Geology and ground-water resources of Madison County, Florida /

)I

II

I

-I--~~--'lll("-r- j;;;;;~lll. i

;C

STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
Tom Gardner, Executive Director

DIVISION OF RESOURCE MANAGEMENT
Jeremy A. Craft, Director

FLORIDA GEOLOGICAL SURVEY
Walter Schmidt, State Geologist and Chief

BULLETIN NO. 61

GEOLOGY AND GROUND-WATER RESOURCES OF
MADISON COUNTY, FLORIDA

BY
Ronald W. Hoenstine, Steven M. Spencer
and Teresa O'Carroll

Published for the

FLORIDA GEOLOGICAL SURVEY
in cooperation with the
SUWANNEE RIVER WATER MANAGEMENT DISTRICT

Tallahassee, Florida
1990

mw W a. IT LIB R A" $

DEPARTMENT
OF
NATURAL RESOURCES

BOB MARTINEZ
Governor

BOB BUTTERWORTH
Attorney General

GERALD LEWIS
State Comptroller

BETTY CASTOR
Commissioner of Education

DOYLE CONNER
Commissioner of Agriculture

TOM GARDNER
Executive Director

SCIENCE
LIBRARYf

OK"

1AV2

JIM SMITH
Secretary of State

TOM GALLAGHER
State Treasurer

LETTER OF TRANSMITTAL

Florida Geological Survey
Tallahassee

June, 1990

Governor Bob Martinez, Chairman
Florida Department of Natural Resources
Tallahassee, Florida 32301

Dear Governor Martinez:

The Florida Geological Survey, Division of Resource Management, Department of Natural Resources, is
publishing as Bulletin No. 61, "Geology and Ground-water Resources of Madison County, Florida," prepared
by Ronald W. Hoenstine and Steven M. Spencer (Florida Geological Survey) and Teresa O'Carroll (formerly
of the Suwannee River Water Management District).

Madison County is projected to experience population and industrial growth within the near future. This
report fulfills a need for information on the stratigraphy of the area, which is the foundation for ground-water
resources investigations. Information on the mineral deposits is also presented, along with data which will
be helpful to county and state planners and other officials, as well as the private sector. This information will
assist these groups in developing and implementing long range plans for effectively managing this growth in
a manner that protects the environment while accommodating growth.

Respectfully,

Walter Schmidt, Ph.D.
State Geologist and Chief
Florida Geological Survey

Printed for the

Florida Geological Survey

Tallahassee
1990

ISSN 0271-7832

iv

CONTENTS

Acknowledgements ..............

Introduction ..................
Purpose and Database ..........
Location ..................
Previous Investigations . . . . .
M aps . . . . . . . . . .
Transportation . . . . . . . .
Clim ate .. .. . .. .. .. .. ..
Population and Development . . .
Metric Conversion Factors . . . . .
Well and Outcrop Numbering System .

Geology ....................
Geomorphology . . . . . . .
Northern Highlands . . . . . .
Tallahassee Hills . . . . . .
Gulf Coastal Lowlands . . . . .
Wicomico Terrace . . . . .
River Valley Lowlands . . . . .
Suwannee River Valley Lowlands ..
Withlacoochee River Valley Lowlands
Aucilla River Valley Lowlands . .
Springs .. ................
Blue Spring ..............
Suwanacoochee Spring ......
Other Springs .............
Lakes ................. .
Cherry Lake ..............

Stratigraphy ........... .
Introduction ...............
Paleozoic Erathem ...........
Mesozoic Erathem . . . . .
Triassic System . . . . .
Cretaceous System ..........
Cenozoic Erathem . . . . .
Tertiary System .. ........
Paleocene Series ..........
Cedar Keys Formation ....
Distribution ........
General Lithology . .
Thickness . . . . .
Stratigraphic Relations .
Eocene Series . . . . .
Oldsmar Limestone .....
Distribution . . . .
General Lithology ....
Thickness .........
Stratigraphic Relations .
Avon Park Formation ....
Distribution . . . .

S. . . ix

. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

General Uthology ................... ............... 27
Thickness . . . . . . . ..... . . . . . . . .. ... 27
Stratigraphic Relations .. ........................... . 27
Ocala Group ........................................ 27
Distribution ...................................... 27
Distribution . . . . . . . . . . . . . . . . . . . 27
General Lithology . . . . . . . ..... . . . . . . . . 27
Thickness ................... .................. 31
Stratigraphic Relations .............................. 31
Geologic Outcrops .................................. 31
Oligocene Series . . . . . . . . . . . . . . . . . . 31
Suwannee Limestone ................... ............... 31
Distribution . . . . . . . ..... . . . . . . . ..... 31
General Lithology . . . . . . . ..... . . . . . ..... 31
Thickness . . . . . . . ..... . . . . . . . ..... .. 32
Stratigraphic Relations . . . . . . . ..... . . . . ... 32
Geologic Outcrops ................... ............... 32
Miocene Series . . . . .... . . . . . . . . . . . . 32
St. Marks Formation .............. .... .............. 32
Distribution . . . . . . . ..... . . . . . . . ..... 32
General Lithology . . . . . . . ..... . . . . . . ... 33
Thickness ................... .................. 33
Stratigraphic Relations . . . . . . . . . . . . . . ... 33
Hawthorn Group ..................................... 33
Distribution . . . . . . . . . . . . . . . . . . . 33
Distribution . . . . . . . . . . . . . . . . . . . 33
General Lithology . . . . . . . . . . . . . . . . . 34
Thickness . ........................................ 34
Stratigraphic Relations ....... .... ................ . .. 34
Geologic Outcrops . . . . ... . . . . . . . . . . . 34
Pliocene Series . . . . . . . .. . . . . . . . . . . . 37
Miccosukee Formation . . . . . . . . . . . . . . . 37
Distribution ... ... .... ... ... .. .. .. .. .. .. .. .. .. 37
General Lithology ..... ... ..................... .. 37
Thickness . . . . . . . . . . . . . . . . .... . 37
Stratigraphic Relations ...... ....... ................. 39
Geologic Outcrops . . . . . . . . . . . . . . . ... 39
Quaternary System ...................................... .. 40
Pleistocene and Holocene Series . . . . . . . . . . . . . ... 40
Distribution . . . . . . . . . . . . . . . . . ... . 40
General Lithology . . . . . . . ........ . . . . ... 40
Thickness . . . . . . . . . . . . . . . . . 40
Stratigraphic Relations ....... ..... ............... 40
Geologic History .......................................... 42

Structure . . . . . . . . . . . . . . . . . . . . . . . 42

Economic Geology ............. ...................... .. ... .. .. . 44
Introduction . . . . . . . . . . . . . . . . . . . . ... . 44
Sand . . . . . . . . . . . . . . . . . . . . . . . 46
Clay . . . . . . . ...... . . . . . . . . . . . . 46
Peat . . . . . . . ..... . . . . . . . . . . . . . 46
Phosphate . . . . . . . . . . . . . . . . . . . 49
Limestone ............ .... ... ....................... . . . ..... 49
Petroleum . .. ... .... ...... . . . . . . . . . . . 49

Landfill Site . . . . . . . . . . . . . . . . . 49

Waste Disposal .................................... ........ 49

Hydrogeology .................................... .......... 50
Surficial aquifer system ...................................... 53
Intermediate aquifer system ..................................... 54
Floridan aquifer system ...................................... 59
Summary ...................................... ......... 62

References ................................................ 65

Appendices ............................................... 69
I. Selected Core Descriptions ................... ................ 69
II. Potentiometric Network ...................................... 93
III. W ater Quality Network ...................................... 97

ILLUSTRATIONS

FIGURE

1 Location of Madison County ................... ............... 2

2 Index to 7.5 minute topographic quadrangle maps . . . . . . . ..... . ... 3

3 Major transportation routes in Madison County . . . . . . . ..... . . .. 5

4 Locality and well numbering system used in this report . . . . . . . ..... ... 7

5 Geomorphic subdivisions in Madison County . . . . . . . .... . . .. 9

6 Significant surface water features ................... ............ 10

7 North-south and west-east topographic profiles . . . . . . ...... . 12- 13

8 Photograph of Withlacoochee River from State Road 6 at Blue Springs
during high water stage in 1986 ................... ............ 15

9 Geologic map of Madison County ............................... 18

10 Geologic Data Base location map ................... ............ 19

11 Index map of geologic cross sections ............................. 20

12 Geologic cross section A-A' .................. ............... 28

13 Geologic cross section B-B' .................. ............... 28

14 Geologic cross section C-C' .................. ............... 29

15 Geologic cross section D-D' .................. ............... 29

16 Generalized structure contour map of the top of the Ocala Group . . . . . .... 30

17 Structure contour map of the top of the Suwannee Limestone . . . . . ..... 30

18 Isopach map of the Hawthorn Group ............................. 35

19 Structure contour map of the top of the Hawthorn Group . . . . . . ..... 35

20 Photograph of high water stage at a sinkhole in Lee, Florida . . . . . . ..... 36

21 Photograph of Miccosukee Formation section at railroad cut near Pinetta . . ... 38

22 Isopach map of the Miccosukee Formation . . . . . . . ..... ........ 41

23 Isopach map of the Undifferentiated Sands and Clays . . . . . . . ..... 41

24 Location of the Ocala Platform ............................... .. 43

25 Mineral resources map .. .... .................... ............ 45

26 Geologic cross section E-E' (Landfill site) . . . . . . . . . . . .. 51

27 General hydrogeologic conditions of the Floridan aquifer system
in Madison County ..................................... 51

28 Floridan aquifer system potentiometric network (1950-1989) . . . . . . ..... 55

29 Potentiometric surface of the Floridan aquifer system
November 1981 low water period .............................. 56

30 Potentiometric surface of the Floridan aquifer system
April 1984 high water period ................................. 57

31 Net fluctuation in the potentiometric surface of the Floridan
aquifer system, 1950-1989 ........................ ............ 58

32 Distribution of recharge to the Floridan aquifer system in the
Suwannee River Water Management District . . . . . . . ..... ....... 60

33 Potentiometric surface of the principal artesian Floridan aquifer
system in south-central Georgia and north-central Florida . . . . . . . ... 61

TABLES

1 Metric conversion factors ................... ................ 4

2 Geologic data base ................... ................ 21 -24

3 Selected sand analyses ......... ........................ . . 47

4 Selected peat analyses ............................ ... . . 48

5 Selected well data showing granular phosphate . . . . . . ... ....... 48

6 Geologic and hydrostratigraphic nomenclature of the eastern panhandle of Florida . 52

7 Permitted ground water and surface water withdrawals in Madison County, Florida . . 53

ACKNOWLEDGEMENTS

The authors would like to express their sincere thanks to the Suwannee River Water Management District
for their support and assistance in providing data essential to the hydrogeology portion of this study. In
addition, recognition is due to the following Suwannee River Water Management District funded graduate
students who provided help and assistance to this study. Special appreciation to Connie Garrett for her
assistance in core descriptions. Thanks are also due to Renee Cooper and Mike Weinberg for permeability
and porosity tests. Recognition is due to Roger Durham for his assistance in compiling well information.
Additional thanks is extended to David Allison for his invaluable assistance in the area of computer data entry
and formating.
Special thanks are due to our Florida Geological Survey colleagues Bill Yon, Ed Lane, Frank Rupert, Alison
Lewis, Walter Schmidt, Paulette Bond and Tom Scott, for their assistance in interpreting stratigraphic data,
helpful suggestions and review of the text.
Appreciation is due Cindy Collier for typing the manuscript and to Melissa Doyle, Jim Jones and Ted Kiper
for drafting the figures. Thanks to Jo Borden and Jerry McClune (Madison County Road Department) for their
cooperation in this county-wide study.

X

Bulletin No. 61

GEOLOGY AND GROUND-WATER RESOURCES OF
MADISON COUNTY, FLORIDA

By
Ronald W. Hoenstine, P.G.#57, Steven M. Spencer, P.G.#319
and Teresa O'Carroll, P.G.#711

INTRODUCTION

PURPOSE AND DATABASE

The purpose of this study was to conduct a
detailed geologic investigation of Madison County
in order to provide information in the form of basic
data and its interpretation to governmental agen-
cies and the private sector concerning the county's
stratigraphy, mineral resources, ground water and
environment. This information will provide valuable
assistance in all areas of land use concerns, includ-
ing zoning, mineral potential and the identification
of environmental factors affecting landfills and
areas of ground-water recharge.
This study was based on information from 7
cores drilled by the Florida Geological Survey, in
addition to 18 cores drilled through a cooperative
hydrogeologic study with the Suwannee River
Water Management. District (SRWMD), as well as
cuttings from a number of water and oil exploration
wells from Madison and surrounding counties,
stored at the Florida Geological Survey's sample
repository. An augering program was undertaken
to supplement areas with inadequate data. Addi-
tionally, outcrops were mapped and described.
The Florida Geological Survey encoded com-
puterized format for recording geologic well cutting
and core data was utilized for this study (Appendix
1).

LOCATION

Madison County is located in the northeastern
part of the Florida panhandle (Figure 1). The coun-
ty is bordered to the north by the State of Georgia,
to the east by Hamilton and Suwannee Counties, to
the south by Lafayette and Taylor Counties, and to

the west by Jefferson County. The Aucilla River
forms part of the western boundary while the With-
lacoochee and Suwannee Rivers comprise the
eastern boundary of Madison County (Figure 1).
In addition to being the county seat, the city of
Madison is the largest city in the county. Madison
County, which encompasses an area of 703 square
miles, is located approximately 35 miles south of
Valdosta, Georgia, 110 miles west of Jacksonville,
Florida, and 55 miles east of Tallahassee, Florida.

PREVIOUS INVESTIGATIONS

There have been a number of publications ad-
dressing a wide range of topics including topog-
raphy, general geology, paleontology,
ground-water and soil surveys of the regional area
encompassing Madison County. Those geologic
reports that are most applicable and comprehen-
sive include: Cooke (1945), Applin (1951), Purl and
Vernon (1964), White (1970), and Colton, (1978).
Knapp (1978) described the occurrences and lithol-
ogy of near-surface sediments of Madison County
as well as surrounding areas. Ceryak et al. (1983)
addressed the geology and hydrogeology of the
upper Suwannee River Basin in which the study
area included the southeastern part of Madison
County. Crane (1986) reported or, Lne hydrogeol-
ogy of the lower Suwannee River Basin which in-
cluded the southeastern part of Madison County.
The United States Soil Conservation Service (in
press) has conducted a soil survey in Madison
County.

MAPS

Maps used for field work in this study include the

Florida Geological Survey

Al ABAMA % GEORGIA

ATLANTIC
OCEAN

R5E + R6E + R7E + R8E + R9E + R10E -- R11E

T3N
4--

T2N

+
T1N

-I-

T1S

T2S
T2S

0 5 mi
0 mi LAFAYETI
COUNTY
0 8 km

HAMILTON
COUNTY

SUWANNEE
COUNTY

Figure 1. Location of Madison County.

Bulletin No. 61

Figure 2. Index to 7.5 minute topographic quadrangle maps.

Florida Geological Survey

United States Geological Survey (USGS) 7.5 minute
(1:24,000) topographic quadrangles. The index to
these published topographic quadrangle maps is
shown in Figure 2. Other maps utilized in this study
include the general highway map of Madison Coun-
ty and Mark Hurd Aerial Photos Inc. (1976) which
cover the same area as the USGS 7.5 minute
topographic quadrangles.

TRANSPORTATION

Madison County is served by the Seaboard
Coastline and the Georgia Southern and Florida
railway systems. The nearest commercial airport is
located in Valdosta, Georgia. Numerous highways
cross the county with U.S. Highway 221, State
Roads 53,145 and County Roads 146,150 and 255
representing the major north-south routes while
Interstate 10 and U.S. Highway 90 serve as the
major east-west routes (Figure 3). In addition, there
are many secondary roads, which make the
majority of the county accessible.

CLIMATE

Madison County's average annual precipitation
is 52.5 inches. The wet season generally occurs
from June through September and the dry season
occurs October through November. The average
annual temperature is 640 Fahrenheit with the
winter season (December through February)
averaging 460 Fahrenheit and the summer season
(June through August) averaging 830 Fahrenheit
(Fernald, 1981).

POPULATION AND DEVELOPMENT

Madison County was established as the four-
teenth county in Florida on December 26, 1827.
The county was named for James Madison, the
fourth President of the United States.
As originally surveyed, Madison County, in addi-
tion to its present configuration, included the area
encompassing Taylor, Lafayette and Dixie Coun-

ties. In December 1856, Madison County was
divided and two additional new counties (Taylor
and Lafayette) were created. In 1921, Dixie County
was created from the southern part of Lafayette
County.

The population of Madison County in 1987 was
15,858, up 8.72 percent from a 1980 population of
13,841 (Office of the Governor, 1987). The
projected population for the year 2000 is 16,400.
The major industries in Madison County include
farming and timber pulpwoodd). Agricultural crops
include peaches, vegetables, corn, soybeans and
tobacco. There are approximately 60,000 acres of
improved pastureland used for raising cattle, calves
and hogs. In addition, poultry is raised extensively
in several areas of the county.

METRIC CONVERSION FACTORS

In order to prevent the awkward duplication of
English and metric units in the text of reports, the
Florida Geological Survey has adopted the practice
of inserting a table of conversion factors. For the
use of those readers who may prefer to use metric
units rather than English units, the conversion fac-
tors for terms used in this report are given in Table
1.

Table 1. Metric conversion factors.

MULTIPLY

acres
acres
cubic yards
cubic feet/sec.
feet
inches
inches
miles
sq. miles
Fahrenheit (F)

0.4047
4047.0
0.7646
448.8
0.3048
2.540
0.0254
1.609
2.590
5/9 (F-32)

TO OBTAIN

hectares
sq. meters
cu. meters
gallons/min.
meters
centimeters
meters
kilometers
sq. kilometers
Centigrade

C J GREENVILLE m..Ue a r

MADISON a
I COUNTY

EXPLANATION
221 INTERSTATE
cc 0 O U.S. HIGHWAY
SAt- f 0 STATE ROAD
+I / Hm RAILWAY
TAYLOR COUNTY I COUNTYROA

LAFAYETTE o
SCALE COUNTY
km

Figure 3. Major transportation routes in Madison County.

Florida Geological Survey

GEOLOGY
GEOMORPHOLOGY

WELL AND OUTCROP NUMBERING SYSTEM

The locality and well numbering system used in
this report is the rectangular system of section,
township and range for identification (Figure 4).
The number consists of five parts. These are: 1) a
prefix of three letters designating L for locality or W
for well and the county abbreviation; 2) the well
accession number; 3) the section; 4) the
quarter/quarter location within the section; 5) the
township; and 6) the range.

The basic rectangle is the township, which is 6
miles on a side. It is consecutively identified bytiers
both north and south of the Florida base line, an
east-west line that passes through Tallahassee,
starting with Township 1 North and 1 South.
Townships are also consecutively numbered both
east and west of the principal meridian, a north-
south line that passes through Tallahassee as
Range 1 East or West. In recording the township
and range numbers, the 'T" is left off the township
numbers, and the "R" is left off the range numbers.
Each township is divided into 36 square miles called
sections, and are numbered 1 through 36 as shown
in Figure 4.
The sections are divided into quarters which are
labeled "a" through "d" as shown on Figure 4. Each
of these quarter sections is divided into quarters
and these quarter/quarter squares are labeled "a"
through "d" in the same manner.
The location of the well WMd-13214 as shown in
Figure 4 would be in the center of the northwest
quarter of the northwest quarter of section 12,
Township 2 North, Range 9 East, Madison County.
The exception to the system mentioned above
will be those localities or wells occurring north of
the Watson Line near the Georgia-Florida state line.
This region was originally surveyed and settled as
a part of Georgia. In 1887, this region officially
became part of Florida but continued to use the
Georgia survey system. Therefore, localities and
wells from this area will be listed by the Georgia
survey system section number only.

Florida has been divided into a number of
geomorphic regions by various investigators. The
following is a brief list of regional names in current
usage as well as others which have gained serious
consideration at one time or another.
Cooke (1939) proposed a geomorphic division
of Florida based on such parameters as location
and elevation. This classification divides Florida
into five natural topographic regions: Coastal
Lowlands, Western Highlands, Marianna Lowlands,
Tallahassee Hills, and the Central Highlands. This
classification is still frequently mentioned in the
literature.
A genetic classification, based on geological
origin, was proposed by Vernon (1951). This
proposal, which comprised fewer geomorphic
divisions, consisted of the following: the Delta Plain
Highlands, Tertiary Highlands, Terraced Coastal
Lowlands, and River Valley Lowlands. In addition,
Vernon subdivided these major divisions into
smaller units and applied local names to them. In
this genetic classification Vernon placed Cooke's
'Tallahassee Hills" region in his Tertiary Highlands,
combined the Central Highlands and Western High-
lands into his Delta Plain Highlands division and
renamed Cooke's "Coastal Lowlands" and "Marian-
na Lowlands" to Terraced Coastal Lowlands and
River Valley Lowlands, respectively.
In this system, based on geological origin, the
Highlands are comprised of sediments deposited
at higher elevations in a widespread, aggradational
delta plain or are associated with Tertiary land mas-
ses rising above the plain. In contrast, sediments
occurring in the Lowlands were formed either by
deposition and erosion along coastlines by marine
processes or by deposition and stream erosion
along stream valleys.
Later, White, Puri and Vernon (Puri and Vernon,
1964) proposed a classification dividing Florida into
six primary geomorphic provinces: Coastal
Lowlands, Intermediate Coastal Lowlands, Gulf
Coastal Lowlands, Central Highlands, Northern
Highlands, and the Marianna Lowlands. These

Bulletin No. 61

SCALE
0 5 mi

0 8 km

Figure 4. Locality and well numbering system used in this report.

R5E t R6E + R7E + R8E + R9E + R10E + R11E
WATSON LIN---.----

T3N

T2N

T1N

+
T1S

T2S
T2S

Florida Geological Survey

provinces were further divided into secondary and
tertiary units.
Subdivisions were proposed by White, Purl and
Vernon (Puri and Vernon, 1964) for Vernon's Ter-
raced Coastal Lowlands. Intended to be more
descriptive of this general landform, these divisions
are: Coastal Lowlands, Intermediate Coastal
Lowlands, and Gulf Coastal Lowlands.
More recently, White (1970) divided the Florida
peninsula into three distinct geomorphic zones:
Northern (Proximal) Zone, Central(Mid-peninsular)
Zone, and the Southern (Distal) Zone. In this clas-
sification, the Northern Zone, which includes
Madison County, is generally a highland area ex-
tending from the Trail Ridge westward to the
Apalachicola River Valley.
For the purposes of this study, the following
geomorphic provinces of Vernon (1951) and of
White, Puri and Vernon (Puri and Vernon, 1964) and
Cooke (1939) are recognized in Madison County:
Northern Highlands, Gulf Coastal Lowlands, and
Aucilla, Withlacoochee, and Suwannee River Valley
Lowlands (Figure 5). A discussion of these
geomorphic regions which occur in the Eastern
Gulf Coastal Plain follows.

NORTHERN HIGHLANDS
Tallahassee Hills

The Tallahassee Hills is a subunit of the Northern
Highlands. As defined by Puri and Vernon (1964),
it includes the area between the Georgia State line
on the north and the northern boundary of the
coastal terraces as defined by the Cody Escarp-
ment on the south- a width of nearly 25 miles and
between the Withlacoochee River on the east and
the Apalachicola River on the west a length of 100
miles. In Madison County, this geomorphic
province includes the area southward from the
Florida-Georgia border to the Gulf Coastal
Lowlands (Figure 5).
Weathering has played a key role in shaping the
topography of this geomorphic division in Madison
County. Stream erosion and sub-surface dissolu-
tion have changed what is believed to have been a

once relatively featureless Pliocene prodelta to a
land area characterized by undulating hills and
ridges (Hendry and Sproul, 1966). These
topographic highs attain maximum elevations in
excess of 220 feet above mean sea level (MSL) in
the area west of Cherry Lake and in an area to the
north of the Watson line (sections 30 and 169 of
Township 3N and Range 9E, respectively).
In general, the high areas are capped by a veneer
of undifferentiated sands. These sediments are
underlain by a mixture of reddish and yellowish-
orange, clayey, quartz sands and sandy clays
belonging to the Miccosukee Formation.
Madison County has numerous small lakes and
ponds (Figure 6). Of special prominence is Cherry
Lake, approximately 500 acres. This relatively large
lake is representative of a karst feature that is com-
mon in Madison County. Occurring as a result of
subsidence due to the dissolution of the underlying
limestone and the subsequent collapse of overlying
sediments, these karst lakes are numerous in the
central and north-central part of the county (Figure
6).
The southern limit of the Tallahassee Hills in
Madison County is marked by the Cody Scarp, a
prominent escarpment named and described by
Puri and Vernon (1964) as the most persistent
topographic break in Florida (Figure 5). Although
easily observed to the west in Jefferson County, the
trend of the Cody Scarp in Madison County is
irregular and difficult to observe in the field. How-
ever, north-to-south and west-to-east surface eleva-
tion profiles generated by the authors using USGS
topographic quadrangles show a distinct break at
the 100 feet MSL contour (Figure 7). The 100 feet
MSL elevation, used by Crane (1986) and Cooke
(1939) as defining the crest of the Cody Scarp in
this area, is also used in this report and as such
represents the southern limit of the Tallahassee Hills
in Madison County.

GULF COASTAL LOWLANDS

Occupying less than 30 percent of the county,
the Gulf Coastal Lowlands in Madison County lie in

R5E I R6E I R7E I RSE I R9E I RIOE I RIIE

GEORGIA

NORTHERN HIGHLANDS
ITallahassee Hills

Z ..

C. E RR LAKE

_____U6L --:r

TAYLOR COUNTY

LAFAYETTE COUNTY
SCALE
0 5 mi

0 8 km
R5E I R6E I R7E O RFE i R9E I RIOE I RIlE

EXPLANATION
NORTHERN HIGHLANDS

TALLAHASSEE HILLS
GULF COASTAL
LOWLANDS T2S
WICOMICO TERRACE (70-1001)
SAN PEDRO BAY

RIVER VALLEY LOWLANDS
fii AUCILLA RIVER VALLEY

S SUWANNEE RIVER VALLEY

S WITHLACOOCEE RIVER
VALLEY

Figure 5. Geomorphic subdivisions in Madison County.

5-

0

0

IL.o l

V"
0
7
<10
ifp

R5E R6E I R7E RBE I

GEORGIA

9E I RIOE I RIIE I

SCALE

R6E I R7E RBE I RrF

LAFAYETTE COUNTY

Figure 6. Significant surface water features.

-'
o
0C

(D
0
0
o

co

R5E I

I -

RIOF I illlC

Bulletin No. 61

an area bounded to the north by the Cody Scarp,
to the south bythe Taylor and Lafayette County line,
to the west by the Aucilla River and to the east by
the Suwannee and Withlacoochee Rivers (Figure
5). As shown by the topographic profiles (Figure
7), the northern boundary generally coincides with
the 100 feet contour (Cooke, 1939 and Crane,
1986).
Cooke (1931) initially recognized seven intergla-
cial marine terraces throughout Florida. Vernon
(1942, 1951) cited evidence for four interglacial
marine terraces and a deltaic plain. Cooke (1945)
added an additional terrace to his original seven
marine terraces. MacNeil (1950) proposed four
interglacial marine terraces. More recently, Puri
and Vernon (1964) proposed an additional terrace
for a total of five marine terraces. Healy (1975)
recognized four terraces based on elevation as
being present in Madison County. The higher
elevations present in the Northern Highlands
Region of neighboring Jefferson County are highly
dissected remnants of a Pliocene prodelta (Yon,
1966), an interpretation that is in this report ex-
tended to the Northern Highlands Region of
Madison County.

Wicomico Terrace

One marine terrace proposed by Cooke (1945)
is recognized by the authors in Madison County.
This is the Pleistocene Epoch Wicomico Terrace
occurring at the 70 to 100 feet MSL elevation range
which coincides with the Gulf Coastal Lowlands in
Madison County (Figure 5). In Madison County, the
upper range of the Wicomico Terrace coincides
with the top of the Cody Scarp. This escarpment,
which represents a former shoreline of the
Wicomico Sea, has a general elevation of 90 to 100
feet MSL. Initial terrace elevations of 100 feet to 105
feet MSL have experienced over time a general
reduction in elevation in Madison County. This
reduction, which is much more pronounced to the
west in Jefferson County, is the result of erosion and
karst processes. In Jefferson County, Yon (1966)
identified this terrace as coinciding with the top of

the Cody Scarp, whose base occurs at 40 to 45 feet
MSL.. The westward extension of this scarp into
Leon County shows an increase in elevation to
approximately 100 feet elevation.
The Wicomico Terrace deposits of Madison
County includes all of the area between the Cody
Scarp and the Taylor and Lafayette County lines.
Consisting of sands, silty sands and clays, these
deposits form a relatively thin veneer overlying a
limestone shelf upon which they were deposited. In
general, much of this area, which includes a broad
low area known as the San Pedro Bay, has poor
surface drainage and is dotted with swamps in such
areas as the Aucilla and Suwannee River flood-
plains.
San Pedro Bay (Figure 5), which occupies much
of southern Madison County, extends into Taylor
and Lafayette Counties. This geomorphic feature
has elevations varying from 80 to 90 feet MSL In
general, its surface includes a veneer of organic
sands underlain by a clay bed of varying thickness
which in turn overlies the Suwannee Limestone.
The low permeability clay acts as a confining bed
to the Floridan aquifer system below, inhibiting the
downward percolation of water causing a perched
water table at the land surface.

River Valley Lowlands

The River Valley Lowlands occur in the form of
narrow strips of land paralleling both sides of the
Suwannee, the Withlacoochee and Aucilla Rivers
(Figure 5). Numerous tributaries, in the form of
small streams and creeks originating in the adjoin-
ing Tallahassee Hills, flow into these rivers (Figure
6). Although extending into the Northern High-
lands, these river valley lowlands are placed in the
Gulf Coastal Lowland province on the basis of their
lowest elevations (Ceryak et al., 1983).

Suwannee River Valley Lowlands

With headwaters in the Okefenokee Swamp in
southeastern Georgia, the Suwannee River flows
southward to the Gulf of Mexico along a winding

Florida Geological Survey

R5E + R6E + R7E + R8E + R9E + R10E + R11E
B
t _____
_l 1---_o

A

E

i-

Sn"

a a-

b

I IF/

A' I
SCALE
0 5 mi B' C'

0 8 km
NOTE: VERTICAL EXAGGERATION IS APPROXIMATELY 106 TIMES.

200-0o A A'
JEFFERSON i MADISON CO. MADISON CO. TAYLOR CO.
40 CO.

8; N
100.
20 SL TO S
0i 0
w0. MSL NTOs

SCALE
0o mi
o ONk.

GEORGIA FLORIDA

G MADISON CO. I TAYLOR CO.

2 c 0
L NTOS

C C'
200 "HAMILTON MADISON CO. MADISON CO. LAFAYETTE
CO. CO.
0 IWITHLACOOCHEE
S I RIVER

Q 0 MSL NTOO

Figure 7a. North-south and west-east topographic profiles.

T3N
+

T2N

T1N

T1S

T2S

Bulletin No. 61

SCALE
0 8 km
0 i km

200 oo E E

0 JEFFERSON I MADISON CO. MADISON CO. HAMILTON CO.
C o.

20

F F
200 o.0 MADISON CO. HAMILTON CO.
4,JEFFERSON MADISON CO. WITHLACOOCHEE I

0 I

G G'
20060 JEFFERSON | MADISON CO.

0 I SUWANNEE CO.
o Rr RIVER

-2

Figure 7b.

200o so

140
100- 2

2
10

Florida Geological Survey

path that forms partial boundaries for Madison,
Hamilton, Suwannee, Lafayette, Gilchrist, Dixie and
Levy Counties. The river lowlands, which encom-
pass the largest area of any river valley lowland in
the county, extend from south Georgia to the Gulf
of Mexico. In Madison County, these lowlands
extend from Ellaville to the south-eastern corner of
the county where the western border of Suwannee
and the northeastern corner of Lafayette Counties
intersect (Figure 5). The Suwannee River is joined
by the Withlacoochee River at Ellaville.
The carbonate sediments cropping out on both
sides of the Suwannee River at Ellaville are part of
the Oligocene Series Suwannee Limestone
deposited approximately 30 million years ago. The
lithology of these sediments at this site varies from
a moderately indurated dolomitic limestone to a
poorly indurated (case hardened) limestone.
Dolomite occurs in the area and to the north and
south of the confluence of the Suwannee and With-
lacoochee Rivers. A close examination of the
Suwannee Limestone at Ellaville reveals the
presence of fossil shells, molds, and numerous
foraminifera and some echinoids exhibiting various
degrees of preservation.
Natural levees, which formed during periods of
past floods, can be observed along the river.
Levees are formed during periods of flooding, when
the river overflows its banks, causing an abrupt
decrease in both water velocity and turbulence.
This, in turn, causes the deposition of the coarser
particles of the suspended sediments forming
ridges or levees which generally parallel the river's
banks. These features can be readily observed on
the eastern side of the river just north of its con-
fluence with the Withlacoochee River in the Suwan-
nee River State Park.

Withlacoochee River Valley Lowlands

Originating in south-central Georgia, the
meandering Withlacoochee River flows southward
to the Suwannee River State Park at Ellaville where
it merges with the Suwannee River. The river forms
a natural boundary separating Madison and Hamil-

ton Counties (Figure 5). Figure 8 is a photograph
of the Withlacoochee River at high water stage
during the flood of 1986.
The lowlands on either side of the river are
characterized by swampy conditions, with eleva-
tions generally less than 80 feet MSL and extensive
areas below 60 feet MSL These elevations are in
stark contrast to the much higher elevations of 90
to 150 feet MSL associated with the nearby North-
ern Highlands Region through which the With-
lacoochee River flows.

Aucilla River Valley Lowlands

The smallest river in Madison County is the
Aucilla River. The headwaters of this river, which is
located in south Georgia, flow southward into Jef-
ferson County to a point approximately 1.5 miles
north of State Road 90. There, it continues south-
ward forming a meandering boundary between Jef-
ferson and Madison Counties. Continuing further
southward to the Gulf of Mexico, the river also forms
a partial boundary separating Jefferson and Taylor
Counties.
The USGS estimated the area drained by the
Aucilla Riverto be about 750 square miles in Florida,
almost half of which is in Madison County (Yon,
1966). Within this drainage area are a number of
minor tributaries including the Little Aucilla River,
Gum Creek, Rocky Creek and Alligator Creek (Fig-
ure 6).
During periods of high rainfall the river overflows
the channel contributing significantly to the swam-
py conditions present over a large part of the valley.
However, the Aucilla River quickly responds to rain-
fall and during periods of little or no rainfall the river
is almost dry.
The river cuts into Hawthorn and Miccosukee
siliciclastic sediments during the first several miles
of its transit through Madison County. This lithol-
ogy changes to calcareous sediments further south
in the Coastal Lowlands Region as the river cuts into
the Oligocene Series Suwannee Limestone.
Although much wider along the northern part of
the river's course, with an average width of one mile,

z

-! 67

Figure 8. Photograph of Withiacoochee River from State Road 6 at Blue Springs during high water stage
in 1986. Photograph by authors.

Florida Geological Survey

the River Valley Lowlands narrows significantly to
the south. The origin of this wide valley and narrow
river channel may be attributed to dissolution of the
underlying limestone and subsequent collapse of
the overlying sediments (Yon, 1966).

Springs

Several springs, of which only one (Blue Spring)
is of significant size, are present in Madison County
(Figure 6). Blue Spring is a first magnitude spring
as it discharges more than 100 cubic feet of water
per second. The other springs are much smaller
and less accessible.

Blue Spring

Blue Spring is located on the west bank of the
Withlacoochee River about 10 miles east of the city
of Madison just off of State Road 6 (section 17dc,
Township 1 N, Range 11E, Figure 6). A popular site
for swimming, snorkeling and scuba diving, Blue
Spring attracts many visitors from surrounding
counties in both Florida and Georgia. This spring
has had added importance in the past as a sig-
nificant source of potable water for early inhabitants
of the area.
The main spring pool is an irregular circle with a
diameter of 75 feet. A cavern is present at an
approximate depth of 30 feet below the water sur-
face. A thin veneer of sand overlying Suwannee
Limestone sediments cover the pool bottom. A
20-foot cliff consisting of Suwannee Limestone
capped by a thin veneer of sand is present on the
south bank.
The spring discharge flows northeastward into
the Withlacoochee River through a run ap-
proximately 100-feet long. Measurements of this
discharge have been conducted for a number of
years. These measurements, taken by the USGS
(Rosenau et al., 1977), show that the spring flow is
highly variable, ranging from a minimum measured
flow of 75 cubic feet per second (ft3/sec) on March
16, 1932, to a maximum measured flow of 141
ft3/sec. on November 15, 1960.

Suwanacoochee Spring

Suwanacoochee Spring is located on the west
side of the Withlacoochee and north side of the
Suwannee Rivers about 14 miles southeast of the
city of Madison in the Suwannee River State Park
(Figure 6). Although visible during low river flow,
this small spring is inundated by the river during
periods of high river stands.

The spring pool, which measures 20 feet in
diameter, is ringed by dolomitized Suwannee Lime-
stone sediments. A concrete wall constructed on
the east end of the pool separates the spring from
the river except during periods of high water and
flooding.
Discharge takes place from a single vent on the
west side of the pool from beneath a limestone
ledge. A minimum measured discharge of 18.3
ft3/sec was recorded by the USGS (Rosenau, et al.,
1977) on March 16, 1932 and a maximum measured
discharge of 51.6 ft3/sec was recorded on March 8,
1973. The minimum discharge at this spring coin-
cided with the date of minimum discharge recorded
at Blue Spring.

Other Springs

Two other springs have been reported in the
county. One of these, Cherry Lake Spring, was
reported to be 3.5 miles west of the town of Pinetta,
however, it could not be located for this study.
The other spring, Pettis Spring, was observed to
be flowing from a three-inch pipe in 1946 at a site
five miles west of Greenville on the east side of the
Aucilla River (section 27a, Township 1 N, Range 6E)
(Yon, 1966). This pipe has since been capped and
could not be located for this study.

Lakes

A number of lakes and ponds are present in
Madison County that range in size from less than
one acre to hundreds of acres. Some of these lakes
are seasonal, disappearing during periods of

Bulletin No. 61

prolonged dry weather, while others contain water
year-round.
A few lakes occur in the Coastal Lowlands,
however, this region is flat and poorly drained and
these lakes are primarily confined to a small area in
the San Pedro Bay. In contrast, a number of ponds
and small lakes occur in the Northern Highlands
Region, an area of rolling uplands having porous
carbonates and/or cavities underlying the surface
sediments. The resultant karst topography is char-
acterized by the formation of many closed surface
depressions (dolines) that extend northward into
Georgia and eastward and westward into parts of
Hamilton and Jefferson Counties, respectively. The
natural drainage is into these closed depressions,
which are drained by seepage into the underlying
limestone aquifer.
Figure 6 depicts a number of areas where sig-
nificant surface water features occur. One of the
most prominent concentrations occurs in an area
south and southwest of Cherry Lake. Additional
concentrations occur near Lee, and the area be-
tween Greenville and the city of Madison. These
features can be attributed to local karstic condi-
tions, including the close proximity of limestone to
land surface and the presence of permeable over-
lying sediments.

Cherry Lake

Cherry Lake is by far the largest lake in Madison
County with an area totaling more than 500 acres
and a water surface elevation of 154 feet MSL This
prominent feature occupies an irregular, circular
basin approximately one mile in diameter in north-
central Madison County.

The surrounding topography is characterized by
high elevations of more than 200 feet MSL to the
north, west and southwest and lower elevations
ranging from 150 to 160 feet MSL on the southeast.
A number of small ponds and depressions are
located around the lake. These karstic features are
especially numerous in this area as compared to
other parts of the county.

STRATIGRAPHY
Introduction

Madison County is part of a transitional geologic
area that lies between the thick, lower Tertiary
(Paleogene) and Cretaceous carbonate sediments
characteristic of the Florida peninsula and the age-
equivalent, predominantly siliciclastic sediments of
western Florida. The area is underlain by thick
limestone deposits of the Oligocene and Eocene
Epochs, which in turn are covered by younger
limestones, dolomites, sands and clays (Figure 9).
In Madison County, a total of 66 sets of well cuttings
and 25 cores were examined (Figure 10, Table 2).
Unless otherwise noted, structure contour maps
and isopachs used in this report are based on cores
due to their widespread coverage. Sediments
range in age from Paleozoic to Holocene.

Paleozoic Erathem

To date, the deepest penetration of subsurface
sediments in the county is to a depth of 10,049 feet
below mean sea level (MSL) in the Amoco Produc-
tion Company, Gilman Paper 22-2, No. 1, oil test
well (Permit-1033, WMd-15017). Four other oil test
wells have been drilled in Madison County (Table
2). Of the five oil test wells only three have
penetrated Paleozoic sediments; they are the Gil-
man Paper 22-2 (WMd-15017), the Gibson No. 2
(WMd-1596), and No. 4 (WMd-1598). The Gibson
No. 2 well penetrated a Paleozoic black shale at a
depth of 4,521 feet below MSL and the Gibson No.
4 penetrated Paleozoic quartzitic sandstone and
shale at 3,992 feet below MSL (Applin, 1951).

At a depth of 4,521 feet below ,/iL the Gibson
No. 2 well, core No. 2 (WMd-1596) encountered
dark gray shale containing the trilobite Col-
pocoryphe exsul considered to be Middle Or-
dovician (Pojeta et al., 1976). The undifferentiated
Paleozoic sediments of the Gilman Paper 22-2 well
(WMd-15017) consisted of shales, siltstones and
sandstones. At this site, the top of the Paleozoic
sediments are recognized on the electric log at
4,700 feet below MSL and continue to a total depth

ROE ROE + R7E + ROE + ROE R10E t R11E

---- -

JEFFERSON

-

N 1

1 -)

-
TAYLOR I

THE LOCATION OF TERTIARY AGE FORMATIONS
REFLECT THEIR PRESENCE WITHIN 20 FEET OF I LAFAYETTE
LAND SURFACE.

GEOLOGIC MAP

OF

MADISON COUNTY

FLORIDA
NEE

0 2 4 ml
0 \ 6 km
SCALE

RSE + R.E + R7E + RBE ROE + R10E + R11E

Figure 9. Geologic map of Madison County.

Holocene -
Pleistocene

Pliocene
Miocene
Oligocene
Eocene

Undifferentiated
Sands and Clays

Miccosukee Fm.
Hawthorn Group
Suwannee Ls.
Ocala Group

R5E I RE RE R RE RE R10E

EXPLANATION

CORE HOLES
WELL CUTTINGS

MULTIPLE WELL CUTTINGS
OUTCfOPS AND BORROW PMT
INTERSTATE
U.S. HIGHWAY
STATE ROAD
COUNTY ROAD

SCALE

0 E El

OW-4942
R5E I ROE R7E I RBE ROE I R10E

LAFAYETTE COUNTY

W-13205

R11E

Figure 10. Geologic Data Base location map.

I R11E I

W-15121

W-692S

T2S

R5E

I I I I RI IRIOE R
R6E R7E RSE R9E RIOE RIlE

GEORGIA T
T3N ------.TN

W-15I72

I A w-issis W-INETTA A

T2N JEFFERSON COUNTY W-15-8 -- I T2N
I

INSET A'

B HAMILTON COUNTY 0
\ -1B9\1) -.

\ ^W-18LEE 0 EXPLANATION -

0 WELL CORE
*' 0 WELL CUTTING$ 0O
SIN \KHOLE
TIS TIS

W- LEE PSUWANNEE COUNTY

W-18974 C'
S-------------
W-15Wl0

TAYLOR COUNTY W------- -N
I CROSS SECTION
LOCATION AT
SCALE LAFAYETTE COUNTY MADISON COUNTY LANDFILL
0 l
I 1 INSET A
o a km sUo ur26)

R5E I R6E I R7E I R8E I R9E RIDE RIIE I

Figure 11. Index map of geologic cross sections.

Bulletin No. 61

TABLE 2. Geologic Data Base

UD- Undifferentiated Sediments.
MCSK- Miccosukee Formation.

AP- Avon Park Formation.

WELL NO. TOWNSHIP/RANGE/SEC

Latitude

HTRN- Hawthorn Group SWNN- Suwannee Limestone.
SMRK- St. Marks Formation. OCA- Ocala Group.
TD- Total Depth.

Longitude ELEV UD MCSK HTRN SMRK SWNN OCA AP TD

Madison County
187 T. 2i
188 T. 1
704 T. 1
705 T. 2i
1061 T. 2i
1596 T. 1i
1597 T. 2i
1598 T. 2i
1751 T. 1I
2145 T. 1
2155 T. 1I
2357 T. 1i
2418 T. 1I
2424 T. 1I
2536 T. 1I
2548 T. 1I
2549 T. 11
2550 T. 1I
2576 T. 1I
2987 T. 1I
3468 T. 2f
3679 T. 2N
5208 T. 1S
6211 T. 2N
6377 T. 2N
6558 c T. 1I
7220 T. 1N
7222 T. 1N
7225 T. IN
7226 T. 1N
7228 T. 1N
7229 T. 1N
7231 T. 1l
7232 T. 1N

S R.10E S.27 BA
S R.11E S.24 DA
S R.10E S.19 AD
S R. 6E S. 5 BD
S R.10E S.28 B
S R.10E S. 6 CD
S R.11E S.18 BC
S R.11E S. 5 DBB
N R. 9E S.22
S R.11E S.24 AD
N R. 9E S.26 AA
S R.11E S.16 AB
N R. 9E S.21 CA
N R. 9E S.28 DA
N R. 9E S.23 BC
N R. 9E S.33 DC
N R. 9E S.21 BC
N R. 9E S.34 AA
N R. 9E S.23 BC
N R. 9E S.27
N R. 9E S. 5 CC
SR. 8E S.25 D
SR.11E S.14 DD
I R.10E S. 7 DB
I R. 9E S.28 AD
IR. 6E S. 9 D
I R. 8E S.23 AD
I R. 9E S.21 DC
I R. 7E S.23 BD
I R. 8E S.17 DD
I R. 8E S.19 BB
I R. 8E S.21 BB
I R. 8E S.24 BA
I R. 9E S.20 DD

N D 30 M 17 S 16 W D 83 M 18 S 39
N D 30 M 23 S 3 W D 83 M 10 S 49
N D 30 M 22 S 49 W D 83 M 21 S 18
N D 30 M 20 S 10 W D 83 M 44 S 48
N D 30 M 17 S 14 W D 83 M 19 S 24
N D 30 M 25 S 32 W D 83 M 23 S 26
N D 30 M 18 S 20 W D 83 M 15 S 53
N D 30 M 20 S 39 W D 83 M 14 S 14
N D 30 M 28 S 29 W D 83 M 24 S 35
N D 30 M 23 S 4 W D 83 M 10 S 49
N D 30 M 27 S 48 W D 83 M 24 S 3
N D 30 M 24 S 15 W D 83 M 13 S 21
N D 30 M 28 S 20 W D 83 M 26 S 2
N D 30 M 27 S 32 W D 83 M 25 S 36
N D 30 M 28 S 15 W D 83 M 23 S 32
N D 30 M 26 S 15 U D 83 M 25 S 48
N D 30 M 28 S 11 D 83 M 25 S 46
N D 30 M 26 S 49 W D 83 M 24 S 57
N D 30 M 28 S 16 U D 83 M 23 S 51
N D 30 M 27 S 22 W D 83 M 24 S 23
N D 30 M 35 S 51 W D 83 M 27 S 3
N D 30 M 32 S 29 W D 83 M 28 S 27
N D 30 M 23 S 33 W D 83 M 10 S 57
N D 30 M 35 S 9 W D 83 M 21 S 8
N D 30 M 32 S 33 W D 83 M 25 S 21
N D 30 M 29 S 48 W D 83 M 43 S 21
N D 30 M 28 S 13 W D 83 M 30 S 6
N D 30 M 28 S 30 W D 83 M 25 S 41
N D 30 M 28 S 21 W D 83 M 35 S 21
N D 30 M 28 S 44 W D 83 M 32 S 17
N D 30 M 28 S 30 W D 83 M 33 S 18
N D 30 M 28 S 38 U D 83 M 31 S 25
N D 30 M 28 S 32 W D 83 M 29 S 8
N D 30 M 28 S 24 W D 83 M 26 S 42

20

20 30 40
40 60
24

0 40
0
0 120 153
140
0 30 160
0 65 150 155
0 70 110
0 30 110
0 20 45 50
0 2 42 75 115
0 70 75
0 25 70
10 45 105
0 15 85

0 55
0 10 30
5 83
0 68
20 29
0 29 65
20 50
20 47
20
20
20 23

75 85
110
225

50 53

30 129
30 97
90
80 160
27
200 410 5381
440 3540
110 400 4096
200 325
15 45
153
375 405 3360
165
205
220
210 520
200 385 515
325 540
175
190
157
180 315
20 246
140
149
230
71
56
74
59
89
42
60
56

* : Oil Wells, c : Core

Florida Geological Survey

TABLE 2. Geologic Data Base

UD- Undifferentiated Sediments.
MCSK- Miccosukee Formation.
AP- Avon Park Formation.

WELL NO. TOWNSHIP/RANGE/SEC

T. 1N R. 9E S.20 BD
T. 1N R. 9E S.19 AD
T. 1N R. 7E S.24 DA
T. 1N R. 9E S.14 B
T. 1N R. 9E S.17
T. 1N R.11E S.28 CB
T. 3N R.10E S.206B
T. 1S R.11E S.13 BC
T. 1S R.11E S.14 CA
T. 1S R.10E S. 3 DB
T. 1S R. 9E S.25 CA
T. 1S R. 7E S. 4 BC
T. 2N R. 9E S.12 AA
T. 2N R. 9E S.12 AA
T. 1N R. 9E S.21
T. 1N R. 7E S.32

7233
7234
7236
7611
7876
8390
10480 c
10654 c
10655 c
12516
13024
13196
13213
13214
13268
13297
13312
13317
13364
13365
13366
13367
13369
13424
13479
13775
13946
13989
13991
13996
13998
14001
14051
14693
14856

S. 9
S.14
S. 1
S.205BB
S.25
S. 1 DA
S.11
S.35 AD
S. 2 AD
S.19
S.12 CD
S. 1
S.20
S. 4
S. 3
S.27
S.20 BC
S.14
S.25

Latitude

D 30 M 28 i
D 30 M 28 S
D 30 M 28
D 30 M 29 S
D 30 M 28
D 30 M 27

HTRN- Hawthorn Group

SWNN- Suwannee Limestone.

SMRK- St. Marks Formation. OCA- Ocala Group.
TD- Total Depth.

Longitude ELEV UD MCSK HTRN SMRK SWNN OCA AP TD

24 W D
7 W D
7WD
20 W D
24 W D
58 W D
31 W D

N D 30 M 37 S 39 W D
N D 30 M 23 S 46 W D
N D 30 M 23 S 58 W D
N D 30 M 25 S 44 W D
N D 30 M 22 S 9 W D
N D 30 M 25 S 45 W D
N D 30 M 35 S 31 W D
N D 30 M 35 S 29 W D
N D 30 M 28 S 30 W D
N D 30 M 26 S 38 W D
N D 30 M 30 S 7W D
N D 30 M 29 S 13 W D
N D 30 M 30 S 47 W D
N D 30 M 37 S 29 W D
N D 30 M 21 S 59 W D
N D 30 M 36 S 9 W D
N D 30 M 19 S 26 W D
N D 30 M 31 S 39 W D
N D 30 M 25 S 34 W D
N D 30 M 33 S 22 W D
N D 30 M 29 S 43 W D
N D 30 M 36 S 14 W D
N D 30 M 33 S 31 W D
N D 30 M 30 S 55 W D
N D 30 M 20 S 25 W D
N D 30 M 32 S 45 W D
N D 30 M 28 S 24 W D
N D 30 M 29 S 10 W D
N D 30 M 22 S 16 W D

83 M 26 S 42
83 M 27 S 24
83 M 34 S 52
83 M 23 S 27
83 M 26 S 46
83 M 13 S 26
83 M 18 S 17
83 M 10 S 43
83 M 11 S 46
83 M 18 S 23
83 M 22 S 32
83 M 37 S 57
83 M 22 S 53
83 M 22 S 53
83 M 25 S 44
83 M 38 S 53
83 M 25 S 37
83 M 35 S 48
83 M 22 S 40
83 M 17 S 27
83 M 16 S 28

83 M
83 M
83 M
83 M
83 M
83 M
83 M
83 M
83M
83 M
83 M
83 M

28 S 43
41 S 53
23 S 27
23 S 25
21 S 29
22 S 23
16 S 28
20 S 35
37 S 50
18 S 35
18 S 28
26 S 42

83 M 41 S 48
83 M 28 S 34

100
140
95
150
110
66
99
57
60
90
97
110
160
160
94
90
130
100
120
99
84
210?
75
115
110
90
120
100
145
105
90
150
150
84
110

7
10 20
0 10
35
5 30

0 5 60
0 90
0 5 15
0
0
0 50
0 5
0 5
0 8 70
0 8
0 6 18
0 10
0 10
0 60

110
100
20
23 48
0
0
85
60 70
70
90
70 80
60
110

110

40
130 150

110
90
50 70
30
90
35 45
50 55
120
20
65 70
60

* : Oil Wells, c : Core

1N R. 9E
1N R. 7E
1N R. 9E
3N R.1OE
1S R.1OE
2N R. 8E
2S R. 6E
2N R. 9E
1S R. 9E
2N R.1OE
1N R. 9E
2N R.1OE
2N R.1OE
1N R. 7E
2S R.1OE
2N R.1OE
1N R. 9E
1N R. 6E
1S R. 8E

Bulletin No. 61

TABLE 2. Geologic Data Base

UD- Undifferentiated Sediments.
MCSK- Miccosukee Formation.
AP- Avon Park Formation.

HTRN- Hawthorn Group
SMRK- St. Marks Formation.
TD- Total Depth.

SWNN- Suwannee Limestone.
OCA- Ocala Group.

WELL NO. TOWNSHIP/RANGE/SEC Latitude Longitude ELEV UD MCSK HTRN SMRK SWNN OCA AP TD
.....................................................................................................................

15017 T. 2S
15515 c T. 2N
15537 c T. 2N
15728 c T. 3N
15803 c T. 1N
15846 c T. 2N
15858 c T. 2N
15881 c T. 2S
15884 c T. 1S
15888 c T. 1S
15911 c T. 1S
15931 c T. 1N
15960 c T. 2S
15974 c T. 2S
15980 c T. 2S
15981 c T. 1S
15982 c T. 1S
15983 c T. 2S
15984 c T. 1S
15986 c T. 1N
15991 c T. 1N
16021 c T. 3N

Hamilton County
10300 T. 1N
10656 c T. 1S
12625 T. 2N
13212 T. 2N
15121 c T. 2N

Jefferson County
97 T. 3N
5325 T. 1S
6174 T. 1S

R. 9E S.22
R. 8E S. 5
R. 9E S. 5
R.10E S.33
R. 9E S.34
R. 8E S.22
R.10E S.35
R.10E S.35
R. 6E S. 2
R. 9E S.20
R. 7E S.34
R. 7E S.33
R. 6E S. 3
R. 8E S. 2
R.10E S. 4
R.11E S. 9
R.10E S.30
R. 9E S.34
R.1OE S.11
R. 8E S.34
R. 9E S.11
R. 8E S.28

R.11E S.14
R.11E S.11 BB
R.11E S.20 BC
R.11E S.27
R.12E S.03 BA

R. 7E S.181
R. 5E S. 1 AD
R. 5E S.22 BC

N D 30 M 17
N D 30 M 36
N D 30 M 36
N D 30 M 36
N D 30 M 26
N D 30 M 33
N D 30 M 31
N D 30 M 15
N D 30 M 25
N D 30 M 23
N D 30 M 21
N D 30 M 26
N D 30 M 20
N D 30 M 20
N D 30 M 20
N D 30 M 24
N D 30 M 22
N D 30 M 16
N D 30 M 24
N D 30 M 26
N D 30 M 30
N D 30 M 37

D 30 M 29
D 30 M 25
D 30 M 33
D 30 M 32
D 30 M 37

D 30 M 38
D 30 M 25
D 30 M 23

37 W D 83 M 24 S 40
18 U D 83 M 33 S 10
38 W D 83 M 26 S 28
50 W D 83 M 18 S 33
30 W D 83 M 24 S 19
48 W D 83 M 30 S 48
38 W D 83 M 17 S 53
49 W D 83 M 17 S 11
21 U D 83 M 42 S 13
6 W D 83 M 26 S 49
14 W D 83 M 36 S 51
20 U D 83 M 37 S 21
26 W D 83 M 42 S 31
37 W D 83 M 29 S 47
20 W D 83 M 19 S 45
48 W D 83 M 13 S 33
4 W D 83 M 21 S 33
14 W D 83 M 24 S 33
35 W D 83 M 17 S 40
30 W D 83 M 30 S 34
8 W D 83 M 23 S 52
44 W D 83 M 31 S 57

83 M 11 S 28
83 M 11 S 7
83 M 14 S 44
83 M 12 S 25
83 M 6 S 55

83 M 36 S 48
83 M 47 S 8
83 M 48 S 50

15
5 27
2
5 58

17
22

2 32
50
0 29

10149
72 299 315
109 129 293 322
82 87 287
79 86 100
51 99
93 99 110
24 40 45
60 73
72 82 89
83 94
100 102
73 97
82 95
33 52
25 62
36 45
32 62
57
98 101
103 125
90 121

5 35 45
21
0 50
50
11 149

75
77
28 75

80
44 62
80
165
175

120
104 151
80

6559 c T. 1N R. 5E S.25 CA

* : Oil Wells, c : Core

N D 30 M 27 S 35 W D 83 M 47 S 10

80 0

Florida Geological Survey

TABLE 2. Geologic Data Base

UD- Undifferentiated Sediments.
MCSK- Miccosukee Formation.
AP- Avon Park Formation.

HTRN- Hawthorn Group
SMRK- St. Marks Formation.
TD- Total Depth.

SWNN- Suwannee Limestone.
OCA- Ocala Group.

WELL NO. TOWNSHIP/RANGE/SEC Latitude Longitude ELEV UD MCSK HTRN SMRK SWNN OCA AP TD
.....................................................................................................................
6560 T. 1N R. 6E S. 8 DD N D 30 M 29 S 38 W D 83 M 44 S 21 82 0 180
6561 c T. 2N R. 6E S. 1 DD N D 30 M 35 S 46 W D 83 M 40 S 35 184 0 36 82 103
6925 c T. 1S R. 5E S.32 AC N D 30 M 21 S 14 W D 83 M 51 S 18 134 0 35 45 50 69
15438 c T. 3N R. 7E S.30 AD N D 30 M 37 S 52 W D 83 M 39 S 39 158 0 10 60 120 240
15439 c T. 3N R. 7E S.30 AD N D 30 M 37 S 52 W D 83 M 39 S 40 157 0 40 100 105 150
15761 c T. 3N R. 7E S.32 N D 30 M 37 S 31 UD 83 M 39 S 10 135 0 1 54 125
15785 c T. 3N R. 7E S.30 N D 30 M 37 S 52 W D 83 M 39 S 40 157 0 2 65 108 120 128
15786 c T. 2N R. 6E S.11 A N D 30 M 35 S 44 W D 83 M 41 S 56 145 0 5 65 79 82
15912 c T. 1S R. 5E S.22 N D 30 M 23 S 42 W D 83 M 48 S 45 70 0 4 24 34 70

Lafayette
4942 T. 3S R.10E S.27 C
13205 T. 3S R.11E S.19 DA

Suwannee
13200 T. 2S R.11E S.28 CB

Taylor
15943 c T. 2S R. 8E S.28
15959 c T. 2S R. 7E S.31
15985 c T. 2S R. 5E S.28

N D 30 M 11 S 27 W D 83 M 18 S 45
N D 30 M 12 S 35 W D 83 M 18 S 40

N D 30 M 17 S 3 W D 83 M 13 S 0

N D 30 M 17 S 40 W D 83 M 32 S 9
N D 30 M 16 S 2 W D 83 M 39 S 48
N D 30 M 0 S 0 W D 83 M 0 S 0

86 0
75 0

55 0

32 45 145 175
27 28

Bulletin No. 61

of 10,049 feet below MSL The Paleozoic section in
this well is about 5,350 feet thick.

MESOZOIC ERATHEM
Triassic System

To date, Jurassic sediments have not been iden-
tified in Madison County. However, several diabase
intrusions penetrated Paleozoic sediments in WMd-
1596, WMd-1598 and WMd-15017. In WMd-1596
and WMd-1598 intrusions were encountered at
4,482 feet below MSL and 3,971 feet below MSL
respectively. These intrusions, which have thick-
nesses of 39 and 16 feet, respectively, were tenta-
tively identified as Triassic diabase (Arthur, 1988).
In WMd-15017, three intervals of altered diabase
were encountered at depths of 5,350, 5,700 and
9,100 feet below MSL with respective thicknesses
of 120, 400 and 100 feet.

Cretaceous System

In the geological transitional area encompass-
ing Madison County the Cretaceous sediments are
variable in character ranging from siliciclastics to
carbonates. Unnamed sequences of shales and
sandstones, some of which are calcareous,
dominate the Lower Cretaceous section. The
Upper Cretaceous sediments consist of, in ascend-
ing order, the Atkinson Formation, unnamed shales
and mars, and the Lawson Formation (Braunstein
et al., 1988).
A description of Upper Cretaceous sediments
from the Gibson No. 2 well in Madison County by
Chen (1965) is on file at the Florida Geological
Survey. Chen described Upper Cretaceous sedi-
ments in the Gibson No. 2 well (WMd-1596) from
2,163 to 2,403 feet below MSL as light grayish-
brown, cherty, fossiliferous limestone, containing
Inoceramus sp. prisms. In the interval from 2,028
to 2,163 feet below MSL, the Lawson Formation is
described as a light grayish-brown to dark brown,
well cemented, cherty and recrystallized fos-
siliferous limestone. Chen (1965) in a regional
study placed the top of the Cretaceous sediments,

which dip to the west, at approximately 2,000 to
2,100 feet below MSL in the Madison County area.

CENOZOIC ERATHEM
Tertiary System
Paleocene Series
Cedar Keys Formation

The Cedar Keys Formation was first named by
Cole (1944) for the upper Lower Paleocene, cream
to tan colored, hard limestones containing the
foraminifera Borelis gunteri and Borelis floridanus.
Cole further states that although these two
foraminifera are found in the upper part of the
formation the lower part is nearly devoid of fossils.

Distribution

Cole's (1944) original description states that the
Cedar Keys Formation covers an area which en-
compasses the northeastern panhandle and the
Florida peninsula. Five oil test wells in Madison
County penetrated this formation at depths ranging
from 1,213 to 1,672 feet below MSL (WMd-1598 and
WMd-1596 respectively). These wells (WMd-1596
and WMd-1598) are located in the central and
southeastern parts of the county respectively (Fig-
ure 10).

General Lithology

The Cedar Keys contains three lithologic units
(Winston, 1978). The lower unit is a cream to tan,
pelloidal, skeletal dolomite with euhedral dolomite
rhombs near the base. The middle unit is a
dolomitic limestone with occurrences of anhydrite.
The upper unit is predominantly a gray, chalky,
anhedral dolomite.

Thickness

The Cedar Keys Formation increases in thick-
ness from less than 300 feet in northern Florida to
as much as 2,000 feet in southern Florida in Collier

Florida Geological Survey

and Lee Counties (Chen, 1965). In Madison County
this unit ranges from approximately 200 to 300 feet
in thickness (Chen, 1965).

Stratigraphic Relations

The Cedar Keys Formation unconformably over-
lies the Upper Cretaceous Lawson Formation. It
unconformably underlies the Early to Middle
Eocene age Oldsmar Limestone.

Eocene Series
Oldsmar Limestone

Applin and Applin (1944) originally applied the
name Oldsmar Limestone to the carbonate rocks
deposited during the Early to Middle Eocene
Epoch. The Applins defined this formation on the
basis of the abundance of the foraminifera Helico-
stegina gyralis and further stated that the base of
this formation rests upon the Cedar Keys Forma-
tion.

Distribution

The original description by Applin and Applin
(1944) stated that the Oldsmar is present in both the
peninsula and northeastern Florida panhandle. In
Madison County, a total of five oil test wells
penetrated these sediments at depths ranging from
793 to 1,137 feet below MSL (Chen, 1965).

General Lithology

The lower section of the Oldsmar Limestone in
the eastern Florida panhandle is a fine grain, skele-
tal carbonate. This lithology changes upward to a
chalky white to tan or cream colored carbonate
(Chen, 1965).

Thickness

In general, the Oldsmar Limestone is thicker than
the underlying Cedar Keys Formation. In Madison

County, thicknesses range from 200 to more than
500 feet (Chen, 1965).

Stratigraphic Relations

The Oldsmar Limestone unconformably overlies
the Lower Eocene Cedar Keys Formation. The
Avon Park Formation (Miller, 1986), which com-
bines the previously defined Lake City Limestone
(Applin and Applin, 1944) and the Avon Park Lme-
stone (Applin and Applin, 1944), unconformably (?)
overlies the Oldsmar Limestone.

Avon Park Formation

The Lake City Limestone was proposed by Ap-
plin and Applin (1944) for limestone sediments of
early Middle Eocene age present in north Florida.
The Avon Park Formation was named by Applin and
Applin (1944) for the late Middle Eocene limestone
recognized in a Florida Geological Survey well
(WPk-668) drilled at the Avon Park Bombing Range
in Polk County, Florida. The Florida Geological
Survey well WPk-668 was designated as the type
well. Crane (1986) informally combined the Avon
Park Limestone, the Lake City Limestone, and the
Oldsmar Limestone into two lithofacies, a dolomite
lithofacies and the undifferentiated carbonate
lithofacies. Miller (1986) combined the lithological-
ly similar Lake City Limestone and the Avon Park
Limestone of Applin and Applin (1944) into a single
unit, the Avon Park Formation.

Distribution

The Avon Park Formation is the oldest strati-
graphic unit to crop out in Florida. Exposures of
this unit are limited to areas in Levy and Citrus
Counties. The Avon Park Formation forms the
lower part of the potable Floridan aquifer system in
Madison County. This unit, which occurs in the
subsurface throughout Madison County can be
observed in cuttings from relatively deep wells.
These include well WMd-2549 (section 21 bc,

Bulletin No. 61

Township 1N, Range 9E) and WMd-1596 (section
6, Township 1S, Range 10E). The Avon Park in
WMd-2549 is present at 286 feet below MSL. In well
WMd-1596 the top of the Avon Park is at 303 feet
below MSL.

General Lithology

In Madison County, the Avon Park Formation is
a moderately to well indurated limestone or
dolomite. It frequently occurs as a very pale orange
to white to light olive-gray, moderately porous, fos-
siliferous, gypsiferous, and fragmental limestone.
The dolomite occurs as a brown to grayish brown,
moderately to well indurated, fossiliferous,
microcrystalline to very fine grained carbonate.
The Avon Park has been reported to include char-
acteristic peat flecks in regions to the west in Jef-
ferson County and to the southeast in the Florida
peninsula (Yon, 1966). However, no organic
material was observed in the Avon Park Formation
in Madison County.

Thickness

Only two wells completely penetrated the Avon
Park Formation. These two wells WMd-1596 and
WMd-1598 had thicknesses of 220 feet and 80 feet,
respectively.

Stratigraphic Relations

The Avon Park Formation unconformably (?)
overlies the Oldsmar Limestone. It also unconfor-
mably underlies the Ocala Group.

Ocala Group

Dall and Harris (1892) proposed the term Ocala
Limestone for exposed carbonate sediments
present near the vicinity of Ocala. Puri (1957)
raised the Ocala Limestone to the rank of group.
He further subdivided the Ocala Group into three
formations which are, from oldest to youngest: the

Inglis Formation, the Williston Formation, and the
Crystal River Formation. These formations are not
differentiated in this study due to limited outcrops
and subsurface data and are referred to in the cross
sections (Figure 11, cross section locations) as the
Ocala Group Undifferentiated (Figures 12,13, and
15). Purl (1957) gives an excellent historical review
of the Ocala Group.

Distribution

The Ocala Group, which was deposited during
the Late Eocene Epoch, represents the oldest sedi-
ments exposed in Madison County. These lime-
stones, which form an integral part of the Floridan
aquifer system in Madison County, occur at varying
depths throughout the county (Figures 12, 13, 14
and 15). This observation is based on limited data
as outcrops of the Ocala are limited to the extreme
southeastern part of Madison County along the
Suwannee River. Several wells in the county
penetrated these calcareous sediments at depths
ranging from 50 feet above MSL (WMd-15981) to
139 feet below MSL (WMd-15515) (Figure 16). Out
of 66 sets of well cuttings and 25 cores in Madison
County used in this study only 21 were deep
enough to encounter the Ocala Group limestone.
Of these 21 wells, seven from Madison County are
cores (WMd-15515, WMd-15537, WMd-10480,
WMd-15981, WMd-15881, WMd-10654, WMd-
10655) the first three of which are located along an
east-west line across the northern third of the coun-
ty. Two cores (WMd-10655 and WMd-15981) are
located near the confluence of the Withlacoochee
and Suwannee Rivers near Ellaville (Figure 10).

General Lithology

The Ocala Group is generally a pale orange to
white, poorly to moderately indurated, moderately
to highly porous, micro-fossiliferous, partially
dolomitized, partially recrystallized limestone.
Several cores including WMd-15515 and WMd-
15537 have sediments comprised primarily of
dolomite. The occurrence of the distinctive
foraminifera genus Lepidocyclina is common to

Figure 12. Geologic cross section A-A'.

FEET/METERS
200160

150 -
40

FEET/METER

200-I0.

WMd-2N-9E-5bS

UNDIFFERENTIATED TD 287'

SCALE
0 5 ml

0 8 km
CROSS SECTION A-A'
NOTE: VERTICAL EXAGGERATION IS APPROXIMATELY 106 TIMES.

,s B UNDIFFERENTIATED
S SANDS AND CLAYS
OVERLIE MICCOSUKEE FORMATION
WMd-1N-6E-9d WMd-1N-7E-33cd WMd-lN-834db WME-34d9E-34db LMd-1S-1OE-10db WMd-18-11E-14c0
W-6558 W-15931 W-15986 W-15803 MICCOSUKEE FORMATION SINKHOLE W-10655

MICCOSUKEE FORMATION I ----- ---

HAWTHORN GROUP UNDIFFERENTIATED ST. MARKS FM. TD 100' SUWANNEE LIMESTONE ? --------
MSL- --- . _________TOD101 OCALA GROUP UNDIFFERENTIATED 4
HAWTORNOROP .---'", --- --- ----- ---- --- -------- -------------9-
HAWTHORN GROUP
UNDIFFERENTIATED TD 102

SUWANNEE LIMESTONE

TD 230'
CROSS SECTION B-B'
SCALE
0 N ml
I NOTE: VERTICAL EXAGGERATION IS APPROXIMATELY 106 TIMES.

o0 km

' MSL

FEET/METERS

TD 9

SCALE

-s-- m
I Ikm I
0 8km

C'

AMd-28-BE-2ab WMd-2S-10E-40d
W-15974 W-15980

FERENTIATED SANDS ANCA

HAWTHORN GROUP UNDIFFERENTIATED AWlTHORN GROUP UNDIFFERENTIATED

SUWANNEE LIMESTONE TO 52
------------ f ---------------------------- --M8L

CROSS SECTION C-C'

NOTE: VERTICAL EXAGGERATION 18 APPROXIMATELY 106 TIMES.

Figure 14. Geologic cross section C-C'.

WMd-2N-SE-5Sc WMd-2N-SE-22ba WMd-IN-SE-21bl
W-15515 W-15848 W-2849
SMUNDIFFERENTIATED SANDS AND CLAYS
V'ORMATIO N MICCOSUKEE FORMATION- J

TD 99'

SUWANNEE LIMESTONE
-0 MSL ----------------------

WMd-1N-9E-34db
W-15803 UMDIFFERENTIATED SANDS AND CLAYS D'
OVERLIE MICCOSUKEE FORMATION
WMd-18-10E-30da WMd-28-10E-4cb WMd-2S-10E-35bd
I W-15982 W-15910 W-15E81
UNDIFFERENTIATED HAWTHORN GROUP

TD 100o BT. MARKS FORMATION UWANNEELMTSTON -
TD 48 - -...1-!0
TD 80' ? "-CTLA GROUP TD 405
SA UNDIFFERENTIATED
TUWANNEE LIMESTONE

OCALA GROUP UNDIFFERENTIATED

TD 315'

SCALE

1---5 m
I 8 Sm
0o km

OCALA GROUP UNDIFFERENTIATED

TD S1'

CROSS SECTION D-D'
NOTE: VERTICAL EXAGGERATION IS APPROXIMATELY 106 TIMES.

Figure 15. Geologic cross section D-D'.

FEET/METERS

200--60

-200-* 60

Florida Geological Survey

EXPLANATION

CORE HOLES
0 WELL CUTTINGS
40 STRUCTURE CONTOURS

CONTOUR INTERVAL IS 20 FEET.
DATUM IS MEAN SEA LEVEL

10654
|W-21;5I

0 SCALE 5 m

0 8 km

Figure 16. Generalized structure contour map of the top of the Ocala Group.

EXPLANATION

CORE HOLES
O WELL CUTTING
20 R STRUCTURE CONTOURS
cO SUWANNEE LIMESTONE
MISSING
OUTCROP

CONTOUR INTERVAL IS 8O FIET.
DATUM IS MEAN IEA LEVEL.
'-10 54

SCALE
0 5 ml

0 8 km

LAFAYETTE COUNTY

Figure 17. Structure contour map of the top of the Suwannee Limestone.

Bulletin No. 61

abundant and is often used as an aid in distinguish-
ing this formation from the overlying younger
Suwannee Limestone.

Thickness

A determination of unit thickness is difficult be-
cause none of the cores penetrated a complete
Ocala sequence. However, approximations can be
made based on several deep wells in Madison
County (WMd-1596, WMd-1598 and WMd-2549)
that penetrated complete Ocala intervals. In Wmd-
1596, located near the city of Madison (section 06,
Township 1 S, Range 10E), a maximum thickness of
210 feet was encountered in the interval from 93 to
224 feet below MSL A minimum thickness of 80
feet was encountered in the interval from 42 to 122
feet below MSL in WMd-1598 (section 5db,
Township 2S, Range 11E).

Stratigraphic Relations

The Ocala Group unconformably overlies the
Middle Eocene Avon Park Formation. It unconfor-
mably underlies the Oligocene Suwannee Lime-
stone.

Geologic Outcrops

Outcrops of the Ocala are limited in Madison
County to a reach of the Suwannee River south of
Ellaville. Here, in the extreme southeastern part of
the county, Ocala Group limestones can be ob-
served along the banks of the river during periods
of low water levels. South of the Madison-Lafayette
County boundary, exposures of Ocala can be
viewed in the inactive Dowling Park Quarry owned
by Anderson Mining Corporation (section 2,
Township 3S, Range 11E).

Oligocene Series
Suwannee Limestone

Cooke and Mansfield (1936) named the tan

limestone exposed along the Suwannee River from
Ellaville eastward to a point near White Springs in
Hamilton County, the Suwannee Limestone. An
historical review of the stratigraphic nomenclature
of the Suwannee Limestone is given by Purl and
Vernon (1964), Colton (1978) and Crane (1986).

Distribution

The Suwannee Limestone is continuous
throughout most of Madison County. One excep-
tion is a narrow strip in the southeastern part of the
county near and along the Suwannee River where
the older Ocala Group is at or near the surface.

The majority of cores examined for this study
penetrated the Suwannee Limestone. This forma-
tion was encountered at various depths ranging
from the surface along the banks of the Suwannee
River at Ellaville (approximately 35 feet above MSL)
to as deep as 109 feet below MSL in core WMd-6558
(section 9d, Township 1N, Range 6E). Figure 17 is
a structure contour map drawn on top of the Suwan-
nee Limestone.

General Lithology

The Suwannee Limestone is of marine origin and
consists of a partially recrystallized limestone (cal-
carenite). It is very pale orange, finely crystalline,
moderately to well indurated, with moderate to
good porosity and is very fossiliferous. Chemical
analysis of this formation in Jefferson County indi-
cates a composition that is nearly 97 percent cal-
cium carbonate (CaCO3) (Yon, 1966). In various
locations, such as along the Suwannee River at
Ellaville, the top of the formation is silicified at the
land surface and near surface. In addition, chert
was encountered in well cutting samples and cores.

Well cutting samples and cores of the Suwan-
nee Limestone show that dolomite CaMg(CO3)2
can occur throughout the complete section. In
general, the dolomite occurs as a light orange to
gray intergranular well indurated, microcrystalline

Florida Geological Survey

to very fine grained sediment. These dolomitic
beds can often be delineated by electric and
gamma logs as well as being identified in cores and
well cuttings.

Thickness

In this report, the formation's thickness is ap-
proximated because most of the information avail-
able is from wells that terminate in the Suwannee.
Thicknesses ranged from a maximum observed
thickness of 227 feet in core WMd-15515 (section
5ca, Township 2N, Range 8E) to being absent in
some wells in the eastern part of the county (WMd-
15984 and WMd-15981).

Stratigraphic Relations

The Suwannee Limestone unconformably over-
lies the Ocala Group (Figures 12, 13, and 15). The
Suwannee Limestone is unconformably overlain by
the Hawthorn Group sediments or St. Marks For-
mation. Where the above units are absent, the
Suwannee underlies younger undifferentiated sand
and clay (Figures 13 and 15).

Geologic Outcrops

Outcrops of limestone and dolomitic limestone
belonging to the Suwannee Limestone are present
along the banks of the Suwannee River at Ellaville.
These outcrops, which are fairly continuous
eastward to near White Springs, are readily acces-
sible via canoe during low to moderate river levels.
The outcrop on the east bank of the Suwannee
River directly under the old U.S. 90 Highway bridge
approximately 0.1 mile north of the new bridge near
Ellaville is considered typical of the section. A
description of this section is as follows:

Described by Steve Spencer (1987).
LSu section 24da, Township 1S, Range 11E (direct-
ly under the old US 90 Highway bridge ap-
proximately 0.1 mile north of the new bridge).

Thickness
Feet

Unit Description

A Suwannee Limestone (Oligocene).
Limestone. Very pale orange to
white, moderately to well indurated,
microcrystalline to coarse grained,
fossiliferous foraminiferaa),
calcilutute matrix................................

B Limestone. Very pale orange
to white, moderately to well indurated,
dolomitic, bedded, highly weathered,
recrystallized, fossiliferous
foraminiferaa and mollusks)................

C Dolomite. Brown, moderately to
well indurated, moldic, massive,
dolomitic cement.........................

D Undifferentiated Sands and Clays.
Quartz sand, gray to orange-red,
poorly indurated, medium grained
(fine to coarse range), iron staining,
organic present as rootlets,
unfossiliferous..................................

Miocene Series
St. Marks Formation

Lithologic units assigned to the Early Miocene
have undergone various revisions since L. C.
Johnson (1888) first applied the name Tampa to
deposits that are stratigraphically equivalent to cal-
careous sediments occurring in Madison County.
An extensive historical treatment of the St. Marks
stratigraphic nomenclature is summarized by Puri
(1953) and Schmidt and Clark (1980).

Distribution

In contrast to the nearly continuous underlying

Bulletin No. 61

Suwannee Limestone, the St. Marks sediments are
discontinuous in occurrence due to nondeposition
or erosion in Madison County (Figures 12, 13 and
15). In general, the St. Marks Formation has widest
occurrences in the northern part of the county as
well as an area near the city of Madison. This
formation was encountered at depths ranging from
69 feet above MSL to 46 feet below MSL

General Lithology

The sediments, which form the St. Marks Forma-
tion, are white to very pale orange, sandy, silty,
clayey, recrystallized limestone. The St. Marks is
poorly to well indurated, has low to medium
porosity, contains various species of foraminifera
including Sorites sp., Archaias floridanus and mol-
luskan molds and casts.

Thickness

The cross sections in Figures 12, 13 and 15 show
thickness variability of the St. Marks throughout the
study area. Formation thickness varies from being
thin to absent in the central part of the county. A
maximum core thickness of 20 feet in WMd-15537
(section 5ba, Township 2N, Range 9E) was ob-
served in north-central Madison County in an area
west of Cherry Lake. No exposures of St. Marks
were observed in Madison County.

Stratigraphic Relations

The St. Marks Formation unconformably overlies
the Suwannee Limestone in Madison County.
Younger Miocene sediments belonging to the Haw-
thorn Group unconformably overlie the St. Marks
Formation.

Hawthorn Group

Historically, the Hawthorn Formation has been
a catch-all for Miocene sediments in peninsular

Florida, Georgia, and parts of South Carolina (Ab-
bott and Andrews, 1979). This extremely compli-
cated unit, which consists generally of clay,
carbonate (primarily dolomite), and clayey,
quartzitic, phosphatic sand, was named by Dall and
Harris (1892) after the town of Hawthorne, Florida.
Huddlestun (1982) informally proposed raising
this formational unit in Georgia to group level. He
further expanded this group concept by informally
recognizing the Parachucla Formation, Marks
Head Formation, and its equivalent the Torreya
Formation with its type section in Liberty County,
Florida, and the Coosawhatchie Formation as com-
prising the Hawthorn Group along with their respec-
tive ages of deposition (Huddlestun, 1981). Later,
Huddlestun (1988) formally raised the Hawthorn to
group level in Georgia. Scott (1988) has formally
extended the Hawthorn Group concept into Florida
and recognized its component formations.
An extensive historical review of the term Haw-
thorn is given by Hoenstine (1984) and Scott (1983,
1988). Scott (1988) recognized only the Torreya
Formation of the Hawthorn Group as being present
in Madison County. The Hawthorn Group was not
differentiated in Madison County for this study and
is referred to in the cross sections as Hawthorn
Group Undifferentiated (Figures 12, 13, 14 and 15).

Distribution

Hawthorn Group sediments are present
throughout most of Madison County. Exceptions
occur along the southern portion of the With-
lacoochee River in Madison County and the ex-
treme southwestern and the southeastern portions
of Madison County along the Suwannee River,
where the Hawthorn is absent. Figures 12, 13, 14
and 15 show the general distribution of these
Miocene Series sediments. These sediments were
encountered at depths ranging from surface occur-
rencesto 35 feet above MSL in WMd-13996 (section
4, Township 1N, Range 7E).
The occurrence of Hawthorn clays in
southeastern Madison County greatly influences
surface conditions. In this area, Hawthorn clays

Florida Geological Survey

underlie a broad low area known as San Pedro Bay.
These relatively thick clays, which range in thick-
ness from 10 feet to 30 feet, inhibit the downward
percolation of water resulting in extensive swampy
conditions throughout the area (Copeland, in
preparation).

General Lithology

Hawthorn sediments throughout Madison Coun-
ty are extremely variable ranging from phosphatic
dolomites and clayey sands to dolomitic, silty clays.
In general, these sediments consist of pale olive to
moderate yellow, sandy, phosphatic clays and
sands. Phosphate grains are a common con-
stituent of the Hawthorn Group and aid in its iden-
tification. Phosphate, which may comprise up to
eight percent of the sediment sample, is generally
disseminated throughout sandy clays and very fine
to medium, clayey, quartz sands and carbonates.
The phosphate grains are present in variable
amounts that commonly range from less than one
percent to eight percent of the sample, with average
values of approximately three percent (visual es-
timate).

Thickness

The Hawthorn is thin to absent in a broad area
of south Madison County and a smaller portion in
extreme southwestern Madison County. In con-
trast, thick deposits of Hawthorn Group sediments
are present in the northeastern portion of Madison
County as well as eastern and south-central parts
of the county (Figure 18). A maximum thickness of
142 feet of Hawthorn sediments was observed in
core WMd-6558 (section 9d, Township 1N, Range
6E) near State Road 90. This anomalous thick
section may be related to karst activity.

Stratigraphic Relations

The Hawthorn Group sediments in Madison
County lie unconformably upon either the Suwan-
nee Limestone or the St. Marks Formation. They
are in turn unconformably overlain by the Mic-
cosukee Formation or, where the Miccosukee is

absent such as in southeast Madison County, by
Pleistocene to Holocene undifferentiated sands.
The Hawthorn-Miccosukee contact is usually
lithologically identifiable. The heterogeneous na-
ture of water well cuttings can present a problem in
distinguishing between the sands and clays of
these respective units. However, the presence of
phosphate can serve as a guide in identifying the
Hawthorn sediments.

Geologic Outcrops

Surface outcrops of Hawthorn sediments occur
on the eastern side of the county along the northern
portion of the Withlacoochee River. These sedi-
ments are visible except during periods of high
water levels. An accessible outcrop occurs 100
yards to the south of State Road 90 approximately
1.5 miles west of the Suwannee River at an elevation
of 60 feet MSL, as measured from the USGS 7.5
minute Ellaville Topographic Quadrangle (Figure
19). The description of this outcrop is as follows:

Described by Ron Hoenstine and Steve Spencer
(1987).
LMd section 23aa, Township 1S, Range 11E (1.5
miles west of bridge, south side of State Road 90).

Thickness
IUni Description Feet

A Hawthorn Undifferentiated (Miocene).
Quartz sand, gray to yellowish to orange-
red, poorly indurated, fine grained (silt
to fine range) phosphorite grains, clay
matrix, iron staining, well mottled,
organic present as rootlets,
unfossiliferous.................................... 1.3

B Undifferentiated Sands and Clays.
Quartz sand, brownish orange, poorly
indurated, fine grained (silt to fine
range), faintly mottled, unfossiliferous
micaceous, organic present as rootlets,
radational base.................................... 1.3

Bulletin No. 61

COUNTY

EXPLANATION
CORE HOLES
0 WELL CUTTINGS
STRUCTURE CONTOURS
HAWTHORN
MISSING
A OUT CROPS

CONTOUR INTERVAL IS 20 FEET
DATUM IS MEAN SEA LEVEL

SCALE
! 5 mi

0 8 km

LAFAYETTE COUNTY

Figure 18. Isopach map of the Hawthorn Group.

EXPLANATION
CORE HOLES
O WELL CUTTINGS
HAWTHORN
MISSING
ISOPAGH CONTOURS
A OUTCROP

CONTOUR INTERVAL IS 0 FEET

OYS4
10654

0 SCALE 5 mi

o a km

LAFAYETTE COUNTY

Figure 19. Structure contour map of the top of the Hawthorn Group.

V ~ i :.Ell
'i

",~~~ .1 1t:r 1

CD

CFi)
'' )

-~,. *.4. a.
(Q.

'' 2."

.4 4'"t 2. ";; "4.-r'

-'"" 4 $;. .
., -

A...
:,jw_

Figr 2te s t asehr -h

Figure 20. Photograph of high water stage at a sinkhole in Lee, Florida. Photograph by the authors.

Bulletin No. 61

In a sinkhole near Lee, Florida, behind the
Methodist Church, (section 10db, Township 1S,
Range 10E, Figure 13) the Hawthorn Group occurs
as a white to yellowish-brown, well indurated, finely
crystalline, clayey limestone with low porosity. This
Hawthorn outcrop has limited exposure due to
slumpage and becomes inaccessible during
periods of high water. This occurred in February of
1986 when the Hawthorn was covered by more than
10 feet of water (Figure 20).

Pliocene Series
Miccosukee Formation

Prominent throughout the county is the
varicolored (red to reddish-orange to gray)
heterogenous complex of sediments referred to as
the Miccosukee Formation. These siliciclastics
have experienced a number of changes in
stratigraphic nomenclature over the years and have
been included in the Lafayette Formation (Matson
and Clapp, 1909), the Alum Bluff Formation (Sel-
lards, 1917) the Hawthorn Formation (Cooke and
Mossom, 1929), the "Unnamed Coarse Clastics"
(Puri and Vernon, 1964), and the Citronelle Forma-
tion (Doering, 1960). In addition, the period of
deposition assigned to these sediments by various
investigators over the years has ranged from the
Oligocene to the Plio-Pleistocene. More recently,
these sediments, which extend from Madison
County westward into Jefferson, Leon and
Gadsden counties and northward into Georgia,
have been formally named the Miccosukee Forma-
tion by Hendry and Yon (1967). A comprehensive
treatment of these sediments is given by Hendry
and Sproul (1966) and Yon (1966).

Distribution

The Miccosukee Formation is widespread in
Madison County, being generally present at the
surface and in the subsurface in all areas except the
river valley lowlands and the southern and extreme
eastern parts of the county. These sediments are
very distinctive in color and can be observed in

numerous roadcuts throughout the northern part of
the county.
The type locality of this formation is located at a
roadcut on the east side of U.S. Highway 19, about
3.1 miles south of the Georgia-Florida state line in
neighboring Jefferson County (Yon, 1966; Hendry
and Yon, 1967). The sequence of sediments in this
section illustrates rapid depositional changes, in-
cluding channel cut and fill features of a pro-deltaic
environment. Puri and Vernon (1964) postulated
that the siliciclastic sediments from Tallahassee
eastward were once part of a large delta.

General Lithology

The Miccosukee Formation is an aggregate of
lenticular clayey sands and clay beds which in-
dividually can be traced laterally for only short dis-
tances. These sediments are fine to coarse
grained, poorly to moderately sorted, poorly to
moderately indurated, reddish-orange sands to
gray sandy clays (Figure 21). Cross-bedded sands
frequently contain cross-bedded laminae of white
to light gray clay. Yon (1966) described these
sands as being widespread and generally the most
persistent lithologic constituent of this unit.
Miccosukee sediments in Madison County are
very heterogeneous in character with changes in
lithology observed to occur over relatively short
distances. Outcrops, one of which measures more
than 35 feet in height (section 6bb, Township 1S,
Range 9E), are extremely weathered (Figure 10).
The weathering process has frequently destroyed
bedding that may have been present and imparted
a massive appearance to many of the exposed
sediments.

Thickness

As shown on the geologic cross sections
(Figures 12, 13, and 15) the Miccosukee is variable
in thickness. In core WMd-15515 (section 5ca,
Township 2N, Range 8E) 44 feet of Miccosukee
clayey sands and clay beds were penetrated (Fig-
ure 22). The top of these sediments in the core

Florida Geological Survey

Figure 21. Photograph of Miccosukee Formation section at railroad cut near Pinetta. Abandoned railroad
cut is 2 miles north of Pinetta, 200 feet past end of dirt road, west side of road. Note pen for scale.

Bulletin No. 61

occurs at 155 feet MSL. A maximum core thickness
of 78 feet was observed in a core (WMd-6558,
section 9d, Township 1N, Range 6E) located in
western Madison County. In general, the top of the
Miccosukee Formation coincides with surface
elevations in the area north of the Cody Scarp in
Madison County. Exceptions to this include core
WMd-15858, (section 35, Township 2N, Range 10E)
and water well WMd-13366 (section 25, Township
1S, Range 10E) in which 55 and 50 feet of Mic-
cosukee sediments respectively were encountered.
The top of the Miccosukee sediments in WMd-
15858 occurs at an elevation of 157 feet MSL sug-
gesting that this area is an erosional remnant.:
Figure 22 is an isopach of the Miccosukee show-
ing maximum thicknesses based on core data,
occurring in the west-central part of the county. A
thickening also occurs in an area southeast of the
town of Pinetta in the northeastern part of the coun-
ty.

Stratigraphic Relations

The Miccosukee Formation is underlain by the
Hawthorn Group.The contact between these units
may not always be readily discernible due to fre-
quent similarities in gross appearances; however,
the absence of phosphate grains can be used as a
guide in identifying the Miccosukee (Yon, 1966).
Chronostratigraphic control has thus far been insuf-
ficient in determining the conformable or unconfor-
mable relationship of these two units.
The overlying stratigraphic relationship is more
easily determined as undifferentiated sands and
clays overlie the Miccosukee Formation. In places,
these sands and clays have developed from
weathering of the underlying parent Miccosukee
Formation.

Geologic Outcrops

The Miccosukee Formation crops out primarily in
an area bounded on the south by 1-10 just east of
the city of Madison and bounded on the east by
State Road 145 and continues to the north into

Georgia and to the west into Gadsden County. A
maximum observed vertical thickness of 36 feet of
Miccosukee sediments are exposed in a borrow pit
southwest of the city of Madison in the northwest
corner of the intersection of 1-10 and State Road 14
(Figure 10). This represents one of the thickest
vertical exposures of the Miccosukee Formation in
Florida. A description of this outcrop is as follows:

Described by Ron Hoenstine and Steve Spencer
(1987).
Lmd section 6bb, Township 1S, Range 9E.

Thickness
Unt Description eet

A Miccosukee Formation.
Quartz sand, white to reddish-
orange, poor to moderately
indurated, clay-silt matrix, fine
grained (fine to medium range),
laminae of reddish-orange
oxidized sands alternating with white
sand laminae, all of which dip to the
north at approximately 30 degrees to
the vertical, frequent clay nodules
present............................ .............

B Quartz sand: Reddish-orange to
gray, poorly indurated, highly
oxidized, mottled, fine grained
(fine to medium range), clay
m atrix............................... ..............

C Quartz sand: Reddish-orange, poorly
indurated, fine grained (very fine
to fine range), silt-clay matrix,
homogeneous...................................

D Undifferentiated Sands and Clays.
Quartz sand, gray to brownish-tan,
unconsolidated, fine grained (fine
to medium range), organic present
in the form of rootlets........................

11.0

22.0

2.5

Florida Geological Survey

These were the only Miccosukee sediments,
other than cross-bedded laminae, observed to dip
in Madison County, This bedding, which dips north
at an angle of 30 degrees, may be attributed to karst
collapse.
Other significant exposures occur along U. S. 90
Just east of Greenville and along State Road 146 in
the northwestern part of the county. The area
around Cherry Lake, which has some of the highest
surface elevations in the county, has a number of
exposures including a six-foot exposure on the east
side of the intersection of State Road 253 and State
Road 53 (section 4aa, Township 2N, Range 9E,
Figure 9).

A description of the outcrop near Pinetta which
measures 12.5 feet is as follows:

Described by Ron Hoenstine and Steve Spencer
(1987). Lmd section 31ab, Township 3N, Range
10E: 2 miles north of Pinetta, 200 feet past end of
paved road on the west side in abandoned railroad
bed (Figure 10).

Thickness
Fent

Unit Descrition

A Miccosukee Formation.
Quartz sand, reddish-yellow to red,
poorly to moderately indurated,
medium grained (fine to coarse
range), sillt-ay matrix, iron
stained, mottled, root fragments....... 10.0

B Quartz sand: Light reddish-orange,
unconsolidated to poorly indurated,
fine grained (fine to medium range),
clay matrix, slightly mottled, root
fragments................,....,..... ......... 2.5

C Undifferntiated Sands and Clays.
Quartz sand, light gray to reddish brown
unconsolidated, fine grained (fine to
medium range), silt-clay matrix,
organic present in the form of
rootlets ....... __............................. 0

Quaternary System
Pleistocene and Holocene Deposits

Distribution

Surficial sediments deposited during the Pleis-
tocene Epoch form much of the land surface in the
south and southeastern parts of Madison County.
Less widespread Holocene sediments are confined
primarily to the present stream valleys. These sedi-
ments, which include soils developed on top of the
Miccosukee Formation, consist of clays, silts and
sands. These Pleistocene and Holocene deposits
are referred to in this report and cross sections as
Undifferentiated Sands and Clays (UDSC).

General Lithology

The Undifferentiated Sands and Clays occurring
in the Gulf Coastal Lowlands are predominantly fine
to medium quartz sands, silts and clays. In addi-
tion, significant accumulations of organic material
are present in the low-lying areas of southern
Madison County.
In contrast, the Holocene sediments present in
the river valleys represent reworked quartz sands
derived from older Pleistocene Series sediments as
well as the Pliocene Miccosukee Formation and the
Miocene Hawthorn Group.

Thickness

Figures 12, 13, 14, and 15 illustrate the variable
thickness of these sediments. Thicknesses range
from a thin veneer in northwest Madison County to
more than 70 feet in the southwestern part of the
county below the Cody Scarp (Figure 23).

Stratigraphic Relations

Sediments of Pleistocene and Holocene age
overlie the Miccosukee Formation over most of
Madison County. Exceptions occur in the area
south of the Cody Scarp where these deposits

Bulletin No. 61

LAFAYETTE COUNTY

Figure 22. Isopach map of the Miccosukee Formation.

-W- --.--- 1_021--
JEFFERSON COUNTY W-15537 W-10480
I W-15515 I -15728

W-15846

i W15986 W-15503
W) -15931 L
W-15931 1 1 \ LEE

-N-

COUNTY

EXPLANATION
S CORE HOLES
OUTCROP
40. ISOPACH CONTOURS
MICCOSUKEE FORMATION
SNOT PRESENT

CONTOUR INTERVAL IS 20 FEET

0;W-10654

-IC

SSCALE
0 5 ml

0 8 km

N

'ON COUNTY

EXPLANATION

CORE HOLES
O WELL CUTTINGS
40o ISOPACH CONTOURS

CONTOUR INTERVAL IS 10 FEET

SCALE
0 5 ml

0 8 km

LAFAYETTE COUNTY

Figure 23. Isopach map of the Undifferentiated Sands and Clays.

Florida Geological Survey

unconformably overlie the Hawthorn Group, and a
narrow band paralleling the river in extreme
southeastern Madison County where they uncon-
formably overlie the Ocala Group limestone.

GEOLOGIC HISTORY

Sediments observed underlying Madison County
range in age from Paleozoic to Recent. A major
unconformity, which separates the Paleozoic and
Mesozoic sediments, is present in WMd-1596 (sec-
tion 6, Township 1S, Range 10E) in Madison County
(Puri and Vernon, 1964). The Mesozoic sediments,
which measure approximately 2,800 feet in thick-
ness in WMd-15017, consist of diabase intrusions,
sandstones, marine shales, and chalky limestone
(Arthur, 1988). Although the environment of
deposition was predominantly nearshore marine
throughout the Mesozoic, red beds present in the
Lower Cretaceous in Madison County may be
products of a terrestrial environment.
From the end of the Cretaceous until the Early
Miocene, Madison County was an area of
predominantly marine carbonate deposition.
During this period of time the Paleocene Series
Cedar Keys Formation, the Eocene Series Oldsmar
Limestone, Avon Park Formation, Ocala Group, the
Oligocene Series Suwannee Limestone and the
Early Miocene Series St. Marks Formation were
deposited.
The depositional environment changed during
the Early Miocene resulting in deposition of the
siliciclastic and carbonate sediments of the Haw-
thorn Group. In much of the study area, this unit
overlies the Suwannee Limestone. This period of
sedimentation was followed by another change in
the depositional environment resulting in the
deposition of widespread sands, silts and clays
belonging to the Miccosukee Formation. Yon
(1966) has attributed these deposits to a delta com-
plex, which encompassed many square miles of
Madison, Jefferson, Leon and Gadsden Counties
and extended into southern Georgia directly north
of these counties. Huddlestun (1988) concluded
that the environment of deposition of the Mic-

cosukee Formation was coastal marine based on
occurrences of burrows and bioturbated sedi-
ments. The change in the depositional environ-
ment from shallow marine during Hawthorn time to
a prodeltaic and deltaic sedimentation associated
with the Miccosukee deposits appears to have been
gradational (Yon, 1966).
It was noted that the Hawthorn Group and
younger Miccosukee Formation had anomalously
thick deposits along the Jefferson-Madison County
boundary in west-central Madison County. This
thickening may be attributed to karst activity which
influenced subsequent sediment deposition during
the Miocene and Pliocene.
The next major change occurred during the
Pleistocene, when seas covered much of Madison
County forming terraces and other associated fea-
tures of the Gulf Coastal Lowlands. During this
time, erosion may have removed additional St.
Marks sediments in the southern part of the county
leaving the majority of St. Marks sediments in the
northeastern and east-central parts of the county.
It was during this time that the present drainage
system of rivers and associated tributaries probably
developed.
Sea level has fluctuated generally below present
mean sea level during the last several thousand
years of the Holocene Epoch (Stapor and Tanner,
1977). Sediment deposition in Madison County
during this period of time has been restricted to
alluvium along the streams and organic deposits in
the low areas.

STRUCTURE

The structure maps and the following interpretive
discussion are based on cores within Madison
County. Additional core and water well data in the
areas contiguous to southern, western and eastern
Madison Countywere also utilized. In addition, Yon
(1966) is used in interpreting the structure on the
western side of the county. An exception occurs in
discussing the Ocala Group as only well cuttings
were available for these sediments.
Only the oil test wells and one water well (WMd-

Bulletin No. 61

M --

0 30 60 mi

0 20 40 60 80100 km

Aa -'

Figure 24. Location of the Ocala Platform (modified from Puri and Vernon, 1964).

Florida Geological Survey

2549) encountered sediments older than the
Eocene Series Ocala Group (Table 2). The oldest
sediments penetrated by stratigraphic cores
belong to the Ocala Group. Structure contour
maps were drawn utilizing data derived from cores
and water well cuttings listed in Table 2.
A structure contour map drawn on top of the
Ocala is shown in Figure 16. This structure map
shows highest elevations occurring in the
southeastern corner of the county with the general
attitude of the sediments dipping to the north-
northwest. The higher elevations in the
southeastern part of the county occur on the
northwest flank of the Ocala Uplift (Vernon, 1951),
"blister dome" (Winston, 1978) or Ocala platform
(Scott, 1988) as it is commonly referred to today
(Figure 24). Although surface outcrops occur in
extreme southeast Madison County along the
Suwannee River, the maximum elevation of Ocala
sediments encountered in wells is 50.5 feet MSL
(WMd-15981, section 9, Township 1 S, Range 11E).

Structure contours drawn on top of the Suwan-
nee Limestone are shown in Figure 17. This map
shows the top of the Suwannee Limestone having
three definitive highs and two less prominent low
areas. The highs occur in the northwestern,
western and south-central parts of the county. The
low areas may represent karst features. One of
these is located on the western side of the county
and extends into Jefferson County. Another nega-
tive area occurs in the northeastern part of the
county near the Madison County landfill.
The top of the Suwannee has a very irregular
surface. This undulatory surface is karstic and may
be attributed to dissolution of the carbonate sedi-
ments.

Structure contours drawn on top of the Haw-
thorn Group are shown in Figure 19. In general,
highest elevations occur in the extreme northern
part of the county and in an area just south of the
city of Madison. Typically, lower elevations are
present in the western part of the county. The
Hawthorn is missing in southeastern and extreme
southwestern Madison County. The Hawthorn oc-

curs at a maximum observed elevation of 156 feet
MSL in core WMd-15537 (section 5ba, Township
2N, Range 9E) in the northern part of the county just
west of Cherry Lake. An observed minimum eleva-
tion of 33 feet MSL occurs in western Madison
County in core WMd-6558 (section 9d, Township
1 N, Range 6E). The Hawthorn Group has a general
south-southeast dip.
Figure 19 shows a high in northern Madison
County and a less prominent high located in an area
just south of the city of Madison. A distinct linear
depression is present near the western boundary of
Madison County. This depression and the ir-
regularity of the Hawthorn top may be attributed to
a number of factors, including sediment deposition
over limestone with post-depositional karstic
development.

The Miccosukee Formation either crops out or
is within a few feet of the surface over the majority
of its area of occurrence. Therefore, a structure
contour map drawn on top of this formation would
closely parallel a topographic map.

ECONOMIC GEOLOGY

INTRODUCTION

The following discussion provides information
on the general occurrence of economic minerals in
Madison County, types of tests performed and
analyses of samples collected. The information
presented is not intended to be an exhaustive inves-
tigation leading to immediate mineral resource
development. However, where data are favorable
may indicate that certain areas might warrant fur-
ther investigation. The Mineral Resources Map
(Figure 25) is designed to present an overview of
the major mineral commodities present in an area.
Factors such as thickness of overburden, quality
and volume of the deposit could affect the mining
of the mineral commodity at any specific site. The
resources discussed are sand, clay, peat, phos-
phate, limestone and petroleum.

_i_ .^MINERAL RESOURCES OF +
SMADISON COUNTY
0 00 8 km
r--- o "- m0
5O 0 Z

___ocou_ u _\ y IFLORIDA

Figure 25. Mineral resources map (reproduced from Florida Geological Survey Map Series 121,1988).

T + ..E + F, + +, + .E + +

Figure 25. Mineral resources map (reproduced from Florida Geological Survey Map Series 121, 1988).

Florida Geological Survey

Sand

Much of Florida is covered by quartz sand or
clayey sands which, through time, have been
reworked and shifted by fluctuating sea levels and
fluvial systems. Sea level stands formed terraces
and associated features such as dunes and sand
bars. Streams eroded sediments from higher
elevations and deposited in low areas.

In the Northern Highlands, the clayey sands of
the Miccosukee Formation cover extensive areas of
Madison County. The sediments from the Mic-
cosukee Formation in Madison County consist of
clayey to very clayey, silty, iron stained, reddish-
orange to yellowish-orange, poor to moderately
indurated, fine to coarse grained quartz sand, with
mottling and fine laminae occurring throughout.
Sediments of the Gulf Coastal Lowlands are fine
grained, clayey, and contain organic material. The
River Valley Lowland sediments consist primarily of
alluvial sand and abundant organic material.

Currently the sands and clayey sands of the
Miccosukee Formation are being used by the
Madison County Road Department. The road
department maintains two borrow pits (Figure 25),
one in the Cherry Lake region (section 31 bb,
Township 2N, Range 9E), the other just southwest
of the city of Madison (section 2ca, Township 1S,
Range 8E). Approximately 2,000 cubic yards of
clayey sand are obtained from these pits annually
(Madison County Road Department personal
communication, 1986). Transportation of material
from these pits is entirely by truck. Presently, no
commercial sands are mined in Madison County.
In Madison County, these clayey sands are used
for stabilization along roadways, as a base material
for athletic fields such as tennis and basketball
courts and as a filler for baseball infields. Currently,
this material is of small economic value and the
potential for commercial mining activity is minimal
for the foreseeable future. Table 3 gives sand
analyses for selected locations in Madison County.
Analyses suggest that these sands may be suitable
for concrete.

Clay

To date, in Madison County, there have been no
commercial clay mining operations. However, the
county road department extracts very clayey sand
from its borrow pits for use in stabilizing roadway
and athletic fields (Figure 25). This material has
minimal commercial value.
Clays in Madison County occur primarily in two
units, the Miccosukee Formation and the Hawthorn
Group. The clays in the Miccosukee Formation are
extremely variable, occurring as thin stringers or
lenses with little lateral continuity. This type of
occurrence precludes their use as a mineable com-
modity. In contrast, the Hawthorn clays are thicker,
but their sporadic occurrences place serious limita-
tions on their commercial utilization.

Peat

Conditions for accumulation of potentially mine-
able organic deposits (peat) exist in regions of
Madison County (Figure 25). Peat, a product of
partial decomposition of organic materials such as
sedges, mosses, and other plants, forms when the
rate of accumulation exceeds decomposition
(Bond et al., 1986). The process of peat formation
requires wetland areas of low topographic relief and
reducing environments. The highest potential for
mining deposits occurs in southern Madison Coun-
ty in areas such as the San Pedro Bay where
swamps and forests dominate (Davis, 1946). Other
areas where conditions for accumulations of peat
are favorable occur along the Aucilla River Valley
Lowlands. Analyses conducted by the United
States Geological Survey and University of Florida
on samples taken five miles east of the town of
Greenville and samples obtained from peat ac-
cumulations in southwestern Madison County (sec-
tion 35cc, Township 1S, Range 5E) are presented
in Table 4.
Two companies have mined peat in Madison
County, Anderson Organics, Inc. (section 35cc,
Township 1 S, Range 5E) off State Road 27 and the
Pasco Products Company located west of Green-
ville (section 24bb, Township 1N, Range 6E) off

Bulletin No. 61

Table 3. Screen Analysis of Sand in Madison County, Florida.

Laboratory Test Data
Deposits Screen Analysis
Sieve No. and Cummulative Weight Precent Retained

Method of Fineness
Sample No. Location Sampling 4 8 16 30 50 100 Modulus*

Section 8ba
Md-1 T2N, R8E Channel --- --- 0.058 4.694 33.078 99.999 1.39

Section 4aa
Md-2 T2N, R9E Spot ---- --- 0.313 4.948 31.039 100.000 1.36

Section 31ab
Md-3a T3N, R10E Channel ---- 0.068 1.514 24.277 86.134 99.999 2.12

Section 31ab
Md-3b T3N, R10E Channel ---- 0.252 4.123 29.745 82.784 100.000 2.17

Section 6bb
Md-4a T1S, R9E Channel --- --- 0.018 0.774 30.125 100.000 1.31

Section 6bb
Md-4b T1S, R9E Channel ---- ---- 0.307 4.579 27.380 100.000 1.32

*Fineness Modulus: a means of evaluating sand and gravel deposits which consist of sieving
samples through a standardized set of sieves, adding the cumulative weight percentages of the
individual screens, dividing by 100, and comparing the resultant fineness modulus number to
various specification requirements (Bates and Jackson, 1980).

The fineness modulus is an index to the fineness or coarseness of an aggregate, but gives no
indication of the grading. The higher the fineness modulus the coarser the aggregate (American
Society for Testing and Materials, 1987).

The method of sieve analysis presented here follows that outlined in ASTM, 1987, v. 402, section
C136-84a. The reader is also referred to the Florida DOT Manual of Florida sampling and testing
methods for aggregates, FDOT, designation FM 1-T 027.

Florida Geological Survey

Table 4. Selected Peat Analyses.

Moisture % loss
Airdrying Overdrying

Moisture Free Analysis (%)
Ash Volatiles C N S

20, 1N, 8E*

Location
(Sec, T,R)

63.9

Soluble Salts

63.7 32.5 -- 2.9 10,048

Ca Mg P NO3

35cc,1S,5E** 4.6

3 2 0.2 39

* (after Harper, 1910)
** (Anderson Organics, personal communication, 1986)

Table 5. Selected Well Data Showing Granular
(Visual Estimates)

Well No.

2424
2987
3679
7226
7234
7876
13213
13364
13424
13946
15515c*
15537c*

Location
(Sec, T, R)

Surface
Elevation
(feet MSL)

28aa,
27,
25d,
17dd,
19ad,
17,
12aa,
1,
35ad,
12ad,
5ca,
5ba,

Phosphate.

Depth of
Sample
(feet)

Phosphate
(highest est.
percent)

70-80
30-40
40-45
38-41
41-45
60-70
60-80
60-70
70-80
50-60
46-54
34-79

* c indicates core

Location
(Sec, T,R)

Bulletin No. 61

State Road 90 (Figure 25). Although no longer in
operation, Anderson Organics maintained a 35 acre
site and mined to an average depth of eight feet. A
high fiber peat was extracted, shredded and stock-
piled for shipping. In 1985, approximately 70,000
cubic yards of material were mined and shipped by
Anderson Organics in bulk by truck to processing
plants in Adell and Cressant, Texas (Anderson Or-
ganics personal communication, 1986). Another
company, Pasco Products currently maintains a 10
acre site. At this site, peat is mined and top soil is
extracted as a commercial by-product. Pasco
Products processes and markets its product on
site.
The future potential for continued commercial
mineable peat deposits is considered good. In
addition, the marketability and transport of this
commodity is further enhanced by the county's
existing road system.

Phosphate

In 1986, Florida produced almost 80 percent of
the total United States phosphate and nearly 25
percent of the world phosphate production (Florida
Phosphate Council, 1987). In recent years, ap-
proximately 90 percent of the mined phosphate has
been used in the production of agricultural fertilizer
(Florida Phosphate Council, 1987).
Table 5 shows those cores and cuttings where
granular phosphate was observed. These data in-
dicate that the phosphate, although sporadic, is
more abundant in northern Madison County. Col-
loidal phosphate, which is embedded in the clay
matrix of the Hawthorn sediments, tends to be of a
limited nature and varies from one area to another.
The analyses shown in Table 5 indicates that the
future potential of economically mineable phos-
phorites are low.

Limestone

Limestone is a term applied to a sedimentary
rock comprised of predominantly calcium car-
bonate (CaCO3). Impurities such as clay, sand,

iron oxide, magnesium carbonate and others may
be found in limestone. Commerical quality lime-
stone used in the manufacture of lime must attain a
purity greater than 97 percent total calcium car-
bonates, whereas road base material requires 70
percent or greater total carbonates (Schmidt et al.,
1979).
Limestone sediments mined in Florida range In
age from Middle Eocene to Pleistocene. There are
no limestone quarry operations in Madison County.
Although the road department obtains limestone
from outside the county on an "as needed" basis,
the potential does exist for economic deposits of
this commodity in a band along the eastem side of
the county (Figure 25). The potential in this region
is enhanced by a thin overburden of sands and
clays that range in thickness from a few feet to
tens-of-feet. Limestone suitable as an economic
commodity from this part of Madison County would
include the Suwannee Limestone and the Ocala
Group.

Petroleum

A total of five oil test wells have been drilled in
Madison County (Table 2). The maximum depth
penetrated occurred in test well WMd-15017 (sec-
tion 22, Township 2S, Range 9E) which terminated
in quartz sand at a depth of 10,149 feet. This well
was plugged and abandoned as a dry hole. None
of the test wells encountered any oil. Present data
suggests that the potential for oil in Madison County
is minimal.

LANDFILL SITE
Waste Disposal

The potential contamination of Madison
County's domestic water supply is a topic of con-
tinuing concern. In this county, a vast array of
chemicals are used by a large agricultural com-
munity. These chemicals are present in the form of
pesticides, herbicides and fertilizers for row crops
and livestock operations. Added to this are chemi-
cal wastes generated by local industry as well as
common household wastes including cleaning

Florida Geological Survey

agents, paint thinner and medicines. Although
precautions in the form of warnings as to waste
disposition and inspections of waste are taken,
some of these contaminants inevitably end up at the
landfill site.
Disposal of these wastes currently takes place
at the Madison County landfill site located off Coun-
ty Road 591 (Figure 11). Currently, wastes totaling
more than 40 tons per day are being dumped at this
disposal site, which occupies an area in excess of
80 acres. It has been in continual operation since
1970 as the county's sole waste disposal site. Here,
a variety of waste products are dumped into unlined
cell excavations, which average 50 feet in length, 30
feet in width and 16 to 20 feet in depth. When filled
to capacity, these cells are capped with soil.
Background data originally available for the
evaluation of the Madison County site consisted of
a number of shallow soil probe samples measuring
80 inches in length taken by the United States Soil
Conservation Service (SCS). Descriptions of these
soils were incorporated into a soil map by the SCS.
The soil map and accompanying descriptions
formed the bulk of information utilized in the evalua-
tion of this local county owned parcel for a waste
disposal site.
Recently, wells to the southeast of this landfill
showed signs of contamination. Subsequently,
several holes were drilled on the landfill site to
depths ranging from 50 to 90 feet in order to deter-
mine the geology of the underlying sediments and
structure. In addition, a core (WMd-15991) was
drilled to a depth of 125 feet below land surface
along County Road 591 just west of the landfill
(Figure 11). Data from this preliminary investigation
suggests that this site is located over an old
sinkhole (Hoenstine et al., 1987). As cross section
E-E' (Figure 26) shows, porous and permeable
Hawthorn sands, silty sands and discontinuous
clay beds directly overlie the Suwannee Limestone
which forms the top of the Floridan aquifer system
at this site. There appears to be no intervening
confining layer at well M-2 and contaminants from
a variety of waste products have potential access
to the underlying aquifer.
In this situation, a geologic site investigation

conducted prior to site selection would have, in all
probability, pointed out the potential geologic
hazards associated with this site. Such a study
would have either located a more suitable site or
determined the need for plastic liners.
Landfills represent the most popular method of
disposal as they can accommodate a variety of
wastes at relatively low operating costs. However,
this method of disposal has inherent risks including
the potential contamination of the underlying
Floridan aquifer system by the downward percola-
tion of contaminants. For this reason, a suitable
natural site should have an impermeable clay un-
derlying the area to prevent ground-water con-
tamination.
The county is seeking a new landfill site since the
old one is near capacity. A number of potential sites
have been investigated, however, to date no loca-
tion has been found to have a satisfactory underly-
ing continuous impermeable clay layer. This clay,
if present, would probably be part of the Hawthorn
Group and, except for the San Pedro Bay area, the
Hawthorn clays are, in general, sporadic in occur-
rence throughout Madison County. It appears like-
ly that a new landfill site will have to utilize plastic
liners, plus other leachate treatment technology.

HYDROGEOLOGY

Three distinct aquifer systems have been iden-
tified in Madison County through core analysis and
well construction. The three aquifers present are
the Floridan aquifer system, an intermediate aquifer
system and a surficial (perched water table) aquifer
system. Table 6 correlates the geologic formations
with the various aquifer systems. The three aquifer
systems can be differentiated by water chemistry,
stratigraphic position, lithology and hydraulic
heads.
The Floridan aquifer system, which exists under
confined, semi-confined and unconfined condi-
tions, is the major source of ground water in
Madison County. Figure 27 represents the general
hydrogeologic conditions of the Floridan aquifer
system in the study area.

Bulletin No. 61

E

E
M-6

-40

SANDO^i M
.AND
LIMESTONETOE

-...o.
-------- -.:::::::: .
-C LAY-I-Hi
-20 -\j::
SAND:

r0 IM-6
- 10 ,. L-OE
2M-2

"/ N'
.'t I^

L........ I

M-8

SANU -
NAlI "IP -

IVVI In
M-8 PHOSPHA

tCROSS-SECTION

TE

CLAY-
ND .:
'ERBURDEN

-1 SA-3

jJ iiii HHAW TJ_ ORN R :-::-::- "
RO P
---- ----
S A N D- - --: :-:-:: : : : :A
CI~LAY-

150
METERS

Figure 26. Geologic cross section E-E' (Landfill site) (modified from Kirkner and Associates, 1986;
Hoenstine et al., 1987).

GEORGIA

JEFFERSON COUNTY

M 11Usn ,
} 1_.lF h ll I---
\

TAYLOR COUNTY

SCALE
0 5 ml

HAMILTON COUNTY

O
0

EXPLANATION
FLORIDAN AQUIFER UNCONFINED
FLORIDAN AQUIFER SEMI-CONFINED
FLORIDAN AQUIFER CONFINED

Figure 27. General Hydrogeologic conditions of the Floridan aquifer system in Madison County (after
SRWMD).

51

+140

+120-

+100-

+80

+60

+40

Z +20-

I-
U -20-
UJ -
_j
W -40-

SE- U'

SANY
WITH ~~~
C L A Y iii
.. .. .. .. .. .. .
iiiiiiL E N S E S:: i i
rr::iiij~i-~II ...............-~

'i':::::::--

SA
^,,

I

Florida Geological Survey

Geologic Eastern Panhandle FLORIDA
System Series Time Geologic Formation Hydrostratigraphic

(M.Y.) Unit

Pleistocene 1.8

Undifferentiated
terrace marine and
fluvial deposits
(Undifferentiated Sands
and Clays this report)

Miccosukee Formation

Miocene 22.5
Hawthorn Group
Undifferentiated

St. Marks Formation

Oligocene 37.5
Suwannee Limestone

Eocene 54.0 Ocala Group
Avon Park Formation
Oldsmar Limestone

I ,II

141.0

Cedar Keys Limestone

Undifferentiated

Surficial aquifer system

,s

intermediate aquifer system
or intermediate confining
unit,--

Floridan aquifer system

sub-Floridan
confining unit .

j^s

II [---------- -

Holocene

Pliocene

t + .".--------------------

Quaternary

Tertiary

Cretaceous
and Older

Paleocene

65.0

Bulletin No. 61

Table 7 was derived from data obtained through
the Suwannee River Water Management District
(SRWMD) Permitting Program. Within the study
area, the town of Greenville and the city of Madison
have municipal public supply well systems. There
are an additional 60 private community and non-
community public supply well systems in Madison
County (SRWMD data). Withdrawals for irrigation
use are seasonally distributed, but for the purpose
of permitting, are calculated as average daily
withdrawals for an entire year. Most irrigation ac-
tually takes place during the spring and early sum-
mer months. A maximum volume of 102.3 million
gallons per day (mgd) is the value obtained when
estimating peak irrigation requirements during
these periods. Presently, industrial use is minimal.
Other uses (Table 7) include withdrawals for aes-
thetic, nursery, recreational and power production
purposes.
The only known wells completed into the inter-
mediate aquifer system are ground-water quality
monitoring wells constructed by the Suwannee
River Water Management District as part of the
district-wide Water Quality Assurance Network.
Other private or public withdrawals from the inter-
mediate aquifer system have not been identified.
Few wells are completed into the surficial aquifer
system. Private wells tapping the surficial aquifer
system are primarily used for livestock and low

demand domestic purposes. However, numerous
surface water diversions for agricultural uses are
made from the ubiquitous private ponds which are
hydraulically connected to the surficial aquifer sys-
tem.

SURFICIAL AQUIFER SYSTEM

An unconfined, surficial aquifer system covers a
large portion of Madison County. In the Tallahas-
see Hills, the surficial aquifer system consists of
Pliocene and younger siliciclastic sediments.
These surficial sediments are underlain by low per-
meability units of the Hawthorn Group. South of the
Cody Scarp, in the San Pedro Bay, the surficial
aquifer system consists of Pleistocene Series sands
and clayey sands overlying Hawthorn Group clays
of varying thickness.
The San Pedro Bay surficial aquifer system and
related aquiclude are laterally continuous and ex-
tend from Madison County southward into Taylor
and Lafayette Counties. In the study area, the
sands of the surficial aquifer system generally range
in thickness from 10 to 40 feet (Figure 23). The
thickness of the basal clay, which acts as a semi-
confining aquiclude, generally ranges from 10 to 30
feet (Copeland, in preparation). Auger samples
obtained throughout the San Pedro Bay indicate

Table 7. Permitted Ground-water Withdrawals in Madison County, Florida
(SRWMD Data, 1986)

Water Use in Million
Type of Use Gallons/Day (mgd) Water Consumed (mgd)

Public Supply 1.23 1.05
Industrial 0.15 0.14
Private Domestic 0.024 0.021
Agricultural Livestock 0.37 0.33
Agricultural Irrigation 13.81 13.68
Other 0.65 0.65
Total 16.23 15.87

Florida Geological Survey

that, in numerous locations, dissolution of the un-
derlying limestone has occurred, resulting in
anomalous thicknesses of the surficial sands and/or
basal clays.
The topography of the Tallahassee Hills has
been shaped by weathering and karst activity. It is
characterized by high hills surrounding closed
basins. The closed basins are the result of sub-
sidence due to the dissolution of the underlying
limestone and the subsequent collapse of overlying
sediments. In and around the basins, the St. Marks
Formation, Hawthorn Group, Miccosukee Forma-
tion and marine terrace deposits have thinned, or
have been breached (Price, 1984). Natural
drainage is into these closed basins resulting in the
formation of numerous isolated surface water
bodies. Generally, the surficial sands underlying
these basins vary from 5 to 20 feet in thickness
(drillers logs, SRWMD). The surficial aquifer system
occurs within these sands. It is supported by low
permeability beds of the underlying formations
which act as an aquitard.
At the higher elevations of the surrounding hills
all of the geologic units are generally intact. Fre-
quently, the surficial sands at these elevations are
unsaturated. Rainfall percolates downward
through these sands until reaching the relatively
impermeable underlying sediments. Ground water
within the sands then flows laterally into the closed
basins where it recharges the surficial aquifer sys-
tem and its hydraulically connected lakes, ponds
and swamps.
Water levels within the surficial aquifer system of
both regions (Tallahassee Hills and San Pedro Bay)
are at or within a few feet of land surface. The water
table is a subdued replica of the topography and
coincides with the water levels of local lakes, ponds
and swamps. Water level fluctuations and recharge
to the surficial aquifer system are directly depend-
ent on rainfall, runoff and evapotranspiration. Mean
annual rainfall for the study area is 52 inches per
year, while water lost to evapotranspiration is ap-
proximately 42 inches per year (Fisk, 1977). To
date, an accurate measure of water level fluctua-
tions within the surficial aquifer system and sub-
sequent correlation with rainfall records has not

been possible. This is primarily due to the lack of
existing wells completed into the surficial aquifer
system.
Discharge from the surficial aquifer system has
both downward and lateral components. The
downward movement of water is an important
source of recharge to the underlying Floridan
aquifer system. The surficial aquifer system also
discharges laterally into the topographically lower
areas of the River Valley Lowlands.
Ground water in the surficial aquifer system
typically shows high sodium, chloride, potassium,
and nitrate values (unpublished SRWMD data,
1987). This suggests the possibility that these high
values may be derived from marine aerosols (salts
in ocean derived precipitation) indicating that
ground water in the surficial aquifer system is es-
sentially rainwater (Ceryak et al., 1983). High nitrate
values are typically the result of human agricultural
and domestic activities.

INTERMEDIATE AQUIFER SYSTEM

An intermediate aquifer system exists in Madison
County within the Tallahassee Hills. This aquifer
system is extremely variable and discontinuous
both laterally and vertically. It has been identified
in the clayey sands of the Miccosukee Formation
and the sands and carbonates of the Hawthorn
Group. Locally, clays within the Miccosukee For-
mation or the Hawthorn Group act as confining
units.
The intermediate aquifer system, which is ar-
tesian, is recharged from the overlying surficial
aquifer system where the confining beds are dis-
continuous or leaky. Discharge from the inter-
mediate aquifer system is vertically downward, into
the Floridan aquifer system. Again, this occurs
where the confining beds separating the two
aquifers are breached or are relatively permeable.
The quality of water in the intermediate aquifer
system is diminished relative to the underlying
Floridan aquifer due to the presence of higher con-
centrations of dissolved minerals. Potentially a
source of potable supply, wells completed into this

R5E I R6E I R7E R8E I R9E I RIOE I RIIE

GEORGIA
I E I A

-j 7
PINETTA

(J
T2N 0

( \
TIN G REE VE 0MS

T1S

03 /

T2S -------- 1 "

SCALE
S- i"
8km
N Rn,

T3N

-N-

EXPLANATION

PERIODIC MONITORING SITE
CONTINUOUS MONITORING SITE

/c

Figure 28. Floridan aquifer system potentiometric network (1950-1989) (data from SRWMD).

I

ac*c

oce I ore o~e ovle olle

R5E SE R7 SN N SO

T3N f T3N

\ \ \\*
IPINETTA 0

OITIN GREENVILLE TN

M 0

CONTINUOUS MONITORING SITE
T2S --._ __ -4 CONTOUR LINE T2S
POTENTIOMETRIC 8L1FACE IN
SE 80 FEET ABOVE MEAN SEA LEVEL
O (CONTOUR INTERVAL 5 FEET)
TAYLOR COUNTY,75

6-)
LAFAYETTE COUNTY
ICALK
0 ml
I km
R5E I R6E I R E RE I I RIE I IRIlE

Figure 29. Potentiometric surface of the Floridan aquifer system November 1981 low water period (data
from SRWMD).

R5E I R6E I R7E

RBE

R9E I RIOE

RIIE I

R5E I R6E I R7E I R8E I R9E I RIOE I RIE I I
00
S\ \ GEORGIA
1 o T3N
T-N --

PINETTA 0

T2N -

TI I 1 L MADISON TIN
TIN INV ILLE

TIS

-m EXPLANATION
O PERIODIC MONITORING SITE
SN CONTINUOUS MONITORING SITE
-8' so CONTOUR LINE TZS
T2S ------- ---------- --- -- POTENTIOMETRIC SURFACE IN
.FEET ABOVE MEAN SEA LEVEL
TAYLOR COUNTY (CONTOUR INTERVAL 5 FEET)
TAYLOR COUNTY /I
~~. ~' ~ ~ ~^- - ? -

LAFAYETTE COUNTY
SCALE

0-------i
0km
R5E I R6E I R7E RBE I R9E I RIOE I RIIE

Figure 30. Potentiometric surface of the Floridan aquifer system April 1984 high water period (data

from SRWMD).

R5E I R6E R7E I RE I R9E I RIOE I RIE I

4 GEORGIA

fTTA

ON 5 TIN
TIN ENVILLE

o6 \-
CD

0 \TIS
TIS CO

\ EXPLANATION
S PERIODIC MONITORING SITE
U CONTINUOUS MONITORING SITE
T2S --- -----.-- - ---- -0lo CONTOUR LINE T2S
T -- \ I \ \NET CHANGE IN THE
POTENTIOMETRIC SURFACE
TAYLOR COUNTY (CONTOUR INTERVAL 2 FEET)
L.-- _-- ^-- -- -- - -

LAFAYETTE COUNTY
WCALK
1--------1
R5E I R6E I R7E I RE R9E I RIOE I RIIE I

Figure 31. Net fluctuation in the potentiometric surface of the Floridan aquifer system, 1950-1989 (data
from SRWMD).

Bulletin No. 61

aquifer system have historically been difficult to
developfor production duetothe abundance of fine
sediments.

FLORIDAN AQUIFER SYSTEM

The Floridan aquifer system is the principle
ground-water source for much of the State of
Florida. This carbonate aquifer, which underlies all
of Florida, is referred to as the "Floridan aquifer
system" in Alabama, Florida, Georgia and South
Carolina (Miller, 1986). The stratigraphic units com-
prising the potable water-bearing portion of the
Floridan aquifer system are, from oldest to
youngest: the Avon Park Formation and Ocala
Group (Eocene), the Suwannee Limestone
(Oligocene), and the St. Marks Formation
(Miocene).
In the study area, the top of the Floridan aquifer
system corresponds to the top of either the Suwan-
nee Limestone (Figure 17) or to the top of the St.
Marks Formation where present. However, in
southeastern Madison County, where both the St.
Marks Formation and the Suwannee Limestone are
missing, the Ocala Group forms the top of the
Floridan aquifer system. The base of potable water,
which occurs within the Avon Park Formation in this
area, is estimated to be present at approximately
1,250 feet below land surface based on a chloride
concentration of less than 500 milligrams per liter
(Klein, 1975).
In the Tallahassee Hills, the Floridan aquifer
system is confined under artesian pressure by the
relatively impermeable beds of the Hawthorn
Group. Under these conditions, the surface of the
water table is no longer free to rise. However, the
water level in wells penetrating the aquifer will rise
above the top of the saturated carbonates. The
level to which water will rise in cased wells is defined
as the potentiometric surface of the aquifer.
In San Pedro Bay, the Floridan aquifer system is
semi-confined by overlying clays of low per-
meability (unpublished SRWMD data, 1986). The
hydraulic gradient between the potentiometric sur-
faces of the Floridan aquifer system and the San

Pedro Bay surficial aquifer system is generally less
than five feet.
In the River Valley Lowlands, the Floridan aquifer
system is unconfined. The top of the limestone
crops out or is overlain by a veneer of permeable
sands. The saturated zone of the aquifer is at
atmospheric pressure and water levels can fluc-
tuate from below the top of the limestone up into
the overlying sands.
A potentiometric network was established by
SRWMD for the study area to monitor short and
long term ground-water trends. The network con-
sists of 23 wells completed into the Floridan aquifer
system (Figure 28). Figures 29 and 30 show the
potentiometric surface of the Floridan aquifer sys-
tem in Madison County during the periods of
November 1981 and April 1984, representing con-
ditions when water levels were generally at their
highest and lowest, respectively. Continued
monitoring of the well network has shown that the
configuration of the potentiometric surface remains
relatively constant.
Figure 31 shows net fluctuation in the poten-
tiometric surface based on the maximum and min-
imum ground-water levels recorded in the Floridan
aquifer system at each well location. Total fluctua-
tions within the aquifer range from 10 feet to 26 feet.
The greatest range of fluctuation occurs along the
Withlacoochee River Valley Lowlands. In this
region, ground-water levels quickly respond to rain-
fall, which readily percolates downward and rechar-
ges the Floridan aquifer system. In addition, large
quantities of rainfall can cause river stages in the
Withlacoochee River to rise rapidly. An increase in
a river's water stage to a level that is higher than the
potentiometric surface of the unconfined aquifer
will be quickly followed by an increase in the poten-
tiometric surface immediately adjacent to the river,
which recharges the aquifer (Copeland, in prepara-
tion).
Where the Floridan aquifer system is confined
or semi-confined, ground-water level fluctuations
occur at a slower rate and to a lesser extent.
Downward percolation of precipitation is retarded.
Therefore, while ground-water levels in the uncon-
fined Floridan aquifer system may be declining in

GEORGIA

S o o o o OoOO 0 00 o -
0 0 0 000 0

S" " EXPLANATION_ N
1 TAYLOR COU. 0L Uo TO 1 5
0TO R 0 0 00 0 0 00 0 0 0 0 0 0 0o.
S00, 000 COUNTY
I0 0 0 0' 0 00

0 8 km
ment District (Fisk, 1984b). 0 0
00. 000 00.....0..
E VILE ', M D '0 oG)
0000 Eo 00- o G HAMILTON COUNTY

0ooo:,KK 000 EXPLANATION 0_

I (Inches per year)
7 0 0 : f 0..0 o0 . . 7 A
0::* o O _o :0ooo0 15 TO 20 D
% ~ ,,10 TO 10

TAYLOR COUNTY lo5 TO 10

SCALE UP TO a
SCALE m. LAFAYETTE

0 8 km COUNTY

Figure 32. Distribution of recharge to the Floridan aquifer system in the Suwannee River Water Manage-
ment District (Fisk, 1984b).

Bulletin No. 61

direct response to lower rainfall conditions, ground-
water levels in the adjacent confined Floridan
aquifer system may be stable or even increasing
due to the retarded release of continued storage
and subsequent downward recharge from the sur-
ficial aquifer system.
Recharge to the Floridan aquifer system is
generalized in Figure 32. In the study area, the
highest rate of recharge, 15 to 20 inches per year,
occurs in the River Valley Lowlands, reflecting the
direct interaction between ground water and rain-
fall. Recharge to the Floridan aquifer system in the
Tallahassee Hills and the San Pedro Bay occurs at
a lower rate than in the adjacent area where the
Floridan aquifer system is unconfined. In these
areas, recharge is estimated to be 10 to 15 inches
per year.
The configuration of the potentiometric surface
of the Floridan aquifer system in Madison County

/- VALD

90

-- GEORGIA "
FLORIDA
-J

JEFFERSON MA
s / MADISON

I

R- -- r1

shown in Figures 29 and 30 (SRWMD data, 1986)
correlates favorably with the regional mapping of
the potentiometric surface of the Floridan aquifer
system in south-central Georgia and north-central
Florida (Figure 33, SRWMD data, 1986). A poten-
tiometric high in the Valdosta area is principally
located within the boundaries of the Withlacoochee
River Basin. This potentiometric high is created by
a high rate of recharge that primarily occurs as flow
from the Withlacoochee River and other streams
that enter the Floridan aquifer system via sinkholes
and solution cavities (Ceryak et al., 1983). This
potentiometric high acts as a pressure head that
moves ground water southward across the state
line into Madison County. Ground water within the
Floridan aquifer system flows from this poten-
tiometric high toward the River Valley Lowlands and
Northern Highlands of Madison County.
Most potable supply wells in Madison County are

N

0 g
.--50

MILTON EXPLANATION
0o -70 CONTOUR LINE -
SPOTENTIOMETRIC SURFACE IN FEET
ABOVE MEAN SEA LEVEL
CONTOUR INTERVAL 10 FEET

SCALE
0 5 ml
ANNEE 0 8 km

LAFAYETTE
LAFAYETTE

Figure 33. Potentiometric surface of the principal artesian Floridan aquifer system in south-central Geor-
gia and north-central Florida (data from SRWMD).

Florida Geological Survey

completed into the upper 100 feet of the Floridan
aquifer system. Ground water from this upper zone
is generally of good quality and is within the limits
recommended by the United States Environmental
Protection Agency for drinking water standards. In
Madison County, the major dissolved constituents
are calcium and bicarbonate, which are typically
characterized by high values for specific conduc-
tance, calcium, alkalinity, magnesium, pH and sul-
fate. These high values are due to the dissolution
of limestone by ground water. The concentrations
up to the point of saturation for the above
parameters, increase proportionally with the length
of time that ground water is in contact with sedi-
ments or rocks. Comparatively, artesian water from
the Foridan aquifer system displays higher con-
centrations than the non-artesian Foridan aquifer
system. The exception is calcium. Higher values
of calcium in non-artesian ground waters are re-
lated to more rapid percolation downward of acidic
rainwaters, contributing to more rapid dissolution
of the limestone (Ceryak et al., 1983). A higher
nitrate value relates to the downward leaching of
man-induced nitrates through the permeable sedi-
ments overlying the unconfined aquifer.
Excessive iron, tannic acid, and unpleasant taste
and odor caused by various iron-and sulfur-reduc-
ing bacteria are the major causes of ground-water
complaints within the study area. Iron, which is an
abundant mineral in the earth's crust, is found in
most water. The presence of iron in water is objec-
tionable because of its taste, staining capacity and
encrusting property. The source of iron in the
Floridan aquifer system is surface waterthat rechar-
ges the aquifer. Iron is introduced into the Floridan
aquifer system through the numerous sinkholes,
lakes and adjacent rivers.
Tannic acid imparts an undesirable brown color
to ground water. This discoloration is the result of
natural organic processes that occur when the sur-
face water of rivers, ponds, and swamps come into
contact with organic debris. Although tannic acid
is not a health hazard, it is aesthetically undesirable.
Uke iron, tannic acid enters ground water through
recharge of the aquifer by surface water.
Iron and sulfur-reducing bacteria are a common

problem in Madison County. However, they are
considered a nuisance problem and not a health
hazard. These bacteria thrive on the dissolved iron
and sulfate in ground water. Sulfur-reducing bac-
teria utilize sulfates and sulfide and transform them
into hydrogen sulfide. Hydrogen sulfide, which im-
parts an offensive "rotten egg" odor to the ground
water, is very corrosive. Iron-reducing bacteria
produce acids that cause blocking or corrosion of
pipes. They also impart an unpleasant taste and
discoloration to the water. Iron and sulfur-reducing
bacteria are introduced into the Floridan aquifer
system in the same manner as iron and tannic acid.
In addition, they can be introduced by con-
taminated well drilling and pumping equipment.
Iron and sulfur-reducing bacteria are virtually im-
possible to eliminate once they have been intro-
duced into a well.

SUMMARY

Private and public potable water supplies in
Madison County are obtained entirely from ground-
water sources. There are three aquifer systems
present a surficial, an intermediate, and the
Floridan aquifer system, which can be differentiated
by water chemistry, stratigraphic position, lithol-
ogy, and hydraulic heads.
The Floridan aquifer system is the principal
water-bearing unit in Madison County. It includes
all of the Middle Eocene to Oligocene age sedi-
ments and part of the Lower Miocene carbonates.
This system exists under unconfined, semi-con-
fined, and confined conditions. Hawthorn Group
clays form the overlying unit in areas where the
Floridan aquifer system exists under confined con-
ditions.
The intermediate aquifer system is present in
northern Madison County. This artesian aquifer
system occurs within discontinuous units of both
the Miccosukee Formation and Hawthorn Group.
To date, minimal data are available on the water-
bearing properties of this system. Clays within the
Miccosukee Formation or the Hawthorn Group act
as confining units.

Bulletin No. 61

The surficial aquifer system occurs within the
undifferentiated sands and clays overlying the Mic-
cosukee Formation or the Hawthorn Group clays.
Ground-water levels within the surficial aquifer sys-
tem are at or within a few feet of land surface and
respond directly to precipitation and
evapotranspiration. Ground water in the surficial
aquifer system has high sodium, chloride, potas-
sium, and nitrate values.
Ground-water fluctuations within the unconfined
Floridan aquifer system respond rapidly to
precipitation. Over 20 feet of fluctuation has been
recorded in these areas. The response time is

slower and the total fluctuation is less in areas
where the Floridan aquifer system is confined or
semi-confined.
Ground-water quality in the surficial aquifer sys-
tem and in the unconfined portions of the Floridan
aquifer system is highly susceptible to degradation
from various land uses, storage, and waste disposal
practices. Where the Floridan aquifer system is
confined or semi-confined, degradation of the
water quality in the overlying surficial aquifer system
can subsequently diminish the ground-water
quality of the Floridan aquifer system via the
numerous hydrologic connections.

Florida Geological Survey

Bulletin No. 61

REFERENCES

Abbott, W. H., and Andrews, G. W., 1979, Middle Miocene marine diatoms from the Hawthorn Formation within
the Ridgeland Trough, South Carolina and Georgia: Micropaleontology, v. 25, no. 3, p. 225-271.

American Society for Testing and Materials, 1987, Annual book of ASTM standards, section 4, v. 4.02 Concrete
and Mineral Aggregates: ASTM, Philadelphia, PA, 997 p.

Applin, P. L, 1951, Preliminary report on buried pre-Mesozoic rocks in Florida and adjacent states: United
States Geological Survey Circular 91, 28 p.

and Applin, E. R., 1944, Regional subsurface stratigraphy and structure of Florida and southern
Georgia: American Association of Petroleum Geologists Bulletin, v. 28, no. 12, p. 1673-1753.

Arthur, J. D., 1988, Petrogenesis of Early Mesozoic tholeiite in the Florida basement and an overview of Florida
basement geology: Florida Geological Survey Report of Investigation 97, 39 p.

Bates, R. L, and Jackson, J. A., eds., 1980, Glossary of geology (second edition): Falls Church, Virginia,
American Geological Institute, 751 p.

Bond, P. A., Campbell, K. M., and Scott, T. M., 1986, An overview of peat in Florida and related issues: Florida
Geological Survey Special Publication 27, 151 p.

Braunstein, J., Huddlestun, P., Biel, R., 1988, Gulf Coast Region: Correlation of stratigraphic units of North
America (COSUNA) Project, The American Association of Petroleum Geologists.

Ceryak, R., Knapp, M. S., and Burnson, T., 1983, The geology and water resources of the Upper Suwannee
River Basin, Florida: Florida Bureau of Geology Report of Investigation 87,165 p.

Chen, C. S., 1965, The regional lithostratigraphic analysis of Paleocene and Eocene Rocks of Florida: Florida
Geological Survey Bulletin 45, 105 p.

Cole, W. S., 1944, Stratigraphic and Paleontologic studies of wells in Florida no. 3: Florida Geological Survey
Bulletin 26,168 p.

Colton, R.C., 1978, The subsurface geology of Hamilton County, Florida with emphasis on the Oligocene age
Suwannee Limestone: Masters Thesis, Florida State University, 185 p.

Cooke, C. W., 1931, Seven coastal terraces in the southeastern states: Washington Academy of Science
Journal v. 21, no. 21, p. 503-513.

1939, Scenery of Florida interpreted by a geologist: Florida Geological Survey Bulletin 17, 118
p.

1945, Geology of Florida: Florida Geological Survey Bulletin 29, 339 p.

and Mansfield, W. C., 1936, Suwannee Limestone of Florida (abs.): Geological Society of America,
Proceedings for 1935, p. 71-72.

and Mossom, S., 1929, Geology of Florida: Florida Geological Survey, 20th Annual Report, 294
p.

Florida Geological Survey

Copeland, R. E., in preparation, The hydrogeology of the coastal rivers basin, Suwannee River Water
Management District: Suwannee River Water Management District, Live Oak, FL.

Crane, J., 1986, An Investigation of the geology, hydrogeology and hydrochemistry of the Lower Suwannee
River Basin: Florida Bureau of Geology, Report of Investigation 96, 205 p.

Dall, W. H., and Harris, G. D., 1892, Correlation papers Neogene: United States Geological Survey Bulletin
84, 107 p.

Davis, J. H., Jr., 1946, The peat deposits of Florida: Their occurrence, development, and uses: Florida
Geological Survey Bulletin 30, 247 p.

Doering, J. A., 1960, Quaternary surface formations of southern parts of Atlantic Coastal Plain: Journal of
Geology, v. 68, no. 2, p. 182-202.

Fernald, E. A., ed., 1981, Atlas of Florida: The Florida State University Foundation, Tallahassee, Florida, 276
p.

Fisk, D. W., 1977, A water balance for the Suwannee River Water Management District: Suwannee River Water
Management District Information Circular 3, Live Oak, FL, 19 p.

1984a, General hydrogeologic conditions of the Floridan Aquifer in The Suwannee River Water
Management district: Suwannee River Water Management District, Live Oak, FL, Open File Map.

1984b, Distribution of recharge to and discharge from the Floridan Aquifer in the Suwannee River
Water Management District: Suwannee River Water Management District, Live Oak, FL, Open File Map.

Florida Department of Transportation, 1984, Manual of Florida sampling and testing methods, sieve analysis
of fine and coarse aggregates: FDOT, designation FM 1-T 027, 6 p.

Florida Phosphate Council, 1987, Phosphate feeds you, 2 p.

Harper, R. M., 1910, Preliminary report on peat deposits of Florida: Florida Geological Survey Third Annual
Report, p. 300-305.

Healy, H. G., 1975, Terraces and shorelines of Florida: Florida Bureau of Geology Map Series 71, scale
1:2,000,000.

Hendry, C. W., Jr., and Sproul, C. R., 1966, Geology and ground-water resources of Leon County, Florida:
Florida Geological Survey Bulletin 47,178 p.

Hendry, C. W., Jr., and Yon, J. W., Jr., 1967, Stratigraphy of Upper Miocene Miccosukee Formation, Jefferson
and Leon Counties, Florida: American Association of Petroleum Geologists Bulletin, v. 51, p. 250-256.

Hoenstine, R. W., 1984, Biostratigraphy of selected cores of the Hawthorn Formation in northeast and
east-central Florida: Florida Bureau of Geology Report of Investigation 93, 68 p.

Lane, E., Spencer, S. M., and O'Carroll, T., 1987, A landfill site in a karst environment,
Madison County, Florida a case study: in Beck, B. F., and Wilson, W. L. (eds.) Karst Hydrogeology:
Engineering and environmental applications: Florida Sinkhole Research Institute, University of Central
Florida, Orlando, Florida, p. 253-258.

Bulletin No. 61

Huddlestun, P. F., 1981, Correlation chart of the Georgia Coastal Plain: Georgia Geological Survey Open File
Report 82-1.

1982, The stratigraphic subdivision of the Hawthorn Group in Georgia, (abs.), in Scott, T.
M., and Upchurch, S. B. (eds.), Miocene of the southeastern United States: Florida Geological Survey
Special Publication 25, p. 183.

1988, A revision of the lithostratigraphic units of the Coastal Plain of Georgia, the Miocene
through Holocene: Georgia Geological Survey Bulletin 104, 162 p.

Johnson, L. C., 1888, The structure of Florida: American Journal of Science, 3rd series, v. 36, p. 230-236.

Kirkner, R. A. and Associates, Inc., 1986, Contamination and assessment report, Lake Wales, Florida. Report
prepared for Madison County, 32 p.

Klein, H., 1975, Depth to base of potable water in the Floridan Aquifer: Florida Bureau of Geology Map Series
42, Revised.

Knapp, M. S., 1978, Environmental geology series Gainesville sheet: Florida Bureau of Geology Map Series
79.

MacNeil, F. S., 1950, Pleistocene shorelines in Florida and Georgia: United States Geological Survey
Professional Paper 221-F, p. 95-107.

Matson, G. C., and Clapp, F. G., 1909, A preliminary report of the geology of Florida with special reference to
the stratigraphy: Florida Geological Survey, 2nd Annual Report, 299 p.

Miller, J. A., 1986, Hydrogeologic framework of the Floridan aquifer system in Florida and in parts of Georgia,
Alabama and South Carolina: United States Geological Survey Professional Paper 1403-B, p. 25-27.

Office of the Governor, 1987, Official 1987 population estimates for the State of Florida, 16 p.

Pojeta, J., Jr., Kriz, J., and Berdan, J. M., 1976, Silurian-Devonian pelecypods and Paleozoic stratigraphy of
subsurface rocks in Florida and Georgia and related Silurian pelecypods from Bolivia and Turkey: United
States Geological Survey Professional Paper 879, 32 p.

Price, D. J., 1984, Karst progression: in Beck, B., (ed.), Sinkholes: their geology, engineering and environ-
mental impact: Florida Sinkhole Research Institute, University of Central Florida, Orlando, FL, p. 17-22.

Puri, H. S., 1953, Contribution to the study of the Miocene of the Florida panhandle: Florida Geological Survey
Bulletin 36, 345 p.

,1957, Stratigraphy and zonation of the Ocala Group: Florida Geological Survey Bulletin
38, 248 p.
and Vernon, R. O., 1964, Summary of the geology of Florida and a guidebook to the
classic exposures: Florida Geological Survey Special Publication 5 (revised), 312 p.

Rosenau, J. C., Faulkner, G. L, Hendry, C. W., Jr., and Hull, R. W., 1977, Springs of Florida: Florida Bureau
of Geology Bulletin 31, (revised), 461 p.

Schmidt, W., Hoenstine, R. W., Knapp, M. S., Lane, E., Ogden, G. M., Jr., and Scott, T. M., 1979, The limestone,
dolomite and coquina resources of Florida: Florida Bureau of Geology Report of Investigation 88, 54 p.

Florida Geological Survey

and Clark, M., 1980, Geology of Bay County, Florida: Florida Geological Survey Bulletin 57, 96
p.

Scott, T. M., 1983, The Hawthorn Formation of northeastern Florida: Part 1: The geology of the Hawthorn
Formation of northeastern Florida: Florida Bureau of Geology Report of Investigation 94, 90 p.

1988, The lithostratigraphy of the Hawthorn Group (Miocene) of Florida: Florida Geological
Survey Bulletin 59, 148 p.

Sellards, E. H., 1917, Geology between the Ocklockonee and Aucilla rivers in Florida: Florida Geological
Survey, 9th Annual Report, 151 p.

Southeastern Geological Society Ad Hoc Committee on Florida Hydrostratigraphic Unit Definition, 1986,
Hydrogeological units of Florida: Florida Geological Survey Special Publication 28, 8 p.

Stapor, F. W., and Tanner, W. F., 1977, Late Holocene mean sea level data from St. Vincent Island and the
shape of the Late Holocene mean sea level curve: in Proceedings Coastal Sedimentary Symposium,
Florida State University, Department of Geology, p. 35-68.

United States Soil Conservation Service, (in press), Madison County Soil Survey Report.

Vernon, R. 0., 1942, Geology of Holmes and Washington Counties, Florida: Florida Geological Survey Bulletin
21,161 p.

1951, Geology of Citrus and Levy Counties, Florida: Florida Geological Survey Bulletin 33,
256 p.

White, W. A., 1970, Geomorphology of the Florida peninsula: Florida Geological Survey Bulletin 51, 164 p.

Winston, G. 0., 1978, Rebecca Shoal reef complex (Upper Cretaceous and Paleocene) in south Florida: The
American Association of Petroleum Geologists Bulletin, v. 62, no. 1, p. 121-127.

Yon, J. W., Jr., 1966, Geology of Jefferson County, Florida: Florida Geological Survey Bulletin 48,119 p.

Bulletin No. 61

APPENDIX I

SELECTED CORE DESCRIPTIONS
W-15515
W-15537

Florida Geological Survey

LITHOLOGIC WELL LOG PRINTOUT SOURCE FGS

WELL NUMBER: W- 15515 COUNTY MADISON
TOTAL DEPTH: 00287 FT. LOCATION: T.02N R.08E S.05 C
SAMPLES NONE LAT = N 30D 36M 18
LON = W 83D 33M 10
COMPLETION DATE 02/22/84 ELEVATION 160 FT
OTHER TYPES OF LOGS AVAILABLE NONE

OWNER/DRILLER: HOWARD (JUSTIN HODGES)

WORKED BY: RON HOENSTINE,FEB,1984,CRYSTAL RIVER FM SHOWS ATYPICAL DOLOMITIZATION

0.0- 5.0 UNDIFFERENTIATED SAND AND CLAY
5.0- 49.0 MICCOSUKEE FM.
49.0- 72.0 HAWTHORN GROUP
72.0- 299.0 SUWANNEE LIMESTONE
299.0- 315.0 OCALA GROUP

0 0.1 NO SAMPLES

0.1- 1 SAND; GRAYISH ORANGE; 25% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: SUB-ANGULAR TO ROUNDED; MEDIUM SPHERICITY; UNCONSOLIDATED;
ACCESSORY MINERALS: HEAVY MINERALS-O1%, PHOSPHATIC SAND-01%, CLAY-02%;
OTHER FEATURES: PARTINGS;
UNIFORM IN APPEARANCE

1 5 SAND; MODERATE YELLOWISH BROWN; 26% POROSITY, INTERCRYSTALLINE, INTERGRANULAR;
GRAIN SIZE: FINE; RANGE: FINE TO MEDIUM;
ROUNDNESS: SUB-ANGULAR TO ROUNDED; MEDIUM SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: HEAVY MINERALS-01%, CLAY-03%;
OTHER FEATURES: PARTINGS;

5 6.5 SAND; LIGHT BROWN; 20% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN SIZE: FINE; RANGE: FINE TO COARSE;
ROUNDNESS: SUB-ANGULAR TO ROUNDED; MEDIUM SPHERICITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: SILT-15%, CLAY-05%, IRON STAIN-01%;
FOSSILS: NO FOSSILS;

Bulletin No. 61

W- 15515 CONTINUED PAGE 2

6.5- 8 SAND; MODERATE REDDISH BROWN TO GREENISH GRAY; 18% POROSITY, INTERGRANULAR,
INTERCRYSTALLINE;
GRAIN SIZE: VERY FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: SUB-ANGULAR TO ROUNDED; MEDIUM SPHERICITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: STREAKED, MOTTLED,
ACCESSORY MINERALS: SILT-10X, CLAY-25X, IRON STAIN-01%;
IRREGULAR CLAY LENSES INTERBEDDED WITH SAND AND SILT

8 11.5 SAND; LIGHT BROWN TO VERY LIGHT GRAY; 20% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; MEDIUM SPHERICITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: CLAY-05%, IRON STAIN-01%;
OTHER FEATURES: PARTINGS;

11.5- 17 CLAY; LIGHT OLIVE GRAY; 12% POROSITY, LOW PERMEABILITY, INTERGRANULAR, INTERCRYSTALLINE;
MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: IRON STAIN-01%, QUARTZ SAND-03X, PHOSPHATIC SAND-01%;

17 17.3 SAND; DARK YELLOWISH ORANGE; 17% POROSITY, INTERCRYSTALLINE, INTERGRANULAR;
GRAIN SIZE: FINE; RANGE: VERY FINE TO MEDIUM;
ROUNDNESS: SUB-ANGULAR TO ROUNDED; MEDIUM SPHERICITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-05%, SILT-10X, PHOSPHATIC SAND-01X;
OTHER FEATURES: PARTINGS;

17.3- 18.5 CLAY; YELLOWISH GRAY TO LIGHT BROWN; 13% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE,
INTERGRANULAR; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: SILT-10%, PHOSPHATIC SAND-01X;
DISTINCT LITHOLOGIC BREAK

18.5- 20 SAND; VERY LIGHT GRAY TO WHITE; 22% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; MEDIUM SPHERICITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: PHOSPHATIC SAND-01O, IRON STAIN-01O, CLAY-03X, SILT-05%;

Florida Geological Survey

W- 15515 CONTINUED PAGE 3

20 20.9 SILT; LIGHT OLIVE GRAY TO DARK YELLOWISH ORANGE; 15% POROSITY, INTERGRANULAR,
INTERCRYSTALLINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: CLAY-03%, QUARTZ SAND-08%, IRON STAIN-01%, PHOSPHATIC SAND-02%;
OTHER FEATURES: PARTINGS;
MOTTLING AND IRREGULAR STREAKING PRESENT

20.9- 22.3 CLAY; LIGHT OLIVE GRAY TO LIGHT BROWN; 11% POROSITY, INTERGRANULAR, INTERCRYSTALLINE,
LOW PERMEABILITY; MODERATE INDURATION;
CEMENT TYPESS: CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: SILT-10%, IRON STAIN-01%, PHOSPHATIC SAND-01%, QUARTZ SAND-01%;

22.3- 23.5 SILT; DARK YELLOWISH ORANGE TO GRAYISH ORANGE; 17% POROSITY, INTERCRYSTALLINE,
INTERGRANULAR; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-01%, PHOSPHATIC SAND-01%;

23.5- 25.5 SILT; YELLOWISH GRAY; 15% POROSITY, INTERGRANULAR, INTERCRYSTALLINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-10%, PHOSPHATIC SAND-01%, QUARTZ SAND-15%;
OTHER FEATURES: PARTINGS;
ISOLATED PATCHES OF ORGANIC

25.5- 28.5 CLAY; GRAYISH GREEN; 11% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE, INTERGRANULAR;
MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MASSIVE,
ACCESSORY MINERALS: PHOSPHATIC SAND-01%;
OTHER FEATURES: PARTINGS;
TYPICAL GRAYISH GREEN HAWTHORN CLAY, ORGANIC PRESENT

28.5- 33 NO SAMPLES

33 37 CLAY; LIGHT GRAYISH GREEN TO WHITE; 11% POROSITY, LOW PERMEABILITY, INTERGRANULAR,
INTERCRYSTALLINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED, STREAKED,
ACCESSORY MINERALS: PYRITE-01%, IRON STAIN-01%;
ORGANIC INCLUSIONS

37 40 CLAY; WHITE TO LIGHT OLIVE; 12% POROSITY, LOW PERMEABILITY, INTERGRANULAR,
INTERCRYSTALLINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
PREDOMINANTLY KAOLIN

Bulletin No. 61

W- 15515 CONTINUED PAGE 4

40 42 CLAY; GRAYISH ORANGE TO VERY LIGHT ORANGE; 11% POROSITY, LOW PERMEABILITY, INTERGRANULAR,
INTERCRYSTALLINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;

42 42.5 CLAY; VERY LIGHT ORANGE TO YELLOWISH GRAY; 11% POROSITY, LOW PERMEABILITY, INTERGRANULAR,
INTERCRYSTALLINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MASSIVE,
ACCESSORY MINERALS: QUARTZ SAND-01%, PHOSPHATIC SAND-01%;

42.5- 44.3 CLAY; WHITE; 13% POROSITY, INTERCRYSTALLINE, INTERGRANULAR; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: PHOSPHATIC SAND-01%;
FOSSILS: PLANT REMAINS;

44.3- 46 CLAY; LIGHT OLIVE GRAY; 12% POROSITY, LOW PERMEABILITY, INTERGRANULAR, INTERCRYSTALLINE;
MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
MASSIVE OLIVE CLAY WITH KAOLIN AND PEAT INCLUSIONS

46 49 CLAY; GRAYISH BROWN TO LIGHT OLIVE GRAY; 11% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE,
INTERGRANULAR; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: PHOSPHATIC SAND-03%, QUARTZ SAND-01%;
OTHER FEATURES: CALCAREOUS;

49 50 CLAY; WHITE; 14% POROSITY, INTERCRYSTALLINE, INTERGRANULAR; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: PHOSPHATIC SAND-01%, IRON STAIN-01%, QUARTZ SAND-01%;
OTHER FEATURES: CALCAREOUS;

50 54 SILT; GRAYISH ORANGE; 17% POROSITY, INTERGRANULAR, INTERCRYSTALLINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-05%, CLAY-10%, PHOSPHATIC SAND-03%;
LEACHED PHOSPHATE PRESENT

54 54.5 CALCILUTITE; WHITE; 20% POROSITY, INTERGRANULAR, INTERCRYSTALLINE, MOLDIC;
ACCESSORY MINERALS: QUARTZ SAND-01%, PHOSPHATIC SAND-01%, CLAY-05%;
FAIRLY UNIFORM TEXTURE

54.5- 61 CLAY; LIGHT OLIVE; 10% POROSITY, LOW PERMEABILITY, INTERGRANULAR, INTERCRYSTALLINE;
MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MASSIVE,
OTHER FEATURES: CALCAREOUS;

Florida Geological Survey

W- 15515 CONTINUED PAGE 5

61 62.5 CALCILUTITE; VERY LIGHT ORANGE TO LIGHT OLIVE; 20% POROSITY, LOW PERMEABILITY,
INTERGRANULAR, INTERCRYSTALLINE;
MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-01%, CLAY-10%;
DOMINANTLY MICRITE WITH GREEN OLIVE CLAY INCLUSIONS

62.5- 71 CHERT; WHITE TO LIGHT GRAY; 07% POROSITY, LOW PERMEABILITY, INTERGRANULAR,
INTERCRYSTALLINE; GOOD INDURATION;
CEMENT TYPE(S): SILICIC CEMENT;
ACCESSORY MINERALS: CALCILUTITE-05%;
CHERT NODULES WITH MICRITE COATING

71 72 CALCILUTITE; WHITE; 21% POROSITY, PIN POINT VUGS, INTERGRANULAR, INTERCRYSTALLINE;
MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-03%, PHOSPHATIC SAND-01%, CLAY-05%;

72 72.5 LIMESTONE; WHITE TO VERY LIGHT ORANGE; 18% POROSITY,
GRAIN TYPE: CALCILUTITE; 80% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: VERY FINE; RANGE: VERY FINE TO FINE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, CLAY MATRIX;
ACCESSORY MINERALS: CLAY-08%, CHERT-02%;

72.5- 77 LIMESTONE; WHITE; 22% POROSITY, PIN POINT VUGS, VUGULAR, INTERGRANULAR;
GRAIN TYPE: CALCILUTITE, CRYSTALS; 85% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: GRANULE; RANGE: FINE TO GRANULE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-01%, PHOSPHATIC SAND-01%;
OTHER FEATURES: CHALKY;

77 82 CALCARENITE; WHITE; 25% POROSITY, MOLDIC, INTERGRANULAR, VUGULAR;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC; 90% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: COARSE; RANGE: MEDIUM TO VERY COARSE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
ACCESSORY MINERALS: PYRITE-01%, QUARTZ SAND-01%;
FOSSILS: FOSSIL FRAGMENTS, FOSSIL MOLDS;

82 87 LIMESTONE; VERY LIGHT ORANGE TO LIGHT OLIVE GRAY; 20% POROSITY, PIN POINT VUGS,
INTERCRYSTALLINE, INTERGRANULAR;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC; 85% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: GRANULE; RANGE: GRANULE TO GRAVEL; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, CLAY MATRIX;
ACCESSORY MINERALS: CLAY-10%;
FOSSILS: BENTHIC FORAMINIFERA, FOSSIL MOLDS;

Bulletin No. 61

W- 15515 CONTINUED PAGE 6

87 92 LIMESTONE; WHITE; 19% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN TYPE: CALCILUTITE; 80% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: LITHOGRAPHIC; GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-01%;
OTHER FEATURES: SUCROSIC;

92 92.5 LIMESTONE; VERY LIGHT ORANGE TO GRAYISH ORANGE PINK; I % POROSITY, INTERCRYSTALLINE,
PIN POINT VUGS;
GRAIN TYPE: CALCILUTITE, CRYSTALS; 80% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
ACCESSORY MINERALS: CLAY-03%;
FOSSILS: MOLLUSKS, FOSSIL FRAGMENTS, FOSSIL MOLDS;

92.5- 97 CALCARENITE; VERY LIGHT ORANGE; 22% POROSITY, PIN POINT VUGS, INTERGRANULAR, MOLDIC;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC; 85% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: FINE; RANGE: FINE TO MEDIUM;
ACCESSORY MINERALS: CLAY-02%;
FOSSILS: BENTHIC FORAMINIFERA, MOLLUSKS, FOSSIL FRAGMENTS, FOSSIL MOLDS;

97 103 NO SAMPLES

103 106 CALCARENITE; VERY LIGHT ORANGE; 24% POROSITY, PIN POINT VUGS, VUGULAR, INTERGRANULAR;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC; 90% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: MEDIUM; RANGE: FINE TO COARSE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, CLAY MATRIX;
ACCESSORY MINERALS: CLAY-15%;
FOSSILS: BENTHIC FORAMINIFERA, CONES, MOLLUSKS, FOSSIL FRAGMENTS, FOSSIL MOLDS;

106 107 CALCARENITE; VERY LIGHT ORANGE; 22% POROSITY, PIN POINT VUGS, INTERGRANULAR,
INTERCRYSTALLINE;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC; 85% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: MEDIUM; RANGE: MEDIUM TO COARSE; MODERATE INDURATION;
CEMENT TYPESS: CALCILUTITE MATRIX;
ACCESSORY MINERALS: PYRITE-01%;
FOSSILS: MOLLUSKS, FOSSIL FRAGMENTS, BENTHIC FORAMINIFERA, FOSSIL MOLDS;
UNIFORM TEXTURE

107 113 CALCARENITE; VERY LIGHT ORANGE; 26% POROSITY, VUGULAR, PIN POINT VUGS, INTERGRANULAR;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC; 90% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: MEDIUM; RANGE: MEDIUM TO COARSE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
ACCESSORY MINERALS: CLAY-04%;
FOSSILS: MOLLUSKS, FOSSIL FRAGMENTS, BENTHIC FORAMINIFERA, FOSSIL MOLDS;
RECRYSTALIZED COQUINA

Florida Geological Survey

W- 15515 CONTINUED PAGE 7

113 114 CALCILUTITE; VERY LIGHT ORANGE; 21% POROSITY, PIN POINT VUGS, INTERGRANULAR;
MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
FOSSILS: FOSSIL MOLDS;

114 114.5 CHERT; PINKISH GRAY; 08% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE; GOOD INDURATION;
CEMENT TYPE(S): SILICIC CEMENT;
ACCESSORY MINERALS: CALCILUTITE-05%;

114.5- 115 AS ABOVE

115 116 LIMESTONE; VERY LIGHT ORANGE; 22% POROSITY, INTERCRYSTALLINE, INTERGRANULAR;
GRAIN TYPE: CALCILUTITE, CRYSTALS; 80% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: LITHOGRAPHIC; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
OTHER FEATURES: SUCROSIC;
FOSSILS: FOSSIL MOLDS;

116 117 CALCARENITE; VERY LIGHT ORANGE; 26% POROSITY, PIN POINT VUGS, INTERGRANULAR, VUGULAR;
GRAIN TYPE: BIOGENIC, CALCILUTITE, CRYSTALS; 90% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: MEDIUM; RANGE: .MEDIUM TO COARSE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
FOSSILS: BENTHIC FORAMINIFERA, MOLLUSKS, FOSSIL FRAGMENTS, FOSSIL MOLDS, CONES;
COQUINA

117 118 CALCILUTITE; VERY LIGHT ORANGE; 22% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
FOSSILS: BENTHIC FORAMINIFERA, FOSSIL FRAGMENTS, FOSSIL MOLDS;

118 141.5 CALCARENITE; VERY LIGHT ORANGE; 24% POROSITY, PIN POINT VUGS, INTERGRANULAR,
INTERCRYSTALLINE;
GRAIN TYPE: CRYSTALS, CALCILUTITE, BIOGENIC; 85% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: MEDIUM; RANGE: MEDIUM TO COARSE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
OTHER FEATURES: SUCROSIC;
FOSSILS: MOLLUSKS, BENTHIC FORAMINIFERA, FOSSIL FRAGMENTS, FOSSIL MOLDS;
RECRYSTALIZED

141.5- 150 CALCILUTITE; WHITE; 23% POROSITY, INTERCRYSTALLINE, INTERGRANULAR, PIN POINT VUGS;
MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-01%;
FOSSILS: FOSSIL MOLDS;
MICRITIC LIMESTONE DISPLAYING UNIFORM TEXTURE

150 160 AS ABOVE

160 170 AS ABOVE

Bulletin No. 61

W- 15515 CONTINUED PAGE 8

170 177 DOLOMITE; VERY LIGHT ORANGE; 09% POROSITY, LOW PERMEABILITY, INTERGRANULAR,
INTERCRYSTALLINE; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: CRYPTOCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: MICA-01%;
OTHER FEATURES: CALCAREOUS;

177 179 DOLOMITE; GRAYISH BROWN TO DARK YELLOWISH BROWN; 08% POROSITY, LOW PERMEABILITY,
INTERCRYSTALLINE, INTERGRANULAR; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: CRYPTOCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
HIGHLY INDURATED TIGHT DOLOMITE

179 182 CALCARENITE; VERY LIGHT ORANGE; 24% POROSITY, PIN POINT VUGS, VUGULAR, INTERGRANULAR;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC; 80% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
FOSSILS: BENTHIC FORAMINIFERA, FOSSIL MOLDS, FOSSIL FRAGMENTS;
RECRYSTALIZED LIMESTONE, UNIFORM TEXTURE

182 184.5 DOLOMITE; LIGHT OLIVE GRAY TO BROWNISH GRAY; 09% POROSITY, LOW PERMEABILITY,
INTERCRYSTALLINE, INTERGRANULAR; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: CRYPTOCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
OTHER FEATURES: SPECKLED;
SILT INCLUSIONS PRESENT(193') INTERVAL

184.5- 196 DOLOMITE; GRAYISH BROWN TO MODERATE YELLOWISH BROWN; 08% POROSITY, LOW PERMEABILITY,
INTERGRANULAR, PIN POINT VUGS; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: CALCITE-01%;
OTHER FEATURES: SPECKLED, SUCROSIC, CALCAREOUS;
FOSSILS: FOSSIL MOLDS, MOLLUSKS;
TIGHT IMPERMEABLE DOLOMITE

196 204 DOLOMITE; GRAYISH ORANGE; 09% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE, INTERGRANULAR;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: CLAY-01%;
OTHER FEATURES: SUCROSIC;
FINE UNIFORM TEXTURED TIGHT DOLOMITE

Florida Geological Survey

W- 15515 CONTINUED PAGE 9

204 205 DOLOMITE; GRAYISH BROWN TO MODERATE YELLOWISH BROWN; 09% POROSITY, LOW PERMEABILITY,
INTERGRANULAR, PIN POINT VUGS; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
OTHER FEATURES: SUCROSIC, SPECKLED;
FOSSILS: FOSSIL MOLDS, MOLLUSKS;

205 206.5 DOLOMITE; GRAYISH ORANGE; 09% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE, INTERGRANULAR;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: CLAY-01%;
SIMILAR TO THE (204') INTERVAL

206.5- 207 DOLOMITE; GRAYISH ORANGE; 10% POROSITY, LOW PERMEABILITY, INTERGRANULAR, INTERCRYSTALLINE;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
OTHER FEATURES: SUCROSIC;

207 209 DOLOMITE; LIGHT GRAYISH RED; 08% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE,
INTERGRANULAR; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: CRYPTOCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: CLAY-01%;
OTHER FEATURES: SUCROSIC;
FOSSILS: MOLLUSKS, FOSSIL MOLDS, FOSSIL FRAGMENTS;
BORINGS AND BURROWS PRESENT

209 219 NO SAMPLES

219 220 DOLOMITE; MODERATE GRAY TO LIGHT GRAY; 08% POROSITY, LOW PERMEABILITY,
INTERCRYSTALLINE; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGEc CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPESS: DOLOMITE CEMENT;
OTHER FEATURES: SUCROSIC;
FOSSILS: FOSSIL MOLDS, MOLLUSKS;
CLAY INCLUSIONS IN CAVITIES

Bulletin No. 61

W- 15515 CONTINUED PAGE 10

220 222 DOLOMITE; LIGHT GRAY TO YELLOWISH GRAY; 09% POROSITY, LOW PERMEABILITY,
INTERCRYSTALLINE; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: CLAY-01%, QUARTZ SAND-01%, MICA-01X;
OTHER FEATURES: SUCROSIC;
FOSSILS: FOSSIL MOLDS, MOLLUSKS;

222 224 NO SAMPLES

224 225 NUMEROUS ALTERED MICROFOSSILS

225 226 AS ABOVE

226 227 DOLOMITE; LIGHT GRAY TO YELLOWISH GRAY; 09% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE,
PIN POINT VUGS; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: MICROCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
OTHER FEATURES: CALCAREOUS, SUCROSIC;

227 229 DOLOMITE; LIGHT GRAY; 11% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: MICROCRYSTALLINE TO VERY FINE; GOOD INDURATION;
FOSSILS: BENTHIC FORAMINIFERA, MOLLUSKS, FOSSIL MOLDS, FOSSIL FRAGMENTS;

229 243 DOLOMITE; GRAYISH BROWN; 10% POROSITY, LOW PERMEABILITY, PIN POINT VUGS;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: VERY FINE; RANGE: MICROCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: PHOSPHATIC SAND-01%;
OTHER FEATURES: SUCROSIC, SPECKLED;
FOSSILS: BENTHIC FORAMINIFERA, MOLLUSKS, FOSSIL MOLDS, FOSSIL FRAGMENTS;
NUMEROUS ALTERED MICROFOSSILS

243 250 DOLOMITE; YELLOWISH GRAY; 11% POROSITY, LOW PERMEABILITY, PIN POINT VUGS;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: MICROCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
OTHER FEATURES: SUCROSIC;
FOSSILS: MOLLUSKS;

250 251 DOLOMITE; YELLOWISH GRAY; 12% POROSITY, LOW PERMEABILITY, PIN POINT VUGS,
VUGULAR; 50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
OTHER FEATURES: CALCAREOUS, SUCROSIC;
FOSSILS: FOSSIL MOLDS, MOLLUSKS, BENTHIC FORAMINIFERA;
HIGHLY ALTERED COQUINA DISPLAYING PROMINENT MOLDS

Florida Geological Survey

W- 15515 CONTINUED PAGE 11

251 260 AS ABOVE

260 267 CALCARENITE; YELLOWISH GRAY; 22% POROSITY, MOLDIC, INTERGRANULAR, PIN POINT VUGS;
GRAIN TYPE: CALCILUTITE, BIOGENIC, CRYSTALS; 85% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: GRANULE; RANGE: COARSE TO GRANULE; GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, DOLOMITE CEMENT;
ACCESSORY MINERALS: DOLOMITE-15%;
FOSSILS: MOLLUSKS, BENTHIC FORAMINIFERA, FOSSIL FRAGMENTS, FOSSIL MOLDS, ALGAE;
RECRYSTALIZED COQUINA PREDOMINANTLY BIVALVES

267 268 DOLOMITE; GRAYISH ORANGE; 09% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: MICROCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: PHOSPHATIC SAND-01%, HEAVY MINERALS-01%;
OTHER FEATURES: SUCROSIC;
UNIFORM TEXTURE

268 270 DOLOMITE; YELLOWISH GRAY; 10% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: VERY FINE; RANGE: MICROCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
ACCESSORY MINERALS: MICA-O1%;
OTHER FEATURES: SUCROSIC;
FOSSILS: FOSSIL MOLDS, MOLLUSKS, FOSSIL MOLDS, FOSSIL FRAGMENTS;
DOLOMITIZED COQUINA

270 287.5 DOLOMITE; YELLOWISH GRAY; 09% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: CRYPTOCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO MICROCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPESS: DOLOMITE CEMENT;
FOSSILS: MOLLUSKS;
LEPIDOCYCLINA SP PRESENT

287.5- 299 DOLOMITE; YELLOWISH GRAY; 08% POROSITY, LOW PERMEABILITY, INTERCRYSTALLINE;
50-90% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO VERY FINE; GOOD INDURATION;
CEMENT TYPE(S): DOLOMITE CEMENT;
FOSSILS: FOSSIL MOLDS, FOSSIL FRAGMENTS, BENTHIC FORAMINIFERA;

299 315 LIMESTONE; YELLOWISH GRAY; 19% POROSITY, INTERCRYSTALLINE, INTERGRANULAR;
GRAIN TYPE: CRYSTALS, CALCILUTITE; 80% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: VERY FINE; RANGE: VERY FINE TO FINE; GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, DOLOMITE CEMENT;
OTHER FEATURES: DOLOMITIC, SUCROSIC;
FOSSILS: FOSSIL MOLDS;
PROBABLE TOP OF OCALA

315 TOTAL DEPTH

Bulletin No. 61

LITHOLOGIC WELL LOG PRINTOUT SOURCE FGS

WELL NUMBER: W- 15537 COUNTY MADISON
TOTAL DEPTH: 322 FT. LOCATION: T.02N R.09E S.05 B
SAMPLES NONE LAT = N 30D 36H 38
LON = W 83D 26M.28
COMPLETION DATE 04/10/84 ELEVATION 185 FT
OTHER TYPES OF LOGS AVAILABLE ELECTRIC, GAMMA, NEUTRON

OWNER/DRILLER: BURNETT FBG CORE HOLE (JUSTIN HODGES)

WORKED BY: STEVEN M. SPENCER MAY 15, 1984 GOOD CORE SAMPLES

0.0- 3.0 UNDIFFERENTIATED SAND AND CLAY
3.0- 29.3 MICCOSUKEE FM.
29.3- 109.0 HAWTHORN GROUP
109.0- 129.0 ST. MARKS FM.
129.0- 293.2 SUWANNEE LIMESTONE
293.2- 322.0 OCALA GROUP

0 2 NO SAMPLES

2 3 SAND; YELLOWISH GRAY TO YELLOWISH GRAY; 30% POROSITY, INTERGRANULAR;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; MEDIUM SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-10%, SILT-01%, PLANT REMAINS-01%;

3 4 SAND; MODERATE ORANGE PINK TO VERY LIGHT ORANGE; 15% POROSITY, INTERGRANULAR;
GRAIN SIZE: MEDIUM; RANGE: FINE TO MEDIUM;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; MEDIUM SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: CLAY-15%, HEAVY MINERALS-01%, IRON STAIN-01%;
INTERVAL 3-4' IS TRANSITION FROM TOPSOIL INTO MICCOSUKEE FM.

4 11.7 SAND; GRAYISH ORANGE PINK TO MODERATE ORANGE PINK; 15% POROSITY, INTERGRANULAR;
GRAIN SIZE: MEDIUM; RANGE: FINE TO MEDIUM;
ROUNDNESS: ANGULAR TO SUB-ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: CLAY-15%, IRON STAIN-01%, HEAVY MINERALS-01%;
DISTINCT PURPLES AND PINK COLORS. THIN CLAY LAMINAE COMMON. GRADES ABRUPTLY INTO COARSER
CLAYEY SANDS.

Florida Geological Survey

W- 15537 CONTINUED PAGE 2

11.7- 13.7 SAND; LIGHT YELLOWISH ORANGE TO DARK YELLOWISH ORANGE; 18% POROSITY, INTERGRANULAR;
GRAIN SIZE: COARSE; RANGE: MEDIUM TO COARSE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; MEDIUM SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: CLAY-10%, HEAVY MINERALS-01%;

13.7- 15 SAND; GRAYISH ORANGE TO DARK GRAYISH RED; 15% POROSITY, INTERGRANULAR;
GRAIN SIZE: FINE; RANGE: FINE TO MEDIUM;
ROUNDNESS: ANGULAR TO SUB-ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: CLAY-10%, HEAVY MINERALS-01%, IRON STAIN-01%;
CLAY LAMINAE COMMON.

15 16 SAND; LIGHT YELLOWISH ORANGE TO DARK YELLOWISH ORANGE; 18% POROSITY, INTERGRANULAR;
GRAIN SIZE: MEDIUM; RANGE: MEDIUM TO FINE;
ROUNDNESS: ANGULAR TO SUB-ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: CLAY-10%;
CLAY LAMINAE COMMON. BECOMES UNCONSOLIDATED AT BOTTOM.

16 17.5 SAND; VERY LIGHT ORANGE TO LIGHT YELLOWISH ORANGE; 20% POROSITY, INTERGRANULAR;
GRAIN SIZE: MEDIUM; RANGE: FINE TO MEDIUM;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; LOW SPHERICITY; UNCONSOLIDATED;
ACCESSORY MINERALS: CLAY-03%, HEAVY MINERALS-01%;
CLAY LENSES ARE FEW.

17.5- 19.2 SAND; VERY LIGHT ORANGE TO LIGHT YELLOWISH ORANGE; 20% POROSITY, INTERGRANULAR;
GRAIN SIZE: MEDIUM; RANGE: FINE TO MEDIUM;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-07%, HEAVY MINERALS-01%;
GRADATIONALLY BECOMING MORE CLAYEY AND DARKER AT BOTTOM.

19.2- 19.9 CLAY BLEBS COMMON.

19.9- 21 CLAY; LIGHT YELLOWISH ORANGE TO MODERATE BROWN; LOW PERMEABILITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: LAMINATED, BEDDED, INTERBEDDED,
ACCESSORY MINERALS: QUARTZ SAND-25%, LIMONITE-05%, IRON STAIN-01%;
INTERBEDDED SAND AND LIMONITIC SAND COARSE TO FINE SIZE.

Bulletin No. 61

W- 15537 CONTINUED PAGE 3

21 28.7 SAND; DARK YELLOWISH ORANGE TO LIGHT YELLOWISH ORANGE; 15% POROSITY, INTERGRANULAR;
GRAIN SIZE: MEDIUM; RANGE: FINE TO COARSE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-07%, HEAVY MINERALS-01%;
SAND INTERBEDDED WITH CLAY LENSES AT 27.5' CLAY CONTENT INCREASING TOWARD BOTTOM.

28.7- 29.3 CLAY; GRAYISH ORANGE TO LIGHT YELLOWISH ORANGE; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-35%, HEAVY MINERALS-03%, MICA-01%;

29.3- 29.9 SAND LENSES COMMON WITH HEAVY MINERALS WITHIN.

29.9- 31.5 SAND; GRAYISH YELLOW TO DARK YELLOWISH ORANGE; 10% POROSITY, INTERGRANULAR;
GRAIN SIZE: MEDIUM; RANGE: FINE TO COARSE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: INTERBEDDED,
ACCESSORY MINERALS: CLAY-20%, HEAVY MINERALS-03%, MICA-01%;
CLAY LENS AT 29.5 & 30.5,SAND BECOMES BETTER CEMENTED BELOW 30.5'

31.5- 34 CLAY; LIGHT YELLOWISH ORANGE TO DARK YELLOWISH ORANGE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED, LAMINATED,
ACCESSORY MINERALS: QUARTZ SAND-35%, PHOSPHATIC SAND-03%, MICA-01%, HEAVY MINERALS-01%;
VERY SANDY IRON STAINED CLAY BECOMING MASSIVE AT 34', PHOSHATE. GRAINS (MEDIUM TO FINE)
BLEACHED WHITE, TRACE TO 2 OR 3%, BEGINNING AT 32.5'. KAOLINITE BLEBS THROUGHOUT.

34 36.5 CLAY; GRAYISH YELLOW TO LIGHT GRAYISH GREEN; LOW PERMEABILITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MASSIVE,
ACCESSORY MINERALS: PHOSPHATIC SAND-03%, QUARTZ SAND-03%, IRON STAIN-01%, MICA-01%;
WAXEY GRAY IRON STAINED CLAY WITH BLEACHED, FINE SIZE PHOSPHORITE SAND CONTENT INCREASES
AT 36.5'

36.5- 47 CLAY; VERY LIGHT ORANGE TO LIGHT YELLOWISH ORANGE; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-40%, PHOSPHATIC SAND-04%, HEAVY MINERALS-01%,
IRON STAIN-01%;
VERY SANDY WITH TRACE MICAS. GRADES INTO GRAYISH MASSIVE CLAY AT ABOUT 47'. 46.5-47.5
BLEACHED PHOSPHORITE PEBBLES IN UNCONSOLIDATED SAND AND CLAY.

47 49.2 CLAY; LIGHT GRAYISH GREEN TO LIGHT GREENISH YELLOW; LOW PERMEABILITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-05%, PHOSPHATIC SAND-03%, MICA-01%, IRON STAIN-01%;
BLEACHED PHOSPHORITE THROUGHOUT, VERY FINE SIZE. ABRUPT LITHO CHANGE AT 49.2' FROM WAXEY
CLAY TO CLAYEY SAND. TRACE HEAVIES.

Florida Geological Survey

W- 15537 CONTINUED PAGE 4

49.2- 55.7 SAND; VERY LIGHT ORANGE TO GRAYISH YELLOW; 15% POROSITY, INTERGRANULAR;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-20%, PHOSPHATIC SAND-04%, IRON STAIN-01%, MICA-01%;
THIN CLAY LENSES COMMON. GRADES INTO A MASSIVE CLAY. 2 INCHES THICK, MEDIUM TO COARSE SIZE
PHOSPHORITE SEAM AT 53.2'. TRACE HEAVIES.

55.7- 58 CLAY; LIGHT OLIVE GRAY TO VERY LIGHT ORANGE; LOW PERMEABILITY; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MOTTLED,
ACCESSORY MINERALS: QUARTZ SAND-05%, PHOSPHATIC SAND-04%;
GRADES INTO FINE SAND BELOW. WAXEY.

58 58.7 SAND; VERY LIGHT ORANGE TO GRAYISH YELLOW; 15% POROSITY, INTERGRANULAR;
GRAIN SIZE: FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: SUB-ANGULAR TO ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-10%, PHOSPHATIC SAND-04%, HEAVY MINERALS-01%;

58.7- 59.7 CLAY; LIGHT OLIVE GRAY TO LIGHT OLIVE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
SEDIMENTARY STRUCTURES: MASSIVE,
ACCESSORY MINERALS: PHOSPHATIC SAND-05%, QUARTZ SAND-04%, HEAVY MINERALS-01%;
WAXEY CLAY WITH BLEACHED PHOSPHORITE THROUGHOUT.

59.7- 60.7 SAND; VERY LIGHT ORANGE TO LIGHT OLIVE GRAY; 07% POROSITY, INTERGRANULAR;
GRAIN SIZE: VERY FINE; RANGE: VERY FINE TO FINE;
ROUNDNESS: ANGULAR TO SUB-ANGULAR; LOW SPHERICITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: CLAY-12%, HEAVY MINERALS-01%, PHOSPHATIC SAND-01%;

60.7- 64 CLAY; WHITE TO VERY LIGHT ORANGE; LOW PERMEABILITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-15%, HEAVY MINERALS-01%;
DARK MATERIAL THROUGHOUT TRACE AMOUNTS.

64 79 CLAY; WHITE TO YELLOWISH GRAY; LOW PERMEABILITY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
ACCESSORY MINERALS: QUARTZ SAND-15%, HEAVY MINERALS-01%;
CLAY INDURATION IS POOR TO UNCONSOLIDATED. SOME OF CORE MATERIAL LOST DURING DRILLING DUE
TO NATURE OF CLAY. UNCONSOLIDATED.

79 90.5 CLAY; WHITE TO VERY LIGHT ORANGE; GOOD INDURATION;
CEMENT TYPE(S): CLAY MATRIX, SILICIC CEMENT;
ACCESSORY MINERALS: QUARTZ SAND-05%, HEAVY MINERALS-01%, PHOSPHATIC SAND-01%;
P04 INDICATES DEFINITE PHOSPHATE CONTENT IN ROCK. CAVITY AT 84' -84.5, CAVITY FILLING
MATERIAL i.e.,SAND AND CLAY,FROM 83-84.5 AND 88-89. ABRUPT TRANSITION AT 90.5 INTO CLAY
CLAST ZONE.

Bulletin No. 61

W- 15537 CONTINUED PAGE 5

90.5- 104 CLAY; LIGHT GREENISH GRAY TO YELLOWISH GRAY; INTERGRANULAR; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX;
CLASTS OF HARD CLAY AS FLOAT IN CLAY MATRIX. P04 INDICATES PHOSPHATE IN OR ON WAXEY CLASTS
AND IN MATRIX MATERIAL.

104 109 CLAY; LIGHT GREENISH GRAY TO YELLOWISH GRAY; POOR INDURATION;
CEMENT TYPE(S): CLAY MATRIX, CALCILUTITE MATRIX;
ACCESSORY MINERALS: DOLOMITE-%;
FEW DOLOMITE NODULES. ABRUPT TRANSITION INTO INDURATED ZONE BELOW

109 111 DOLOMITE; YELLOWISH GRAY TO VERY LIGHT ORANGE; INTERGRANULAR,
INTERCRYSTALLINE; 10-50% ALTERED; SUBHEDRAL;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: MICROCRYSTALLINE TO VERY FINE; MODERATE INDURATION;
CEMENT TYPE(S): CLAY MATRIX, DOLOMITE CEMENT;
ACCESSORY MINERALS: CLAY-07%, QUARTZ SAND-05%;
QUARTZ SAND IN THE DOLOMITE. CLAY CONTENT DECREASING AT BOTTOM. TRACE ORGANIC.

111 115 LIMESTONE; VERY LIGHT ORANGE TO YELLOWISH GRAY; 05% POROSITY, INTERGRANULAR,
INTERCRYSTALLINE;
GRAIN TYPE: CALCILUTITE, CRYSTALS, BIOGENIC;
MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, CLAY MATRIX;
ACCESSORY MINERALS: DOLOMITE-10%, QUARTZ SAND-05%, CLAY-05%;
FOSSILS: FOSSIL FRAGMENTS;

115 115.5 DOLOMITE,CLAY AND QUARTZ SAND CONTENT VARIABLE AND DECREASING WITH DEPTH.
LOST CIRCULATION AT 115'.

115.5- 120 LIMESTONE; VERY LIGHT ORANGE TO WHITE; 05% POROSITY, INTERGRANULAR, INTERCRYSTALLINE,
MOLDIC;
GRAIN TYPE: CALCILUTITE, BIOGENIC, CRYSTALS;
GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, SPARRY CALCITE CEMENT;
ACCESSORY MINERALS: QUARTZ SAND-03%;
OTHER FEATURES: MEDIUM RECRYSTALLIZATION;
FOSSILS: MOLLUSKS, FOSSIL FRAGMENTS;

120 126 LIMESTONE; VERY LIGHT ORANGE TO WHITE; 08% POROSITY, INTERGRANULAR, INTERCRYSTALLINE,
MOLDIC;
GRAIN TYPE: CALCILUTITE, BIOGENIC, CRYSTALS;
GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, SPARRY CALCITE CEMENT, DOLOMITE CEMENT;
ACCESSORY MINERALS: DOLOMITE-25%, QUARTZ SAND-02%;
OTHER FEATURES: MEDIUM RECRYSTALLIZATION;
FOSSILS: MOLLUSKS, FOSSIL FRAGMENTS;
CAVITY 122-123. COMPOSITION VARIABLE CALCILUTITE TO CALCARINITE. GRADING INTO MORE
BIOGENIC AND DOLOMITIC MATERIAL.

Florida Geological Survey

W- 15537 CONTINUED PAGE 6

126 129 LIMESTONE; VERY LIGHT ORANGE TO YELLOWISH GRAY; 08% POROSITY, INTERGRANULAR,
INTERCRYSTALLINE, MOLDIC;
GRAIN TYPE: CALCILUTITE, BIOGENIC, CRYSTALS;
GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, DOLOMITE CEMENT;
ACCESSORY MINERALS: DOLOMITE-30%, QUARTZ SAND-02%;
OTHER FEATURES: MEDIUM RECRYSTALLIZATION;
FOSSILS: MOLLUSKS, FOSSIL FRAGMENTS;
CAVITY AT 126-129. BIOGENIC MATERIAL IN CRACKS. MINOR OR TRACE QUARTZ SAND EMBEDDED IN
LIMESTONE.

129 139 CALCARENITE; VERY LIGHT ORANGE; 15% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN TYPE: SKELETAL, BIOGENIC, CRYSTALS; 95% ALLOCHEMICAL CONSTITUENTS;
GRAIN SIZE: MEDIUM; RANGE: MEDIUM TO COARSE; GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, SPARRY CALCITE CEMENT;
ACCESSORY MINERALS: QUARTZ SAND-01%, IRON STAIN-01%;
FOSSILS: BENTHIC FORAMINIFERA, FOSSIL FRAGMENTS, MILIOLIDS, CONES;
WACKESTONE TO GRAINSTONE.

139 141 CALCARENITE; VERY LIGHT ORANGE TO DARK YELLOWISH BROWN; 10% POROSITY, INTERGRANULAR,
INTERCRYSTALLINE;
GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX, SILICIC CEMENT;
ACCESSORY MINERALS: CHERT-30%, IRON STAIN-01%;
WACKESTONE TO GRIANSTONE. 2-4 INCH CHERT LENSES PRESENT.

141 146 CALCARENITE; VERY LIGHT ORANGE TO WHITE; 16% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN TYPE: SKELETAL, BIOGENIC, CRYSTALS;
GRAIN SIZE: MEDIUM; RANGE: FINE TO COARSE; GOOD INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
FOSSILS: BENTHIC FORAMINIFERA, CONES, MILIOLIDS, FOSSIL FRAGMENTS;
ALLOCHEMS BECOME SMALLER IN SIZE.

146 154 CALCARENITE; VERY LIGHT ORANGE; 15% POROSITY, INTERGRANULAR, INTERCRYSTALLINE;
GRAIN TYPE: SKELETAL, BIOGENIC, CRYSTALS;
GRAIN SIZE: MEDIUM; RANGE: FINE TO COARSE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
FOSSILS: BENTHIC FORAMINIFERA, CONES, MILIOLIDS, FOSSIL FRAGMENTS;
GRADES FROM FINER GRAIN TO COARSE THEN GRADING TO FINER AT BASE.

154 160 CALCILUTITE; WHITE TO VERY LIGHT ORANGE; 05% POROSITY, INTERGRANULAR, LOW PERMEABILITY,
INTERCRYSTALLINE;
GRAIN TYPE: CALCILUTITE, BIOGENIC, CRYSTALS;
GRAIN SIZE: MICROCRYSTALLINE; RANGE: CRYPTOCRYSTALLINE TO FINE; MODERATE INDURATION;
CEMENT TYPE(S): CALCILUTITE MATRIX;
OTHER FEATURES: CHALKY;
FOSSILS: FOSSIL FRAGMENTS;
VERY TIGHT,GRADING INTO RECRYSTALIZED LIMESTONE. 3' CAVITY AT 16

	Front Cover
	Title Page
	Front Matter
	Table of Contents
	List of Illustrations
	List of Tables
	Acknowledgement
	Main
	Back Cover
	Spine

MILLISECOND	CLASS.METHOD	MESSAGE
0	sobekcm_page_globals.constructor
0	sobekcm_page_globals.constructor	Application State validated or built
0	sobekcm_database.verify_item_lookup_object
0	sobekcm_page_globals.constructor	Navigation Object created from URI query string
0	sobekcm_database.verify_item_lookup_object
0	sobekcm_page_globals.display_item	Retrieving item or group information
0	sobekcm_page_globals.get_entire_collection_hierarchy	Retrieving hierarchy information
0	sobekcm_assistant.get_entire_collection_hierarchy
0	cached_data_manager.retrieve_item_aggregation
0	cached_data_manager.retrieve_item_aggregation	Found item aggregation on local cache
0	item_aggregation_builder.get_item_aggregation	Found 'all' item aggregation in cache
0	system.web.ui.page.page_load (ufdc.page_load)
0	sobekcm_page_globals.constructor.on_page_load
0	html_echo_mainwriter.add_style_references	Adding style references to HTML
0	html_echo_mainwriter.add_text_to_page	Reading the text from the file and echoing back to the output stream
96	html_echo_mainwriter.add_text_to_page	Finished reading and writing the file