercalated layers of massive olive-drab clay and quartz sand (elev. 81'9")
27 32 128'3"-129'3" 18.43 76.34 5.17 .98 .39
28 31 129'3"-130'6" 88.63 8.86 2.29 .42 .93
29 30 130'6"-132' 26.86 66.85 6.19 1.09 .39
30 28 141'-145' 90.92 4.59 4.09 .84 .66
31 28 145'-150' 91.55 5.20 2.80 .63 .52
32 28 150'-155' 90.63 5.48 3.49 .74 .72
33 28 155'-160' 87.99 7.29 4.10 1.07 .87
34 28 160'-163'6" 81.90 9.57 7.78 2.16 .74
35 27 163'6"-167' 3.72 86.99 9.21 2.04 .06
36 26 167'-169' 82.27 5.48 9.87 2.80 1.17
Shell marl, Late Miocene (elev. 41 ft.)
37 25 169'-174' 38.33 8.37 52.90 4.22 .30
Hawthorn Formation, Miocene (elev. 36 ft.)
38 24 174'-187' 60.50 10.05 28.96 2.81 .35
39 23 187'-193' 26.27 5.07 68.52 1.67 .06
40 21 201'-208'6" 1.24 13.77 84.98 .43 .004
41 20 208'6"-213' 42.74 4.79 52.41 1.79 .14
42 18 219'-234' 50.08 19.74 22.53 2.95 .69
43 17 234'-238' .46 83.01 16.35 1.13 .02
44 16 238'-239' .43 14.46 85.12 .72 .002
BULLETIN NO. 52
21
TABLE 8. BAYWOOD PROMONTORY DRILL HOLE Continued
Hawthorn Formation, Miocene (elev. 36 ft.)
Clay
Deepth in Quartz (-325 Total Total
feet and sand mesh) soluble P205 heavies
Spl. Unit inches in % in % in % in % in %
Hawthorn Formation, Miocene (elev. 41 ft.)
45 15 239'-240' 63.70 15.96 20.06 3.30 .14
46 14 240'-241' 17.24 15.20 67.30 2.41 .11
47 13 241'-243' 57.90 17.76 23.64 3.05 .36
48 12 243'-245' 35.67 15.46 48.58 1.19 .47
49 11 245'-248' 63.25 18.80 17.21 2.45 .57
50 10 248'-251'6" 25.63 9.65 64.27 6.74 .21
51 9 251'6"-262' 28.89 17.25 51.74 2.41 .15
52 8 262'-264'6" 53.95 29.21 15.65 2.84 .16
53 7 264'6"-267' 38.66 7.46 53.30 1.20 .08
54 6 267'-274' 20.14 44.61 32.26 3.99 .21
55 5 274'-284' 11.45 4.42 83.75 8.05 .18
56 4 284'-292'6" 37.25 6.87 55.78 3.73 .12
57 3 292'6"-295' 16.64 4.17 79.01 7.18 .06
Crystal River Formation, Eocene (elev. 87 ft.)
58 1 297'-302' .12 .30 99.58 .26 .002
*Sample and unit number correspond to those of the detailed log in the Appendix.
22 BUREAU OF GEOLOGY
TABLE 9. BAYWOOD PROMONTORY DRILL HOLE
Mechanical Analyses of Quartz Sand Extracted From Sediments
Per cent quartz sand retained on mesh
Quartz Median
sand (diam.
Spl. in % 10 18 35 60 120 230 mm.)
Loose surface sands with organic zones
1 98.14 .04 .33 9.54 79.64 10.46 .18
2 98.65 .04 .48 12.75 78.02 8.71 .19
3 98.13 .10 .95 13.71 77.85 7.38 .19
4 98.67 .04 .59 10.98 81.31 7.09 .19
5 97.13 .27 9.49 81.58 8.67 .19
6 98.53 .06 .50 11.41 81.51 6.52 .18
7 94.72 .40 11.08 83.18 5.34 .19
8 96.52 .31 13.09 81.88 4.72 .19
9 96.35 .31 11.68 81.87 6.13 .19
10 94.20 .47 13.45 80.42 5.66 .19
11 96.86 .23 10.35 83.36 6.06 .19
12 95.58 .13 7.11 85.73 7.04 .19
13 98.73 .16 7.29 87.40 5.15 .19
14 96.46 .23 8.54 84.15 7.08 .19
15 96.12 .04 .08 4.73 89.00 6.14 .19
16 96.00 .06 2.72 93.90 3.32 .19
17 96.31 .37 14.11 80.40 5.11 .19
18 94.75 .02 .36 14.89 82.14 2.58 .20
19 96.01 .04 .69 23.55 74.40 1.33 .21
20 92.94 .36 13.23 82.78 3.63 .20
21 95.61 .46 12.72 82.60 4.22 .20
22 93.88 .19 11.71 85.40 2.70 .19
Finely laminated sands
23 91.93 .22 10.42 85.53 3.83 .20
24 96.91 .23 13.24 83.38 3.15 .20
25 94.03 .13 7.62 87.36 4.89 .19
26 95.42 .88 12.38 77.80 8.90 .19
Intercalated layers or lenses of massive olive-drab clay and quartz sand
27 18.43 .65 11.97 75.94 11.43 .19
28 88.63 .04 1.84 71.12 26.99 .16
29 26.86 .15 3.86 61.66 34.32 .15
30 90.92 .07 .75 56.69 42.49 .14
31 91.55 .02 .28 54.70 44.99 .13
32 90.63 .04 .88 47.27 51.80 .12
33 87.99 .07 1.02 26.57 72.34 .11
34 81.90 .07 .19 4.11 40.43 55.19 .12
35 3.72 1.08 8.60 50.00 40.32 .14
36 82.27 .07 .46 7.81 45.14 46.52 .13
Shell marl, Late Miocene
37 38.33 .26 1.09 5.93 37.37 43.81 11.54 .24
Hawthorn Formation, Miocene
38 60.50 1.81 10.00 24.41 50.07 13.72 .23
39 26.27 .91 10.30 24.83 35.43 22.79 5.75 .40
40 1.24 11.48 26.23 55.74 6.56 .23
41 42.74 3.64 29.52 51.56 13.87 1.40 .41
42 50.08 3.07 9.51 21.82 23.89 41.72 .17
43 .46 8.70 13.04 21.74 56.52 .12
44 .43 14.29 42.86 28.57 14.29 .29
45 63.70 1.85 6.74 63.38 14.54 13.50 .34
46 17.24 .58 3.02 7.08 45.71 24.13 19.49 .28
BULLETIN NO. 52
23
TABLE 9. BAYWOOD PROMONTORY DRILL HOLE Continued
Quartz Median
sand (diam.
Spl. in % 10 18 35 60 120 230 mm.)
Hawthorn Formation, Miocene
47 57.90 .10 2.34 7.41 36.42 26.15 27.57 .23
48 35.67 2.01 9.84 7.21 45.19 35.74 .16
49 63.25 .13 3.11 13.27 8.43 28.94 46.12 .14
50 25.63 .70 3.57 13.98 31.06 25.47 25.23 .25
51 28.89 .97 6.42 19.32 25.33 47.96 .13
52 53.95 .18 1.03 11.75 42.39 22.69 21.95 .28
53 38.66 .77 11.27 71.86 8.23 7.87 .38
54 20.14 .99 3.96 29.67 15.23 13.16 36.99 .25
55 11.45 1.58 18.07 40.35 11.05 28.95 .31
56 37.25 12.37 78.51 7.76 1.36 .39
57 16.64 .36 3.11 75.15 15.89 5.50 .36
Crystal River Formation, Eocene
58 .12 33.33 50.00 16.67 .21
*Sample numbers correspond to those of the detailed log in the Appendix.
BUREAU OF GEOLOGY
TABLE 10. BAYWOOD PROMONTORY DRILL HOLE
Percentage of Selected Heavy Mineral in
1/8 to 1/16 mm Fraction
Leucoxene Ilmenite Epidote Garnet
Spl. Unit in % in % in % in %
Loose surface sands with organic zones
10.96 35.22 11.63
17.98 27.13 12.30
14.52 41.58 5.94
19.31 25.23 1.25
15.03 34.36 .61
14.45 32.37 0.00
14.24 44.98 0.00
13.58 49.07 0.00
8.00 47.67 0.00
10.66 46.71 0.00
6.69 55.32 0.00
16.96 33.33 0.00
13.44 43.93 0.00
18.58 43.34 0.00
26.07 29.75 0.00
13.89 37.65 0.00
27.62 22.54 0.00
12.06 43.49 0.00
4.67 65.73 0:00
3.46 57.23 0.00
6.01 49.05 0.00
3.85 58.97 1.28
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Shell marl, Late Miocene
.98 34.43
Hawthorn Formation, Miocene
.96 22.68
2.12 34.85
3.93 32.13
1.00 35.67
.98 33.44
3.78 28.11
3.96 51.49
2.77 44.31
4.30 46.03
2.33 42.52
2.97 49.26
17.17
15.60
14.46
7.90
and quartz sand
12.65
19.93
15.38
26.75
34.50
29.41
33.44
28.92
20.43
23.92
15.65
8.48
8.20
12.67
10.82
9.19
1.98
2.46
1.99
3.32
.30
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
34
24
0.00
.28
.98
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
2.37
2.55
5.57
2.81
2.19
3.94
2.34
3.45
2.58
3.24
2.26
1.54
2.41
.32
2.42
1.80
2.09
1.61
3.38
3.10
.74
4.34
4.55
7.59
2.97
5.71
5.48
4.24
3.10
Finely laminated sands
33 1.81 59.34
33 2.75 48.93
33 1.85 47.08
33 2.43 50.15
Intercalated layers or lenses of massive olive-drab clay
32 1.23 50.31
31 2.33 27.57
30 4.17 41.67
28 1.27 23.25
28 2.56 24.92
28 1.63 30.72
28 2.98 26.49
28 3.38 35.08
27 .62 32.20
26 1.99 27.24
25
24
23
21
20
18
17
16
15
14
13
12
BULLETIN NO. 52
TABLE 10. BAYWOOD PROMONTORY DRILL HOLE Continued
Leucoxene Ilmenite Epidote Garnet
Spl. Unit in % in % in % in %
Hawthorn Formation, Miocene
49 11 5.36 53.00 1.58 6.98
50 10 2.45 50.35 1.05 6.94
51 9 1.52 35.67 1.52 7.16
52 8 2.11 46.22 2.11 5.31
53 7 3.95 34.21 3.95 4.87
54 6 4.61 39.17 2.23 7.38
55 5 2.61 46.08 1.31 5.72
56 4 1.82 39.27 1.09 9.38
57 3 0.00 27.86 2.14 14.59
Crystal River Formation, Eocene
58 1 0.00 34.88 0.00 6.67
BUREAU OF GEOLOGY
made by the Radiocarbon Laboratories of the Florida State University. That
laboratory determined the apparent age as 31,400 +500 years (Pirkle and Yoho,
1970). The quartz sands from a depth of 110 feet to 128 feet are finely
laminated (Spls. 23-26, Table 8). The laminations are shown by stringers of
black heavy minerals.
OLIVE-GREEN CLAYS OF POST-HAWTHORN CLASTICS
Sediments consisting of intercalated layers or lenses of massive olive-green
clay and fine to very fine quartz sand begin at a depth of 128 feet and continue
to a depth of 169 feet (Spls. 27-36, Table 8). These post-Hawthorn clastics
appear almost identical to the post-Hawthorn clastics encountered from a depth
of 90 feet to 139 feet in TR No. 1 (Spls. 22-36, Table 2).
In addition to finely-divided organic matter, brown wood and wood fibers are
present in the olive-green clays. Wood debris was noted in the clays of Units 32,
30 and 27 (Spls. 27, 29 and 35, Table 8). In addition to wood, leaf impressions
were seen in the clays of Unit 27. Furthermore the sediments throughout the
interval contain a small amount of pebble-size and sand-size black phosphorite.
LATE MIOCENE SHELL MARL
A late Miocene shall marl is present at the top of the Hawthorn Formation
(Spl. 37, Table 8). Green hornblende constitutes approximately 5 per cent of the
1/8 to 1/16 mm fraction of heavy minerals in the bed. This mineral also is
relatively abundant in the quartz sand collected immediately overthe shell bed
(Spl. 36, Table 8). In no other sediments from this drill hole is hornblende an
important constituent of the heavy mineral suite, although occasional grains are
present, particularly in the sediments of the upper part of the Hawthorn
Formation and in the post-Hawthorn clastics. The significartce of the green
hornblende is not known.
HAWTHORN FORMATION
Of the 107 feet of Hawthorn sediments sampled, an aggregate of about 30
feet (28 per cent) contains more than 50 per cent carbonate, an aggregate of 36
feet (34 per cent) contains more than 50 per cent quartz sand, and an aggregate
of 4 feet (4 per cent) contains more than 50 per cent clay (Table 8). In the
remainder, a total of approximately 36 feet of the sediments (34 per cent), no
one component makes up as much as 50 per cent of the total material. The
Hawthorn sediments at this particular locality contain slightly less carbonate
than the Hawthorn sediments encountered in the TR No. 1 drill hole.
26
BULLETIN NO. 52
HEAVY MINERALS IN SEDIMENTS
In Tables 4, 7 and 10 the percentages for certain selected heavy minerals are
given for the 1/8 to 1/16 mm fraction of sediments. Ilmenite and leucoxene are
included in the tables because these are important ore minerals of titanium.
Furthermore, leucoxene is a weathering product of ilmenite and can be of
interest in problems concerning geological history. Epidote and garnet are given
because these two heavy minerals are relatively easily destroyed through
weathering in humid subtropical climates and are of interest in problems of
correlation.
TRAIL RIDGE DRILL HOLES
A number of features of the distribution of heavy minerals are.evident from
an examination of the data in Tables 4 and 7. Ilmenite is relatively abundant in
the upper sand zone of the Trail Ridge sequence (Spls. 1-13, Table 4; Spls. 1-17,
Table 7). Although not recorded in these tables, zircon likewise is relatively
abundant in these upper sands. This increase in ilmenite and zircon should be
expected. As the quantity of heavy minerals increases in sediments, heavy
minerals that have the highest specific gravities tend to be concentrated at the
expense of heavy minerals with lower specific gravities (Martens, 1935, p. 1585).
A conspicuous feature of the heavy mineral distribution is the occurrence of
epidote and garnet. Epidote is completely absent in the sediments of the Trail
Ridge sequence (Spls. 1-21, Table 4; Spls. 1-25, Table 7). The mineral is present
in varying amounts in almost all of the materials penetrated beneath the Trail
Ridge sequence (Tables 4 and 7). At the site of TR No. 1 there is a sharp
increase in epidote in the upper 45 to 50 feet of the Hawthorn Formation (Spls.
37-45, Table 4). At the TR No. 2 locality the amount of epidote increases
markedly in the late miocene shell bed and in the immediately overlying
sediments of the post-Hawthorn clastics (Spls. 52-54, Table 7). A sharp increase
in epidote in the upper sediments of the Hawthorn Formation and in late
Miocene shell beds has been recorded for other localities in northern peninsular
Florida (Pirkle et al., 1965, p. 14 and p. 18).
Garnet is almost totally absent in the Trail Ridge sequence of sediments (Spls.
1-21, Table 4; Spls. 1-25, Table 7). This mineral is present, however, in all of the
sediments of the post-Hawthorn clastics, the late Miocene shell marl, and the
Hawthorn Formation (Spls. 22-65, Table 4; Spls. 26-54, Table 7). At the site of
TR No. 1 there is an increase in garnet in the lower 30 feet of the Hawthorn
Formation (Spls. 59-65, Table 4).
The distribution of leucoxene is intriguing. In the Trail Ridge drill holes the
amount of this mineral is relatively high from the land surface to a depth of
about 10 to 15 feet (Spls. 1-3, Table 4; Spls. 1-5, Table 7). The high content of
leucoxene with a corresponding low content of ilmenite indicates that ilmenite
has been weathered in situ to give much of the leucoxene. Similar relationships
27
BUREAU OF GEOLOGY
between ilmenite and leucoxene are present in the upper part of the lower zone
of the Trail Ridge sequence (Spls. 18-23, Table 7). The relatively high content of
leucoxene with a corresponding low content of ilmenite suggests that the lower
zone of the Trail Ridge sequence accumulated in a subaerial environment or was
exposed to such an environment before the deposition of the overlying quartz
sand zone.
BAYWOOD PROMONTORY DRILL HOLE
Table 10 gives data for the four selected heavy minerals extracted from the
1/8 to 1/16 mm size fraction of sediments from the Baywood Promontory drill
hole. In the first 90 feet of sediments the content of leucoxene is relatively high
(Spls. 1-18, Table 10). None of the sediments underlying these upper 90 feet of
sands contains nearly as much leucoxene. Furthermore from the land surface to
a depth of about 12 or 15 feet the sands contain substantial epidote and a trace
of garnet (Spls. 1-3, Table 10). The problems raised by the presence of epidote
in the upper sands at this site have not been solved.
The finely-laminated sands from 110 feet to 128 feet contain a relatively high
amount of epidote (Spls. 23-26, Table 10). This high content of epidote
continues downward through the intercalated layers of olive-green clay and
quartz sand (Spls. 27-36, Table 10), through the late Miocene shell marl (Spl. 37,
Table 10) and well into the upper part of the Hawthorn Formation (Spls. 38-43,
Table 10). The heavy mineral distribution is consistent with the possibility that
the upper Hawthorn sediments, the late Miocene shell marl and the
post-Hawthorn clastics are closely related, and may, in fact, all be late Miocene
in age.
The cores from this core hole are on file at the Bureau of Geology,
Tallahassee, Florida. The file number is W-8400.
RIDGES IN STUDY AREA
The quartz sand in the upper sand zone of the Trail Ridge sequence is
characterized by its uniform size distribution (Spls. 1-13, Table 3; Spls. 1-17,
Table 6). In fact, this uniform size distribution is one of the most striking
features of these Trail Ridge sands. In general from about 50 to 70 per cent of
the quartz sand is medium in size (+60 mesh to -35 mesh, 1/4 to 1/2 mm), and
approximately 25 to 40 per cent of the sand is fine (+120 mesh to -60 mesh, 1/8
to 1/4 mm). The size of the quartz sand composing the Baywood Pl~montory
is markedly different. The Baywood Promontory sands are very high in the fine
fraction (+120 mesh to -60 mesh). Approximately 80 to 90 per cent of the total
sand is this size (Spls. 1-26, Table 9).
Certainly the sands making up Trail Ridge and the Baywood Promontory are
very different. Such a pronounced difference indicates the possibility that these
ridges formed along different shore lines. If these ridges formed along different
BULLETIN NO. 52
shore lines, it seems plausible that some of the other ridges and sand hills in the
area would be related to the shore line along which the sands of Trail Ridge
accumulated, and other sand hills and ridges would be related to the shore line
along which the sands of the Baywood Promontory accumulated. Furthermore,
the sand-size distribution of the quartz grains might be an aid in recognizing and
distinguishing the different sand hills and ridges. Sand samples, therefore, were
collected through the study area and analyzed (Fig. 2).
The results of these analyses reveal that there are, in fact, two distinct sets of
ridges in the study area (Pirkle and Yoho, 1970). One set occurs along the
western side of the area of Citronelle outcrop and tends to wrap around and to
partly cover the northern end of the outcrop area. These ridges and hills are
composed of sand of the Trail Ridge type. The second set of ridges is present
along the eastern side of the Citronelle area of outcrop. The sands of these ridges
are similar to the sands of the Baywood Promontory. The valley followed by the
North Fork of Black Creek separates the Trail Ridge type to the west from the
Baywood Promontory type to the east. At some sites around the northern end
the area of Citronelle outcrop, sand hills and ridges of the Baywood Promontory
type appear to truncate sand hills and ridges of the Trail Ridge type. Therefore
the ridges of-the Baywood Promontory type apparently are younger than ridges
and sand hills of the Trail Ridge type, thus giving more reason to believe that
these two sets of ridges might be genetically related to different shore lines.
Additional considerations of the data given for the Trail Ridge drill holes and for
the Baywood Promontory drill hole lend further insights into the occurrences
and characteristics of the sand hills and ridges.
TRAIL RIDGE
The base of the Trail Ridge sequence is approximately 149 feet above present
sea level in TR No. 1 (Table 2) and 147 feet in TR No. 2 (Table 5). The break is
distinct. In addition to a change in the nature of the sediments, there is a change
in the nature of the heavy mineral suites. The almost total absence of epidote
and garnet in the sediments of the Trail Ridge sequence and the presence of
these minerals in almost all of the materials underlying the Trail Ridge sequence
presents a problem. Either the minerals were never deposited in the Trail Ridge
sediments, or the minerals were deposited with the sediments and later
destroyed through weathering. If the epidote and garnet have been removed
from the Trail Ridge sequence by weathering in situ, the break between the Trail
Ridge sequence and the underlying post-Hawthorn clastics might not be of major
stratigraphic importance. On the other hand, if ppidote was never deposited in
the sediments of the Trail Ridge sequence, the implications of the stratigraphic
break between the Trail Ridge sequence and the underlying post-Hawthorn
clastics would be more far-reaching.
Of interest to the problem is the fact that epidote is not present in the peaty
and sapropelic sediments of the lower zone of the Trail Ridge sequence (Spls.
29
BUREAU OF GEOLOGY
14-21, Table 4; Spls. 18-25, Table 7). Apparently epidote was never deposited in
the sediments, or if deposited was destroyed by weathering while the sediments
were accumulating. If the sediments of the lower zone of the Trail Ridge
sequence had been subjected to severe weathering under subtropical conditions
during post-depositional time, it seems reasonable to assume that the wood
and other organic matter so common in that lower part of the Trail Ridge
sequence would have been destroyed. Perhaps it could be argued that because of
the presence of organic matter, acids formed during post-depositional times and
played a role in leaching out epidote and garnet from the peaty and sapropelic
sediments of the Trail Ridge sequence. However, the question could then be
asked why acids did not form and leach out epidote and garnet from the
olive-green clays and quartz sands of the post-Hawthorn clastics immediately
underlying the Trail Ridge sequence. The olive-green clays and clayey sands
carry wood and finely-divided organic matter. There is no reason to believe that
beds of fine sand and other large parts of the post-Hawthorn clastics are less
permeable to the movements of ground water than are large parts of the peaty
and sapropelic sediments present in the lower zone of the Trail Ridge sequence.
It must be concluded that the break between the Trail Ridge sequence and
the underlying sediments is characterized by original differences in the sediments.
Also the break is characterized by differences in the heavy mineral suites. This
break is at an elevation of about 150 feet above present sea level.
BAYWOOD PROMONTORY
The Baywood Promontory is underlain by a thick section of quartz sand.
There is a sharp break at a depth of 110 feet beneath the ridge crest. This depth
is at an elevation of approximately 100 feet above present sea level. The loose
sands underlying the break are finely laminated in contrast to the massive
character of the overlying sands. In addition, the heavy mineral suites are
different. The finely-laminated sands are characterized by a relatively high
content of epidote (Spls. 23-26, Table 10). It is significant that there is a sharp
change in the heavy mineral suites and in the sedimentary features at the same
depth. It is also significant that there is no change in the size of the quartz sand,
thus indicating that the sand-size distribution of the quartz grains is not the
controlling factor in the presence or absence of epidote.
The break at a depth of 110 feet (elevation 100 feet) is important. Suppose,
for example, that the sediments from the land surface downward through the
olive-green clay portion of the post-Hawthorn clastics (or the upper 169 feet of
the sediments) are alternating terrestrial, shore-line, and lagoonal deposits laid
down along a fluctuating coast line. In such a case the massive surface sands
might be wind-blown or beach ridge deposits that pass downward into lagoonal
or marine sediments. The depth at which the massive sands pass downward into
lagoonal or other marine sediments would correlate with the changes in
sedimentary features and heavy mineral suites. The depth at which these changes
take place is at an elevation of approximately 100 feet above present sea level.
30
BULLETIN NO. 52
It must be recognized, however, that it would be difficult to account for the
lack of epidote in the sands of dunes and ridges that accumulated on the
landward side of a shore line along which epidote was common. Studies along
present-day sea coasts show that all of the various kinds of heavy minerals
common along shore lines are deposited in the sand dune areas landward from
the shore lines. In fact, some of the lighter heavy minerals are more concentrated
in the sand dune areas (Gillson, 1959, P. 425).
Actually a case can be built that the laminated quartz sands, which begin at a
depth of 110 feet, and the underlying olive-green clays and quartz sands of the
post-Hawthorn clastics are older than the massive surface sands making up the
Baywood Promontory and are separated from those upper massive sands by a
significant stratigraphic interval. The heavy mineral distribution is consistent
with this possibility. Furthermore the olive-green or olive-drab clays, the late
Miocene shell beds and the Hawthorn materials contain black phosphorite and
small amounts of feldspar. These minerals are almost totally absent in the
massive surface sands. It is evident that the break between the massive surface
sands and the underlying sediments is one along which there is a change in
sedimentary features and a change in heavy mineral suites. This break is at an
elevation of approximately 100 feet above present sea level, an elevation given
by numerous workers for one of the ancient sea-level stands.
ELEVATIONS OF SEA-LEVEL STANDS
If these breaks at 150 feet and 100 feet above present sea level do represent
elevations at which terrestrial or beach sediments pass downward into lagoonal,
deltaic or marine materials, a question still remains as to whether the elevations
represent the highest elevations of sea-level rises recorded in the area. A fuller
understanding of this problem requires the consideration of another ridge, the
Lake Wales Ridge (Fig. 1).
The Lake Wales Ridge is present in central peninsular Florida. It trends in a
generally north-south direction (slightly northwest-southeast) dividing the
peninsula into two nearly equal parts. The ridge is underlain by Citronelle
sediments which usually rest on the Hawthorn Formation. The Citronelle
materials consist of mixtures of quartz sand, quartz granules and kaolinitic clay.
Locally quartz or quartzite pebeles are abundant. In some areas much of the
Lake Wales Ridge has been destroyed by erosion. Nevertheless, in such areas the
characteristic Citronelle sediments may indicate the former presence of the
ridge.
The Lake Wales Ridge is older than Trail Ridge or the Baywood Promontory
(Pirkle et al., 1963, p. 128-135). Citronelle sediments making up much of the
Lake Wales Ridge have been dated as late Miocene by Ketner and McGreevy
(1959, p. 49). This date is based on occurrences of invertebrate fossils. Trail
Ridge, on the other hand, cannot be older than Pliocene (Pirkle and Yoho,
1970), and the Baywood Promontory is still younger than Trail Ridge.
31
BUREAU OF GEOLOGY
Therefore, within the study area the older Lake Wales remnant, revealed by the
presence of the characteristic Citronelle sediments, occupies a central position
(Fig. 2). It is flanked on the west by Trail Ridge, and it is flanked on the east by
Baywood Promontory. The seas along whose shore lines Trail Ridge and the
Baywood Promontory formed must have encroached on the older Lake Wales
remnant.
PRESENT INTERPRETATION
The stratigraphic position and age of the post-Hawthorn clastics underlying
Trail Ridge and the Baywood Promontory are critical in arriving at the correct
interpretation of the ridges. Suppose, for example, that the post-Hawthorn
clastics are late Miocene in age. Trail Ridge and the Baywood Promontory could
then be interpreted as beach ridges formed where seas reached their highest
advances during encroachment on the Lake Wales remnant. If, on the other
hand, the post-Hawthorn clastics are lagoonal materials genetically related to the
same shore lines along which Trail Ridge formed and along which the sands of
the Baywood Promontory accumulated, it could be concluded that the ridges
formed during standstills of regressing seas.
Although unquestioned conclusions cannot be drawn, the writers believe that
the olive-green clays and fine. to very fine quartz sands of the post-Hawthorn
clastics are more closely related to the late Miocene shell beds than to the
overlying surface sands, and that the Baywood Promontory and the southern
part of Trail Ridge formed as beach ridges.
The Baywood Promontory, therefore, could be interpreted as a beach ridge
formed along a "100-foot shore line" at a time the 100-foot seas reached their
highest encroachment on the Lake Wales remnant. This interpretation would be
consistent with conclusions drawn by numerous investigators from a study of
surface topography, and a vertical section through the Baywood Promontory
would give a valid height which would approximate the elevation to which the
ancient 100-foot seas rose.
The interpretation of Trail Ridge, however, is more complicated, and
conclusions drawn from a consideration of the sediments underlying the ridge
are not as easily fitted to conclusions that have been drawn from studies of
surface features. For example, various interpretations can be given to the
sediments of the lower sapropelic zone of the Trail Ridge sequence. In fact a
case can be made that the Trail Ridge seas rose to elevations higher than 150 feet'
above present sea level and may have covered the Lake Wales remnant. Although
the southern part of Trail Ridge is believed to be a beach ridge formed along the
flanks of the Lake Wales remnant, sufficient data are not available to establish
whether that southern part of the ridge formed during encroachment by the
"Trail Ridge seas" onto the Lake Wales remnant or during a standstill of a
regressing "Trail Ridge sea." Vertical sections through Trail Ridge at the sites of
the drill holes would give elevations at which beach ridge sands pass downward
32
BULLETIN NO. 52 33
into lagoonal, terrestrial or other types of sediments, but it cannot be said that
the sections would reveal the height to which the Trail Ridge seas rose.
It can be concluded that the types of data presented in this report are
invaluable in studying ridges formed along the shore lines of ancient seas.
Although data from the drill holes are insufficient to allow undisputed
interpretations, the value of the approach as a support to studies based on
surface topography is demonstrated, and it becomes clear that with more and
more of these-types of data, a better understanding of sand ridges and ancient
sea-level stands will evolve.
BULLETIN NO. 52 35
REFERENCES
Alt, D., and H.K. Brooks
1965 Age of the Florida marine terraces: Jour. Geology, vol. 73, pp. 406-411.
Clark, W.E., R.H. Musgrove, C.G. Menke, and J.W. Cagle, Jr.
1964 Water resources of Alachua, Bradford, Clay and Union counties, Florida:
Florida State Geol. Surv., Rept. of Inv., no. 35, pp. 1-170.
Cooke, C. Wythe
1945 Geology of Florida: Florida State Geol. Surv., Geol. Bull., no. 29, pp. 1-339.
Gillson, J.L.
1959 Sand deposits of titanium minerals: Min. Eng., vol. 11, pp. 421-429.
MacNeil, F. Stearns
1950 Pleistocene shore lines in Florida and Georgia: U.S. Geol. Surv., Prof. Papea
221-F, pp. 95-107.
Martens, James H.C.
1935 Beach sand between Charleston, South Carolina, and Miami, Florida: Geol.
Soc. America Bull., vol. 46, pp. 1563-1596.
Ketner, K.B., and L.J. McGreevy
1959 Stratigraphy of the area between Hernando and Hardee counties, Florida: U.S.
Geol. Surv. Bull. 1074-C, pp. 49-124.
Pirkle, E.C., W.H. Yoho, A.T. Allen, and A.C. Edgar
1963 Citronelle sediments of peninsular Florida: Quart. Jour. Florida Acad. Sci.,
vol. 26, pp. 105-149.
Pirkle, E.C., W.H. Yoho, and A.T. Allen
1965 Hawthorne, Bone Valley, and Citronelle sediments of Florida: Quart. Jour.
Florida Acad. Sci., vol. 28, pp. 7-58.
Pirkle, E.C., and W.H. Yoho
1970 The heavy mineral ore body of Trail Ridge, Florida: Econ. Geol., vol. 65, pp.
17-30.
Vernon, Robert 0.
1951 Geology of Citrus and Levy counties, Florida: Florida State Geol. Survey
Bull., 33, pp. 1-256.
APPENDIX 1
39
BULLETIN NO. 52
APPENDIX
Trail Ridge Drill Hole No. 1*
NE4, SE4, Section 31, T. 6 S., R. 23 E., Clay County, Florida
Approximately 412 Miles Southeast of Starke
Surface elevation 239 Feet
E.C. Pirkle, W.H. Yoho, Charles W. Hendry, Jr.
Description
Thickness
In Feet and Inches
Surface Sands
59. Quartz sand, medium to fine. The upper 1 foot 3 inches of this
unit is white. Present beneath this upper 1 foot 3 inches is a
6-inch brown zone which grades downward into white and
gray sand ................... ................ 5' 0"
(From O' to 5')
Spl. 1 Channel sample of upper 1 foot 3 inches.
Spl. 2 Channel sample of lower 3 feet 9 inches.
58. Dark brown to black organic zone. Quartz sand containing
finely-divided organic matter.
Quartz sand is medium to fine.
The lower 6 inches of this unit is very hard (hardpan) . . .
Spl. 3 Channel sample of upper 5 feet of unit.
Spl. 4 Channel sample of lower 7 feet 6 inches of unit.
57. Quartz sand, fine to coarse. Moderate brown.
Stringers and small lenses of darker sediments are present
through the sands. Some of the dark stringers are black from
the presence of concentrations of heavy minerals. Other dark
streaks are black from the presence of concentrations of
finely-divided organic matter.
The moderate brown color is somewhat uniform throughout
this part of the surface sands.
Bedding features are revealed by the dark streaks of heavy
minerals and organic matter. Horizontal bedding was noted
at a depth of 9 feet below the upper surface of the unit.
Highly inclined bedding was conspicuous in the interval from
38 feet to 45 feet 6 inches below the upper surface of the
unit.
The sediments from the land surface to a depth of 63 feet are
riined for their heavy mineral content ............
*This hole was drilled by the Bureau of Geology, Florida
Department of Natural Resources, under the active super-
vision of Charles W. Hendry, Jr. The drilling was completed
May 23, 1968. Analyses of the samples are given in Tables 2
through 4.
. . . . 12' 6"
(From 5' to 17'6")
. . . 45' 6"
(From 17'6" to 63')
Unit
BUREAU OF GEOLOGY
A series of channel samples of the unit was taken at the
following depths below the land surface.
Spl. 5 Channel sample from 17 feet 6 inches to 25 feet
below land surface (upper 7 feet 6 inches of Unit
57).
Spl. 6 Sample from depth of 25 to 30 feet below land
surface.
Spl. 7 30 to 35 feet.
Spl. 8 35 to 40 feet.
Spl. 9 40 to 45 feet.
Spl. 10 45 to 50 feet.
Spl. 11 50to 55 feet.
Spl. 12 55 to 60 feet.
Spl. 13 60 to 63 feet below land surface (lower 3 feet of
Unit 57).
Intercalated Layers of Peaty or Sapropelic Sediments and Quartz Sand
56. "Peat" layer. Black to brown.
Approximately 92 per cent by weight of this unit is woody
material.
The quartz sand mixed with the woody material is very fine to
medium ................ .. ........ .......... 5'0"
(From 63' to 68')
Spl. 14 Channel sample of peat layer.
55. Quartz sand, medium to very fine. White, to light brown, to
gray with black mottling.
In the upper 1 foot of this unit (just below the overlying wood
layer) the sand is very fine . ............ ..
.. . . 5' 0"
(From 68' to 73')
Spl. 15 Channel sample of Unit 55.
54. Black organic zone. Quartz sand with wood and finely-divided
organic matter.
This interval differs from Unit 56 in being mainly quartz sand
with some wood, whereas Unit 56 is mainly wood with some
sand.
As a result of techniques used in treating these sediments, a part
of the value listed in Table 2 under the clay fraction of this
unit consists of finely-divided organic matter. Likewise, the
clay fraction for Units 52 and 50 (Spls. 18 and 20) contains
finely-divided organic matter.
Quartz sand is medium to very fine .. . ..........
. . . 1'6"
(From 73' to 74' 6")
Spl. 16 Channel sample of black organic zone.
53. Quartz sand, very fine to medium. White with some black
mottling .................. .. ... ... ......... . 2' 6"
(From 74' 6" to 77')
Spl. 17 Channel sample of sand of Unit 53.
40
BULLETIN NO. 52 41
52. Black organic zone. Quartz sand with wood and finely-divided
organic matter.
This unit is similar to Unit 54.
Quartz sand is medium to very fine ...... . . . . . . . . 1' 0"
(From 77'to 78')
Spl. 18 Channel sample of Unit 52.
51. Quartz sand, medium to very fine. White with black mottling .. . . . 2'6"
(From 78' to 80' 6")
Spl. 19 Channel sample of Unit 51.
50. Black to brown organic zone. Quartz sand with wood and much
finely-divided organic material.
This unit is similar to Units 54 and 52.
Quartz sand is fine to coarse ............... .. . . . . .4' 0"
(From 80'6" to 84'6")
Spl. 20 Channel sample of Unit 50.
49. Clayey quartz sand. Quartz sand is fine to coarse. Gray.
This layer underlies the peaty sediments of the section . . . . . . 1'6"
(From 84'6" to 86')
Spl. 21 Channel sample of the clayey sand.
48. No recovery ................. ........... ... 4'0"
(From 86'to 90')
Intercalated Layers or Lenses of Quartz Sand, Clayey Sand and Massive Drab Clay
47. Quartz sand, fine to coarse, Brown.
Approximately 10 feet beneath the upper surface of the unit
the color becomes darker with some black mottling.
The bottom 6 inches of the unit is characterized by a marked
increase in clay ........ .......... ... ........ 16' 0"
(From 90'to 106')
Spl. 22 Channel sample of upper 4 feet of unit.
Spl. 23 Channel sample of interval from 4 feet to 9 feet
beneath upper surface of unit (depth of 95 to 100
feet below land surface).
Spl. 24 Channel sample of lower 6 feet of unit.
46. Sandy Clay. Drab to olive. Massive.
Rare Marine micofossils are present.
Quartz sand is very fine to medium .................. ...... 1' 0"
(From 106'to 107')
Spl. 25 Channel sample of the massive drab clay.
42 BUREAU OF GEOLOGY
45. Clayey quartz sand. White.
Almost 99 per cent of the quartz sand in this unit is very fine.
The fraction of sediments that passed through the 230-mesh
screen and was retained on the 325-mesh screen is relatively
high. This fraction of sediments is not recorded in Table 2
for this unit or for any of the other units . . . . . . . . 1' 6"
(From 107' to 108'6")
Spl. 26 Channel sample of the fine sand.
44. Clay, sandy. Drab to olive. Massive. Similar to Unit 46.
Quartz sand is very fine to fine .... . ........ .......... 1' 6"
(From 108'6" to 110')
Spl. 27 Channel sample of the drab clay.
43. Quartz sand, very fine to coarse. Loose. White to light gray . . . . .. 2'9"
(From 110'to 112'9")
Spl. 28 Channel sample of Unit 43.
42. Clayey quartz sand. White to light gray. Quartz sand is very fine
to fine.
Borings are present in the sediments ............ . . ... 2' 3"
(From 112'9" to 115')
Spl. 2'9 Channel sample of the clayey sand.
41. Stringers and small lenses of fine white quartz sand intercalated
with stringers and small lenses of drab clay.
The sediments are characterized by conspicuous laminations
which give the unit a varved appearance.
In the upper 3 feet the stringers and small lenses of quartz sand
are more abundant.
In the lower 3 feet the clay stringers and clay lenses are more
abundant. The lower foot is mainly massive drab clay.
The quartz sand is very fine to medium . . . .
. . . 6' 0"
(From 115' to 121')
Spl. 30 Channel sample of upper 3 feet of unit.
Spl. 31 Channel sample of lower 3 feet of unit.
40. Clayey quartz sand. Drab to olive. Has a massive appearance.
The quartz sand is very fine to medium .............
Spl. 32 Channel sample of the drab clayey sand of Unit
40.
39. Clayey quartz sand. Quartz sand is medium to fine. Gray.
Clay is disseminated throughout the unit.
This unit contains more clay than underlying unit . . . .
. . . . 3' 0"
(From 121' to 124')
.. . . 2' 0"
(From 124' to 126')
Spl. 33 Channel sample of Unit 39.
38. Quartz sand. Loose. Medium to fine. White to light gray . . . . . 4' 0"
(From 126'to 130')
Spl. 34 Channel sample of loose sand.
BULLETIN NO. 52
37. Clay. Drab to olive to black. Massive.
Upper 2 feet of clay is drab and is similar to units 46 and 44.
The clay in the lower 3 feet is black.
Quartz sand present in the unit is medium to very fine . . . . . . 5' 0"
(From 130'to 135')
Spl. 35 Channel sample of clay.
36. Quartz sand, medium to fine. Horizontally laminated.
Some black mottling ................... ....... 3' 6"
(From 135' to 138'6")
Spl. 36 Channel sample of sand of Unit 36.
Hawthorn Formation Miocene
35. Clayey quartz sand. Some stringers and small lenses of drab clay
are present in the unit.
The upper 6 inches of this unit have a relatively high content of
the drab clay.
Sand-size black phosphorite is common. Pyrite is present.
Quartz sand is fine to medium .................. ...... 2' 0"
(From 138'6 "to 140'6")
Spl. 37 Channel sample of Unit 35.
34. Sandy dolomite. Cream to pale yellow and buff. Moderately
hard.
A few grains and small pebbles of black phosphorite are present
in the dolomite.
Occasional impressions of marine mollusks.
The quartz sand is fine to medium .. . ...........
Spl. 38 Chips selected from all parts of the unit.
33. Sandy and clayey dolomite. Cream.to light tan to buff. Soft.
Sand-size grains and small pebbles of black phosphorite are
present in the unit. A few of the phosphate particles are
brown. The small phosphate pebbles are more common in
the upper 3 feet of the unit.
The quartz sand is fine to medium .. . ..........
Spl. 39 Channel sample of unit.
32. Mixture of carbonate, quartz sand, clay and phosphorite. Gray.
Soft.
In the upper 2 feet 6 inches of the unit there is an increase in
small pebble and sand-size black phosphorite. Some
phosphate particles are brown.
Quartz sand is fine to medium .................
. . . . 2' 6"
(From 140'6" to 143')
. . . 7' 0"
(From 143'to 150')
. . . 5' 6"
(From 150' to 155'6")
Spl. 40 Channel sample of Unit 32.
43
BUREAU OF GEOLOGY
31. Dolomite, Sandy and clayey. Gray. Hard.
Fossil impressions of marine mollusks.
A few sand-size grains of shiny black phosphorite.
The quartz sand is fine to medium .... . . . . .. . 1'0"
(From 155'6"to 156'6")
Spl. 41 Selected chips representative of unit.
30. Mixture of carbonate, quartz sand and clay. Gray.
A few small pebbles and sand-size grains of black phosphorite.
From the upper surface of the Hawthorn Formation (Unit 35)
through this unit, there has been no real concentration of
pebble-sized phosphorite. Most of the phosphorite has been
concentrate-or sand-size.
The quartz sand is fine to medium .................. ..... 1' 6"
(From 156'6"to 158')
Spl. 42 Channel sample of Unit 30.
29. Mixture of carbonate, quartz sand and clay. Gray. Hard.
A few small black pebbles of phosphorite disseminated through
unit.
Impressions of marine mollusks are present. These fossils are
especially abundant in the interval from 165 feet to 167
feet. There the rock has a high carbonate content and is a
mass of fossil impressions.
The quartz sand is fine to coarse....... . . . . .
Spl. 43 Sample of chips selected throughout unit.
28. No recovery . . . . . . . . . . . . ..
27. Clayey quartz sand, dolomitic. Dark gray. Soft.
An increase in clastics from overlying sediments and a decrease
in carbonate.
Common black, shiny, sand-size grains of phosphorite.
Quartz sand is fine to coarse ...................
. . . 14' 0"
(From 158'to 172')
..... 1 t 3' 0"
(From 172'to 175')
. . . 5' 0"
(From 175' to 180')
Spl. 44 Channel sample of sediments.
26. Mixture of quartz sand, carbonate and clay. Cream to light tan.
Hard.
The unit contains common sand-size particles and small pebbles
of black phosphorite.
The quartz sand is fine to coarse .. . ...........
. . . . 5' 0"
(From 180' to 185')
Spl. 45 Selected chips representative of unit.
25. Mixture of quartz sand, carbonate and clay. Gray. Lithified.
Black phosphorite of sand size is present.
The quartz sand is very fine to medium . . . .
. . 5' 0"
(From 185'to 190')
Spl. 46 Channel sample of unit.
44
BULLETIN NO. 52 45
24. Mixture of quartz sand, clay and carbonate. Gray. Lithified.
A few small pebbles and sand-size particles of black, shiny
phosphorite.
Quartz sand is very fine to fine .................. ..... 4' 0"
(From 190' to 194')
Spl. 47 Channel sample of unit.
23. Sandy dolomite, clayey. Gray. Hard. Mollusk-bored.
The mollusk borings are filled with clay and black phosphorite.
The quartz sand is fine to coarse .............. .... .... .. 7' 6"
(From 194' to 201'6")
Spl. 48 Sample of selected chips.
22. Clayey quartz sand, dolomitic. Dark gray to olive. Soft.
Black pebble-size and sand-size phosphorite is common. There
is an increase in pebble-size phosphorite in the interval from
201 feet to 202 feet 6 inches.
The quartz sand is coarse to very fine .... . . . . . .. . 4' 6"
(From 201'6" to 206')
Spl. 49 Channel sample of Unit 22.
21. Mixture of carbonate, quartz sand, clay and phosphorite.
Light gray to tan to cream. Hard.
Small black pebbles and sand-size grains of phosphorite are
abundant. There are a few small pebbles of cream to light
gray phosphorite.
Impressions of marine mollusks.
Quartz sand is fine to coarse .................. ....... 6' 6"
(From 206'to 212'6")
Spl. 50 Selected chips representative of unit.
20. No recovery. It is believed that the dominant type of sediment
within this unit is fine quartz sand . . . . ..... .. .... 9' 6"
(From 212'6" to 222')
19. Quartz sand, clayey and dolomitic. The quartz sand is fine.
Light gray. Soft.
Sand-size shiny black phosphorite is present . . . . . . .... 9' 0"
(From 222'to 231')
Spl. 51 Channel sample of Unit 19.
18. No recovery ............. .................. ... .. 6' 0"
(From 231'to 237')
17. Mixture of quartz sand, carbonate and clay. Gray. Moderately
hard.
Small pebbles and sand-size grains of black phosphorite are
present.
The quartz sand is very fine to medium ................ . . 3' 0"
(From 237'to 240')
Spl. 52 Channel sample of unit.
BUREAU OF GEOLOGY
16. No recovery. Believed to be fine quartz sand .
15. Sandy dolomite, clayey. Tan to light gray. Hard.
Very little phosphorite is present in this unit.
The quartz sand is fine to very fine . . . . .
. . . 12' 0"
(From 240'to 252')
. . . 2' 0"
(From 252' to 254')
Spl. 53 Sample of selected chips.
14. Clayey and dolomitic quartz sand. Gray.
Fine black phosphorite is present.
The quartz sand is fine to very fine . . . .
. . . . 3' 0"
(From 254' to 257')
Spl. 54 Channel sample of Unit 14.
13. Clay sandy and dolomitic. Dark green. Soft.
In the interval from 257 feet 6 inches to 258 feet megascopic
secondary dolomite crystals have formed in the sediments.
Also secondary dolomite crystals are present from 262 feet
to 263 feet.
The quartz sand is very fine to fine ............... .. ...... 11' 0"
(From 257'to 268')
Spl. 55 Channel sample of the dark green clay.
12. Hard massive clay, silicified. Fine-grained Gray.
No visible grains of phosphorite.
Similar in appearance to the blocky, silicified clay exposed
locally at the Devil's Mill Hopper in Alachua County . . . . . 0' 6"
(From 268' to 268'6")
Spl. 56 Chips representative of the silicified clay.
11. Dolomitic clay. Dark green. Soft.
No phosphorite was noted in this unit.
The quartz sand is very fine to medium . . . .
. . . . . 6 "
(From 268'6" to 270')
Spl. 57 Channel sample of Unit 11.
10. Clayey dolomite. Fine-grained. Lithified. Moderately hard.
No phosphorite was noted in the sediments.
The quartz sand is fine to very fine . . . ...
. . . . 1'6"
(From 270' to 271'6 ")
Spl. 58 Channel sample of unit.
9. Very little recovery. The sediments of this unit are soft and are
a mixture of quartz sand and dark green clay with some
black phosphorite (sand-size and small pebble-size) . . . . . 10' 6"
(From 271'6" to 282')
46
BULLETIN NO. 52
8. Clayey dolomite. Fine-grained. Light gray to dark gray. Hard.
The upper part of the dolomite is riddle with solution channels.
These channels are filled with mixtures of limestone
fragments, quartz sand and shiny sand-size grains and small
pebbles of black phosphorite. Some of the limestone
fragments are mollusk-bored. This unit is similar to Unit 1 at
Brooks Sink, Bradford County (Pirkle et al., 1965, p. 46).
The quartz sand is coarse to very .fine. Quartz granules are
present ... ................ . ...
Spl. 59 Sample of sediments filling solution channels.
Spl. 60 Sample of the dolomite.
7. Sandy dolomite, clayey. Gray. Hard.
There are a few black sand-size grains of phosphorite in the
unit. There is an increase in the amount of quartz sand and
fine phosphorite in the lower foot of the sediments.
Impressions of marine mollusks.
The quartz sand is very fine to medium. Quartz granules are
present.
The unit grades into the underlying unit . . . ...
$pl. 61 Sample of selected chips.
6. Mixture of carbonate, quartz sand, clay and phosphorite. Gray.
Hard.
Shiny black phosphate particles are common.
In the interval from 295 feet to 297 feet there is an apparent
increase in carbonate, and numerous mollusk impressions are
present.
The quartz sand is fine to coarse. Some quartz grains are rice-size
. . . 5' 0"
(From 282'to 287')
. . . . 3' 0"
(From 287' to 290')
. . . 8' 0"
(From 290' to 298')
Spl. 62 Sample representative of unit.
5. Sandy dolomite. Gray. Hard and tough. Fragments of
mollusk-bored limestone are present.
There is an increase in quartz sand beginning at a depth of
approximately 300 feet.
Some sand-size cream, tan and brown grains of phosphorite are
disseminated through the unit. This is the first unit down
from the upper surface of the Hawthorn Formation in which
cream to brown phosphorite is more abundant than black
phosphorite.
The quartz sand is medium to fine ................... .... .. 8' 6"
(From 298' to 306'6")
Spl. 63 Sample of chips representative of unit.
4. No recovery ............ ..... ......... 2'0"
(From 306'6" to 308'6")
47
48 BUREAU OF GEOLOGY
3. Mixture of carbonate, quartz sand, clay and sand-size
phosphorite. The upper 3 inches of this unit is dark gray.
The lower part of the unit is light gray. Moderately hard.
Quartz sand is medium to fine .................. .. .... . 1' 6"
(From 308'6" to 310')
Spl. 64 Selected chips from Unit 3.
2. Sandy dolomite Gray. Dense.
There are a few black grains of phosphorite present in the
dolomite.
The quartz sand is medium to fine .................. ..... 4' 0"
(From 310'to 314')
Spl. 65 Representative chips of the dolomite.
Crystal River Formation Eocene
1. Limestone. White to cream.
A cavity from 314 feet to 315 feet is present at the top of this
limestone. The limestone is more than 99 per cent carbonate . . ... 18' 0"
(From 314' to 332')
Spl. 66 Channel sample of Unit 1.
Total depth of drill hole ................ .. ..... 332' 0"
BULLETIN NO. 52
Trail Ridge Drill Hole No. 2*
NE4, NW'4, Section 19, T. 5 S., R. 23 E., Clay County, Florida
Approximately 2 Miles Northeast of Lawtey
Surface Elevation 206 Feet
E. C. Pirkle, W. H. Yoho, Charles W. Hendry, Jr.
Description
Thickness
In Feet and Inches
37. Loose quartz sand, fine to coarse. Light brown, to moderate
brown, to dark brown. Black zones with a relatively high
content of finely-divided organic matter are present from 4
feet 6 inches to 7 feet and from 9 feet 6 inches to 15 feet.
The interval from 9 feet 6 inches to 15 feet is very sapropelic
with abundant wood from 12 feet to 15 feet. Other
sapropelic zones are present at depths of 27 feet 9 inches, 28
feet to 28 feet 6 inches and from 40 feet 6 inches to 43 feet
6 inches.
There is very little visible bedding. However faint stratification,
some slightly inclined from the horizontal, is present in the
interval from 30 feet 6 inches to 38 feet . . . . ...
Channel samples were taken at the following depths below
the land surface.
Spl. 1 Channel sample from land surface to a depth of 3
feet. Gray sand.
Spl. 2 Channel sample from 3 feet to 4 feet 6 inches. Tan
sand.
Spl. 3 Channel sample from 4 feet 6 inches to 7 feet.
Black sand.
Spl. 4 Channel sample from 7 feet to 9 feet 6 inches.
Gray sand.
Spl. 5 Channel sample from 9 feet 6 inches to 15 feet.
Black sapropelic sand with abundant wood from
12 feet to 15 feet.
Spl. 6 Channel sample from 15 feet to 21 feet. Light
brown sand.
Spl. 7 Channel sample from 21 feet to 24 feet 6 inches.
Brown sand.
*This hole was drilled by the Bureau of Geology, Florida
Department of Natural Resources, under the immediate
supervision of Charles W. Hendry, Jr. The drilling was com-
pleted in June, 1968. Analyses of the samples are given in
Tables 5 through 7.
Spl. 8 Channel sample from 24 feet 6 inches to 27 feet 6
inches. Light brown sand.
Spl. 9 Channel sample from 27 feet 6 inches to 27 feet 9
inches. Dark brown sand with an increase in clay.
Spl. 10 Channel sample from 27 feet 9 inches to 28 feet.
Medium brown sand with a /4-inch sapropelic zone
at 27 feet 9 inches.
.. . . 46' 6"
(From O' to 46'6")
Unit
Surface Sands
49
50 BUREAU OF GEOLOGY
Spl. 11 Channel sample from 28 feet to 28 teet 6 inches.
Dark brown sand, sapropelic.
Spl. 12 Channel sample from 28 feet 6 inches to 30 feet 6
inches. Medium-dark brown sand.
Spl. 13 Channel sample from 30 feet 6 inches to 33 feet.
Dark brown sand.
Spl. 14 Channel sample from 33 feet to 38 feet.
Medium-dark brown sand.
Spl. 15 Channel sample from 38 feet to 40 feet 6 inches.
Light brown sand.
Spl. 16 Channel sample from 40 feet 6 inches to 43 feet 6
inches. Dark brown sand, slightly sapropelic.
Spl. 17 Channel sample from 43 feet 6 inches to 46 feet 6
inches. Medium dark brown sand.
Intercalated Layers of Sapropelic Sediments and Quartz Sand
36. Quartz Sand. Very fine to medium. Light brown . . . . . . . . 2' 3"
(From 46'6" to 48'9")
Spl. 18 Channel sample of the light brown quartz sand.
35. Quartz sand. Very fine to medium. Dark brown to black.
Sapropellic .................. .............. .0' 3"
(From 48'9" to 49')
Spl. 19 Channel sample of the quartz sand.
34. Quartz sand, clayey. Quartz is very fine to medium. Dark
brown ................... .................. 1'0"
(From 49' to 50')
Spl. 20 Channel sample of Unit 34.
33. Quartz sand, clayey. Quartz is very fine to medium. Black. Soft
and highly sapropelic ........... . . . . . . .... 1' 0"
(From 50' to 51')
Spl. 21 Channel sample of unit.
32. Clayey sand. Quartz sand is very fine to fine. Dark brown . . . . . . 3' 0"
(From 51'to 54')
Spl. 22 Channel sample from 51 to 53 feet.
Spl. 23 Channel sample of all of Unit 32.
31. Quartz sand, clayey. Quartz is very fine to fine. Dark brownish
gray ................ .......... ......... 2' 6"
(From 54' to 56'6")
Spl. 24 Channel sample of Unit 31.
30. Quartz sand. Very fine to medium. Light brown with interval
from 58 feet 3 inches to 59 feet almost white . . . . . . . .. 2' 6"
(From 56' 6" to 59')
Spl. 25 Channel sample of the quartz sand.
Greensih gray clayey sands and sandy clays
BULLETIN NO. 52
29. Sand, clayey. Quartz sand is very fine to coarse. The clay in the
interval from 59 feet through 86 feet. (Units 29 19; Spls.
26 36) is greenish-gray to gray. Upon exposure to the air
the clay color changes to tan or brown. Black spots high in
organic matter (some showing wood fibers) are present in
the sediments and are especially conspicuous in the interval
from approximately 61 feet to 74 feet.
Sapropelic from 59 feet to 60 feet . . . . . . .
S. . 2' 3"
(From 59' to 61' 3")
Spl. 26 Channel sample of Unit 29.
28. Clayey sand. Sand is medium to very fine. Tan to gray . . . . . . . 3'3"
(From 61' 3" to 64'6")
Spl. 27 Channel sample of the clayey sand.
27. Clayey sand. Sand is medium to very fine. This clayey sand cuts
like cheese and oxidizes to tan upon exposure to the air.
Wood is present ................. ................. 2' 6"
(From 64'6" to 67')
Spl. 28 Channel sample of Unit 27.
26. Clayey sand. Sand is very fine Gray to tan. The quartz sand in
this unit is much finer than the quartz sand in the overlying
unit . . . . . . . . . . . . ... .. .
Spl. 29 Channel sample of the clayey sand of Unit 26.
25. Mixture of clay, sand and silt. The quartz sand is very fine to
fine. Gray.
The value of the -230 to +325-mesh fraction of these sediments,
and the underlying sediments through Unit 19 (Spl. 36), is
relatively high. This fraction consists of quartz and is not
recorded in any of the tables. The amount of the fraction
can be approximately determined from Table 5 by
calculating the per cent of the sediments not represented by
the combined value of the columns for quartz sand and clay
(-325 mesh) .. . . .. . . .. .. . ... ..
. . . . 2' 6"
(From 67' to 69'6")
. . . . . 4' 3"
(From 69'6" to 73'9")
Spl. 30 Channel sample of Unit 25.
24. Mixture of silt, quartz sand and clay. Quartz sand is fine to very
fine. Gray color changes to light tan upon exposure to air
. . . . 3' 9"
(From 73'9" to 77'6")
Spl. 31 Channel sample of Unit 24.
23. Mixture of clay, quartz sand and silt. Quartz sand is very fine to
medium. Gray. The clay turns tan upon exposure to air .
. . . . 0' 6"
(From 77'6" to 78')
Spl. 32 Channel sample of Unit 23.
51
BUREAU OF GEOLOGY
22. Mixture of silt, quartz sand and clay. Quartz sand is very fine to
medium. Gray.
Faint horizontal bedding is visible from 79 feet to 80 feet . .
Spl. 33 Channel sample of sediments in Unit 22.
21. Mixture of clay, quartz sand and silt. Quartz sand is very fine to
fine. Gray ............... .. .........
Spl. 34 Channel sample of Unit 21.
20. Mixture of quartz sand, clay and silt. Quartz sand is very fine to
medium. Gray when fresh; tan where exposed to air.
Inclined bedding visible at 84 feet ........ . .
Spl. 35 Channel sample of Unit 20.
19. Clayey sand. Quartz sand is very fine to medium. Gray to tan
Spl. 36 Channel sample of the clayey sand.
White to Gray Sands and Clayey Sands
18. Quartz sand, clayey. Quartz sand is fine to medium. Cream.
The units making up the interval from 86 feet to 101 feet 6
inches (Units 18-13; Spls. 37-42) do not have the high
content of very fine sand and silt characteristic of the
overlying interval (Units 29-19; Spls. 26-.36) . . . .
Spl. 37 Channel sample of Unit 18.
17. Quartz sand, clayey. Quartz sand is fine to medium. Tan to
cream.
Slightly micaceous ................ ... ....
Spl. 38 Channel sample of sediments of Unit 17.
16. Quartz sand, clayey. Quartz sand is fine to medium. Tan to
light gray.
Micaceous ... . . . . .
Spl. 39 Channel sample of Unit 16.
15. Quartz sand. Coarse to fine. Gray . . . . .
. . . . 2' 0"
(From 78' to 80')
. . . . 2' 6"
(From 80' to 82'6")
. . . . . 2' 6"
(From 82'6" to 85')
. . . . 0"
(From 85' to 86')
. . 3' 0"
(From 86' to 89')
. . 4' 0"
(From 89' to 93')
S. . 4' 0"
(From 93' to 97')
. . . . 2' 0"
(From 97' to 99')
Spl. 40 Channel sample of the quartz sand.
52
BULLETIN NO. 52 53
14. Quartz sand. Medium to very coarse. Light gray.
A layer, 1/-inch in thickness, of massive gray clay is present at
the base of these coarse sediments . . . . . . . . . . . 0'6"
(From 99' to 99'6")
Spl. 41 Channel sample of the quartz sand.
13. Quartz sand. Coarse to fine. Gray. Contains a few irregular
masses of clay. Micaceous.
Bedding is not distinct, but some faint cross-bedding is present
in the interval from 100 feet 6 inches to 101 feet 6 inches . . . . . 2' 0"
(From 99'6" to 101'6")
Spl. 42 Channel sample of the quartz sand.
Drab to Tan Clayey Sands
12. Quartz sand, clayey. Quartz sand is fine to medium. Mottled
gray and tan.
Most of the interval from 101 feet 6 inches downward to the
late Miocene shell marl at a depth of 143 feet 3 inches is
characterized by tan to drab clay. There are occasional
stringers of massive drab clay present in the sediments .... . . . 5' 0"
(From 101'6" to 106'6")
Spl. 43 Channel sample of Unit 12.
11. Clayey sand. Quartz sand is medium to very fine. Tan to gray . . . . 2' 0"
(From 106' 6" to 108'6")
Spl. 44 Channel sample of clayey sand.
10. Quartz sand, clayey. Quartz sand is fine to coarse. Dark gray
with some black mottling. Small lenses and stringers of white
sand cut the sediments ........ .................. 1' 3"
(From 108'6" to 109'9")
Spl. 45 Channel sample of sediments.
9. Clayey sand. Quartz sand is medium to very fine.
Tan to brown ........ ........ .............. 1'3"
(From 109'9" to 111')
Spl. 46 Channel sample of clayey sand.
8. Quartz sand, clayey. Quartz sand is fine to very fine.
Drab to tan ......... . ....... .............. 4'6"
(From 111' to 115'6")
Spl. 47 Channel sample of Unit 8.
7. Quartz sand, clayey. Quartz sand is fine to medium.
Drab to tan .. .......... . .. . ...... ....... 2' 6"
(From 115'6"to 118')
Spl. 48 Channel sample of sediments of Unit 7.
54 BUREAU OF GEOLOGY
6. Quartz sand, clayey. Quartz sand is fine to medium.
Drab to tan . . . . . . . . . . . . . 6'0"
(From 118' to 124')
Spl. 49 Channel sample of Unit 6.
5. Quartz sand, clayey. Quartz sand is fine to medium.
Drab to tan . . . . . . . . . .. .. 5'0"
(From 124' to 129')
Spl. 50 Channel sample of Unit 5.
4. Quartz sand, clayey. Quartz sand is fine to medium.
Drab to tan. Has a mottled appearance .... . . . . ... . 5'0"
(From 129' to 134')
Spl. 51 Channel sample of Unit 4.
3. Quartz sand, clayey. Quartz sand is fine to medium.
Drab to dark gray. Gets darker, almost black, at depth of
141 feet.
Occasional marble-size masses of gray clay that change rapidly
to a tan color on exposure to air.
The interval from 134 feet to 135 feet 6 inches was not sampled . . . 6' 6"
(From 135' 6" to 142')
Spl. 52 Channel sample of sediments of Unit 3.
2. Mixture of carbonate, quartz sand and clay. Gray to almost
black. Light gray just over contact with underlying shell
marl. The gray colors change to light tan to brown upon
exposure to the air.
There was no recovery of sediments from a depth of 142 feet to
143 feet ............ ........ .... ......... 0 3"
(From 143'to 143'3")
Spl. 53 Channel sample of Unit 2.
Late Miocene Shell Marl
1. Fossiliferous late Miocene shell bed . . . . . . . ....... 2' 3"
(From 143'3" to 145'6")
Spl. 54 Channel sample of the late Miocene shell marl.
Total depth of drill hole .................... ..........145'6"
BULLETIN NO. 52
Baywood Promontory Drill Hole
SW, NW4, Section 18, T. 9 S., R. 25 E., Putnam County, Florida
Approximately 2/2 Miles Southeast of Florahome
Surface Elevation 210 Feet (Estimate)
E. C. Pirkle, W. H. Yoho, Charles W. Hendry, Jr.
Description
Thickness
In Feet and Inches
34. Quartz sand, loose. These thick surface sands are characterized
by numerous dark brown to black zones containing a
relatively high content of finely-divided organic matter.
Some of the black zones are very hard and are referred to
locally as "hardpan." The sand zones are white, pale yellow,
brown and gray. Locally the sands have a black mottling.
A tree trunk or large limb was encountered at a depth of 60
feet 9 inches. The sample from that depth to a depth of 62
feet 6 inches is entirely wood. Fragments of wood were
noted in sediments of other intervals. For example, wood
fragments, including one fragment 6 inches long, were
present from 70 feet 6 inches to 77 feet.
The quartz sand is medium to very fine. More than 75 per cent
of the sand falls into the fine size fraction (- mm to
1/8 mm) . .. . .. . . .. ..
A series of 5-foot channel samples was taken from the land
surface to the base of the unit. The samples were labeled Spl.
1 (0 to 5 feet), Spl. 2 (5 to 10 feet), etc., through Spl. 22
(105 to 110 feet).
Spl. 1 Channel sample from land surface to depth of 5
feet.
Spl. 2 Channel sample from 5 to 10 feet.
Spl. 3 10 to 15 feet.
Spl. 4 15 to 20 feet.
Spl. 5 20 to 25 feet.
Spl. 6 25 to 30 feet.
Spl. 7 30 to 35 feet.
*This hole was drilled by the Bureau of Geology, Department
of Natural Resources, under the active supervision of Charles
W. Hendry, Jr. The drilling was completed April 25, 1968.
Analyses of samples are given in Tables 8 through 10.
Spl. 8 35 to 40 feet.
Spl. 9 -40 to 45 feet.
Spl. 10 45 to 50 feet.
Spl. 11 50 to 55 feet.
Spl. 12 55 to 60 feet.
Spl. 13 60 to 65 feet.
Spl. 14 65 to 70 feet.
Spl. 15 70 to 75 feet.
Spl. 16 75 to 80 feet.
Spl. 17 80 to 85 feet.
. .. .. .. 110' 0"
(From O' to 110')
Unit
Surface Sands
55
56 BUREAU OF GEOLOGY
Spl. 18 85 to 90 feet.
Spl. 19 90 to 95 feet.
Spl. 20 95 to 100 feet.
Spl. 21 100 to 105 feet.
Spl. 22 105 to 110 feet.
Finely Laminated Surface Sands
33. Quartz sand, loose but firm. Sand fine to medium.
Have lost organic zones so characteristic of overlying sands.
Fine laminations are shown throughout the zone by stringers of
black heavy minerals.
The upper 4 feet 6 inches of the unit are banded dark and
medium brown.
Beneath the upper banded zone are 5 feet 6 inches of light gray
or greenish gray sediments. Cross bedding is shown in these
sediments by stringers of heavy minerals.
Below the 5 feet 6 inches of light greenish gray sediments is an
interval, 1 foot 6 inches in thickness, of tan to light brown
sediments.
The lower 6 feet 9 inches of the unit is light greenish gray . . . . . . 18' 3"
(From 110' to 128'3")
Spl. 23 Channel sample from 110 feet to 114 feet 6
inches.
Spl. 24 Channel sample from 114 feet 6 inches to 120
feet.
Spl. 25 Channel sample from 120 feet to 125 feet.
Spl. 26 Channel sample from 125 feet to 128 feet 3
inches.
Intercalated Layers or Lenses of Drab Clay and Quartz Sand
32. Sandy clay. Dark drab olive green. Massive.
Wood fragments and wood fibers are common in the clay.
The quartz sand is medium to very fine .. . . . . . . .... .1' 0"
(From 128'3" to 129'3")
Spl. 27 Channel sample of the drab clay.
31. Sand, clayey. Quartz sand is fine to very fine.
Light gray ........... ..... ... ...... 1' 3"
(From 129'3" to 130'6")
Spl. 28 Channel sample of Unit 31.
30. Sandy clay. Dark drab olive green. Massive.
This clay is like the clay in Unit 32. Brown wood and brown
wood fibers are present throughout the interval. One wood
layer is /2 inch thick.
The quartz sand is fine to very fine .................. ....... 1' 6"
(From 130'6" to 132')
Spl. 29 Channel sample of the drab olive clay.
29. No recovery. Probably fine quartz sand .... . . . . . .. .9' 0"
(From 132' to 141')
BULLETIN NO. 52
28. Sand, clayey, Quartz sand is very fine to fine. Various shades of
white to light green. Micaceous.
Clay content increases with depth.
Rare fragments of mollusk shells. These are marine shell
fragments. They are fresh in appearance.
A few sand-size black particles of phosphorite are present in the
lower part of the unit ............... . ........ ..22' 6"
(From 141' to 163'6")
Spl. 30 Channel sample from 141 feet to 145 feet.
Spl. 31 Channel sample from 145 feet to 150 feet.
Spl. 32 Channel sample from 150 feet to 155 feet.
Spl. 33 Channel sample from 155 feet to 160 feet.
Spl. 34 Channel sample from 160 feet to 163 feet 6
inches.
27. Clay. Dark drab olive green. Massive.
This clay is similar to the clay in units 30 and 32.
Wood fragments, wood fibers and a few leaf impressions are
present in the clay.
Rare sand-size particles of black phosphorite.
Quartz sand is fine to very fine ... .... ... .. ........ 3' 6"
(From 163'6" to 167')
Spl. 35 Channel sanple of the drab clay.
26. Sand, clayey. Quartz sand is very fine to fine. Gray to light
green.
Rare fragments of mollusk shells.
A few small pebbles and sand-size particles of black phosphorite
. . . . .. 2' 0"
(From 167' to 169')
Spl. 36 Channel sample of Unit 26.
Shell Marl Late Miocene
25. Mixture of shells, quartz sand, clay and phosphorite. Light olive
green.
Abundant broken fragments of macrofossils and abundant
foraminiferia. Most of the larger shells are cream to white.
Many of the foraminiferia shells are transparent and clear.
Small pebbles and sand-size particles of black phosphorite are
common, especially in the upper 4 or 5 inches of the unit.
The quartz sand is coarse to very fine . . . .
. . . . . 5' 0"
(From 169' to 174')
Spl. 37 Channel sample of the shell marl.
Hawthorn Formation Miocene
24. Quartz sand in a calcareous and clayey matrix.
Olive to grayish green.
The quartz sand is very fine to coarse.
Black sand-size phosphorite is present ..... . . . . . .... .13' 0"
(From 174' to 187')
Spl. 38 Channel sample of Unit 24.
57
BUREAU OF GEOLOGY
23. Dolomite. Lithified. Light yellowish orange. Firm but soft.
Quartz sand is disseminated through the dolomite. The quartz
sand is fine to very coarse.
A few small black pebbles and shiny sand-size particles of phosphorite . . .6' 0"
(From 187'to 193')
Spl. 39 Channel sample of the sandy dolomite.
22. No recovery. Probably soft calcareous sediments . . . .
21. Dolomite. Very light grayish green. Firm but soft.
There is only a very little quartz sand or phosphorite in the
dolomite. The quartz sand that is present is fine to coarse.
Clay is present in the dolomite .. . . ..........
. . . . 8' 0"
(From 193' to 201')
. . . . 7' 6"
(From 201'to 208'6")
Spl. 40 Channel sample of the clayey dolomite.
20. Mixture of carbonate, quartz sand, and clay. Greenish gray.
Slightly indurated.
Shiny black sand-size grains of phosphorite are common.
The quartz sand is coarse to fine .. . . ..........
. . . . . 4' 6"
(From 208'6" to 213')
Spl. 41 Channel sample of Unit 20.
19. No recovery. Probably soft calcareous sediments . . . . . . . .. 6' 0"
(From 213'to 219')
18. Quartz sand in a clayey and calcareous matrix. Olive green
Firm.
The quartz sand is very fine to medium.
A lense of hard, dense light green dolomite is present at a depth
of 227 feet. This dolomite is 1 foot in thickness and is
mollusk-bored.
Sand-size grains of shiny black phosphorite are common. A
small amount of the phosphorite is brown . . . . . . .... 15' 0"
(From 219' to 234')
Spl. 42 Channel sample of Unit 18.
17. Clay. Olive green. Massive. Firm. The clay is slightly dolomitic.
There is only a minute amount of quartz sand or sand-size
phosphorite in the clay. However there are a few small black
pebbles of phosphorite visible in the sediments.
The quartz sand is very fine to medium . . . .
. . . 4' 0"
(From 234' to 238')
Spl. 43 Channel sample of the clay.
16. Dolomite. Light green. Very firm.
The dolomite contains some insoluble clay.
Only a very small amount of quartz sand is present in the
dolomite. This sand is very fine .................. ...... 1' 0"
(From 238' to 239')
Spl. 44 Channel sample of the clayey dolomite.
BULLETIN NO. 52
15. Quartz sand in a clayey and calcareous matrix. Olive green.
The quartz sand is medium to very fine.
There are a few tan to light brown sand-size particles of
phosphorite and a few small black phosphate pebbles . .
Spl. 45 Channel sample of the olive green clayey sand.
14. Dolomite with included quartz sand and clay. Light gray.
Small black pebbles of phosphorite.
The quartz sand is medium to very fine . . .
59
. . . . .. 1' 0"
(From 239' to 240')
. . . . 1' 0"
(From 240' to 241')
Spl. 46 Channel sample of the dolomite.
13. Quartz sand in a matrix of clay and carbonate. Gray to olive
green.
The quartz sand is medium to very fine.
Small pebbles of brown phosphorite and brown and black
sand-size phosphate particles are present . . . .
. . . . 2' 0"
(From 241' to 243')
Spl. 47 Channel sample of Unit 13
12. Mixture of carbonate, quartz sand and clay.
Dark olive green. Very firm.
Sand-size grains of phosphorite are present. Most of these grains
are shiny black; a few are brown.
Quartz sand is very fine to fine ...... .. ................ 2' 0"
(From 243'to 245')
Spl. 48 Channel sample of the sediments of Unit 12. r
1 i. Quartz sand with a matrix of clay and carbonate.
Dark olive green.
The quartz sand is very fine to fine and coarse.
A few black sand-size particles of phosphorite . . . . . . . 3' 0"
(From 245'to 248')
Spl. 49 Channel sample of the clayey sand.
10. Mixture of carbonate, quartz sand, clay, and phosphorite. Light
gray to dark greenish gray.
Small black pebbles and sand-sized grains of phosphorite are
common.
The quartz sand is very fine to coarse . . .
. . . . 3' 6"
(From 248' to 251'6")
Spl. 50 Channel sample of Unit 10.
9. Mixture of carbonate, quartz sand and clay. Lithified. Finely
crystalline. Light Green.
Fossil impressions of marine mollusks.
Sand-size particles of black phosphorite are present.
The quartz sand is very fine to medium . . . . . . .. 10' 6"
(From 251'6" to 262')
Spl. 51 -Channel sample of the mixture of carbonate, quartz
sand and clay.
BUREAU OF GEOLOGY
8. Quartz sand in a matrix of clay and carbonate. Dark olive green.
Soft.
The quartz sand is very fine to coarse.
Small pebbles and sand-size phosphate particles are common.
These particles are various shades of black, brown and white
. . . . 2' 6"
(From 262' to 264'6")
Spl. 52 Channel sample of the clayey sand.
7. Dolomite. Light green, hard, crystalline. Very sandy. Clayey.
Occasional sand-size particles of black and brown phosphorite.
Quartz sand is medium to coarse .. ............
. . . . 2' 6"
(From 264'6" to 267')
Spl. 53 -Channel sample of the sandy dolomite.
6. Mixture of clay, carbonate, quartz sand and phosphorite. Dark
olive green. Lithified.
Small blocks or fragments of almost pure greenish clay are
present in the sediments.
Small pebbles and sand-size particles of phosphorite are present.
These particles are brown, cream and black.
Quartz sand is very fine to coarse .. . ...........
. . . 7' 0"
(From 267'to 274')
Spl. 54 Channel sample of Unit 6.
5. Dolomite. Dark yellow gray. Soft to hard, but dominantly hard.
Dense and very finely crystalline.
Quartz sand is disseminated through the dolomite. The sand is
very fine to coarse.
Many fossil impressions of marine mollusks. Some vugs and
macrofossil molds are filled with sand and phosphorite.
White, tan and black sand-size grains of phosphorite are
abundant. Some small tan and black phosphate pebbles are present . . . 10' 0"
(From 274' to 284')
Spl. 55 Channel sample of the sandy dolomite.
4. Mixture of carbonate, quartz sand, clay and phosphorite. Gray.
Very finely crystalline.
Most of the phosphorite is sand-size. Many of the grains are
shiny black, but some grains are brown and tan. Minor
amounts of small black, brown and gray phosphate pebbles.
Quartz sand is medium to coarse .... . . . . . .... . 8' 6"
(From 284' to 292'6")
Spl. 56 Channel sample of Unit 4.
3. Dolomite. Light yellow gray. Very finely crystalline. Hard.
Quartz sand is present in the dolomite. This sand is medium to
fine.
Phosphorite is abundant. Pebbles are black, brown, tan and
cream. Pebble-size phosphorite is more abundant in this
basal unit than in the overlying unit ... . . . . . ... .. 2' 6"
(From 292'6" to 295')
Spl. 57 Channel sample of the sandy dolomite.
60
BULLETIN NO. 52 61
2. No recovery. Possibly soft clay and carbonate . . . . . . . 2' 0"
(From 295'to 297')
Crystal River Formation Eocene
1. Limestone. Fossiliferous, cream-colored.
Very pure.
Very microfossiliferous, porous and permeable . . . ............ S' 0"
(From 297' to 302')
Spl. 58 Channel sample of Unit 1.
Total depth of drill hole .................. .. .. 302' 0"
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