Artesian Water in 

Tertiary Limestone in 

the Southeastern States 

By V. T.. STRINGFIELD 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 517 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEW ART L. UDALL, Secretar:v 

GEOLOGICAL SURVEY 

William T. Pecora, Director 

Library of Congress catalog-card No. GS 66-293 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price $1.50 (paper cover) 
Abstract ----------------·------------·-----------------------------------------------· 

Introduction ----------------------------------------------------------------------· 

Previous reports ---------------------------------------------------------· 

Ackn ow ledg1nen ts --------·----------------------------------------------· Summary of geologic history and structure ___________________ _ 

Topography ------------------------------------------------------------------------· 

Physical divisions ------------------------------------------------------- Divisions in Florida _____________________________________________ _ 

Coastal Low lands ---------------------------------------

Central Highlands --------------------------------------

Tallahassee Hills ---------------------------------------

Marianna Lowlands ----------------------------------· 

Western Highlands ----------------------------------- Divisions in Georgia __________________________________________ _ 

Coastal Terraces -----------------------------------·------

Tifton Upland ---------------------------------------------- Dougherty Plain and Louisville Plateau .. Fort Valley Plateau ____________________________________ _ 

Fall Line Hills --------------------------------------------- Divisions in South Carolina. ____________________________ _ 

Drainage ---------------------------------------------------------------------------·· Relation of drainage to the principal artesian 

aquifer ----------------------------------------------------------------------

Suwannee, Withlacoochee, and Santa Fe 

Rivers ---------------------------------------------------------------- Streams south of the Suwannee River __________ _ 

Wi thlacoochee River ------------------------------------ St. Johns River _____________________________________________ _ 

Oklawaha River ------------------------------------~----

Lakes -------------------------------------------------------------------· 

Swamps and the Everglades------------------------------

Climate ------------------------------------------------------------------------------- Soils and their relation to aquifers. ________________________________ _ 

Coastal terraces and coastal lowlands _____________________ _ 

Uplands ------------------------------------------------------------------------

Geologic formations and their water-bearing 

properties ------------------------------------------------------------------------

General features ----------------------------------------------------------

Cretaceous System ------------------------------------------------------

Tertiary System ----------------------------------------------------------

Paleocene Series ------------------------------------------·------

Midway age -------------------·-··--------------------·------ Clayton, Porters Creek, and 

N aheola Formations -----------------·------ Cedar Keys Limestone _________________________ _ 

Eocene Series -------------------------------------------------------

Wilcox age -------------------------------------------------- Nanafalia, Tuscahoma, and 

Hatchetigbee Formations ---------·------

Oldsmar Limestone -----------------------------· 

Claiborne age ------------------------------------------------ Lake City Limestone in Florida .. _____ _ 

Highlands County -~---------------------­

Indian River County -------------------· 

CONTENTS 

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Geologic formations and their water-bearing 

properties-Continued 

Tertiary System-Continued 

Eocene Series-Continued 

Claiborne age-Continued 

Lake City Limestone in FloridaContinued 

Putnam County ----------------------------

Seminole County --------------------------

Volusia County ----------------------------

Tallahassee Limestone ------------------------

A von Park Limestone in Florida _______ _ 

Brevard County --------·-------------------

Highlands County ------------------------

Hillsborough County--------------------

Manatee County --------------------------

Martin County ------------------------------

Polk County ----------------------------------

Putnam County -------------·--------------

Seminole County ------·-------------------

Vol usia County ----------------------------

Jackson age -------------------------------------------------- Ocala Limestone in Florida. ______________ _ 

Brevard County ---·---------·---------·----

Highlands County ---------·---------·----

Hillsborough County ------------------ Indian River County ___________________ _ 

Manatee County --------------------------

Martin County -~-------------------------­

Pinellas County ----------------------------

Polk County -----------------------------·----

Putnam County ----------------------------

Seminole County --------------------------

Volusia County -----------------------·---- Ocala Limestone in Georgia. ______________ _ 

Savannah area ------------------------------

Calhoun County -----------------·----·----

Clay County ----------------------------------

Crisp County -------------·------------------

Dougherty County ---------------------- Lee and Sumter Counties ___________ _ 

Terrell County ------------------------------

Southwestern Georgia ----------------

Ocala Limestone in Escambia 

County, Ala. --------------------------------------

0 ligocen e Series --------------------------------------------------

Byram Formation ----------------------------------------

Chickasawhay Limestone -----------------------·----

Cooper Mar 1 -------------------------------------------------- Suwannee Limestone in Florida. ______________ _ 

Highlands County -------------------------------

Hillsborough County --------------------------

Martin County --------------------------------------

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IV 

.Goologic formations and their water-bearing 

properties-Continued 

Tertiary System-Continued 

Oligocene Series-Continued 

Suwannee Limestone in Florida--Continued 

Pinellas County ----------------------~-----------­

Polk County -----------------------------------------

Suwannee Limestone in Savannah 

area, Georgia --------------------------------------------

Flint River Formation --------------------------------

Southwestern Georgia -----------------------

Miocene Series ----------------------------------------------------- Tampa Limestone in Florida _____________________ _ 

Highlands County --------------------------------

Hillsborough County --------------------------

Manatee County ---------------------------------

Martin County -------------------------------------

Pinellas County ----------------------------------

Polk County ----------------------------------------- Tampa Limestone in Georgia _____________________ _ 

Savannah area --------------------------------------

Southwestern Georgia ------------------------ Alum Bluff Group ______________________________________ _ 

Hawthorn Formation in Florida _______ _ 

Brevard County ----------------------------

Collier County ------------------------------

Highlands County ------------------------ Hillsborough County ___________________ _ 

Indian River County ___________________ _ 

Manatee County----------------------------

Martin. County ------------------------------

Pinellas County ----------------------------

Polk County ---------------------------------

Seminole County --------------------------

Southeastern Florida _ 

Hawthorn Formation in G~~;ij~~~~=~ Tamiami Formation ------------------------------------

Duplin Marl and Choctawhatchee MarL __ 

Pliocene Series ------------------------------------------------------ . Alachua and Bone Valley Formations _____ _ 

Caloosahatchee Marl __ _ Charlton Formation -------------------------------

Citronelie Formation-----------------------------------

Quaternary System ------------------~~~-------------------------------

Pleistocene and Recent Seri~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Marine terraces 

~7:=:~:l:;;r~:~~~:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Fort Thompson Formation __________ _ Key Largo Limestone_________________ ---------------

Lake Flirt MarL-------------------------~~~~~~~~~~~~~~~~~ 

Geologic structure -------------------------------------------------------------

Major features ------------------------------------------------------------ Joints and fractures ___ _ Solution in limestone ____ ~~~~~~~~~---------------------------------------

Sol uti on ca viti es -------------------~~~~~---------------------------------­

Sinkholes and natural wells ----------------------------------

Lake basins due to solution ~:f--ii~;~t~~~----------------

Artesian water ----------------

Princi pies of--~~~~;;~~-;~~~~-------------------------------------------

Artesian aquifers in Terti~-;;--ii~~~t~~~~~~~~~~~~~~~~~~~ 

CONTENTS 

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Principal artesian aquifer--··-------------------------------------- Exten t and thickness ___________________________________________ _ 

Recharge and discharge -------------------------------------

Water-bearing properties ----------------------------------

Florida ----------------------------------------------------------

Alachua, Bradford, Clay, and 

Union Counties --------------------------------

Brevard County ------------------------------------

Collier County -------------------------------------

Columbia County --------------------------------

Duval and Nassau Counties _______________ _ 

Flagler, Putnam, and St. Johns 

Counties --------------------------------------------

Highlands County --------------------------------

Hills borough County --------------------------

Manatee County ----------------------------------

Martin County --------------------------------------

Pinellas County ------------------------------------

Polk County ------------------------------------------

Putnam County ------------------------------------

Seminole County ----------------------------------

Volusia County ----------------------------------

Georgia ---------------------------------------------------------- Rate of movement of water _______________________________ _ 

Artesian head and water levels ------------------------- Loss of artesian head and flow _________________ _ 

Fluctuations of artesian head and 

water levels ----------------------------------------------

Factors affecting fluctuations of 

artesian head and water levels _____________ _ 

Rainfall in recharge areas _________________ _ 

Surface drainage into wells _______________ _ 

Rivers ----------------------------------------------------

Changes in atmospheric pressure 

and wind -------------------------------------------- Ocean tides and earth tides _______________ _ 

Loads such as railroad trains 

and ships --------------------------------------

Earthquakes ----------------------------------------

Natural artesian flow or pumping 

from wells ------------------------------------------

Areas of artesian flow----------------------------------------

Atlantic Coast ----------------------------------------------

Southern Florida ----------------------------------------

Gulf Coast ----------------------------------------------------

Piezometric surface of water 

Georgia and South Caroli~~~~~~~~~~~~~~~~~~~~~~~~~~ 

Coastal counties ------------------------------------

Florida ----------------------------------------------------------

Western Florida ---------------------------------- Madison County area ___________________ _ 

Wakulla County area ------------------ Jackson County area ___________________ _ 

Florida peninsula -------------------------------- Polk County area _________________________ _ 

Pasco County area _______________________ _ 

Putnam County area ___________________ _ 

Marion County area _____________________ _ 

Volusia County area ___________________ _ 

Hillsborough County area _________ _ 

Citrus County area----------------------

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Artesian water-Continued 

Principal artesian aquifer-Continued 

Piezometric surface of water-Continued 

Florida-Continued 

Florida peninsula-Continued 

Suwannee River area ___________________ _ 

Southern Florida : ________________________ _ 

Relation of structure to solution cavities 

and movement of water in limestone ___________ _ 

Chemical quality of artesian water _________________ _ 

Total dissolved solids ----------------------------------

Silica --------------------------------------------------------------

Iron ---------------------------------------------------------------- Calcium and magnesium _____________________________ _ 

S tron ti urn ------------------------------------------------------

Sodi urn and potassi urn _________________________________ _ 

Bicarbonate ----------------------------··---------------------

Sulfate ---------------------------------------------------------

Chloride ------------------------------------------------------

Fluoride --------------------------------------------------------

Nitrate ------------------------------------------------------

Hardness ------------------------------------------------------

Hydrogen sulfide ------------------------------------------

Hydrogen-ion concentration ----------------------

Color --------------------------------------------------------------

Electrical cond ucti vi ty -------------------------------- Quality of water for irrigation _______________ _ 

Changes in quality of water in aquifers ___ _ 

Contamination of ground water _________ _ 

Ion exchange and natural softening of ground water _______________________________ _ 

Radiochemical elements ------------------------------

Tri ti urn -------------------------------------------------- Uranium and radium _________________________ _ 

Temperature of artesian water _________________ _ 

Thermal gradient --------------------------------

Salt water ------------------------------------------------------------ Chemical composition of sea water ___________ _ 

Relation of salt water to fresh ground 

water --------------------------------------------------------- Relation of salt water to artesian head ___ _ 

Gulf Coast --------------------------------------------

Atlantic Coast --------------------------------------

Salty ground-water areas related to the 

principal artesian aquifer------------------------------

Cretaceous formations --------------------------------

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Artesian water-Contin.ued 

Principal artesian aquifer-Continued 

Salty ground-water areas, etc.-Continued 

Tertiary and Quaternary formations _______ _ 

Savannah area, Georgia and 

South Carolina ----------------------------------

Brunswick, Georgia ----------------------------

East coast of Florida ---------------------------

Nassau County ----------------------------

St. Johns County ----~--------------------­

Putnam County ----------------------------

Flagler County ----------------------------

Volusia County ----------------------------

Seminole County --------------------------

Brevard County----------------------------

Indian River County ___________________ _ 

Southern Florida ---------------------------------- Gulf Coast of Florida _________________________ _ 

Sarasota and Manatee Counties 

Hillsborough and Pinellas 

Counties ------------------------------------

Hernando to Escambia Counties 

S pri"ngs ------------------------------------------------------------------

Wells ----------------------------------------------------------------------

Early exploration --------------------------------------- Records and yield of wells _________________________ _ 

Subsurface leakage in wells _____________________ _ 

Surface drainage into wells _______________________ _ 

Use of water and its effect on the 

principal artesian aquifer _____________________________ _ 

Summary and conclusions ---------------------------------------------------

Geologic formations ---------------------------------------------------

Geologic structure ------------------------------------------------------ So I uti on in limestone ___________________________________________________ _ 

Artesian aquifers -------------------------------------------------------- Artesian head and water levels _______________________________ _ 

Piezometric surface of water ___________________________________ _ 

Chemical quality ---------------------------------------------------------- Temperature of artesian water _______________________________ _ 

Salt water in aquifers--------------------------------------------------

Springs --------------------------------------------------------------------------

Wells ------------------------------------------------------------------------------

Future studies ___ ·------------------------------------------------------------------

Selected references __ ··----------------------------------------------------------

Index -------------------------------------------------------------------------------------

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VI CONTENTS 

ILLUSTRATIONS 

Page 

FIGURE 1. Map showing counties in the Southeastern States____________________________________________________________ 4 

2. Map showing physical divisions-------------------------------------------------------:-------------------------------------- 5 

3. Generalized geologic map of the Coastal Plain of the Southeastern States_____________________ 22 

4. Sketch map of Florida and adjacent States showing Floridian Plateau and top of 

Eocene formations ------------------------------------------------------------------------------------------------------------· 24 

5. Photograph of relief model of Floridian Plateau .. --------------------------------------------------------------· 25 

6. Isopach map of Cenozoic sediments----------------------------------------------------------------------------------------· 26 

7. Geologic section from Hancock County, Ga., to Monroe County, Fla_______________________________ 27 

8-14. Photograph of8. Ocala Limestone in Citrus County, Fla___________________________________________________________________ 46 

9. Mouth of natural well near Brooksville, Fla_______________________________________________________ 47 

10. Cavity in Ocala Limestone south of Ocala, Marion County, Fla_______________________ 47 

11. Ocala Limestone showing eroded surface--------------------------------------------------------------· 4 7 

12. Ocala Limestone showing chalky part of formation in Marion County, Fla... 47 

13. Tampa Limestone showing bedding, Hernando County, Fla_______________________________ 56 

14. Tampa Limestone showing pockets of clay, Hernando County, Fla___________________ 56 

15. Isopach map of Pliocene, Pleistocene, and Recent Series___________________________________________________ 65 

16-20. Map showing16. Early Pleistocene shorelines in the Southeastern States_____________________________________ 69 

17. Shoreline of the Wicomico sea in the Southeastern States_________________________________ 69 

18. Shoreline of the Penholoway sea in the Southeastern States.____________________________ 70 

19. Shoreline of the Talbot sea in the Southeastern States_______________________________________ 70 

20. Shoreline of the Pamlico sea in the Southeastern States___________________________________ 71 

21. Photograph of natural well1:1 or solution tubes in the Miami Oolite near Miami, Fla... 72 

22. Map showing major structural features and sedimentary provinces in southeastern 

Alabama, Florida, and southeastern Georgia_________________________________________________________________ 7 4 

23. Contour map of top of principal artesian aquifer.------------------------------------------------------------· 96 

24. Map showing extent of the chief artesian aquifers in the Coastal Plain in Georgia_____ 97 

25. Fence diagram showing principal artesian aquifer in southeastern Georgia_______________ 99 

26. Photograph of manhole over drainage welL ________________________________________ ·------------------------------· 112 

27. Photograph of drainage well spouting water at Lake Fairview, Orange County, Fla... 112 

28-31. Map showing28. Areas of artesian flow------------------------------------------------------------------------------------------------· 118 

29. Piezometric surface of water in the principal artesian aquifer, 1961.______________ 120 

30. Original piezometric surface in the principal artesian aquifer in the 

coastal area of Georgia and northeastern Florida about 1885------------------· 121 

31. Piezometric surface in the principal artesian aquifer in the coastal area of Georgia and northeastern Florida in 1940 ________________ 7

______________________________ 121 

32. Profiles of piezometric surfaces across central and north-central Florida.____________________ 122 

33. Profile of piezometric surface in the southern part of Marion Count~, Fla___________________ 122 

34. Relation of salt water to fresh water in aquifers·----------------------------------------------------------· 156 

35. Section across southern Florida showing relation of salt water to fresh water in 

the principal artesian aquifer------------------------------------------------------------------------------------------· 15 9 

36. Map showing areas where water of principal artesian aquifer has more than 

100 ppm chloride ____________________________________________________________________________________ ------------------------------· 166 

37. Map showing location of large springs___________________________________________________________________________________ 177 

38-41. Photograph of38. Silver Springs, Marion County, Fla. ___________ ---------------------------------------------------------· 179 

39. Rainbow Springs, Marion County, Fla___________________________________________________________________ 179 

40. Weekiwachee Spring, Hernando County, Fla -----------------------------------------------------· 179 

41. Submarine Spring, 2% miles east of coast at Crescent Beach, Fla ___ ,_______________ 183 

42. Section across Putnam and St. Johns Counties, Fla ------------------------------------------------ 183 

43. Section through Kissengen Springs, Polk County, Fla.-----------------------------------------------------· 184 

44. Photograph of artesian well near Belle Glade, Palm Beach County, Fla_______________________ 187 

45. Photograph of artesian well in Flagler County, Fla._________________________________________________________ 187 

46. Diagram of four methods used in casing wells____________________________________________________________________ 188 

47. Map showing consumption of artesian water in the principal industrial areas 

in coastal counties of Georgia and northeastern Florida___________________________________________ 192 
CONTENTS 

TABLES 

Page 

TABLE 1. Correlation of Tertiary formations in south-central and southeastern Alabama, 

Florida, Georgia, and southeastern South Carolina_____________________________________________________ 28 

2-5. General stratigraphic sections and water-bearing properties of Tertiary 

formations in2. Southeastern Alabama --------------------------------------------------------------------------------------------· 29 

S. Florida ------------------------------------------------------------------------------------------------------------------· 30 

4. Georgia ----------------------------------------------------------------------------------------------------------------· 32 

5. South Carolina -------------------------------------------------------------------------------------· 34 

VII 
ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

By V. T. STRINGFIELD 

ABSTRACT 

In Florida, southern Georgia, and adjacent parts of Alabama and South Carolina an artesian aquifer system of 

Tertiary age is the source of some of the largest groundwater supplies in the United States. The aquifer system consists of as many as eight formations, chiefly limestone. The 

area of this system discussed in this report includes all 

Florida and most of the Coastal Plain in Georgia as well as 

adjacent parts of South Carolina and Alabama and extends 

from the Atlantic coast as far inland as the Fall Line in a 

few places. The area is in the Atlantic and Gulf Coastal Plain 

province-a region of plains and low hills. Most of the region 

is covered by Pleistocene coastal terraces rising from sea level 

to as much as 270 feet above sea level; the higher hills between the terraces and thf;' Fall Line are as much as 600 feet 

above sea level. Valleys are cut as much as 100 feet below 

some uplands. Some of the principal streams, such as the 

Savannah River, rise in the Piedmont province and flow 

across the Coastal Plain in Georgia and adJacent parts of 

South Carolina, Florida, and Alabama to the sea. The other 

streams rise within the area of the report. 

The climate ranges from temperate in South Carolina and 

Georgia to subtropical in southern Florida. The average annual rainfall ranges from about 38 to 60 inches. The lowest 

rainfall is on the Florida Keys. 

Sedimentary formations which crop out in this region range 

from Cretaceous to Recent in age. Igneous and metamorphic 

rocks underlie the Cretaceous formations and appear at the 

surface in the Piedmont province. The Cretaceous formations 

consist chiefly of sand, gravel, and clay in the areas where 

they are at or near the surface. The overlying Tertiary formations consist chiefly of limestone, dolomite, and marl, with 

some anhydrite and gypsum. Some formations grade into 

sands and other clastic material in western Florida, southeastern Alabama, the southwestern part of the Coastal Plain 

in Georgia, the northeastern part of the Coastal Plain in 

Georgia, and adjacent parts of South Carolina. Pleistocene 

and Recent deposits, consisting chiefly of sand and gravel, 

clay and shells, generally are less than 100 feet thick. In 

southeastern Florida the Pleistocene formations, however, include at least 250 feet of limestone, marl, sand, and shell beds. 

The Tertiary formations are at or near the surface in belts 

approximately parallel to the Cretaceous outcrops and the 

Fall Line in Georgia and adjacent parts of Alabama and 

South Carolina. The Tertiary formations are also near the 

surface on some geologic structural features, such as the 

Ocala uplift in north-central Florida and on the Chattahoochee anticline in western Florida. Except where affected 

by local structural features, the formations dip gently toward 

the coast at right angles to the belt of outcrops. The formations dip in all directions from the Ocala uplift. In Florida, 

the thickness of the Tertiary formations ranges from less 

than 1,600 feet on the northwest side of the Ocala uplift to 

about 4,500 feet in western Florida. The thickness is about 

2,500 feet in southern Georgia, 2,400 feet at Parris Island, 

S. C., and more than 5,500 feet in southern Florida. The 

oldest of the formations are at or near the surface in the 

belt of outcrops extending from northeastern Alabama into 

central Georgia. In Florida the Avon Park Limestone of 

middle Eocene age represents the oldest rocks exposed. These 

exposures are in a small area on the Ocala uplift. The Ocala 

Limestone and younger formations are exposed in large areas 

on the Ocala uplift and in Jackson and adjacent counties in 

western Florida. 

The chief water-bearing limestones, ranging in age from 

middle Eocene to middle Miocene, form the principal artesian 

aquifer, which Is the chief source of ground water in a large 

part of the region. The formations of the principal aquifer 

include, from bottom to top, the Lake City Limestone, Tallahassee Limestone, and A von Park Limestone of middle Eocene 

age; Ocala Limestone of late Eocene age; Marianna and Suwannee Limestones of Oligocene age; and the Tampa Limestone of Miocene age. In part of the area the lower part of 

the Rawthorn of Miocene age forms the upper part of the 

principal artesian aquifer. 

The formations yield water from permeable zones in the 

limestone and from solution cavities, some of which are filled 

with permeable sand. Some of the limestones grade into sandy 

formations in the subsurface in western Florida, southeastern 

Alabama, and in some areas of outcrops in Georgia and South 

Carolina. The shallow formations in southeastern Florida, 

consisting chiefly of cavernous limestone, ranging in age from 

late Miocene to Pleistocene, form a productive aquifer overlying the principal artesian aquifer. The shallow sands are 

good aquifers in the Pensacola and Cantonment areas in 

Escambia County, Fla. 

In addition to the gentle homoclinal eastward dip of the 

beds, the geologic structural features include ( 1) the peninsular arch, (2) Ocala uplift and arch on its east flank, and 

( 3) the Chattahoochee anticline. There are several embayments, including one in southwestern Georgia, which extends 

into the· Apalachicola embayment in Florida and others in 

southeastern Georgia and southern Florida. Two joint systems are present in the limestone in most, if not all, of the 

region. Jointing and faulting on the Ocala uplift appear to 

reflect structural movement during the late Tertiary. Many 

solution cavities formed in the limestone and associated rocks, 

especially where they are at or near the surface. Sinkholes 

and vertical shafts extend from the surface to underground 

solution channels. in some of ~hese areas. In the lake regions 

in Florida and Georgia, the sinkholes, or vertical solution 

openings, extend through the Hawthorn Formation, which 

overlies the limestone of the principal artesian aquifer. Sinkholes also occur in the Gulf of Mexico area west of the 

Florida peninsula. 

Although solution is continuous where there is circulation 

1 
2 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

of water, as at the present time, there is evidence that most 

of the solution in the water-bearing formations occurred in 

Pleistocene time. The principal artesian aquifer has cavities 

and solution channels probably comparable in size and extent 

to those in Mammoth Cave, Ky. 

Water enters artesian aquifers in areas of relatively high 

altitudes where the aquifer is at or near the land surface or 

is overlain . by permeable material. From such intake or recharge areas the water reaches the permeable rocks and 

gradually moves laterally downgradient into the aquifer 

under confining beds in response to pressure produced by 

recharge. All aquifers are both reservoirs and. conduits. 

Under artesian conditions, however, they function chiefly as 

conduits in which water moves many miles from recharge 

areas to discharge areas. 

The Tertiary limestones include many local aquifers and 

one principal aquifer. The principal aquifer, as much as 1,000 

feet thick, underlies Florida, southern Georgia, and adjacent 

parts of South Carolina and Alabama. It is the source of 

nearly all the artesian water in Florida and southeastern 

Georgia. In Florida, it is commonly called the Floridan 

aquifer. The top of the aquifer ranges from more than 100 

feet above sea level to as much as 1,000 feet below sea level. 

As a hydrologic unit, the principal aquifer is unusual in its 

thickness and areal extent. It is the source of the large 

springs in Florida and Georgia and yields water to thousands 

of artesian wells. 

The piezometric surface, or the height (with reference to 

sea level) to which water in an artesian aquifer would rise 

in wells, shows the chief areas of recharge and discharge and 

direction of lateral movement of the artesian water. In general, the high areas of the piezometric surface indicate recharge, and the low areas indicate discharge. Recharge may, 

however, occur in some of the areas of relatively low pressure. 

The piezometric surface ranges from sea level near some 

coastal areas to more than 120 feet above sea level in the lake 

region of central Florida and in the Jackson County area in 

western Florida. The piezometric surface is as much as 250 

feet above sea level in an outcrop area of the aquifer, extending from southeastern Alabama northeastward across Georgia 

to South Carolina. The aquifer is recharged, not only in areas 

where it is at or near the land surface, but also where the 

overlying beds have been penetrated· by sinkholes. In general 

the piezometric surface slopes to the east, southeast, and south 

from the high area in Georgia. In the Valdosta area in 

Lowndes and Brooks Counties, where there is local recharge 

through sinkholes and drainage wells, the piezometric surface 

is as much as 100 feet above sea level. 

The lateral movement of water is generally from the recharge areas. Although the lateral movement may be controlled over considerable distances by geologic structure and 

the movement may be parallel to the dip of the formations, 

the relative positions of the recharge and discharge areas are 

more important than the geologic structure in controlling the 

direction of the movement of the water in the area of this 

report. For example, the lateral movement of the water in 

the Polk County area, Florida, is in all directions from the 

recharge area, even though it is on the flank of the Ocala 

uplift. 

Joints or fractures and bedding planes may have a pronounced effect on the patterns and movement of water in limestone and associated rocks. Solution features, such as vertical 

pipes or natural wells, in the limestone appear to have formed 

in the zone of aeration at the intersection of two sets of joints. 

Long shallow vertical openings were formed along some joint 

planes. Lateral movement may be locally along bedding 

planes, but the movement generally does not appear to be 

· affected by regional structures. The cavities and· horizontal 

solution channels were formed chiefly in the upper part of 

the zone of saturation, nearly parallel to the hydraulic 

gradient. 

The chemical quality of the ground water may be divided 

into the following types: (1) Calcium bicarbonate water, its 

hardness ranging from about 50 to several hundred parts per 

million; most of the artesian water belongs to this type except in southern Florida and in some of the coastal areas 

where the fresh artesian water is mixed with remnants of 

sea water. (2) Calcium sulfate water, its hardness as much 

as 900 ppm (parts per million); some of the artesian water 

in southern Florida is of this type. ( 3) Sodium bicarbonate 

water, its hardness less than 50 ppm, the total dissolved 

solids being relatively high; this type of water occurs in the 

principal artesian aquifer in western Florida and adjacent 

parts of Alabama and Georgia. ( 4) Sodium chloride water in 

some parts of the coastal areas and southern Florida. ( 5) Soft 

water, its total dissolved solids less than 50 ppm in the surficial 

sands; the public supply of Pensacola and other supplies in 

Escambia County, Fla., are of this type, as are many of the 

shallow domestic supplies. 

The temperature of ground water at depths of about 30 to 

60 feet is generally about 2° to 3°F above the mean annual 

temperature. The temperature of water in the principal 

artesian aqu'ifer, as measured at the mouth of flowing wells, 

ranges from about 62°F in South Carolina to 90°F in Martin 

County in southern Florida. 

Salt water in fresh-water aquifers may be from (1) encroachment of sea water in the coastal areas, (2) originally 

entrapped sea water or sea water that entered the aquifer 

during a high stand of the sea in Pleistocene time, or (3) thin 

salt beds and sea water concentrated in tidal lagoons or other 

enclosed areas. Water having a relatively high chloride content is present in the artesian aquifer in coastal areas of 

Florida south of St. Augustine, in southern Florida, and also 

in the St. Johns River valley where the aquifer is near 

sea level. 

The principal artesian aquifer is the source of many large 

springs. Silver Springs and Rainbow Springs in Marion 

County are the largest, their combined flow being 2,310 cfs 

(cubic feet per second). The largest known submarine spring 

is about 2% miles east of Crescent Beach, Fla. There are 

many submarine springs from the principal artesian aquifer 

in the Gulf of Mexico on the coast from Pasco County to 

Wakulla Courity, where the aquifer ~orms the ocean floor. 

Artesian wells range from 50 to more than 1,000 feet in 

depth and from 2 to more than 24 inches in diameter. Wells 

in the principal artesian aquifer are finished without screens 

except, in areas such as western Florida, where the waterbearing formations consist of sand and other unconsolidated 

material. The yield of natural-flow wells ranges from a few 

gallons to several thousand gallons per minute. 

The principal artesian aquifer is the chief source of ground 

water for municipal, industrial, and irrigation supplies in the 

area of this report. Most of the public water supplies, including 

those for Savannah, Jacksonville, and St. Petersburg, are from 

the principal artesian aquifer. Supplies for the Miami area 

and Pensacola are from shallow aquifers overlying the prin-
INTRODUCTION 3 

cipal artesian aquifer. The estimated quantity of water used 

in 1960 for public supplies in Florida, chiefly from the principal artesian aquifer, was 502 mgd (million gallons per day). 

The quantity for private supplies used for industrial and commercial purposes was 657 mgd. Large quantities of water are 

used for irrigation in Florida, especially for truck and citrus 

crops in the peninsula. 

In Georgia the largest use of artesian water is in the coastal 

areas, where the estimated annual discharge was 279 mgd in 

1960. Of that amount, 197 mgd was for industrial use, 31 mgd 

for public supplies, and 21 mgd for domestic supplies. About 

30 mgd, a large part of which is not used, flows continuously 

for domestic and stock use and for game preserves. The quantity of water used for irrigation in Georgia is small in comparison with that in Florida and is only a fraction of 1 

percent of the total discharge in Georgia. 

Although the total quantity of water withdrawn from the 

principal artesian aquifer in the report area is large, it is 

only part of the billions of gallons of water naturally discharged each day. This abundant resource, which is not fully 

utilized in much of the region, will require continued systematic local and regional investigations of the geology and 

hydrology to provide the information required for its wise 

and full use. 

INTRODUCTION 

The area of this report (fig~. 1, 2) includes Florida, 

most of the Coastal Plain in Georgia, and adjacent 

parts of Alabama and South Carolina. In this area, 

artesian water is the source of most of the large 

and many of the small supplies of water. Most of 

the potable artesian water in Florida and in part of 

southeastern Georgia is in limestone of Tertiary age. 

The limestone aquifer, composed of several formations, is overlain and underlain by formations of 

sands, clays, shales, and limestone. The limestone 

unit represents one of the most productive aquifer 

systems in the United States. Although there is an 

apparent abundance ~f ground water, the region 

has many problems, many of which relate to the 

quality of the water. The problems will increase, 

and the management of water resources is especially 

important because of the delicate interrelation of · 

potable and impotable water in the aquifer. The 

main purpose of the report. is to furnish background 

information to persons· interested in ground-water 

conditions in the area. 

This report is based on the results of fieldwork 

and reports of investigations, many of which are 

listed in the references. Discussions are included on 

counties for which ground-water reports are available. In addition to a regional description of the 

geologic formations and their water-bearing properties, artesian conditions and areas of recharge 

and discharge of the principal artesian aquifer are 

given. The discussion on the quality of water contains comments about radium, uranium, and tritium, 

in addition to the major chemical constituents. The 

distribution of salt water and its relation to fresh 

water in aquifers is described. 

PREVIOUS REPORTS 

Many publications relating to the report area of 

the U.S. Geological Survey, of the State Geological 

Surveys, and of other State agencies are included 

in the list of references. A list of publications on 

ground water from 1885 to 1957 is contained in 

bibliographies by Waring and Meinzer (1947) and 

Vorhis (1957). References to reports on ground 

water are contained in the U.S. Geological Survey's 

"Bibliography of North American Geology" published for the years 1785-1962. 

Regional reports on geology of the report ·area 

include those by LeGrand (1961b and 1962), Applin 

and Applin (1944, 1947, and 1965), Toulmin (1955), 

Johnston, Trumbull, and Eaton (1959), and Murray 

( 1961). Previous work on ground water .is given in 

this report by States. Recent sQmmaries by States 

are given by McGuinness (1963). Most. of the investigations ·on ground water in Florida and Alabama 

have been by the U.S. Geological Survey and the State 

Geological Surveys. The work in Georgia has been 

chiefly by the U.S. Geological Survey and the Georgia 

Department of Mines, Mining, and Geology (Georgia 

Geological Survey). In South Carolina much of the 

work has been by the U.S. Geological Survey in co.:. 

operation with the South Carolina Development 

Board. 

One of the earliest of the reports of the Florida 

Geological Survey is by Sellards (1908) on the underground water supply of central Florida. This bulletin 

contains discussions of deep and shallow wells, 

spring and artesian prospects, effects of underground 

solution, drainage of lakes, ponds arid swamp lands, 

water analyses, and well records. A report on the 

underground water supply of west-central and western Florida (Sellards and Gunter, 1912) followed. 

A report by Matson and Sanford (1913) is one of 

the most comprehensive of the reports on the ground 

water of the entire State. In the same year a report 

by Sellards and Gunter (1913, p. 103-290) on the 

artesian water of eastern and southern Florida was 

published. A report by Gunter and Ponton (1931, 

p. 43-55) contains an article. on the need for conservation of the water supply and a contour map 

that represents the height to which artesian water 

would rise in wells in the Ocala Limestone in part 

of Florida. It also includes a contour map (Malcolm 

Pirnie, written commun., 1927) showing the height 

to which water would rise in wells in the Ocala 
4 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

84° 83° 82° 81° $00 

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z 

8 

-

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27° 

26° 

25° INDEX MAP SHOWING AREA OF THIS REPORT 

50 0 50 

L.~~L-L-~-------~--------~ ........ _ .___.____ ___ __ ---- FIGURE 1.-Counties in the Southeastern States. 
30"' 

INTRODUCTION 

t"" 

·~~~~~==~----~~~-F=~~~=~~~~~~~~r---~.----i,->---------T--1 

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0 

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z 

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~ 

~ 

'Z. 

29" .... ---- -

28" ------~------r-------1--------ho------+--fl 

27" 

50 0 50 100 MILES 

25" --------~-------1-------1-------l-------~-------l 

FIGURE 2.-Physical divisions (Cooke, 1939, p. 14; LaForge and others, 1925, p. 17; and Fenneman, 1938). 

5 
6 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Limestone in the Jacksonville area. The original report by Pirnie, consulting engineer for the Water 

Supply Commission of Jacksonville, also includes 

a generalized contour map described as representing 

the ground-water ~able in part of Florida. It, like 

the contour map of J-acksonville, is based on water 

levels in the limestone instead of the water table. 

One of the first county reports (Stringfield, 1933c, 

p. 121-194) on artesian water showed that the artesian water in Sarasota County, Fla., moves through 

the limestone from east to west, indicating that the 

water enters the limestone in an area east of the 

county. Previously, the available information on 

the artesian water and geology of Florida· indicated 

that the limestone aquifer is recharged on the Ocala 

uplift in Marion County, north of Sarasota County 

in the vicinity of Ocala, where the limestone is at 

or near the ground surface and that the water 

moves downdip. 

Stringfield's study in Sarasota County showed the 

need of a regional investigation of artesian water in 

order to obtain a better understanding of the recharge and discharge areas and the direction of 

movement of the artesian water. The work in Sarasota County and other parts of Florida also showed 

the value of obtaining additional information on .the 

relation of the fresh artesian water to the salt water 

. in the artesian aquifer .. Therefore, a general survey 

of the artesian water in the Florida peninsula was 

undert~ken in 1933, when Federal public works 

funds became available. 

The results of that study (Stringfield, 1935, p. 524-

529; Stringfield and Westendick, 1935, p. 5-16; 

Stringfield, 1936, p. 115-195) as .stated by Vernon 

(1955, p. 39) showed that·the artesian limestone is 

recharged in some of the lake regions through lakes 

that occupy sinkholes filled with unconsolidated permeabl~ sand and silt. A piezometric map (Stringfield, 

1936, pl. 12) representing the height to which water 

would rise in tightly cased wells in the artesian 

limestone aquifer showed extensive recharge and 

discharge areas and the general direction of movement of the artesian water throughou~ the Florida 

peninsula. 

In 1936 Stringfield and Westendick mapped and 

described the piezometric surface of artesian water 

in the remainder of the State in an unpublished 

manuscript, "Artesian Water West of the Suwannee 

River in Florida." That map (combined with the 

maps of the Florida peninsula and southeastern 

Georgia and South Carolina)·· has been published 

with slight modification in different reports. With 

this new information on the artesian system in 

Florida came a better understanding of the occur-

_rence and movement of the artesian water and the 

relation of salt water to fresh artesian water. 

A report of the U.S. Army, Corps of Engineers 

(1933) at Jacksonville and a document (U.S. Congress, 1936) on routes for a ship canal across Florida 

contain information on the geology and ground 

water of the central and northern parts of the 

Florida peninsula. The reports include a map described as representing the water table in the peninsula. However, for much of the area the map represents the water in the limestone that is under artesian 

pressure throughout most of Florida. The water 

level in wells in the limestone is generally above or 

below the water table in the overlying formations. 

Reports by Cooke and Mossom (1929, p. 29-228), 

Cooke· (1945), and Puri and Vernon (1959) describe 

the geology of Florida. The report by Cooke and 

Mossom includes a geologic map of the State showing 

the distribution of the geologic formations at or 

near the surface. The 1945 report by Cooke also 

includes a geologic map of the State. Vernon and 

Puri ( 1956) summarized the geology of western 

Florida in a guidebook to surface exposures. 

In their report on the subsurface stratigraphy 

and structure of Florida· and southern Georgia, Applin and Applin (1944, p. 1674-1677) included a 

review of the most significant contributions to that 

subject in Florida and southern Georgia. The geologic structure is described in several reports including those by Mossom (1926, p. 171-268), Applin 

and Applin (1947), Pressler (1947), Toulmin (1955), 

and Vernon (1951). A comprehensive report by 

Parker, Ferguson, Love, and others (1955) gives information on the Cenozoic geology and hydrology 

of southeastern Florida. 

During the past decade, 1955-65, detailed information on ground water by counties and local areas 

has been published by the Florida Geological Survey. 

These are included in the references at the end of 

this report. 

Two of the earliest reports on artesian waters in 

the .Coastal Plain in Georgia and South Carolina 

are by Darton (1896) and McCallie (1898). A preliminary report on the underground waters of Georgia by McCallie (1908) in_cludes information on the 

artesian water in the Coastal Plain in Georgia. Stephenson and Veatch (1915) prepared the first comprehensive report on artesian water in the Coastal 

Plain in Georgia. · · 

The work on the artesian water in Florida in 1933 

showed that the piezometric surface of the artesian 
SUMMARY OF GEOLOGIC HISTORY AND STRUCTURE 7 

water in the principal limestone aquifer underlying 

Florida extends into Georgia. Therefore, in 1939 

and 1940, Warren (1944) mapped the aquifer in 

Georgia and southeastern South Carolina in cooperation with Georgia Department of Mines, Mining and 

Geology. Herrick and Vorhis (1963) included maps 

showing the thickness and structure of the Tertiary 

and Cretaceous formations in Georgia. 

Description of wells and other information on 

ground water by counties in the Coastal Plain in 

South Carolina are included in a report by Cooke 

(1936). Siple (1946) and (1957a) briefly outlined 

the geology and ground water in the Coastal Plain 

in South Carolina. The report in 1957 includes a 

map of the piezometric surface of artesian water in 

the Tuscaloosa Formation in parts of Aiken and 

Barnwell Counties, S.C., and in Burke County, Ga. 

A report by E. A. Smith (1907) includes information on artesian water in the Coastal Plain in Alabama. Ground water in southeastern Alabama is 

described by LaMoreaux (Carter and others, 1949, 

p. 200-265). Cagle and Floyd (1957) described 

ground water in Escambia County with special 

reference to the Brewton area. Cagle and Newton 

(1963) also described the ground-water resources 

of Escambia County, Ala. 

ACKNOWLEDGMENTS 

Among the many associates who contributed 

helpful information concerning Florida are H. H. 

Cooper, Jr., Nevin Hoy, D. W. Brown, Herbert Stewart, W. S. Wetterhall, M. I. Rorabaugh, Clyde Conover, H. G. Healy, J. T. Barraclough, G. Warren Leve, 

and others in the Ground-Water Branch at Tallahassee. Mr. Hoy reviewed the report and made many 

helpful suggestions. Mr. Brown reviewed and revised 

the table of geologic formations in Florida for the 

present report. At Ocala, K. A. MacKichan, Larry 

Toler, and Warren Anderson reviewed parts of the 

report and made helpful suggestions. 

C. W. Cooke was especially helpful on the history 

of the Pleistocene terraces and changes in sea level. 

His interpretation of the Pleistocene is used in this 

report. F. Stearns MacNeil gave suggestions on the 

geology. 

R. 0. Vernon, State Geologist of Florida, and 

members of his staff reviewed the table of geologic 

formations and furnished much information on the 

geology and hydrology of the State. 

Lyman Toulmin, professor of geology, Florida 

State University, Tallahassee, reviewed the report, 

including the correlation charts and tables of formations, and made many helpful suggestions. 

S. M. Herrick and Robert Vorhis reviewed and revised the table of geologic formations in Georgia. 

Other contributors at Atlanta include J. W. Stewart, 

Robert Wait, J. T. Callahan, and H. B. Counts. 

J. W. Powell and John Newton in Alabama reviewed and revised the table of geologic formations 

in Alabama. George Siple prepared the table of 

geologic formations in South Carolina and contributed other information on geology and hyd~ology. 

Among my other associates, H. E. LeGrand, R. M. 

Richardson, and W. C. Rasmussen, U.S. Geological 

Survey, and W. 0. George, consulting geologist in 

Texas, made many suggestions on geology and hydrology. I am especially indebted to LeGrand and 

Richardson for their assistance in revising the first 

draft of the report. L. L. Thatcher made suggestions 

on the section on tritium. Rodney Hart, D. J. Casey, 

Carolyn Jorgensen, and G. M. Bradford prepared 

the first draft of the illustrations. 

Barbara Stringfield assisted in the preparation of 

the final draft of the manuscript. Verda M. Dougherty not only checked the geologic nomenclature and 

the references to the literature but also carefully 

reviewed the entire report. 

SUMMARY OF GEOLOGIC HISTORY AND STRUCTURE 

As the geologic history and structure of the region 

of this report had a significant effect on ( 1) the 

water-bearing properties of the geologic formations, 

(2) the quality of the1 artesian water, (3) the present 

topography, ( 4) drainage, and (5) areas of recharge 

of the aquifers, a brief summary is given here. 

Some of the effects of the regional structure on the 

distribution, thickness, and lithology of the sedimentary formations have been described by Applin 

and Applin (1965, p. 1-80). Their interpretation 

of the structure at different stages in the tectonic 

history of central and southern Florida is shown 

in the cross sections from Marion County on the 

north to Monroe County on the south (1965, pl. 11). 

The sea advanced over the· region and retreated 

many times in the history of the Coastal Plain. 

After each retreat of the sea, formations exposed at 

the surface were affected by weathering and erosion. 

As stated by LeGrand (1962, p. 24-26), after the 

Cretaceous formations were deposited and the sea 

withdrew, a gradual seaward tilting of the Coastal 

Plain caused the sea in Tertiary time to advance and 

deposit sediments, chiefly limestone in the area of 

this report. After being deposited, some limestone 

formations were exposed to erosion and solution 

during the time the sea retreated from the region. 

Like the underlying Cretaceous formations, the 
8 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Tertiary deposits, chiefly limestone with dolomite 

and anhydrite, thicken in a general downdip coastward direction. In the Florida peninsula anhydrite 

increases downdip from the Ocala uplift. Inland 

and updip the limestone merges with sands and 

other clastic material in western Florida and adjacent parts of Alabama and Georgia and also in 

areas of outcrop in Georgia and South Carolina. 

The Quaternary Period, which includes the Pleistocene and Recent, is very short in comparison with 

the Tertiary and Cretaceous. However, the changes 

in sea level during Pleistocene time caused significant 

changes in the formations that compose the principal 

aquifers. The Quaternary deposits are relatively 

thin, forming a surficial blanket of sand and unconsolidated material. In a few areas, marine limestone and shell marl represent the Pleistocene, as 

along the east coast and in southern Florida. Maximum thickness of these deposits is in southeastern 

Florida where they may be as much as 250 feet thick. 

The outstandi~g feature of Pleistocene time was 

extensive continental glaciation in the northern hemisphere. Although this glaciation did not extend to 

the South Atlantic States, worldwide changes of sea 

level were caused by removal of water from the sea 

to form the continental glaciers. At times when the 

glaciers melted, as described by Cooke (1939), water 

returned to the sea, causing a rise in sea level. The 

sea retreated when climatic changes caused ice to 

accumulate on the continental glaciers, or ice sheets. 

The glacial chronology of Cooke, accounting for the 

changes in sea level, also involves crustal changes 

in the ocean basins. 

According to Cooke's sequence, the highest and 

earliest stand of the sea in Pleistocene time was at 

270 feet above the present level during the Aftonian 

Interglaciation when the Hazlehurst (Brandywine) 1 

shoreline was formed at that altitude. All Florida 

was covered by· the sea except a few high areas in 

the center and in the west. The sea retreated to a 

low stand, below its present level, during the Kansan 

Glaciation. The low stand was followed by a rise 

to a height of 215 feet ( Coharie shoreline) above 

the present level in the Yarmouth Interglaciation. 

This rise caused by melting of continental ice, was 

followed by intermittent emergence of at least 170 

feet above the present level, resulting from crustal 

changes in the ocean basins. When the sea retreated 

during the Yarmouth Interglaciation, it paused long 

enough to form shorelines as follows: Sunderland, 

1 The name Hazlehurst was proposed by Cooke in 1925 but was rejected 

in favor of Brandywine. In 1952 Cooke replaced the term "Brandywine" 

with the term "Hazlehurst" to designate the 270-foot terrace. 

175 feet above the present level; Okefenokee, 150 

feet; Wicomico, 100 feet; Penpoloway, 70 feet; and 

Talbot, 42 feet. Sea level declined during the Illinoian 

Glaciation. The decline was followed by a rise in 

sea level to 25 feet above the present level in the 

Sangamon Interglaciation when the Pamlico shoreline was formed. After the accumulation of continental ice during early Wisconsin time, the sea 

retreated. Partial melting of the ice sheet in middle 

Wisconsin time caused the sea to rise to a height of 

about 6 feet above the present level, forming the 

Silver Bluff shoreline at that altitude. During late 

Wisconsin time, the sea retreated again, when continental ice accumulated. In Recent time, the sea 

rose to its present level. Changes in sea level during 

Pleistocene time modified the recharge and discharge 

of the principal artesian aquifer from time to time. 

During lower stands of the sea, water discharged 

from the aquifer at lower levels, resulting in deeper 

circulation of the artesian water. During high stands 

of the sea, recharge areas of the aquifer were submerged and some sinkholes and solution cavities in 

the limestone were filled with unconsolidated sediments. Some of the salt water that entered the region 

during Pleistocene time has not been completely 

flushed from the aquifer. 

In general, the geologic formations dip toward 

the coast except where interrupted by local structures. Major structures in Florida include the peninsular arch and the Ocala uplift. The peninsular arch 

extending from southern Georgia to the vicinity of 

Lake Okeechobee forms the axis of the Florida peninsula (Applin, 1951, p. 3). Its crest of Paleozoic sedimentary rocks is near the center of the northern part 

of the peninsula about 60 miles west of Jacksonville 

(Toulmin, 1955, p. 210). During Tertiary time, the 

Ocala uplift formed, parallel to and about 60-70 

miles southwest of the peninsular arch. The ~rest 

of the uplift in Citrus and Levy Counties is as much 

as 150 feet above sea level. In that area erosion has 

removed the formations younger than middle Eocene, 

exposing middle Eocene rocks. 

TOPOGRAPHY 

The area of this report is in the Coastal Plain 

province-a region of plains and low hills that extends inland to the Piedmont province, which forms 

the foothills of the mountainous regions farther inland. The Piedmont province is under lain by igneous 

and metamorphic rocks that extend under the sedimentary rocks of the Coastal Plain. In Alabama the 

Coastal Plain cuts across the south end of the Piedmont province. A belt of hills corresponding approxi-
TOPOGRAPHY 9 

mately to the inner border of the Coastal Plain is 

known as the Fall Line Hills because streams entering the Coastal Plain from the Piedmont form falls, 

or rapids, where they flow from the hard rocks of 

the Piedmont to the softer, more easily eroded rocks 

in the Coastal Plain. 

Most of the area of this report is covered by 

coastal terraces of Pleistocene age which have been 

described by Cooke in South Carolina (1936, p. 2-9), 

in Georgia (1943, p. 103-116), and in Florida (1939, 

p. 11-59). These terraces range from a few feet 

above sea level along the coast to 270 feet above sea 

level in the interior. In some areas the lower. terraces 

have been only slightly modified by erosional processes. In areas where limestone is at or near the 

surface, however, solution has· resulted in sinkhole 

or karst topography. In the Fall Line Hills northwest of the terraces, some altitudes are as much as 

600 feet above sea level. 

The sinkhole or karst areas form the lake regions 

in the uplands extending from southern Florida into 

southern Georgia. There are. no sinkholes east of 

these regions on the lower terraces in the area of 

artesian flow in southeastern Georgia and northeastern Florida. A few sinkholes are present on the 

coast in southwestern Florida. North of Tampa Bay 

the sinks become more numerous and are abundant 

in Citrus and Levy Counties. In the coastal areas 

sinkholes were submerged and filled with sediments 

when the sea covered the area in Pleistocene time. 

In the areas where the limestone is near the surface, 

however, the sediments in many of these filled sinkholes were removed by circulating water after the 

sea retreated. 

PHYSICAL DIVISIONS 

For convenience in the following discussion, the 

report area is divided into physical divisions (fig. 2). 

DIVISIONS IN FLORIDA 

In describing the topography of Florida, Cooke 

(1939, p. 14) divided the State into five divisions: 

( 1) Coastal Lowlands7 or Coastal Terraces, extending 

northward to Georgia and South· Carolina on the 

Atlantic coast and to Alabama on the gulf coast, (2) 

Central Highlands extending from southern. Florida 

into southern Georgia, where the division merges 

with the high coastal terraces, (3) Tallahassee Hills, 

a strip about 25 miles wide and 100 miles long 

bordering Georgia between the Withlacoochee River 

on the east and the Apalachicola River on the west 

and extending northward into the Tifton Upland in 

southern Georgia, ( 4) Marianna Lowlands in Jackson, Holmes, and Washington Counties in western 

Florida and in Georgia merging with the Dougherty 

Plain, which extends northeastward to the Louisville 

Plateau in eastern Georgia, ( 5) Western Highlands 

extending westward from the Apalachicola River to 

the Perdido River, the boundary between Florida 

and Alabama. The westernmost part of the Western 

Highlands extends northward to the Alabama line, 

and the easternmost part forms a narrow belt between the Marianna Lowlands and the Coastal 

Lowlands. 

COASTAL LOWLANDS 

The altitude of the Coastal Lowlands bordering 

the Atlantic and gulf coasts ranges from sea level 

to about 100 feet above sea level. In the Florida 

panhandle, areas west of Tallahassee and south of 

the Tallahassee Hills are in this division. The area 

consists chiefly of nearly level plains or terraces 

formed during Pleistocene ,time by invasions of the 

sea which left shorelines at 100, 70, 42, 25, and about 

6 feet above the present sea level. The marine terraces corresponding to these shorelines are named, 

from highest to lowest, the Wicomico, Penholoway, 

Talbot, Pamlico, and Silver Bluff. The Pamlico terrace is the most extensive and least dissected. The 

Coastal Lowlands are widest in southern Florida. 

They are narrowest on the gulf coast in Citrus 

and Hernando Counties and in the area west of 

Choctawhatchee Bay in Walton County. At Pensacola, they are only 10 to 12 miles wide. 

On the Coastal Lowlands in southern Florida, the 

Everglades, a frequently flooded region of about 

4,000 square miles generally not more than about 

16 feet above sea level, extends southward from 

Lake Okeechobee to Florida Bay. West of the Everglades is Big Cypress Swamp. Details of Coastal 

Lowlands in southern Florida and a contour map 

showing the elevation of the limestone floor of Lake 

Okeechobee and the Everglades are given by Parker 

(in Parker and others, 1955, p. 147-155). 

CENTRAL HIGHLANDS 

The Central Highlands extends from the Florida 

peninsula to the Okefenokee Swamp in southern 

Georgia. The altitude ranges from less than 40 

feet in ·Some valleys to 325 feet on the top of Iron 

Mountain near Lake Wales in Polk County, Fla. The 

division includes high hills, swampy plains, and 

thousands of lakes. Sinkholes and sinkhole lakes are 

present in most of the region, including the Valdosta area in Georgia. 

As stated by Cooke (1945, p. 8), the most extensive 

plain in the Central Highlands is the Sunderland 
10 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

terrace formed when the sea stood approximately 

170 feet above its present level. The terrace covers 

several counties in the northern part of Florida and 

adjacent parts of Georgia and includes the Okefenokee Swamp. The Sunderland terrace is well developed in Manatee, Hillsborough, and Polk Counties; there are small remnants scattered throughout 

the Central Highlands. The Sunderland sea covered 

Florida, except a few islands in the Central Highlands and part of western Florida adjacent to the 

Georgia and Alabama State lines. The largest of 

these islands, in the northwestern part of Putnam 

County, Fla., extended as a sandy peninsula and bar 

into Georgia (Cooke, 1939, p. 35, fig. 12). The 

remnant of this sandy peninsula is now known as 

Trail Ridge. 

TALLAHASSEE HILLS 

The Tallahassee Hills .ranges in altitude from less 

than 70 to about 340 feet above sea level. As shown 

by topographic maps, the highest point near Dog 

Town in the northern part of Gadsden County seems 

to be remnants of a plain, about 330 to 240 feet 

above sea level, underlain by red sand mapped by 

Cooke (1945, p. 9) as the Citronelle Formation. The 

rest of the area generally consists of rolling hills 

cut into the Citronelle and the underlying clayey sand 

and fuller's earth of the Hawthorn. Some large lake 

basins formed by solution in the limestone are near 

Tallahassee. The Tallahassee Hills merges with the 

Tifton Upland, which extends northeastward across 

Georgia between the Coastal Terraces on the southeast and the Dougherty Plain and Louisville Plateau 

on the northwest. 

MARIANNA LOWLANDS 

The Marianna Lowlands (including Jackson, 

Washington, and Holmes Counties) is underlain by 

the Ocala and other limestones of the principal artesian aquifer. The division in Florida is bounded 

by the Alabama .State line on the north, by the 

Apalachicola River on the east, and by the Western 

Highlands on the south and west. The Ocala Limestone crops out in several areas, the largest of which 

is north of Marianna, where many springs flow into 

the Chipola River. A large part of the Marianna 

Lowlands is underlain by the Suwannee Limestone. 

The Tampa Limestone is present in a narrow band 

around the south margin (Cooke, 1945, p. 10). Limestone solution accounts for the low rolling hills and 

hollows. There are many shallow sinkholes and 

depressions resulting from sinks. Many sinks contain ponds or small lakes. Altitudes range from less 

than 50 feet along the Apalachicola River to as 

much as 209 feet near Marianna. The Marianna 

Lowlands extends into Alabama and Georgia. In 

Georgia it merges with the Dougherty Plain in the 

Flint River valley. 

WESTERN HIGHLANDS 

The Western Highlands, between the Perdido and 

Apalachicola Rivers, extends inland from the Coastal 

Lowlands to the Alabama State line, except in a 

narrow belt south of the Marianna Lowlands. The 

division includes the valleys of the Escambia and 

Yellow Rivers and several other streams. The altitudes range from sea level to more than 300 feet 

above sea level. One of the highest points (a few 

miles southeast of Chipley in Washington County) is 

340 feet above sea level. This place seems to be part 

of the same plain, represented in a small area near 

Dog Town in the Tallahassee Hills. The northern 

part is hilly, the altitude being about 300 feet ; the 

southern part is a broad, gently rolling upland ranging in altitude from approximately 100 to 270 feet 

above sea level. The plateau is deeply trenched by 

narrow, steep-walled valleys which cut down almost 

to sea level. The areas below 270 feet include remnants of three marine terraces-Hazlehurst (Brandywine), Coharie, and Sunderland (Cooke, 1939, 

p. 17). ·The heads of several streams in the northern 

part of the De Funiak Springs quadrangle are circular depressions· that seem to have formed as sinkholes or lakes; they were later captured by headward 

growth of surface streams. Cooke lists Lake Sylvia, 

4 miles west of De Funiak Springs, as an example 

of a sinkhole lake on the verge of being captured 

by Fish Pond Branch. Lake Sylvia is about 60 feet 

below the upland in a funnel-shaped sink. There 

are many sinkhole lakes ranging from about 75 

feet above sea level in the Coastal Lowlands to more 

than 100 feet above sea level in the Western 

Highlands. 

Youthful tributaries of the Yellow River and 

young streams flowing southward to the Coastal 

Lowlands in Santa Rosa and Okaloosa Counties 

have valleys with steep walls at their heads which 

are known as steepheads. These features have given 

rise to such geographic names as Mossy Head, Bear 

Head, Deer Head, White Head, and Deep Head. As 

described by Sellards (1918, p. 27), Cooke (1939, 

p. 17), Vernon (1942, p. 28-29), and Moore (1955, 

p. 17), steepheads form in areas underlain by permeable sand overlying a clay bed or less permeable 

zone. Precipitation on the surface moves downward 

instead of flowing over the surface of the ground. 

After reaching the less permeable zone, the water 
TOPOGRAPHY 11 

moves laterally and forms a spring where the less 

permeable beds crop out. The flow of the spring 

causes the permeable sand at the head of the spring 

to slump into the spring, and the flow carries it 

downstream. The headward movement of the spring 

forms the steephead. A waterfall may form in an 

area where the less permeable beds have sufficient 

resistance and are far above the zone of saturation in 

the underlying sand. 

DIVISIONS IN GEORGIA 

In Georgia, Cooke (in LaForge and others, 1925, 

p. 21-42) divided the Coastal·Plain into: (1) Coastal 

Terraces that cover about half of the Coastal Plain, 

(2) Tifton Upland, a belt about 45 miles in average 

width adjacent to the Coastal Terraces, (3) Dougherty Plain and Louisville Plateau, adjacent to the 

Tifton Upland, (4) Fort Valley Plateau, and (5) 

Fall Line Hills. 

COASTAL TERRACES 

This area in Georgia and South Carolina includes 

the Pleistocene terraces ranging from sea level to 

about 270 feet above sea level. The terraces represent sea bottoms laid bare by the retreat of the sea 

to successively lower levels. The inner margin 

passes from the Florida State line at Ochlockonee 

River near Thomasville and thence northeastward 

to the Savannah River at Sylvania. A large embayment of the Pleistocene sea extended up the Flint 

River valley from Florida and covered part of the 

Dougherty Plain. In Florida and Georgia the coastal 

terraces below 100 feet are shown as the Coastal 

Lowlands (fig. 2). The terraces above 100 feet 

in Florida are included as parts of the topographic 

divisions at higher levels because they have been 

dissected more than those in Georgia and South 

Carolina. 

TIFTON UPLAND 

The Tifton Upland is bordered by the Coastal 

Terraces --on the southeast and the Dougherty Plain 

and Louisville Plateau on the northwest. It occupies 

a broad band crossing the middle part of the Coastal 

Plain. The Hawthorn Formation underlies the upland and extends coastward beneath the Coastal 

Terraces. The more resistant and less soluble sands 

of the Hawthorn overlying the limestones of the 

principal aquifer form a northwestward-facing scarp 

along the northwest edge of the upland, adjacent 

to the Dougherty Plain and Louisville Plateau. West 

of Pelham the altitude of the Dougherty Plain is 175 

feet. Altitudes in the Tifton Upland range from less 

than 120 feet to about 400 feet, the maximum relief 

being 240 feet. However, the hills are generally 

about 100 feet high. Between Cordele and Waynesboro, the thickness of the Hawthorn decreases, and 

the Tifton Upland merges with the Dougherty Plain 

and Louisville Plateau where the Ocala Limestone 

grades into sand. Depressions caused by the solution of limestones beneath are scattered over much of 

the area. Shallow sinkholes occur along the escarpment adjacent to the Dougherty Plain and in other 

areas where the limestone is near the surface. They 

are circular, elliptical, or elongated depressions 

ranging from less than an acre to many acres in 

extent. 

DOUGHERTY PLAIN AND LOUISVILLE PLATEAU 

As described by Cooke (in LaForge and others, 

1925, p. 40) the Dougherty Plain slopes from nearly 

600 feet above sea level along the northwest border 

adjacent to the Fall Line Hills to about 160 feet at 

the edge of the Tifton Upland. The lowest point is 

about 50 feet above sea level at the mouth of the 

Flint River. The northwestern part of the plain is 

rolling; the wider areas between streams are generally flat, as in Sumter County. In a large area 

in the Flint River valley where limestone is at or near 

the surface, sinkhole topography was modified by 

an embayment of the Pleistocene sea which extended 

up the Chattahoochee-Flint River basin. The plain 

has many shallow, ·saucer-shaped sinks or depressions that have been formed by the collapse of 

caverns in the soft soluble limestone. Most of the 

drainage is underground. 

The Louisville Plateau, an area of wide flat uplands, between the Fall Line Hills and the Tifton 

Upland extends about 90 miles from the Oconee River 

to the Savannah River.' Its maximum width is .about 

20 miles. The altitudes of a typical upland in J efferson County range from about 500 feet above sea level 

to about 320 feet in the vicinity of Louisville. Some 

valleys are cut as much as 100 feet below the up-. 

lands. The plateau at Louisville is shown on the 

map of Stapleton quadrangle. The outline of the 

plateau is determined in part by the distribution of 

the red sand of the Barnwell Formation, which is 

easily distinguished from the gray sands of the 

Hawthorn Formation of the Tifton Upland.· 

FORT VALLEY PLATJ):AU 

The Fort Valley Plateau, also underlain by the red 

clayey sand of the Barnwell Formation, occupies an 

area of about 300 square miles between the Flint 

and Ocmulgee Rivers. It adjoins the Fall Line Hills 
12 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

on the west, north, and northeast and the Dougherty Barnwell. Many shallow depressions on the Pamlico 

Plain on the southeast and south. The plateau is and other Pleistocene terraces are surficial irregularnearly flat but slopes gently southeastward. The ities formed on the floor of the ocean or in shallow 

town of Fort Valley, after which the plateau was water of tidal marshes when the sea stood at a higher 

named, is 522 feet above sea level (LaForge and level. These shallow surficial depressions, many of 

others, 1925, p. 42). On the west the plateau descends which are partly enclosed by low sandy ridges, inabout 300 feet to the Flint River Valley. elude Carolina Bays (Cooke, 1936, p. 7; 1954, p. 

FALL LINE HILLS 

The area of hills and valleys, corresponding approximately to the outcrop of the Upper Cretaceous 

sands and clays, extends across Georgia adjacent to 

the Piedmont province. The area ranges in width 

from about 80 miles along the Chattahoochee River 

to a minimum of 3 or 4 miles east of the Flint River. 

DIVISIONS IN SOUTH CAROLINA 

In South Carolina the Coastal Plain, 120 to 150 

miles wide, includes an area of more than -20,000 

square miles. Cooke (1936, p. 3) divided the Coastal 

Plain into five parts : ( 1) the Coastal Terraces which 

cover more than two-thirds of the Coastal Plain, (2) 

the Aiken Plateau, (3) the Richland Red Hills, ( 4) 

the High Hills of Santee, and ( 5) the Congaree Sand 

Hills. 

195-205). 

The Richland Red Hills in the eastern part of 

Richland County and the High Hills of Santee in the 

western part of Sumter County and the southwestern 

part of Lee County are on opposite sides of the 

Wateree River between the Coastal Terraces and 

the Congaree Sand Hills. They are underlain by the 

hard clayey sand of the Black Mingo Formation of 

early Eocene age. The altitudes are as much as 400 

feet above sea level. The High Hills of Santee rises 

as a low ridge above the gently sloping coastal 

terraces. 

The Congaree Sand Hills, extending from the 

Aiken Plateau in Aiken County into North Carolina, 

adjoins the Piedmont Plateau on the northwest. On 

the southeast, it adjoins the Aiken Plateau, the 

Coastal Terraces, the Richland Red Hills, and the 

. High Hills of Santee. They correspond approxiThe Coastal Terraces extend Inland from the sea- mately to the area in which the Tuscaloosa Formation 

shore about. 9.0 miles ... The ... altitudes~ range. from. sea., .. orT~ate Cretaceous~ age is at or near the land surlevel to about 270 feet above sea level. Each terrace face similar to the Fall Line Hills in Georgia. 

is defined by the level shoreline at which the sea ' 

stood when the.terrace was under water. 

Between the valleys of the Savannah and Congaree 

Rivers, the Aiken Plateau extends northwestward 

from the edge of the Coastal Terraces to the Piedmont Plateau in Edgefield and Saluda Counties and 

to the Congaree Sand Hills in eastern Aiken County 

and in Lexington and Calhoun Counties. The Aiken 

Plateau slopes southeastward from 660 feet above 

sea level west of Trenton in Edgefield County to 

about 270 feet at the point where it merges with 

the Coastal Terraces. Near Aiken, the plateau ranges 

in altitude from 550 to 500 feet. It is separated from 

the Louisville Plateau in Georgia by the Savannah 

River. The less dissected parts of the Aiken Plateau 

contain undrained depressions that appear to be 

shallow sinkholes. Cooke suggested that they may 

have resulted from solution of marl or limestone. 

Smith (1931, p. 641-652) and other investigators 

have suggested that they are caused by solution of 

iron and aluminum from sandy sediments. The 

Aiken Plateau is underlain chiefly by the Barnwell 

and McBean Formations, both of which contain 

calcareous beds. There are similar depressions on 

the Louisville Plateau, which also is underlain by the 

DRAINAGE 

RELATION OF DRAINAGE TO THE PRINCIPAL 

ARTESIAN AQUIFER 

Streams of two general types drain the Coastal 

Plain-through-flowing streams and streams that 

rise within the Coastal Plain. All the throughflowing rivers have deep, wide, flat-bottomed valleys. 

Water in the streams from the Piedmont is generally colored with yellow or red mud. The streams 

that rise in the Coastal Plain are seldom muddy, but 

in many of ·them the water is brown or black because of the color received from leaves, straw, and 

other vegetable matter. 

Stringfield (1964, p. 164-169) ·described the relation of artesian water to surface drainage. The main 

source of several limestone springs and of some 

streams is discharge from the principal artesian 

aquifer where it is at or near the surface. During 

flood stage, water from the larger streams may enter 

the aquifer, but recharge is chiefly in interstream 

areas. In recharge areas, the water level in the 

principal aquifer may represent the water table, 

but in other areas, there is a separate water-table 
DRAINAGE 13 

aquifer, wherein the water table may be above or 

below the piezometric surface of the artesian water. 

Nat ural discharge of the principal aquifer occurs 

through springs, in surface streams (at places where 

the aquifer is exposed), in the ocean, and by upward 

leakage into the overlying formations. Movement 

of water in the principal aquifer in coastal Georgia 

is northeastward toward a submarine discharge area 

northeast of Savannah. In the Flint River valley 

in Georgia and in some areas in north and northcentral Florida, the major streams occupy channels 

cut into the aquifer, and water discharges from the 

aquifer into the stream. In the discharge areas, the 

chemical quality of the artesian water affects the 

quality of the surface water. 

Drainage patterns, except on the Coastal Terraces, 

were well established before the beginning of the 

Pleistocene Epoch and probably have undergone 

little change since that time. As stated by Cooke 

(1936, p. 13), during the Pliocene Epoch the seashore probably lay somewhere within the area now 

occupied by the Coastal Terraces, at least the part 

covered by the Waccamaw and other marine formations of Pliocene age. Cooke suggested that the sea 

may have stood about 100 feet higher upoh the land 

than it does today. Widespread earth movements at 

the end of Pliocene time depressed the land about 

170 feet and left the sea at tlie Hazlehurst (Brandywine) shoreline, about 270 feet above the present 

level. Wide va.lleys of streams flowing from the 

Piedmont proyince to the Coastal Plain were converted to bays heading at the Fall Line. Tidewater 

extended up the valleys. When the sea retreated in 

Pleistocene time, the large rivers appear to have 

reoccupied their partly silted valleys and flowed 

across the newly exposed ocean floor, following the 

slope of the land. This process was repeated during 

each subsequent lowering of the sea. During each 

interglaciation, when t~e sea flooded the land, coastal 

features such as bars, islands, and spits were built 

along the shore. These features diverted many of 

the smaller streams from their direct course to the 

sea. The courses of some of the streams, like the 

St. Johns River in Florida, were influenced by tidal 

lagoons where there were offshore islands and bars 

parallel to the coast. As stated by White (1958, 

p. 17) and Cooke (1939, p. 109), most of the valleys 

parallel to the coast seem initially to have been long 

narrow lagoons, bays, or sounds behind offshore 

bars. The larger streams, like the St. Johns, probably resembled the present Indian River and similar 

lagoons, which closely parallel the present east coast 

of Florida. 

The stream patterns and drainage have been influenced by underground solution in some areas 

where the limestone is at or near the surface. The 

streams that rise in the Piedmont province and flow 

across the Coastal Plain ·province into the Atlantic 

Ocean include the Savannah River, the Ogeechee 

River, and the Oconee and Ocmulgee Rivers which 

join to form the Altamaha in the Coastal Plain of 

Georgia. The major stream entering the Gulf of 

Mexico is the Chattahoochee or Apalachicola River. 

The river, called the Chattahoochee in Alabama and 

Georgia and the Apalachicola in Florida, rises in 

the P~edmont province and flows across the Coastal 

Plain into the gulf where it forms a delta. The Flint 

River, a tributary of the Chattahoochee in Georgia, 

has cut its channel at least 15 feet below its flood 

plain. The Flint, flowing on the principal artesian 

aquifer in much of its lower course, has been a 

factor in the formation of the escarpment that separates the Tifton Upland from the Dougherty Plain. 

Streams in the Coastal Plain rise in the area underlain by Tertiary formations. The Conecuh River, 

which forms one of the principal drainage systems 

in south-central Alabama, rises in the area where 

Cretaceous formations are at or near the surface, 

flows southwestward to the Florida State line, thence 

southward as the Escambia River to the· gulf.· :!'f.he 

Pea River and some of its tributaries in southeastern 

Alabama rise in the Cretaceous area. They flow 

southward across the Tertiary formations in Alabama to the Florida State line near Geneva, Ala., 

where they join to form the Choctawhatchee River, 

which has built a large delta at the head of Choctawhatchee Bay (Cooke, 1939, p. 105) on the gulf. 

Among the streams that drain western Florida 

and south-central and southeastern Alabama are: 

the Perdido and Yellow Rivers, which rise in Alabama, and the Chipola River, which rises in an area 

where the principal artesian aquifer is at or near 

the surface (as in Jackson and Washington Counties, 

Fla.; and adjacent parts of Alabama) and flows into 

the Apalachicola River. The Apalachicola is formed 

by the confluence of the Chattahoochee and the Flint 

·at the southwest corner of Georgia. 

The Ochlockonee River, the Aucilla, and the 

Suwannee and its two principal tributaries-the 

Withlacoochee and the ·Alapaha-rise in southern 

Georgia and flow southward across Florida to the 

gulf. The Santa Fe River is a tributary of the Suwannee in Florida. South of the Tallahassee Hills, 

between Ochlockonee and Suwannee Rivers, much of 

the drainage is underground through sinks and 

channels in the limestone of the principal aquifer. 
14 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

The St. Marys River rises on the Coastal Terraces 

in Georgia and flows southward, before turning 

northward and eastward along the Florida-Georgia 

boundary to reach the Atlantic Ocean. The Satilla 

River, which drains southeastern Georgia, rises 

within the area underlain by the Tertiary formations 

and discharges into the Atlantic Ocean at a point 

north of the St. Marys River. 

SUWANNEE, WITHLACOOCHEE, AND SANTA FE. 

RIVERS 

The Suwannee River heads in the Okefenokee 

Swamp in southern Georgia and northern Florida, 

flows southward nearly to White Springs, then turns 

northwestward to its junction with the Alapaha. It 

flows southwestward past Dowling Park, circles 

southeastward to the mouth of the Santa Fe, then 

southward to the Gulf of Mexico (Cooke, 1939, p. 

106). Cooke suggests that, when the Sunderland 

terrace emerged from the Pleistocene sea, natural 

drainage toward the east was blocked by Trail Ridge, 

which impounded the water in Okefenokee Swamp. 

The overflow from this swamp followed the natural 

slope of the land southward until it was diverted 

westward by the higher ground surrounding Lake 

City. Beyond White Springs the overflow was influenced by underground drainage into cavernous 

limestone, by oscillations of the sea level, and other 

factors. Over most of its course the Suwannee flows 

on limestone of the principal artesian aquifer. Above 

White Springs the Suwannee, having cut through the 

thin deposits of the Sunderland terrace, flows on the 

Hawthorn Formation. Below White Springs the Suwannee flows in a channel in the Suwannee Limestone. Beyond the mouth of the Withlacoochee it 

has cut through the Suwannee Limestone into the 

Ocala Limestone. There is an exchange of water 

between the river and the cavernous aquifer; the 

direction of exchange depends on the stage of the 

river with reference to the piezometric surface of 

the artesian water along the river. This relationship 

is also present on the lower part of the Withlacoochee 

and the Santa 'Fe Rivers. 

The Santa Fe River rises east of the Suwannee 

and flows westward in an upland region in Florida 

where the Hawthorn Formation overlies the principal artesian aquifer. In its lower course it flows on 

and in the limestone of the principal artesian aquifer. 

As described by Clark and others (1962, p. 39-48), 

the flow characteristics in the upper part and the 

lower part of the Santa Fe basin differ considerably. 

The flow characteristics. ch~nge abruptly in the vicinity of O'leno State Park, about 6 miles north of 

High Springs, where the river disappears underground, then reappears about 3 miles away. Below 

that point streamflow increases rapidly as the river 

flows through a channel cut in the principal artesian 

aquifer. Almost all the pickup in flow in the lower 

basin is .from the artesian aquifer. Few tributary 

streams feed the lower river except those that flow 

from springs, such as the Ichatucknee Springs near 

Hildreth. In the lower part of the basin the section 

of the river between High Springs and Fort White 

has an average annual runoff of · 84.7 inches per 

square mile-more than llh times the annual rainfall on the 130.:.square-mile area. This runoff is the 

highest of a~y area of like size in Florida. 

The upper part of the river is fed by tributaries 

that drain almost the entire area of Bradford and 

Union Counties and the northern part of Alachua 

County. Much of the streamflow occurs as direct runoff from lakes, lowland areas, and overland flow. 

Small headwater streams cease flowing during extended periods of deficient rainfall. The average 

annual runoff at the Worthington gaging station 

is 8.4 inches per year, based on 27 years of record. 

STREAMS SOUTH OF THE SUWANNEE RIVER 

Six major streams discharge into the Gulf of 

Mexico on the west coast of the Florida peninsula. 

The Withlacoochee Riv~r rises in Polk County, flows 

westward, turns to a generally northerly course 

past Tsala Apopka Lake, then turns westward to the 

gulf. The Hillsborough and Alafia Rivers enter 

Hillsborough Bay at and near Tampa. The Manatee 

and Little Manatee enter Tampa Bay south of Hillsborough Bay. The Peace River rises in Polk County 

and flows southward into Charlotte Harbor. The 

Myakka River rises in Manatee County and flows 

southwestward, thence southeastward parallel to the 

coast into Charlotte Harbor. The Caloosahatchee 

River flows from Lake Okeechobee to the gulf. The 

upper part of the Caloosahatchee River is connected 

to the lake by a canal forming part of the Okeechobee 

Waterway that crosses Florida through Lake Okeechobee. The Kissimmee River rises in Orange County 

in central Florida and flow.s southward to Lake Okeechobee, which flowed southward into the Everglades 

before levees for flood control were constructed on 

the south side of the lake. 

As described by White (1958, p. 27-33), the Kissimmee River is in consequence to an emergent 

marine surface. The drainage formed as the Pleistocene sea retreated from the Wicomico shoreline about 

100 feet above the present sea level. The lower part 

of the valley and southern Florida were covered by 
DRAINAGE 15 

the sea again during Pamlico time. The discharge 

from Lake Okeechobee is now through canals to 

the gulf through the Caloosahatchee River and to 

the Atlantic Ocean through the St. Lucie River and 

canals. The canals are controlled by locks. A levee 

on the border of the south half of· the lake from 

Moore Haven to Port Mayaca prevents the lake 

from flooding the adjacent areas during tropical 

storms that used to sweep the water of the shallow 

lake over its natural levee. Also a levee has been 

constructed along the north shore to protect the 

low area between the lake and the town of Okeechobee, which is on high ground. Levees· around the remainder of the lake are authorized and partly under 

construction (Nevin Hoy, written commun., 1962). 

The Miami canal extends from the south end of the 

lake into the Everglades. Although the middle sec-· 

tion of the canal has not been excavateQ, the south 

end of the canal passes through Miami and drains 

water from the Everglades to Biscayne Bay at 

Miami. 

WITHLACOOCHEE RIVER 

Two streams in the area of this report are named 

Withlacoochee; one is a tributary to the Suwannee 

in Georgia, and the other is in Florida. The Withlacoochee River and Peace River in Florida are the· 

longest streams south of the Suwannee. White (1958, 

p. 19-27) gives a description of the Withlacoochee 

in Florida and its relation to the Hillsborough River 

with a profile of the Withlacoochee, a planimetric 

map, and an aerial photograph of the area in which 

the Hillsborough reaches the Withlacoochee. The 

Ocala Limestone and the Suwannee -Limestone of 

the principal artesian aquifer are at or near the 

surface in the area through which the Withlacoochee 

flows from Hernando County to the gulf. The Tampa 

Limestone of the principal aquifer is at or near the 

surface in the area of the lower course of the Hillsborough River. Solution of the limestone in both 

areas has influenced the course of the rivers. As 

suggested by White, it is entirely possible that the 

upper course of the Withlacoochee was formerly 

a part of the Hillsborough River. Sinkhole topography formed in the areas where the limestone was 

at or near the surface during a low stand of the sea in 

Pleistocene time. Probably most of the drainage 

was through sinkholes. The areas through which 

both rivers flow at the present time were covered 

by the Pleistocene sea when it stood about 100 to 150 

feet above the present sea level. During that time 

sinkhole topography which had formed in the area 

of Lake Tsala Apopka was covered by sediments on 

the ocean floor. As the sea withdrew, Lake Tsala 

Apopka and the no.rthward route of the Withlacoochee formed along with the capture of the upper part 

of the Hillsborough River. 

The lower courses of the Withlacoochee and the 

Hillsborough Rivers in the area, les·s than about 25 

feet above sea level, were covered by the Pamlico 

area. When the Pamlico sea retreated to a position. 

below the present sea level, the ·lower course of 

the. Withlacoochee was formed. In discussing Lake 

Tsala Apopka, the Withlacoochee River, and other 

streams in Citrus and Levy Counties of Florida, 

Vernon (1951, p. 29-37) explained the influence of 

jointing and faulting and other structures on the 

courses of some streams. He stated that the Withla~ . 

coochee is clearly antecedent and the fold of the 

Ocala uplift has ponded the river above Dunellon, 

forming Lake Tsala Apopka. However, the present 

writer prefers the explanation in which solution of 

the limestone and influence of eustatic changes of 

sea level were controlling factors in the formation 

of the lake. 

ST. JOHNS RIVER 

On the east coast of Florida, the St. Johns River 

is the dominant stream. It flows northward through. 

a wide shallow valley nearly 275 miles from its headwaters in the .Coastal Lowlands to Jacksonville, 

thence eastward into the Atlantic Ocean (Cooke, 

1939, p. 108-109). At its source, it is approximately 

20 feet above sea level (D. W. Brown and others, 

1962, p. 7). In the headwaters of the basin the 

stream forms a definite channel at Lake Hellen 

Blazes. The stream channel is interrupted by many 

lakes. The river flows northward to Lake Harney in 

Seminole County, then turns westward to Lake Monroe. From there it continues its general northward 

course to Jacksonville where it turns eastward and 

enters the Atlantic at Mayport. The main use of 

the St. Johns River is for navigation (Clark and 

others, 1962, p. 39). The controlled depth of channel 

from the ocean to Jacksonville (25 miles) is 30 feet; 

from Jacksonville to Palatka (55 miles), 13 feet; 

from Palatka to Sanford ( 90 miles), 8 feet; and from 

Sanford to Lake Harney (26 miles), 5 feet. The 

channel between the ocean and Jacksonville is relatively narrow and well defined, rarely exceeding 30 

feet in depth. At Jacksonville the width of the river 

is reduced to about 500 yards, and the channel 

is scoured by tidal currents to a depth of about 70 

feet (Cooke, 1939, p. 108). Between Jacksonville 

and Palatka, the river has no well-defined channel. 

It ranges in width from nearly a mile to more than 
16 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

3 miles. The depth rarely exceeds 30 feet, and near 

the shores it is 10 feet or less. As stated by Cooke, 

tidal marshes between Palatka and Lake George 

narrow the river to a relatively uniform width, averaging 400 or 500 yards, the maximum depth of 37 

feet being below Murphy Creek. The river is about 

6 to 7 miles wide in Lake George and 9 to 11 feet 

deep. The lake is about 11 miles long. Between 

Lake George and Lake Harney, the river is not more 

than 100 yards wide and 8 to 20 feet deep, with 

expansions in width at Lake Dexter (2 to 20 feet 

deep). The range of the tide at Palatka is 2.9 feet 

(Cooke, 1939, p. 108). At times the chloride content 

of the water is relatively high because of tidewater 

in its lower course and discharge of springs, like 

Salt Springs near Lake Kerr and many small springs 

along the river between Lake George and Lake 

Harney where beds overlying the principal aquifer 

have been cut by the river. 

Cooke suggests that the valley of the St. Johns 

·River above Lake Harney came into existence in late 

Pleistocene time, when a barrier island, now on the 

east bank of the river, accumulated in the Pamlico 

sea. The remainder of the valley also consisted of 

.lagoons and sounds during Pamlico, but, as Cooke 

states, these depressions had an earlier origin. At the 

time of a low sea level, 300 or more feet below the 

present sea level, sinkholes and large lake basins 

formed in the areas where the limestone was at or 

near the surface and where the Hawthorn Formation was thin or had been removed by erosion. Because the St. Johns valley from Palatka to Lake 

Harney is a region of sinkholes and solution basins, 

it seems plausible that the present channel was 

formed by solution and erosion. After the Continental Shelf was exposed as the sea reached lower 

levels, probably most of the drainage in that part 

of the valley was underground through sinkholes 

and lake basins. In northeastern Florida and southeastern Georgia, where the Hawthorn Formation 

is as much as 500 feet thick, erosion did not expose 

the limestone of the principal aquifer as it did farther 

south. Therefore, the surface streams were not 

affected by the artesian aquifer. 

The discharge of the St. Johns River onto the 

gentle slope of the Continental Shelf might suggest 

that no deep river channels would be cut in areas offshore from northeastern Florida and southeastern 

Georgia, where the soluble limestone has not been 

exposed to surface streams. However, it seems likely 

that these stream channels were cut on the Continental Shelf but are now covered by sediments on 

the ocean floor. The channels of some of the drowned 

valleys along the coast, as that of the St. Johns 

and Nassau Rivers, show that they were cut to at 

least 60 feet below sea level. A river channel, probably an ancestral channel of the Susquehanna River, 

was cut to a depth of 200 feet below sea level in 

Chesapeake Bay at the Annapolis Bridge crossing 

(Hack, 1957, p. 817-830) in Maryland. Another 

river channel was cut 370 feet below sea level at 

Cape Henry (Harrison, 1962, p. 47, 52, 53) during 

Pleistocene time. It seems reasonable therefore that 

there are buried Pleistocene channels both under the 

coastal terraces and offshore in the report area. 

OKLAWAHA RIVER 

As stated by Cooper and Kenner (1953, p. 151), 

not only the Oklawaha River but most of the major 

streams in central and northern Florida, including 

the Suwannee, Santa Fe, St. Johns, Withlacoochee, 

and Hillsborough Rivers, receive a large part of 

their flow from artesian springs. The flow of the 

Oklawaha is sustained at medium and low stages 

by Silver Springs. The Oklawaha rises in a group 

of large lakes including Lake Griffin, Lake Eustis, 

Lake Harris, and Lake Dora in Lake County. It flows 

northward across Marion County and turns eastward 

to the St. Johns River between Lake George and 

Palatka. As suggested by Cooke (1939, p. 109-110), 

the Oklawaha is older than the St. Johns River, and 

some of its headwaters probably have been in existence since the Sunderland terrace emerged from the 

sea. The Oklawaha valley was filled with unconsolidated sediments which have remained to the 

present time. The area of the St. Johns valley 

remained submerged until the retreat of the Talbot 

sea. During the low stand of the sea after Talbot 

time, sediments in the channel of the St. Johns 

River probably were removed. The valley was 

covered again by the sea in Pamlico time, but the 

channel was not completely filled or was reopened 

to a depth of as much as 60 feet during a low sea 

level in the late Pleistocene. 

I.AKES 

Lakes are especially numerous in Florida, where 

it is estimated there are 30,000 named lakes (U.S. 

Cong. Senate Select Comm., 1960, p. 40). Of about 

250 fresh water lakes in the United States, with a 

surface area of 10 square miles or more, 19 are in 

Florida (Bue, 1963, p. 18). Lakt Okeechobee in 

Florida is the second largest fresh-w·~ter lake in the 

United States. Many of these large lakes in Florida 

occupy solution basins in limestone. Lake basins 

in the area of this report may be placed in two groups 

according to origin. One group is formed chiefly by 
DRAINAGE 17 

the solution of limestone or other soluble rocks; the 

other group is formed by forces working on surficial material, which include original depressions 

and hollows on the former ocean floor that is exposed 

by the retreat of the sea. Lakes that were formed 

chiefly by solution include those affected by jointing 

or faulting. The lakes formed by solution of limestone are especially significant in a study of the principal artesian aquifer because the lake basins may 

be recharge areas under certain conditions. Under 

other conditions if there were a lowering of sea level, 

as in Pleistocene time, many of the larger artesian 

springs in sinkholes-such as the two salt springs in 

Sarasota County-would stop flowing and form lake 

basins. Also, some submarine springs, discharging 

from sinkholes off the coast of Florida at the present 

time, would form lakes. 

'Most, if not all, of the lakes in the areas where 

the limestone of the principal aquifer is at or near 

the surface are in basins formed chiefly by solution 

of the limestone and collapse of a section of a cavern 

roof. Most of the lakes in the lake region in the 

Central Highlands of Florida occupy old partially 

filled sinkholes. They range in size from mere ponds 

to lakes several miles wide, such as Lake Apopka. 

Many lakes have no surface outlets, but some are 

connected and drain into rivers, or they form part 

of the river such as the lakes through which the 

St. Johns flows. Most of the lakes are shallow, 

although some of the sinks that have not been filled 

with sediments have deep water. The solution basins 

extend into western Florida, southeastern Alabama, 

and southwestern Georgia, including the large lake 

basins at the south edge of the Tallahassee Hills. 

The large lakes in central Florida, including Lake 

Apopka, Lake Harris, and others at the head of the 

Oklawaha River, appear to occupy solution basins 

similar to those near Tallahassee. 

As stated by Cooke, (1939, p. 101), Crescent Lake, 

Lake George, and a series of smaller lakes that form 

expansions of the upper reaches of St. Johns River 

are remnants of Pamlico estuaries. However, except 

possibly for the lakes south of Lake Harney, the 

writer is of the opinion that all the lakes in the 

valley, including Crescent Lake, are in basins that 

originally were formed by solution of limestone 

during a low stand of the sea in Pleistocene time. 

The relatively high salinity of the artesian water 

southeast of Crescent Lake seems to indicate that 

sea water entered the aquifer through these sinks 

during a high stand of the sea. 

The altitudes of the lakes in solution basins range 

from approximately sea level to more than 120 feet 

above sea level. The highest of these lakes in central 

and north-central Florida are in areas where sinkholes penetrated the Hawthorn or other relatively 

impervious beds overlying the principal artesian 

aquifer. In north-central Florida, Clark, Musgrove, 

Menke, and Cagle (19·62, p. 19-38) reported that 

the lakes in Alachua, Bradford, Clay, and Union 

Counties range from about 175 feet to about 55 feet 

above sea level. 

The lake basins formed by agents other than solution of limestone include Lake Okeechobee which 

occupies about 730 square miles. As stated by Cooke 

(1939, p. 101), the basin seems to have originated 

during late Pleistocene time as a slight depression 

in the bottom of the Pamlico sea. After the sea 

retreated, solution of the shell marl and other calcareous material at or near the surface may have 

occurred in the lake and its natural spillway in the 

Everglades to the south. 

Apparently, as suggested by Cooke, Lake Istokpoga, Lake Kissimmee, and other lakes in the Kissimmee River basin in southern Florida originated . 

as depressions in the ocean floor. However, lakes 

such as Lake Kissimmee and Lake Tohopekaliga in 

the northern part of the Kissimmee River valley, near 

areas where lake basins were formed by solution of 

underlying limestone, may also have originated as 

solution depressions that were filled and sealed by 

sediments on the ocean floor. 

SWAMPS AND THE EVERGLADES 

There are many areas with poor drainage on 

the Coastal Terraces, chiefly in the swamps and low 

grassy plains, which are called the Everglades in 

southern Florida. Locally, there are many swamps 

along the flood plains of streams and bordering tidal 

marshes. · 

The Big Cypress Swamp in northern Collier 

County in southern Florida and the Okefenokee 

Swamp in southern Georgia and northern Florida 

are the principal swamps of the region. In southern 

Florida the Everglades occupy a nearly level plain 

about 40 miles wide underlain by organic soil; the 

land slopes from about 15 feet above sea level at the 

south side of Lake Okeechobee to sea level at the 

tip of the peninsula, a distance of more than 100 

miles (Cooke, 1939, p. 55). As the name implies, the 

Everglades are ppen gras·sy meadows. Much of the 

land is covered by tall sawgrass and other vegetation 

characteristic of organic soil. On the west the Everglades merge with the Big Cypress Swamp, which is 

on higher ground. The Everglades ,extend to the gulf 

coast south of the swamp. An arm of the Everglades 
18 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

extends northward between Lake Okeechobee and 

the Atlantic Coastal Ridge. Before parts of the 

Ever~lades were drained by canals and converted 

into farming land, water from Lake Okeechobee 

overflowed through a gap in the natural levee on 

its south side into the Everglades and passed southward across the Everglades to the Bay of Florida 

and Gulf of Mexico. In wet seasons, the Everglades 

are covered by water except for islands of higher 

ground. Unlike swamps, the Everglades have few 

trees. 

In the Miami area, the Everglades are bordered on 

the east by a rim a few miles wide of white crossbedded oolitic limestone of the Miami Oolite. North 

of the Miami area, oolite and the Anastasia Formation form the rim. Parker and Cooke (1944, p. 47, 

51) show by contours the rock floor of the Everglades 

including Lake Okeechobee. They show by arrows 

the direction of surficial drainage in the Everglades 

and the Big Cypress Swamp. Before drainage 

canals were dug, part of the natural drainage of the 

Everglades between Miami and West Palm Beach 

was to the Atlantic through natural courses crossing 

the east rim of the Everglades, known as the Atlantic 

Coastal Ridge. A large part of the drainage is to 

the south and southwest to the Gulf of Mexico. 

The Big Cypress Swamp is bounded on the east 

and southeast by the Everglades. On the south and 

southwest, it merges with the low.:.lying coastal 

marshes and mangrove swamps. Sandy flatlands 

border it on the north and west. The area to the 

north is slightly higher than the swamp; the area 

to the west is lower than the swamp. The drainage 

of the Big Cypress Swamp is to the east and south 

into the Everglades~ North of the swamp and west 

of the Everglades in the Devils Garden in Hendry 

County, part of the drainage is northward to the 

Caloosahatchee River. The swamp is underlain by 

limestone riddled by solution at the surface. However, the limestone is .thin, and the underlying Hawthorn Formation contains relatively impervious beds 

that separate the shallow limestone in southern Florida from the limestone of the principal artesian 

aquifer, the top of which is as much as 1,000 feet 

below sea level. Therefore, the solution cavities do 

not ·extend below the shallow limestone. Only five 

deep sinkhole lakes, all west of the Everglades, have 

been discovered in southern Florida, but there may 

be others filled with sand or other material. The 

sinkholes pass through the shallow limestone but 

appear to terminate in a permeable limestone zone 

of the Hawthorn. · 

The Okefenokee Swamp on one of the higher terraces in southern Georgia and northern Florida is the 

largest of the swamps. It covers an area of about 

660 square miles (LaForge and others, 1925, p. 52) 

extending from a point about 5 miles south of Waycross southward beyond the Florida State line. Parts 

of several sand terraces extend around the swamp. 

The most prominent, known locally as Trail Ridge, 

marks the eastern extent of the swamp. The west 

margin. is irregular because of tributary streams, as 

shown on the Valdosta topographic map, scale 

1 :250,000, U.S. Geological Survey, and by Fortson 

(1961, p. 6). The swamp slopes from about 120 

feet above sea level in the northeastern part to about 

100 feet above sea level in the southwestern part. 

Most of the water drains westward into the Suwannee River and to the Gulf of Mexico, but part of 

it drains southward to the headwaters of the St. 

Marys River, which cuts across Trail Ridge and to 

the Atlantic. The swamp contains many islands, 

remnants of sand terraces. Much of the swamp is 

forested,. but there are areas of grassy prairie like 

the Everglades. On the lower ground are pond cypress, black gum, and several kinds of bay trees 

(LaForge and others, 1925, p. 53). Although there 

are lakes in Okefenokee Swamp, none is comparable 

in size to Lake Okeechobee in the Everglades or Lake 

Drummond in the Dismal Swamp of Virginia and 

North Carolina. Cooke (1939, p. 106) stated that 

when the area emerged from the sea in Pleistocene 

time, its natural drainage toward the east in the area 

of the Okefenokee Swamp was blocked by Trail 

Ridge, which prevented or retarded surface water 

drainage to the east. An exception is the St. Marys 

River which rises in the swamp and cuts across the 

ridge. The overflow of the swamp followed the 

natural slope of the land southward and formed the 

headwaters of the .. Suwannee River. 

Cooke (1945, p. 313) suggested that some of the 

upland swamp, notably Okefenokee Swamp, has been 

in existence, probably with little change, since the 

Illinoian Glaciation, possibly earlier. During the time 

when the sea stood about 120 feet above its present 

level, the area of the swamp was part of a shallow 

sound bounded on the east by a bar, now Trail Ridge. 

The water in the sound rarely was deeper than 40 

feet, but on the east side of Trail Ridge the water 

deepened rapidly to 100 feet or more. Parts of the 

swamp are underlain by peat deposits (Fortson, 

1961, p. 1-21), some of which may be in sinkholes 

which were covered and filled by the Pleistocene sea. 

Peat is present in sinkholes in Lowndes County west 

of the swamp and also in depressions that appear to 

be filled sinks in Effingham and Screven Counties, 
CLIMATE 19 

Ga., north of the swamp near the South Carolina 

State line. 

CLIMATE 

The climate in· this region ranges from temperate 

in the northern part of the report area to subtropical 

in southern Florida (U.S. Weather Bureau, 1958, 

p. 3). Annual precipitation ranges from about 50 

inches in the northern part to 60 inches or more 

along the coast of Alabama and in some parts of 

Florida. The average rainfall for Florida is 53 

inches. South of Miami the annual rainfall decreases 

to a minimum of 38 inches at Key West. Precipitation in southern Florida, within the belt of the 

northeast trade winds in the summer, reaches a peak 

in June. A larger peak in September and October is 

caused in part by hurricanes. The Caribbean and 

Atlantic hurricanes generally occur in later summer 

and autumn. At times rainfall exceeds 20 inches in 

24 consecutive hours near the storm center. Thunderstorms during the summer months frequently result 

in heavy downpours, locally more than 20 inches 

in 24 hours. More than 90 thunderstorms per year 

have been reported in northwestern Florida, June 

and July being peak months. 

Ferguson (in Parker and others, 1955, p. 54-56) 

estimated that evaporation losses from water bodies 

in Florida average 40 to 45 inches a year. He reported that the estimated mean annual evapotranspiration from sawgrass land in the Everglades near 

Belle Glade is about 60 inches a year. Fred M. Elliot 

showed that evapotranspiration was about 110 inches 

in a year by a test with paragrass growing in muck 

in a tank. The water level ranged between 0 and 12 

inches below the top of the muck. During the same 

period a tank having water levels 30 to 36 inches 

below the top of the muck showed a loss of 50 to 

60 inches. 

The details of the climate in this region are given 

in reports of the U.S. Weather Bureau, Washington, 

D.C. Details of the climate in southeastern Florida 

are given by Ferguson (in Parker and others, 1955, 

p. 15-56). 

SOILS AND THEIR RELATION TO AQUIFERS 

There are many soils in the Coastal Plain, and 

their character and composition result in part from 

the geologic conditions during the deposition of the 

surficial formations and the nature and intensity of 

their weathering and erosion (LeGrand, 1962, p. 35). 

Where topographic relief is adequate and the 

water table is not near the land surface, there is 

a tendency for dissolved solids and suspended matter 

to move downward from the surface soil and to be 

deposited in the subsoil. For example, the rolling 

Sand Hills region along the inner margin of the 

Coastal Plain in Georgia and South Carolina (Fall 

Line Hills, fig. 2) has a well-developed sandy soil 

separate from the clayey subsoil. However, where 

the land is flat and poorly drained, there is a tendency 

for the soil profile to be poorly developed. 

A mature soil (Bryan, 1962, p. 5-6) is represented 

by layers or horizons of different thicknesses and 

colors. The upper layer may range from a few inches 

to several feet; it is known as the A horizon, or zone 

of leaching. The second layer, which has different 

thicknesses and colors, is known as the zone of 

accumulation, or B horizon. The parent material 

from which the soil develops is known as the C 

horizon. In the Coastal Plain, the thickness of the 

soils generally is greatest on the upland ridges, where 

they may be several feet thick with loose sandy 

subsoils. In Florida (Bryan, 1962, p. 12) reported 

that the Lakeland soil in the upland lake region of 

central Florida may have a depth of as much as 

6 feet and that the Kershaw soils are deeper and 

less coherent than the Lakeland soils. 

Much of the region of this report is blanketed by 

sandy soils underlain by a subsoil zone of clay, sandy 

clay, or clayey sand. Silica is the predominant mineral of the sand. Harper (1910, p. 40) stated that 

about 80 percent of the State of Florida could be 

roughly classified as sand, 3 percent as red clay, 

12 percent as muck, and the remainder as limestone 

and marl. Bryan (1962) described various groups 

of soils with subdivisions and showed the distribution 

of 10 of these groups on a map (1910, p. 49). Soil 

maps and reports for many counties in the Coastal 

Plain have been published by the U.S. Department 

of Agriculture. Some reports include information on 

the percolation rates of water in undisturbed saturated cores. In general, the rates range from about 

2.5 inches to 10 or more inches per hour. The rate 

for many of the soils was 10 or more inches per hour. 

The 1938 yearbook of the U.S. Department of 

Agriculture (p. 1065-1122) showed seven categories 

of soils in the region of Tertiary formations in the 

southeastern States. The following discussion is 

chiefly from that report. Two of the most extensive 

of these groups of soils are the Leon-Bladen soils of 

the coastal terraces and coastal lowlands and the 

Norfolk-Ruston soils on the uplands. 

COASTAL TERRACES AND COASTAL LOWLANDS 

The area of the Leon-Bladen soils is chiefly on 

the coastal terraces (fig. 2). It includes the greater 
20 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

part of the flatwoods of Florida and Georgia and 

extends inland into the central uplands of Florida 

and the higher coastal terraces of Georgia. In northeastern Florida and southeastern Georgia, the area 

of these soils su·rrounds the peat and muck soils in 

the Okefenokee Swamp. In coastal Georgia the 

soils merge with another group of sandy soils that 

extends along the low terraces in South Carolina. 

The area is characterized by a dominantly flat to · 

undulating surface, numerous low sand ridges, hummocks, ponds (some containing grass pondweed), 

swamps and marshes, and numerous tidal streams 

and estuaries. Natural drainage is poor except for 

the sand ridges. A characteristic feature of the Leon 

soils is· a well-defined black to brown hardpan layer 

consisting of sand cemented by organic matter or 

other material. The Leon soils are light gray to 

gray fine sand, 4 to 8 inches thick, overlying light 

gray sand, 12 to 30 inches deep, resting on the 

hardpan. In some places there are two hardpans. 

Bryan (1962, p. 23-28) described the Leon soils 

and _three other series having hardpan as imperfectly 

drained acid soils. He included the Bladen soils with 

a series of poorly drained acid soils underlain by 

plastic sandy clay. The relatively impervious hardpan retards vertical movement of water and reduces 

recharge to the shallow aquifers. Locally, water 

under the hardpan is under slight artesian pressure. 

The hardpan makes conditions favorable for surface 

irrigation by means of shallow ditches and subirrigation as in the Sanford celery area in Seminole County, 

Fla. 

The Leon-Bladen soils in Georgia and in eastern 

and southern Florida are underla1n by the Hawthorn 

Formation and younger material. In the area on 

the west coast from Tampa Bay to Wakulla County, 

Fla., and extending inland to the Central Highlands 

and Tallahassee Hills, the soils are underlain by 

Eocene limestones and younger formations. In that 

area some soils are changed by the limestone formations containing phosphatic material. Parent materials of soils in the region covered by the Pleistocene sea may include Pleistocene deposits, chiefly 

sand and clay and material of older formations reworked by the sea. 

The soils on the coastal terraces in the southern 

part of Florida, south of Lake Okeechobee, consist 

chiefly of peat and muck in the Everglades, extending 

southward from the lake almost to the coast. The 

area bordering the Everglades 'and extending to the 

coast in southern Florida is Perrine silt loam and 

rock land, where the Miami Oolite and other limestone and marl of post-Miocene age are at or near 

the surface. Bryan showed similar soils in an area 

adjacent to the north shore of Lake Okeechobee and 

along much of the shell ridge on the east coast, also 

in areas on the west coast. The Perrine silt loam, 

known locally as marl land, may be as much as 30 

inches thick. However, there are extensive areas 

with covering of fine loose sand of very shallow silt 

loam and areas of mangrove swamp at tide level. In 

the vicinity of Redland there are small areas of 

brown or reddish-brown soil a few inches thick overlying the limestone. In addition to the large areas of 

muck land in the Everglades and Okefenokee Swamp, 

there are muck areas in the middle and upper St. 

Johns River valley. There are many smaller areas 

in sinkholes, ponds, and local depressions on the 

coastal terraces. Truck crops are ·grown in many 

of these areas, as in the Everglades and elsewhere, 

where the water level in the muck is controlled by 

drainage and irrigation. During wet seasons the 

water table may rise to the land surface in poorly 

drained muck areas. Some of the underdrained areas 

are covered with water. In the Okefenokee Swamp in· 

southern Georgia and northern Florida, where peat 

and muck fill sinkholes, water may pass through 

these materials to the underlying Tertiary limestones 

of the principal artesian aquifer. Water in the shallow sands of the poorly drained areas may have 

relatively high organic color and iron. 

UPLANDS 

In the uplands (fig. 2), which includes the areas 

above the Coastal Terraces and Coastal Lowlands, 

the Norfolk-Ruston soils are the most extensive. 

Bryan (1962, p. 13-19) grouped these soils as welldrained acid soils. In the central Highlands in northcentral Florida, the Norfolk-Ruston soils merge with 

the Norfolk-Blanton soils that occupy the upland 

lake region. The outstanding features of these soils 

are their extremely sandy texture, small amounts of 

organic matter, and strongly acid reaction. Drainage 

is good or excessive, except in some flat areas and 

slight depressions. The Norfolk soil, the predominant 

type, consists of a light-gray or yellowish-gray fine 

sand underlain at a few inches by yellow loose fine 

sand that at 3 to 4 feet grades into brownish-yellow 

loose fine sand. The sand at 5 to .10 feet is usually 

underlain by mottled yellow, light-gray, or brown 

fine sandy clay. Blanton soil differs from the Norfolk 

in being ·lighter colored in both surface and subsurface zones. In Florida Bryan groups the Blanton 

soils with Lakeland and other sandy soils in upland 

areas. On the northwest border at the Norfolk-
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 21 

Ruston soil area is a narrow belt of Norfolk sand in 

the Fall Line Hills (fig. 2). The sands are yellowish 

gray to light gray underlain by pale-yellow loose 

incoherent sands to a depth of 3 to 80 feet. 

Within the large area of the Norfolk-Ruston soils 

are the Greenville-Magnolia soils and the TiftonIrvington soils. The Greenville-Magnolia soils extend from the Dougherty Plain in southwestern 

Georgia into Alabama and the Marianna Lowlands 

in Florida, where the Tertiary limestone is at or 

near the surface. A smaller area of these soils is 

on the Georgia-Florida State line where the Tifton 

Upland and Tallahassee Hills merge. The Hawthorn 

Formation of Miocene age is at or near the surface 

in that area. Several areas of these soils are in 

Florida wes.t of Tallahassee. On the Dougherty Plain 

and Marianna Lowlands, these soils may be influenced by the underlying Tertiary limestone. However, at least part of the area was covered by the 

Pleistocene sea which reworked the unconsolidated 

material. The areas in Florida are underlain by the 

Hawthorn Formation and younger deposits. The 

soils are developed from limestone and beds of noncalcareous heavy sandy clay and clay. The surface 

soils are pr:edominantly sandy with a moderately 

low mineral content and organic matter. They are 

mildly to strongly acid in reaction. Greenville soils 

have brown to reddish-brown surface soils and red 

to deep-red, or maroon, heavy sandy clay subsoil 

which may be influenced by limestone (Bryan, 1962, 

p. 16). Magnolia soils differ essentially from Greenville in having light-brown to gray surface soils and 

yellowish-brown subsurface layers. 

The Tifton-Irvington soils occupy an area on the 

Tifton Upland (fig. 2) in southwestern Georgia underlain by the Hawthorn Formation. The surface is 

almost level, undulating, or gently sloping about 

300 to 400 feet above sea level. The parent material 

is from unconsolidated beds of mottled red, lightgray, yellow, and purple hard brittle sandy clay. 

Outstanding characteristics are the large quantities 

of small rounded brown to almost black pebbles of 

ironstone one-eighth to one-half inch in diameter on 

the surface soil and to a less extent in the subsoils. 

Tifton soils differ from the Norfolk in having finer 

texture and iron pebbles throughout the profile. The 

Tifton soils, the dominant soils of the area, are 

grayish-brown to gray loamy sandy soils, 4 to 6 

inches deep. The subsurface layers are yellow to 

brownish-yellow light-textured sandy loam. The subsoil begins at depths of 8 to 15 inches and extends 

to 30 to 36 inches. Irvington soils, which are not 

extensive, differ from Tifton soils in having a compact or cemented layer below the subsoil. Alluvial 

soils are present in flood plains of river valleys. 

Colluvial soils, brought down from higher elevations by either gravity or water, occur in depressions 

and along some streams. 

In general, the sandy soils of the region are favorable for recharge of the water-bearing formations. 

Recharge through sandy soils underlain by permeable 

limestone is excellent because there is no runoff and 

little or no transpiration. The soils having hardpan 

or clayey subsoil retard the movement of water to 

the underlying aquifer. However, the hardpan makes 

it possible to irrigate the sandy soils. The clayey 

subsoils may be helpful in removing objectionable 

constituents during the movement of the water to 

underlying aquifers. In the area of sluggish drainage on the coastal terraces, a large part of the water 

evaporates or is transpired by vegetation instead of 

moving downward to an aquifer. Water from peat 

or muck acid soils may have relatively high organic 

color. The exceptions are those soils developed from 

beds of sands mixed with shells or beds of sand 

on limestone or marl. 

GEOLOGIC FORMATIONS AND THEIR WATERBEARING PROPERTIES 

GENERAL FEATURES 

The geologic formations that crop out in this area 

range in age from Late Cretaceous to Recent. They 

consist chiefly of alternating beds of limestone and 

marl with some sand, gravel, and clay. The outcrops, 

in general, are belts approximately parallel to the 

Fall Line, the inner boundary of the Coastal Plain. 

Except where affected by local structural features, 

the formations dip gently toward the coast at right 

angles to the belt of outcrops (fig. 3). This pattern 

of outcrops is broken by local geologic features, 

such as the Ocala uplift in Florida. The formations 

dip in all directions from the Ocala uplift. 

Cretaceous formations underlying the Coastal Plain 

form the inner belt of outcrops adjacent to the area 

of this report. The altitude on top of the Cretaceous 

is indicated approximately by contours on the tectonic map of the United States. In northern Florida 

the top ranges from less than 2,000 feet below sea 

level in the panhandle to more than 6,000 feet in 

southern Florida. Along the Fall Line in Georgia, 

Cretaceous formations are as much as 600 feet above 

sea level (Herrick and·Vorhis, 1963, fig. 14). They 

dip southeastward to more than 2,800 feet below 

sea level in southeastern Georgia. The Cretaceous 

formations overlie igneous and metamorphic rocks, 

as shown by Applin (1951, p. 5-17). 
22 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

0 

29° r-------T-----t-----+-------1-------+~ 

28° 

27" 

EXPLANATION 

Recent and Pleistocene deposits 

undifferentiated 

Pliocene rocks 

Upper Miocene rocks 

Hawthorn Formation and equivalents 

[§] 

Tampa Limestone and equivalents 

Oligocene rocks 

>-

}I :J 

0 

>-

0:: 

~ 

i= 

0:: 

w 

I0 

Upper Eocene rocks 

Middle Eocene rocks 

Middle and Lower Eocene rocks 

Paleocene rocks 

Cretaceous rocks undifferentiated 

Paleozoic rocks undifferentiated 

50 0 50 

>-

0:: 

~ 

to:: 

w 

IIf) 

:J 

0 

}~ u 

H ...J 

~ 

D.. 

!OQ MILES 

., 

Complied by D. J . Casey and G. M. Bradford 

from State geologic maps 

FIGURE 3.-Generalized geologic map of the Coastal Plain of the Southeastern States. 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 23 

The igneous and metamorphic rocks (also known 

as crystalline rocks) are at or near the land surface 

in the Piedmont province and at the Fall Line. The 

surface formed by the top of the crystalline rocks· 

under the Coastal Plain, as shown by Applin (1951, 

fig. 2), ranges from a few hundred feet above sea 

level along the Fall Line to more than 13,000 feet 

below sea level in southern Florida. In north-central 

Florida on the crest of the peninsular arch, the surface is about 3,500 feet below sea level. A table 

of well data by Applin (1951, p. 19-25) shows that 

the rocks include granite, diorite, biotite gneiss, 

schist, tuff, and volcanic agglomerate of rhyolitic 

composition, quartzitic sandstone, shale, and dolomite. Some of the data on Florida from Applin's 

report are tabulated by Puri and Vernon (1959, p. 

8-16). 

CRETACEOUS SYSTEM 

Applin and Applin (1944, p. 1708-1723) briefly 

described the subsurface stratigraphy of the Cretaceous System in Florida and southern Georgia. 

Applin (1952; 1965) described the geology in more 

detail and designated the Early Cretaceous as comanche Series and the Late Cretaceous as Gulf 

Series. As described by Applin (1952, p. 1159, 1164), 

rocks of the Comanche Series do not crop out in the 

Southeastern States, because they are overlapped by 

deposits of the Gulf Series. Well data are insufficient for more than an approximation. However, 

formations of ~he Comanche Series are present in 

the subsurface throughout most of Florida and the 

Coastal Plain in Georgia, but they are absent on 

the crest of the peninsular arch in northern Florida 

and in southeastern Georgia. Both clastic and nonclastic facies are recognized in Florida. The nonclastic facies in southern Florida is composed chiefly 

of alternating beds of limestone, dolomite, and anhydrite. The total thickness of the Comanche Series 

is at least 6,250 feet, as indicated by the record of a 

well on Big Pine Key, Monroe County, Fla., in the 

southern Florida basin. In western Florida a well 

in Jackson County penetrated approximately 5,000 

feet of Comanche beds. No fresh water has been 

reported in the Comanche Series in the area of 

this report. 

Formations of the Gulf Series crop out in an 

irregular belt along the inner margin of the Coastal 

Plain. Except for the Atkinson Formation, each 

stratigraphic unit includes both a clastic and nonclastic facies. In western Florida and most of southern Georgia, a clastics facies, similar in its broader 

aspects to the sedimentary rocks of the western gulf 

coast, is chiefly shale and sand containing some 

limestone and chalky marl. In most of the Florida 

peninsula, the sedimentary section of the Gulf Series 

is predominantly nonelastic chalky limestone and 

dolomite. The Gulf Series has a maximum thickness 

of 3,000 feet in the southern Florida basin. It yields 

large supplies of fresh water in parts of the Coastal 

Plain in Georgia, Alabama, and .South Carolina. 

However, the water in the Gulf Series is salty in 

most, if not all, of Florida and southeastern Georgia. 

Fresh water is present in the Cretaceous formations 

on the coast at Parris Island, S.C. Further discussion of the Cretaceous is not given here because 

this report is on the artesian water in the Tertiary 

formations overlying the Cretaceous. 

TERTIARY SYSTEM 

Formations of Tertiary age consist chiefly of limestone in most of Florida and southeastern Georgia . 

.Some of them .grade into sands and other clastics 

in western Florida, southeastern Alabama, southwestern Georgia, and in the northern part of the 

Coastal Plain in Georgia and adjacent parts of South 

Carolina. The Tertiary rocks are underlain by Cretaceous sedimentary rocks, except in a few places 

along the Fall Line in eastern Georgia where Eocene 

rocks overlap the Cretaceous and rest on igneous and 

metamorphic rocks, which are at or near the surface 

in the Piedmont province. A sketch map of Florida 

and adjacent States showing structure contours on 

top of the Eocene formations is shown in figure 4. 

The sedimentary rocks extend oceanward to the edge 

of the Continental Shelf. The large projection of the 

continent, separating the deep water of the Gulf of 

Mexico from the deep water of the Atlantic Ocean, 

is the Floridian Plateau named by Vaughan (1910, 

p. 99). The plateau includes not only the State of 

Florida but an equally large or larger submerged 

area less than 50 fathoms (300 feet) deep (Cooke, 

1945, p. 3). A photograph of a relief model of the 

plateau is shown in figure 5. 

The distribution and thickness for each series of 

the Tertiary are shown by Toulmin (1952, p. 1165-

1175) for Florida, Georgia, and adjacent parts of 

Alabama and South Carolina and by Herrick and 

Vorhis (1963) for Georgia. A comparison of the 

geologic formations along the Chattahoochee River 

in southeastern Alabama and southwestern Georgia 

with those in central Alabama (Toulmin and LaMoreaux, 1963, p. 385-403) shows changes in thickness and lithology in the east-west transition from 

the clastic facies to limestone in Georgia and Florida. 

Toulmin (1955, p. 208, fig. 1; 1952, p. 1165-1175) 
24 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

·, 

\ 

Q <\\.\ ~ g..\ ...., \ 

.-(\\ 

~ ~>~o .... o % ..... 00 

~ -v_... ......... 

~ ~~ '¢. "'"'l!>"'o-;..15' 

~ . \ 

100 MILES\'·... 0 I 

.....__.___.___.___. . ···-.................. -· 

FIGURE 4.-Sketch map of Florida and adjacent States showing Floridian Plateau and top of Eocene formations. (From 

Cooke, 1945, p. 6.) 

showed the total thickness of the formations of the 

Tertiary and Quaternary Systems in the report area. 

As the Quaternary System is only a few feet thick in 

most of the area, the probable maximum thickness 

being about 200 feet in a few places, the thickness 

shown for the Cenozoic (fig. 6) represents in a general way the thickness of the Tertiary. The thickness 

in Florida ranges from less than 1,600 feet in Lafayette and Suwannee Counties on the northwest 

side of the Ocala uplift in north-central Florida to 

about 4,500 feet in western Florida. North of the 

Ocala uplift in southern Georgia, the thickness increases to about 2,600 feet and then decreases to 

zero northward in the belt of outcrops adjacent to 

the Fall Line. Southward from the Ocala uplift, the 

Tertiary formations thicken to about 5,500 or more 

, feet in the southern Florida embayment. In southeastern Alabama the maximum thickness is about 

3,000 feet. In southeastern South Carolina the Tertiary deposits are about 2,400 feet thick. A geologic 

section from Hancock County, Ga., to Monroe County, 

Fla., is shown in figure 7. 

The Tertiary formations are the chief source of 

large ground-water supplies (both artesian and nonartesian) in the area of this report with the following exceptions : ( 1) In some of the outcrop areas of 

the Tertiary in Alabama, Georgia, and South Carolina, where the underlying Cretaceous sands may be 

the chief source of water, (2) in the Miami area, 

where part of the· ground-water supply is from Pleistocene formations, (3) at Pensacola, where part of 

the supply is from sand of Pleistocene age, and ( 4) 

in areas where many shallow domestic wells are in 

Pleistocene and Recent sands. The Tertiary formations and their water-bearing properties are described in the next section of this report. The 

following tables ( 1 to 5) show the geologic correlation and some of the water-bearing properties of 

the formations by States. 

PALEOCENE SERIES 

MIDWAY AGE 

Clayton, Porters Creek, and Naheola Formations 

In southeastern Alabama, the Clayton, Porters 

Creek, and N aheola Formations represent the Midway Group. The Porters Creek does not, however, 

crop out in that area, and the N aheola pinches out 

to a few feet of sand and clay. The Clayton Formation extends into Georgia and possibly into South 

Carolina. The Paleocene Series in southeasternmost 

South Carolina is not named, but S. M. Herrick 

(written commun., 1956) has applied the name Clayton to subsurface rocks in South Carolina (Counts 

and Donsky, 1963, p. 19). Cooke and MacNeil (1952, 

p. 21) indicated that the deposits that have been 

mapped in South Carolina as Black Mingo of early 

Eocene age should, in part, be considered of Paleocene age. The Paleocene deposits in the report area 

in South Carolina are dark-gray to black laminated 

shale with limestone facies in the south coastal areas. 

In Florida there were two basins of depositionone contains chiefly clastic deposits·; the other contains carbonate rocks. The rocks of Midway age are 

represented by the Cedar Keys Limestone, or its 

clastic equivalent, in Florida and adjacent parts of 

Alabama and Georgia. Cooke (1945, p. 16) suggested 

that the clastic facies in western Florida represents 

the Porters Creek Formation. The distribution and 

thickness of the formations of Midway age in Florida 

and Georgia are shown by Toulmin (1952, fig. 2). 

The distribution and thickness of Paleocene deposits 

in Georgia are shown by Herrick and Vorhis ( 1963, 

fig. 12). 

In central Alabama the Clayton Formation 

thickens greatly eastward. The Porters Creek Formation thins eastward and the lithologic character 

changes. The lower part grades into calcareous clay, 

and the upper part, into calcareous. silt and fine sand. 

In eastern Alabama the Clayton Formation makes 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 25 

FIGURE 5.-Photograph of relief model of Floridian Plateau. (After Cooke and Mossom, 1929, pl. 1.) 
26 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN "STATES 

87" 86" as· 81" 

0 

--------+-~~~~~~==~~~~~~~~~----~~~~-7-~+t--~~\-~r---~() -------;--, 

G l1 L 

p 

27"r---------r------------.J-------

26"r---------~r-------------~----

-50 

0 

.P 

EXPLANATION 

---------500---------

Isopach 

Slwws thickness of Cenozoic sediments; interval, 500 feet 

18 19 

Section line showing wells 

See figure 7 

0 50 100 MILES 

25"r-------i-----------+-----------~--------~-----------+-----------}--------/ 

., 

~ 

? 

7... 

FIGURE 6.--Isopach map of Cenozoic sediments in Florida, Georgia, and adjacent parts of Alabama and South Carolina. 

(From Toulmin, 1955, p. 208.) 
500' 

SEA 

LEVEL 

500' 

1000' 

1500' 

2000' 

2500' 

3000' 

3500' 

4000' 

4500' 

5000' 

.5500' 

2 3 4 56 

50 0 50 100 200 MILES 

"18 

PLIOCENE 

TO RECENT 

20 21 

6000'~------------------------------------------------------------------------------------------------------------------------~ 

FIGURE 7.-Geologic section from Hancock County, Ga., to Monroe County, Fla. (From Toulmin, 1952, p. 1165-1175.) See figure 6 for location of section. 

1. Sandersville Public Water Well 51, Washington County, Ga. (LaMoreaux, 1946, p. 121). 

2. Glen Rose, Fowler 1, Treutlen County, Ga. 

(Richards, 1945, p. 923). 

3. Weatherford, Wilkes 1, Montgomery County, 

Ga. 

4. Felsenthal, W. Bradley .1, Appling County, Ga. 

5. W. B. Hinton (Clark), Adams McCaskill 1, 

Pierce County, Ga. (Applin and Applin, 

1944, p. 1744). 

6. Pan Am., Adams McCaskill 1, Pierce County, 

Ga. 

7. California, John A. Buie 1, Camden County, 

Ga. 

8. St. Marys River Oil Corp., Hilliard 1, Nassau 

EXPLANATION OF WELL NUMBERS IN FIGURES 6 AND 7 

County, Fla. (Cole, 1944; Applin and 

Applin, 1944, p. 1734). 

9. Hunt Oil Co., Hunt 1, Baker County, Fla. 

10. Tide Water Associated Oil Co., M. F. Wiggins 

1, Bradford County, Fla. 

11. Tide Water Associated Oil Co., J. A. Phifer . 

1, Alachua County, Fla. 

12. J. S. Cosden, Inc., W. L. Lawson 1, Marion 

County, Fla. (Applin and Applin, 1944, 

p. 1739). 

13. Ocala Oil Corp, York 1, Marion County, Fla. 

14. Dundee Petroleum Co., Bushnell well,· Sumter 

County, Fla. (Applin and Applin, 1944, p. 

1734). 

15. Oil Development Co. of Florida, South Lake 

2, Lake County, Fla. (Applin and Applin, 

1944, p. 1734). 

16. Pioneer Oil Co., Hecksher-Yarnell 1, Polk 

County, Fla. (Applin and Applin, 1944, p. 

1735). 

17. A von Park Bombing Range Water Well, Polk 

County, Fla. (Applin and Applin, 1944, p. 

17 40). Florida Geol. Survey W -668. 

18. Humble Oil and Refining Co., C. C. Carlton 

Est. 1, Highlands County, Fla. 

19. Humble Oil and Refining Co., Gulf Coast 

Realties 1, Collier County, Fla. 

20. Peninsular Oil and Refining Co., J. W. Cory 1, 

Monroe County, Fla. (Cole, 1941; Applin 

and Applin, 1944, p. 1735). 

21. Gulf Oil Corp., State of Florida J. P. Scranton 1, Monroe County, Fla. 

~ 0 

toC 

0 

e 

C"l 

~ is: 

> 1-3 

...... 

0 

z 

Ul 

> z 

t::l 

1-3 

== trJ 

Ed 

~ 

~ I 

~ 

...... 

~ z 

C') 

~ 

~ l;j 

Ul 

1.'1:) 

...;:J 
28 ARTESIAN WATER. IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

TABLE !.-Correlation of Tertiary formations in south-central and southeastern Alabama, Florida, Georgia, and 

southeastern South Carolina 

[Based on information in separate tables for each State. For Quaternary System, Pleistocene and Recent 

Series, see discussion for particular State, p. 29, 30, 32, and 34] 

South-central and Florida Southeastern 

Series southeastern Alabama (*,panhandle; t, peninsula) Georgia South Carolina 

Citronelle Formation 

Pliocene Citronelle Formation Caloosahatchee Marl Charlton Formation Waccamaw Formation1 

Duplin Marl Duplin Marl Duplin Marl 

*Choctawhatchee tTamiami 

Formation8 Formation2 

*Alum *Shoal 

Miocene Bluff River tHawthorn Hawthorn Formation Hawthorn Formation 

Group Forma- Formatio11 

tion 

with 

Oak 

Grove 

Sand 

Member 

Catahoula Sandstone Chipola Paynes Hammock Sand Formation 

Tampa Limestone Tampa Limestone Tampa Limestone 

Chickasawhay Limestone Suwannee Limestone Flint River Formation Flint River Formation 

Byram Formation 

*Byram Suwannee Limestone Cooper Marl 

Formation 

Oligocene Marianna Limestone and Marianna Absent 

Red Bluff Clay 

undifferentiated 

Limestone Cooper Marl 

Upper Ocala Limestone *Ocala tUpper Ocala Limestone, 

Eocene Limestone8 member upper member and 

Jackson (Crystal lower member 

Group in River) 

Alnbama Yazoo Clay tLower (grades updip into 

Moodys Branch Formation member Barnwell Formation) 

(Williston Barnwell Formation 

and Inglis) · 

SW. Georgia SE. GeorgilJ 

Middle Gosport Sand A von Park Limestone Gosport Sandy Castle Hayne Limestone 

Eocene Sand limestone McBean Formation and 

Claiborne Lisbon Formation Tallahassee Limestone Lisbon McBean Santee. Limestone 

Group Formation Formation Warley Hill Marl 

in 

Alabama Tallahatta Formation LakeCity Limestone Tallahatta Formation Congaree Formation 

*UndifferenSW. Georgia SE. Georgia 

Lower Hatchetigbee Formation HatchetigEocene tiated · bee Limestone 

Wilcox Tuscahoma Sand clastics tOldsmar Formation undifferen 

Group in Limestone Tuscahoma tiated Black Mingo Formation 

Alabama Nanafalia Formation Formation where 

Nanafalia present 

Formation 

Paleocene N aheola Formation *Undifferen- tCedar Keys Midway Porters Creek Formation tiated Limestone Clayton Formation Undifferentiated 

Group in Clayton Formation clastics 

Alabama 

Cretaceous and older 

1 DuBar (1962, p. 23) believes that the Waccamaw Formation ·is Pleistocene. 

2 The Choctawhatchee in western Florida is recognized by Flo~ida Geol. Survey as the equivalent of the Tamiami Formation in southeastern Florida. 3 The Ocala Group and its subdivisions as described by Puri (1953) has been adopted by the Florida Geol. Survey. The U.S. Geol. Survey has not adopted 

the names Crystal River, Inglis, and Williston. 
System 

Quaternary 

Tertiary 

Cretaceous 

GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 29 

TABLE 2.-General stratigraphic section and water-bearing properties of Tertiary formations in 

south-central and southeastern Alabama 

[After LaMoreaux (1948, p. 15), LaMoreaux (in Carter and others, 1949, p. 204), Cagle and Floyd (1957, 

p. 12). Cagle and Newton (1968), Mac Neil (1946, 1947)] 

ThickSeries Stratigraphic unit ness Lithology Water-bearing properties 

(feet) 

Undifferentiated 0-100 Chiefly sands, gravel, Yield small supplies to shallow 

and clay. wells. Potential source of large 

Recent and quantities of water where deposits 

Pleistocene are hydrologically connected to 

streams. 

Citronelle Formation 0-150 Lenticular beds of sand, Gravel beds in the basal part of 

Pliocene gravel, and variegated formation are a source of water 

clay. for domestic, industrial, and 

municipal wells . .. Catahoula Sandstone 0-650 Sand, white to pink; Source of moderate to large water 

Miocene and Paynes Hammock gravel, sandstone, and supplies for municipal, industrial, 

Sand undifferentiated varicolored clay. and domestic use. 

Chickasawhay 0-70 Greenish-gray, dolomitic, Solution cavities in limestone supply 

Limestone fossiliferous lime- water to domestic and stock wells. 

stone; contains a few Sand beds yield small quantities 

beds of fine glauco- of water to flowing wells in 

nitic sand. Brewton. 

Oligocene Byram Formation 0-100 Dark-gray to brown Generally not important as a source ( Bucatunna Clay sandy lignitic clay; of water supply. Sands in upper 

Member, marl mem- contains some fine part yield small quantities of 

ber, and Glendon glauconitic sands. water to flowing wells in vicinity 

Limestone Member of Brewton. 

undifferentiated) 

Marianna Limestone 0-40 Light-gray fossiliferous Solution cavities in limestone supply 

and Red Bluff Clay limestone and clayey moderate quantities of water to 

undifferentiated marl. domestic, industrial, municipal, 

and some irrigation wells. 

Ocala Limestone 0-60 Light-gray limestone Water-bearing properties similar . and clayey fossilifer- to those of overlying Marianna ous marl. Limestone. 

Upper Eocene Yazoo Clay ·0-70 Greenish-gray clay and Sand beds are sources of small 

Jackson Group fine to medium glau- quantities of water. 

conitic sand. 

Moodys Branch 0-55 Grayish-green to white Relatively impermeable but may be 

Formation glauconitic fossilif- source of. small quantities of erous limestone and water. 

marl. 

Gosport Sand and 0-325 Fine to medium and Massive sands are an important Middle Eocene Lisbon Formation coarse glauconitic source of ground water. 

Claiborne Group undifferentiated and sand, marl, and clay, 

Tallahatta Formation generally abundant 

fossils, and tan 

siliceous claystones: 

Hatchetigbee Forma- 0-175 lnterlaminated and Some massive sands are a source tion and Tuscahoma interbedded fine olive- of small water supplies. 

Sand gray sand, sandy clay, 

and a few glauconitic 

fossiliferous sand 

Lower Eocene beds. 

Wilcox Group Nanafalia Formation 0-100+ Greenish-gray to gray Sand beds are very permeable and 

fossiliferous coarse form an excellent aquifer. 

glauconitic sand, 

sandstone, marl, and 

clay. 

Naheola Formation 0-25 Interbedded gray sandy Not a· source of water supplies. clay and fine gray 

Paleocene 

sand. 

Midway Group Clayton Formation 0-130 Chiefly light-gray Some water obtained from solution 

Westward the Clayton smooth-textured cavities and permeable limestone, intertongues with the argillaceous lime- although the formation is 

Porters Creek stone containing relatively impermeable. solution cavities. 

Important source of water both 

nonartesian and artesian. 
30 

System 

ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

TABLE 3.-General stratigraphic section and water-bearing properties of Tertiary formations in Florida 

[Geology is based in part on reports, including Applin and Applin (1944), Parker, Ferguson, Love, and others (1955), 

Cooke ( 1945), Puri and Vernon (1959), and Toulmin ( 1955), with revisions by D. W. Brown (1962)] 

Series Stratigraphic unit 

Thickness 

(feet) 

0-250 

Lithology Water-bearing properties 

Yield water to shallow wells. 

Quaternary Recent and 

Pleistocene 

See discussion of Pleisto- cene units (p. 68). Chiefly sands, gravel, 

clay, shells, limestone, 

and marl. See discussion of geologic 

formations. 

Miami Oolite and Fort Thompson 

Formation are part of the shallow 

productive aquifer (Biscayne) in 

the Miami area. 

Pliocene 

T~rtiary 

Miocene 

Oligocene 

Citronelle Formation 0-100 

Caloosahatchee Marl and 0-50 

Charlton Formation 

Alachua and Bone Valley Formations 

Western 

Florida 

Choctawhatchee 

Formation 

(of former 

usage )I 

Tamiami 

Formation 

in southeastern 

Florida 

(late 

Miocene) 

~Shoal River Hawthorn 

f: Formation Formation 

t]with Oak ~Grove Sand ,g~ember. 

IXl 

~ Chipola ~Formation 

Tampa 

Limestone 

Suwannee Limestone 

0-100 

0-150 

0-550 

0-250 

0-450 

Byram Formation chiefly 0-40 

in western Florida 

Marianna Limestone in 

western Florida 

0-60 

Chiefly sands, gravel, 

and clay. 

Shells, sands, and marl. 

Chiefly phosphatic sand 

and clay. Occur only 

in the phosphate area of the Florida 

peninsula. 

Consists chiefly of limestone, sand, and mar 1. 

Sand, clay, and marl. 

Hawthorn consists 

chiefly of interbedded 

sand, clay, and limestone and sandy 

phosphatic limestone 

and marl. 

Limestone with sands, 

silts, and clay. Some 

parts of the limestone are silicified. The 

formation contains 

many solution cavities 

in recharge area. 

Limestone containing 

many solution cavities 

in ·recharge areas. 

Limestone, marl, and 

clay. 

Limestone. 

Yields large quantities of water of 

good quality. 

Yields water to shallow wells. 

Yields small to moderate quantities 

of water to shallow wells. 

Upper part of formation is very 

permeable. Forms lower part of 

the Biscayne aquifer. Lower 

part, with the Hawthorn, confines 

water in the underlying principal 

artesian aquifer. 

Yields small to moderate quantities 

of artesian and nonartesian 

water. Major part of Hawthorn 

forms the confining layer for the 

underlying artesian water, but 

lower part forms the upper part 

of the principal artesian aquifer. 

Yields large quantities of water in 

west-central Florida, but the 

yield is generally lower in other 

parts of the State. 

Yields moderate amounts of water 

but generally less than underlying Eocene formations. 

Yields moderate amounts of water. 

Yields moderate amounts of water. 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 31 

TABLE 3.-General stratigraphic section and water-bearing properties of Tertiary .formations in Florida-Continued 

Thickness 

System Series Stratigraphic unit (feet) Lithology Water-bearing properties 

Upper 0-380 Consists chiefly of chalk~ Ocala Limestone is one of the most 

member fossiliferous lime- productive formations of the 

stone. Equivalent of principal artesian aquifer. 

Crystal River Formation of Ocala Group of 

Upper Ocala Florida Geological 

Eocene Limestone8 Survey. 

Lower 0-150 Consists chiefly of cal- Upper member is more productive 

member citic limestone. .. than lower member. Formation 

Equivalent of the ,.. 

Q) contains many solution cavities 

Williston and Inglis ·~ in recharge areas: Formations of Ocala § 

Group of Florida 

Geological "" Survey. J:: 

.~ Ill 

.s 

Avon Park 0-845 Cream-colored to brown ~~von Park and Tallahassee LimeLimestone chalky limestone and c; stones are principal source of 

dolomite. Contains _e water fn areas where overlying 

gypsum and chert. .~ limestone is thin or absent. 

Middle Tallahassee 0-650 Limestone similar to p.: 

Eocene Undiffer- Limestone overlying A von Park 

entia ted Limestone. 

clastics in 

Tertiary- western 

Continued Florida Lake City 110-990 Alternating beds of Oldest formation of the principal 

Limestone dark-brown dolomite artesian aquifer and an imporand chalky limestone. tant source of artesian water in 

Gypsum is present in some areas. central part of peninsula and in the 

Tallahassee area. 

Oldsmar 250-1,000 Limestone containing Contains salt water. 

Limestone chert and gypsum in 

Lower central part of peninEocene sula. Grades into 

sandy facies in 

western Florida. 

Undiffer- Cedar Keys 165-2,250 Gray and cream-colored Contains salt water. 

entia ted Limestone to white limestone 

clastics in containing gypsum 

western and some anhydrite 

Paleocene Florida stringers and oolitic 

lenses. Grades into 

sand, sandy clay, and 

marl in western 

Florida. 

Cretaceous Contains salt water. 

and older 

1 Florida Geological Survey regards the Choctawhatchee (of former usage) in western Florida as the age equivalent of the Tamiami in the Miami area. 

D The principal artesian aquifer (Floridan) is the source of water for the artesian wells and large springs and includes overlying formations up to middle 

Miocene ( p. 80) • 8 Florida Geological Survey uses Ocala Group, including Crystal River, Williston, and Inglis Formations. 
32 

System 

ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

TABLE 4.-General stratigraphic section and water-bearing prope1·ties of Tertiary formations in Georgia 

[Based in part on the following references: Cooke (1943). Herrick and Wait (in Thomson and others, 

1956), Wait (1960a), and Counts and Donsky (1959)] 

Series Stratigraphic unit 

Thickness 

(feet) Lithology Water-bearing properties 

Quaternary Recent and See discussion of PleisPleistocene tocene units ( p. 68). 

0-100 Chiefly sands, gravel, 

and clay 

Yield small supplies to shallow 

wells. Potential source of large 

quantities of water where · 

Tertiary 

Pliocene 

Miocene 

Oligocene 

Upper 

Eocene 

Undifferentiated 

sands and gravel 

Charlton Formation1 

·Duplin Marl 

0-150 Lenticular beds of sand, 

gravel and variegated 

clay. 

Fine sands interbedded 

with clay and marl 

which is fossiliferous 

in some places. 

0-100 Hawthorn Fotmation 

t------------+------1 consists of marl, clay, 

Hawthorn Forma:tion 

and Tampa Limestone 

Suwannee Limestone 

and Flint River 

Formation 

Cooper Marl2 

Ocaia Limestone, upper 

unit 

Ocala Limestone, lower 

unit 

0-600 sand, limestone, interbedded with pale to 

dark-green phosphatic 

sandy clay and sandy 

0-200. 

0-155 

0-283 

limestone. Tampa 

Limestone consists 

chiefly of limestone. 

Limestone, ranging from 

soft, chalky, and fossiliferous to dense 

calcitized, saccharoidal, and unfossiliferous. Flint River is 

cherty limestone that 

consists chiefly of 

residual flint and chert 

in the Flint River 

valley of Georgia; 

Upper unit differentiated only in northeastern Coastal Plain 

of Georgia. Dull · 

white limestone~ . fossiliferous, some- . wh~t calcitized, and 

crystalline, glauconitic 

at depth. Lower unit 

is cream-colored soft 

granular limestone. 

Thin layers and 

tongues of dense. paleblue calcitized limestone and silty and 

clayey limestone or 

marl. Maximum thick- ness of undifferentiated limestone, 575 

ft. Ocala grades into 

Barnwell Formation 

updip; 

Barnwell Formation 

(0-200 ft. thick) is 

sandy facies of Ocala. 

. deposits are hydrologically con- nected to streams. 

Gravel beds in the basal part of. 

formation are a source of water 

for domestic, industrial, and 

municipal wells. 

Yields water to shallow wells. 

Hawthorn yields as much as 200 

gpm to wells from sands which are little used but are a potential source of water. ·Some of the 

water is artesian. Tampa Limestone yields as much as 200 gpm. 

The water is artesian except in 

outcrop areas. The lower part of 

the Hawthorn Formation and the 

Tampa Limestone where present 

form the upper part of the principal aquifer of Tertiary age. 

Suwannee Limestone yields as much as 500 gpm. The water is artesian 

except in outcrop areas. Yields 

large supply to wells in southwestern Georgia where it and 

formations of principal aquifer 

yield as much as 2,100 gpm in 

Valdosta area. The Suwannee 

and Flint River are part of the 

artesian aquifer. 

Major part of princip~l artesian 

aquifer in coastal area of Georgia. In the Savannah area the 

upper unit of the Ocala and the 

overlying Oligocene deposits · · apparently are the most permeable parts of the aquifer. The 

aquifer yields as much as 4,200 

gpm to wells. Water is moderately hard in Savannah area. 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 33 

TABLE 4.-Generalstratigraphic section and water-bearing p'roperties of Tertiary formations in Georgia-Continued 

System 

TertiaryContinued 

Cretaceous 

and older 

Series 

Middle 

Eocene 

Lower 

Eocene 

Stratigraphic unit 

Gosport Sand 

Lisbon 

Formation 

McBean 

Formation 

Tallahatta Formation 

Hatchetigbee Formation 

Tuscahoma Formation, 

and Nanafalia Formation in southwestern 

Georgia; undifferentiated in southeastern 

Georgia 

Clayton Formation 

Paleocene 

Thickness 

(feet) 

0-100 

0-600 

0-200 

0-400 

0-380 

Lithology 

Calcareous sand or very 

sandy limestone, fossiliferous and glauconitic at depth. Avon 

Park Limestone in 

Florida and southeastern Georgia. 

Marl or soft glauconitic 

limestone, white, gray 

and buff; some sand. 

Facies change from 

limestone on west to 

clayey marl with some limestone on east. A von Park and 

Lake City Limestones 

in Florida. McBean 

Formation in outcrop. 

Pale green glauconitic 

marl and buff silty 

clayey fossiliferous 

limestone. Lake City 

Limestone in Florida. 

Alternating micaceous 

lignitic clay, marl, 

and sandy and minor 

amounts of gray crystalline glauconitic 

sandy limestone. · Equivalent to Oldsmar 

Limestone in Florida. 

Mostly gray crystalline 

glauconitic fossilifer- ous limestone and 

minor amounts of clay 

and sand. 

1 S. M. Herrick (written commun., July 1962) believes that the Charlton may be part of the Duplin Marl. 

n Herrick and Vorhis (1963) describe the Cooper Marl as upper Eocene in Georgia. 

Water-bearing properties 

Reported to yield as much as 650 

gpm to wells from thick sections 

in Savannah area. Water is 

moderately hard. Has high 

chloride in coastal counties. 

Lowest formation of principal 

artesian aquifer along coast and 

southeastern Georgia. It is an important part of principal 

aquifer in southwestern Georgia. 

Forms lower confining bed of principal artesian aquifer in some places in southeasten Georgia but 

generally is part of.the aquifer. 

Forms lower part of principal 

Tertiary aquifer in southwestern 

Georgia and southeastern Alabama but is part of confining beds 

below aquifer in southeastern 

Georgia and Florida. Lisbon and 

Tallahatta Formations yield as much as 1,200 gpm in Dougherty 

County. Principal source of water 

at Albany and Cordele. Contains 

saline water at Thomasville. 

Source of potable water in outcrop area in southwestern Georgia, 

but water is salty in coastal 

areas, southeastern Georgia, and 

Florida peninsula. 

Important source of water in southwestern Georgia and southeastern Alabama. It contains 

salty water in coastal areas, 

southeastern Georgia, and 

Florida, except in Jackson 

County, Fla. Water in basal sand 

yields soft sodium bicarbonate 

water in some areas. The type 

of water in the overlying limestone is calcium bicarbonate. 

Much of the artesian water in the 

Cretaceous aquifers is soft 

sodium bicarbonate water. 
34 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

TABLE 6.-General stratigraphic section and water-bearing properties of TertiarY formations in South Carolina 

[By G. E. Siple, written commun., 1964] 

·Thickness 

System Series Stratigraphic unit (feet) Lithology Water-bearing properties 

Quaternary Recent and See discussion of Pleisto- 0-100 Chiefly sand, gravel, Yields small supplies to shallow 

Pleistocene cene units (p. 68). and clay. wells. 

Waccamaw Formation 0-40 Blue-gray to yellow and Water usually hard and having 

Pliocene (early Pliocene1 ) brown sandy marl, some H2 S odor. Fair to large 

gray to buff fine loose yields. 

quartz sand. 

Duplin Marl (late · 0-60 Buff sandy friable shell Yields small supplies of hard water. 

Miocene) marl and loose sand. 

Hawthorn Formation 0-150 Hard brittle shale, gray Sparse available data indicate the 

(early and middle to black, resembling unit is relatively impermeable, 

Miocene Miocene) stratified fuller's earth but in some areas small yields of 

and sandy phosphatic hard water may be obtained. 

marl.· 

Tampa Limestone (early 0-40 Greenish phosphatic Small to moderate amounts of 

Miocene) (subsurface) sandy clay and water, moderately hard to hard. 

coarsely phosphatic 

limestone. 

Flint River Formation 0-60 Reddish-yellow sand and No data available. 

Oligocene lumps of yellow 

vitreous chert. 

Cooper Marl uridiffer- 0-200 Grayish-green to brown Yields little or no water. 

entiated limestone phosphatic, sometimes 

sandy, marl. 

Barnwell Formation 0-100 Deep-red to brown fine Small yields, sufficient for domestic 

Tertiary to coarse massive and stock use. 

Upper sandy clay and clayey 

sand. Scattered thin 

Eocene lenses of buhrstone. 

Ocala 0-400 White to cream-colored Large water yields in southern part 

Limestone calcitized fossiliferous of State. Water hard to moderlimestone; saccha- ately hard. 

raoidal, nodular, and 

recrystallized; con- tains numerous bryozoan remains. 

Castle Hayne Limestone 0-800 ( ?) Buff-gray tough to hard Very permeable in southern part of 

crumbly fossiliferous State where yields of 2,000 gpm 

limestone in upper have been obtained. Water 

part underlain by moderately hard and may be high 

soft fine-grained in iron or H2 S. 

granular limestone. 

McBean Formation 0-260 Fine to medium green- Moderate to good yields-50-300 

ish-yellow quartz gpm. Water generally soft but 

sand; green glauconitic may be high in iron, dissolved 

Middle marl, silicified beds of oxygen, or carbon dioxide. 

Eocene coquina, and clayey 

sand interbedded with 

red, brown, ochre, and 

yellow plastic clay. 

Light gray fuller's 

·earth and siltstone. 

0-325 Pure white to creamy- Water yields moderate to high. 

yellow fossiliferous Water moderately hard to hard. 

and party glauconitic 

Santee limestone containing 

Limestone numerous Bryozoa. 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 35 

TABLE 5.-Generalstratigraphic section and water-bearing properties of Tertiary formations in South Carolina--Continued 

Thickness 

System Series Stratigraphie unit (feet) 

Warley Hill Marl 0-200 ( ?) 

Middle 

EoceneContinued 

Congaree Formation 0-80 

TertiaryContinued 

Black Mingo 0-250 

Lower 

Eocene 

Undifferentiated; in 0-200 

subsurface only 

Paleocene 

Cretaceous 

and older 

1 DuBar (1962, p, 28) believes that the Waccamaw Formation is Pleistocene. 

up the entire Paleocene Series. The Clayton Formation is exposed as far east as central Georgia where 

it is overlapped by younger formations. Downdip 

in southeastern Alabama the upper part of the Paleocene Series consists of limestone that is correlated 

with the upper limestone of the Clayton Formation. 

The lower part of the Paleocene Series is made up 

chiefly of fossiliferous marl and gray calcareous clay. 

In southeastern Alabama the Clayton Formation, as 

described by LaMoreaux (Carter and others, 1949, 

p. 210), is the oldest and basal Tertiary formation 

having an estimated thickness of 130 feet along the 

Chattahoochee River. It consists chiefly of argillaceous limestone containing. solution cavities. In 

some places there may be basal sands. To the west, 

the upper part of the Clayton becomes sandy and 

glauconitic and intertongues with the Porters Creek 

Formation, which consists chiefly of clay. Ground 

water is present in the solution cavities in the limestone and in the sand beds of the Clayton. 

In southwestern Georgia and southeastern Alabama the Paleocene is thickest of any place in the 

Coastal Plain. The Paleocene in this area consists 

of limestones with some clays and sands, which are 

Lithology Water-bearing properties 

Fine, green to yellow Aquifer potential uncertain but 

glauconitic sand, regarded as poor. 

reddish-yellow massive 

argillaceous sand, and 

gray-green glauconitic 

marl. 

Green to gray brittle Clay beds function primarily as nonplastic clay inter- aquiclude but some sandy parts 

bedded with thin fine may yield moderate quantities of 

semi consolidated soft water which may be high in 

sands and fuller's iron. 

earth. 

Upper red to brown Upper sands have limited water 

sandy clays and partly supply. Lower unit serves as indurated fine white aquiclude. Quality moderately 

to yellow sands under- soft and may be high in iron. 

lain by gray to black 

clay having con- choidal fracture. 

Dark gray to black lami- Very low permeability. Of no nated shale with lime- known significance as aquifer. 

stone facies in south 

coastal areas. (May be 

in part Black Mingo 

of early Eocene age.) 

correlated with the Clayton Formation. The Paleocene in southeastern Georgia is considere~ equivalent 

to the Cedar Keys Limestone of Florida (Counts and 

Donsky, 1963, p. 19). In southwestern Georgia 

(Wait, 1960a, p. 8) the Clayton is a light-gray fine 

sand near the top, white crystalline limestone in the 

middle part; and light-gray conglomeratic feldsp~thic 

sand near the bottom. It is the major aquifer in Clay, 

Randolph, Terrell, Lee, Calhoun, Dougherty, and 

Early Counties. Yields of wells range from 250 to 

.1, 700 gpm. The. limestone yields a calcium bicarbonate water.· The basal sand may yield soft sodium 

bicarbonate water. Wait reported that in Georgia the 

first flowing artesian well drilled in 1881 near Albany yielded water from limestone of the Clayton 

Formation. 

Counts and Donsky (1959, p. 99; 1963, p. 19) reported that the Clayton is as much as 385 feet thick 

in the Savannah area, Georgia, where it consists 

of. sandy limestone and calcareous glauconitic sand. 

In the coastal area of Georgia and South Carolina, · 

the aquifer contains salt water. The thickness of the 

Paleocene in Georgia (Herrick and Vorhis, 1963, 
36 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

fig. 13) increases from a few feet in its area of out- the Nanafalia grades into the Salt Mountain Limecrop to 600 feet in southern Georgia. stone, a white chalky fossiliferous massive biohermal 

limestone of irregular thickness and sporadic occurrence. In Florida the Nanafalia ranges in thickness 

from 70 to 90 feet in Walton and Bay Counties ; it 

is absent near the coast in Gulf County and in the 

Tallahassee area. 

Cedar Keys Limestone 

As described by Applin and Applin (1944, p. 1704) 

and Toulmin (1955, p. 216), the Cedar Keys Limestone is a white, cream-colored, or gray finely granular to fragmental limestone, microcoquina, -and 

dolomite. The name Cedar Keys Formation was proposed by Cole (1944, p. 27) for limestone of Paleocene age in a deep oil test at Cedar Keys, Fla. The 

limestone has thin stringers of anhydrite, which increases in thickness in southern Florida. Commonly, 

gypsum in the pores of the limestone gives it a spotted 

appearance. In some places the limestone is oolitic. 

The thickness of the formation ranges from about 

165 feet in northern Florida to about 2,250 .feet in 

southern Florida. The maximum thickness of the 

clastic equivalent in western FloriC.a is about 1,000 

feet. 

Water from the Cedar Keys Limestone is salty. 

Three samples of water from the Cedar Keys· in the 

South Lake well in Lake County at depths of 2,470, 

2,590, and 2,593 feet had chloride contents of 23,020, 

310, and 12,000 ppm, respectively. A sample from a 

depth of 3,419 feet in the Lawson Limestone of Late 

Cretaceous age, at or near the contact with the overlying Cedar Keys Limestone, had a chloride content 

of 58,100 ppm as indicated by unpublished tests made 

in the quality of water laboratory of the U.S. Geological Survey. 

EOCENE SERIES 

WILCOX AGE 

Nanafalia, Tuscahoma, and Batchetigbee Formations 

The Eocene Series includes, in ascending order, 

formations of Wilcox, Claiborne, and Jackson age. 

Formations of the early Eocene (Wilcox age) crop 

out in a belt south of the Paleocene Series, extending 

across Alabama into western Georgia, east of which 

they are overlapped by middle Eocene formations. In 

Alabama the group is represented by three formations from bottom to top as follows: the Nanafalia 

Formation, the Tuscahoma Sand; and the Hatchetigbee Formation. The Bashi Marl Member forms the 

lower part of the Hatchetigbee. 

The Nanafalia Formation in southeastern Alabama and southwestern Georgia, as described by 

Toulmin (1955, p. 219), consists of as much as 100 

feet of greenish-gray fossiliferous coarse glauconitic 

sand, sandstone, marl, and clay. The sands are very 

permeable and form an excellent aquifer. Downdip 

in southeastern Alabama and the Florida panhandle, 

The updip clastic facies of the formations of early 

Eocene age in southwestern Georgia correlate with 

the formations in Alabama (Herrick and Vorhis, 

1963, p. 32), whereas the down dip limestone equivalent in southeastern Georgia and the Florida peninsula correlates with the Oldsmar Limestone. . As 

shown on a map by Herrick and Vorhis (1963, fig. 

11), the lower Eocene deposits increase in thickness 

from a few feet in the outcrop area to more than 

400 feet in southeastern Georgia. 

· In South Carolina, the deposits of Wilcox age 

are represented by the sandy clays and sands of the 

Black Mingo Formation, which is as much as 250 feet 

thick. Siple considers the Black Mingo Formation 

equivalent to the T'uscahoma and Nanafalia Formations of the Gulf Coast. The Foraminifera obtained 

from outcrop areas of the Black Mingo Formation 

have not indicated decisively whether the formation 

is of Wilcox or Midway age. 

Oldsmar Limestone 

The carbonate facies of the formations of Wilcox 

age extends from southeastern Georgia throughout 

the Florida peninsula and is known as the Oldsmar 

Limestone, which Toulmin (1955, p. 270) and Puri 

and Vernon (1959, p. 30) regarded as essentially 

a faunal rather than a lithologic unit. The name 

was proposed by Applin and Applin (1944, p. 1699) 

for limestone of Wilcox age in a test well for oil 

near Oldsmar, Hillsborough County, Fla. The upper 

and lower boundaries of the formation may not be 

the same as those of the clastic facies in the Florida 

panhandle where the Salt Mountain Limestone 

faunal zone is included in the lower division of the 

clastic facies. That zone is included as the upper 

part of the Oldsmar Limestone in the peninsula. 

As described by Toulmin (1955, p. 220), the Oldsmar in the northern and central parts of the Florida 

peninsula is a tan to brown permeable granular 

chalky limestone interbedded with brown permeable 

coarsely crystalline dolomite. The bottom part of 

the formation is chiefly soft permeable foraminiferal 

microcoquina. In southern Florida the Oldsmar is 

cream-colored permeable chalky nodular limestone 

and tan hard vuggy granular dolomite. The entire 

section is gypsiferous. The Oldsmar Limestone is 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 37 

lithologically similar to the overlying middle Eocene 

Lake City Limestone. It is less than 250 feet thick 

in the northern part of the peninsula over the peninsular arch, but it increa$es in thickness southward 

to more than 1,000 feet in the southern part of the 

peninsula. It is 925 feet thick in the Oldsmar well 

and 1,200 feet thick in the Peninsular Oil and Refining Co. well J. W. Cory 1 in Monroe County. 

Little information is available on the water-bearing properties of the Oldsmar Limestone. In Florida 

most, if not all, of the water in the Oldsmar is salty. 

A sample of water from the Oldsmar at a depth of 

2,258 feet in the South Lake well in Lake County, · 

Fla., had a chloride content of only 781 ppm. However, samples from depths of 2,300 feet and 2,352 

feet in the Oldsmar Limestone had a chloride content 

of 6,020 ppm and 6,290 ppm, respectively. 

CLAIBORNE AGE 

In southeastern Alabama and Georgia, the formations of Claiborne age (middle Eocene) include, from 

bottom to top, the Tallahatta, Lisbon, and Gosport 

Formations. The McBean Formation, which has been 

correlated with the Ostrea sellaeformis zone of the 

Lisbon Formation in southwestern Georgia, appears 

to be present only in northern and eastern Georgia. 

Thus, tentatively at least, the Lisbon Formation will 

be used 'in southern and southwestern Georgia and 

the McBean Formation in northern and eastern Georgia. In Florida, formations of Claiborne age are 

represented chiefly by the Lake City and A von Park 

Limestones in the peninsula and by undifferentiated 

clastics in the panhandle. The Tallahassee Limestone occurs in part of the panhandle. 

Along the Georgia-South Carolina State line, deposits of Claiborne age are undifferentiated in the 

subsurface. In South Carolina, deposits of Claiborne 

age are represented by the Congaree Formation at 

the bottom overlain by the Warley Hill Marl-both 

included in the McBean by Cooke (1936)-Santee 

Limestone, and the McBean Formation with the 

Castle Hayne Limestone at the top. H. E. LeGrand 

(oral commun., 1963) believes that the Warley Hill 

Marl is a facies of one of the formations. 

In eastern Alabama, as described by LaMoreaux 

(in Carter and others, 1949, p. 212), the Tallahatta 

Formation is sandy and glauconitic in the upper 

50 or 60 feet and in the lower 10 or 20 feet. The 

two sandy units are . separated by about 30 feet of 

siliceous claystone. Overlying the Tallahatta, the Lisbon consists of a very glauconitic, .in part fossiliferous, gray sand and clay. The combined thickness 

of the two formations in the outcrop area is less than 

200 feet. The Gosport Sand, the stratigraphic equivalent of the upper part of the Cockfield Formation 

in Mississippi (Toulmin, 1955, p. 220), about 30 

feet thick in western Alabama, consists of yellow to 

orange crossbedded glauconitic fine to coarse sand 

and brown carbonaceous nonmarine clay. Some 

sandy layers contain marine shells. The formation 

is absent on the Chattahoochee River in southeastern· 

Alabama (Toulmin and LaMoreaux, 1963, p. 338). In 

Escambia County, Ala., the formations of Claiborne 

age have ·a total thickness of about 325 feet. The 

thickness increases toward the coast and becomes at 

least 1,000 feet -in the central part of the panhandle 

of Florida. 

As described by Toulmin ( 1955, p. 220), the formations of Claiborne age in the subsurface in southern 

Alabama and the Florida panhandle are predominantly marine clastics. They grade into limestone 

downdip in the Apalachicola area of Florida and eastward in the eastern part of the panhandle and the 

peninsula. The Tallahatta is composed chiefly of 

glauconitic sand that contains in some areas beds 

of light-green siliceous claystone and a little white 

sandy glauconitic limestone. Siliceous claystone is 

common in Okaloosa and Walton Counties, Fla., but 

pinches out eastward, and in Jackson County the 

Tallahatta consists .of loose glauconitic quartz sand. 

In Gulf County, Fla., the lower part of _the Tallahatta 

is cherty and contains small amounts of glauconite. 

The Tallahatta ranges in thickness from 175 feet in 

northern Okaloosa County to nearly 500 feet in Gulf 

County, Fla. (Rainwater and others, 1945, p. 50). 

The Lisbon Formation in southern Alabama and 

adjacent parts of Florida consists chiefly of calcareous glauconitic sand, hard glauconitic sandy 

limestone, soft sandy glauconitic marl and chalk, 

and minor beds of glauconitic sandy shale and brown 

crystalline limestone. The formation becomes cherty 

downdip. In Gulf County, Fla., the limestones are 

partly dolomitized. The thickness of the Lisbon 

ranges from approximately 300 feet in Bay County, 

Fla., to 430 feet in Jackson County (Rainwater and 

others, 1945, p. 49). 

In the Tallahassee and Apalachicola areas Toulmin 

(1955, p. 222) described the Claiborne deposits as 

consisting of three formations : ( 1) the Lake City 

Limestone, probably equivalent to the Tallahatta Formation and most of the Lisbon; (2) the Tallahassee 

Limestone, restricted to the Tallahassee area, apparently equivalent to the upper part of the Lisbon, 

and (3) the Avon Park Limestone, possibly equivalent to the Gosport. The Lake City and A von Park 

are present in southern Georgia and throughout the 
38 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Florida peninsula, except in a small area in northern 

Florida where the A von Park is absent (Applin and 

Applin, 1944, fig. 3). 

In Georgia, Herrick and Vorhis (1963, p. 25) included the Gosport Sand with the Lisbon Formation 

because of lack of fossils to differentiate the two formations. They considered the Lisbon and Tallahatta 

Formations as the updip clastic facies of the middle 

Eocene in Georgia and correlated them with these 

formations in Alabama. They also correlated them 

with the down dip limestone equivalents, the A von 

Park and Lake City Limestones of peninsular Florida. Counts and Donsky (1963, p. 22) used Lisbon 

Formation to include the rocks in the subsurface 

between the Tallahatta and the Gosport and stated 

that it was considered to be equivalent in age to ·the 

McBean Formation in the outcrop area. Veatch and 

Stephenson (1911, p. 237) regarded the Lisbon Formation as the subsurface equivalent of the McBean 

Formation in eastern Georgia. As originally defined, 

the McBean included some beds of upper Eocene 

(Herrick and Vorhis, 1963, p. 25). As used by Cooke 

(1943, p. 54), the McBean included some beds of 

the Tallahatta west of the Flint River. In order to 

eliminate the inconsistencies Herrick and Vorhis 

(1963) and Herrick (1961) used the names Lisbon 

and Tallahatta throughout Georgia. 

The downdip limestone facies of the Tallahatta 

Formation is similar to that of the overlying Lisbon 

but is much more dolomitized and considerably more 

glauconitic. The middle Eocene gradually increases 

in thickness from a few feet in its outcrop area to 

more than 1,300 feet in southeastern Georgia (Herrick and Vorhis, 1963, p. 28). In South Carolina, 

the Lisbon is represented by the McBean Formation, 

which grades into the Santee Limestone farther 

north. Counts and Donsky (1963, p. 22) considered 

the Lisbon Formation in the Savannah area to be 

equivalent in age to the McBean Formation which 

occurs in updip exposures. In outcrops the Lisbon 

(McBean) Formation consists of fine to medium sand 

with fossiliferous clay beds containing hard lime 

nodules. 

Lake City Limestone in Florida 

The name Lake City Limestone was given by Applin and Applin (1944, p. 1694-97) to limestone of 

Claiborne age penetrated between depths of 492 and 

1,010 feet in a city well at Lake City, Columbia 

County, Fla. The formation consists of alternating 

beds of dark-brown dolomite and chalky fossiliferous 

limestone. The limestone is tan to cream colored 

with pasty to fragmental matrix in which are embedded many foraminifers, crystals of calcite, fragments of echinoids, and, commonly, peat fragments. 

Applin and Applin reported that a bed of lignite 25 

feet thick was penetrated near the top of the limestone in a well in Marion County, Fla. Peat and 

lignite beds, clay and sand stringers, and phosphorite 

and limonite nodules are present at the unconformable contact of the Lake City and the overlying A von 

Park Limestone, as described by Puri and Vernon 

( 1959, p. 35). Rock samples from some wells show 

signs of oxidation and weathering of the Lake City 

Limestone at the contact with the A von Park. Vernon 

(1951, p. 92) noted that the peat content increases 

toward the unconformable contact of the underlying 

Oldsmar Limestone. 

As described by Applin and Applin (1944, P• 1693), 

in northern Florida including the northern half of 

the peninsula, the Lake City Limestone underlies the 

Tallahassee and the equivalent nonfossiliferous limestone. Along the northeastern coast of Florida and 

in the southern half of Florida, the Lake City underlies the A von Park. In western Florida where the 

A von Park and the Tallahassee Limestones are absent, the Lake City underlies the Ocala Limestone. 

Commonly, the Lake City is impregnated with .anhydrite and gypsum. The limestone is irregularly 

dolomitized; dolomitization is present in all stages 

from incipient dolomite crystals in the matrix to complete dolomite (Vernon, 1951, p. 91-92). The change 

is usually accompanied by decalcification of the 

fauna to a degree comparable to the amount of dolomitization. Such decalcification is present in stages 

from unaltered fossils, calcite dust retaining some 

of the fossil forms, to molds surrounded by crystalline dolomite. The complete removal of fossils sometimes results in a dolomite that retains the texture 

of a former granular limestone, in which the matrix 

and interiors of the fossils have been filled by dolomite and calcite shells removed to form a very permeable scab and skeletal spongy texture ( Puri and 

Vernon, 1959, p. 33-34). In some places the limestone is essentially a coquina of foraminifers. The 

coquina is so impregnated with gypsum that the fossils appear to be embedded in gypsum in a few places. 

Beds with diagnostic lithology occur throughout the 

formation, but many are concentrated at the top and 

the bottom. These beds include a pseudo-oolite, a 

brown to coffee-colored chert, a clay that appears to 

be bentonitic, and a brownish-gray laminated, finely 

crystalline dolomite containing seams of black carbon and flattened decalcified fossils, which give the 

dolomite a mottled and laminated appearance. Chert 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 39 

is present in rock samples from some wells, especially 

in the Tallahassee area. 

Applin and Applin (1944, p. 1694) reported that 

in the Tallahassee area and in the northern part of 

the peninsula, the Lake City is 400 to 500 feet thick, 

but in Pierce County, Ga., and in the southern part 

of the Florida peninsula it is about 200 to 250 feet 

thick. In the central part of the Florida peninsula 

in Lake County the Lake City is about 990 feet 

thick, the top about 1,010 feet below sea level. In 

Polk County it is 420 feet thick, the top about 1,540 

feet below sea level. Gypsum has been noted in wells 

in the central part of the peninsula, in the Tallahassee 

area, and in southeastern Georgia. The thickness of 

the clastic facies in western Florida increases from 

about 575 feet in Jackson County to about 780 feet 

in Walton County. 

The following table from Applin and Applin (1944, 

p. 1695) gives the thickness of the Lake City penetrated by deep wells. 

Florida Geol. 

Total depth 

Depth Thickness of well 

Counties Survey well (feet) (feet) (feet) 

-· Limestone facies 

Brevard ________ W-104 756- 872 116 872 Broward ________ W-150 2,127-2,500 373 3,010 Columbia _______ W-299 492-1,010 518 1,012 Dade ___________ Dixie W-215 2,490-2,737 247 5,432 ___________ W-636 525-1,085 560 4,776 

Duval---------- W-304 805-1,005 200 1,005 

W-581 965- 980 15 908 Hillsborough ____ W-8 1,910-2,165 255 3,255 Jefferson Lake ______ -· W-19 1,740-2,223 483 3,838 ___________ Leon W-275 1,010-2,000 990 6,120 ___________ W-32 1,600-1,995 395 3,755 Levy _________ --· W-166 811-1,308 497 5,266 Marion _________ W-901 915-1,28!) 370 4,334 Monroe _________ W-445 1,810-2,050 240 10,006 

W-2 1,740-1,920 180 2,310 Nassau _________ W-336 945-1,370 425 4,821 Polk ____________ W-61 1,540-1,96(1 420 4,540 

W-668 930-1,040 110 1,040 

St. Johns-------· W-236 590-1,350 760 1,350 

Sumter--------- W-3 890-1,430 540 3,070 

Ruwannee------- W-6 475- 650 175 650 Wakulla ________ W-12 1.750-2,169 419 2.169 

W-440 1,750-2,122 372 5,746 

Clastic facies 

Calhoun ________ , W-7 1,000-1,320 320 1,320 

Escambia, Ala, __ Applin 311 646-1,350 704 6,025 Jackson _________ Applin 34 200- 776 576 5,022 Walton _________ . Applin 32 755-1,536 781 5,337 Washington _____ W-1 375- 970 595 4,912 

1 Well number assigned by Florida Geological Survey. 

Chemical analyses of water (Wyrick, 1960, p. 

37-38) include analyses of samples from three wells 

that end in the Lake City Limestone. As the wells 

are not cased below the top of the Avon Park Limestone, the samples are a composite of water from the 

A von Park and Lake City. Water from both formations is hard, containing calcium and bicarbonate as 

the chief constituents, except in areas where the 

water has a relatively high chloride content. The low 

magnesium content of the samples from wells in the 

Lake City suggests that the water is from the permeable limestone bed instead of the dolomite. 

Where the chloride is relatively low, the hardness 

of the water sampled ranges from about 125 ppm 

to several hundred parts per million. The salt water 

is much harder. The softest water is in areas where 

local recharge of the aquifer through sinkholes has 

flushed out the salt water. The fresh water in recharge areas has had less time to receive hardness 

from the limestone than water which has moved 

through the limestone. 

The Lake City Limestone is ·the oldest and deepest 

of the water-bearing formations that form an important part of the principal artesian aquifer in 

Florida and southeastern Georgia. In a few places 

the ·underlying Oldsmar Limestone may yield fresh 

water. In the clastic facies of the water-bearing 

formation in southeastern Alabama and Georgia 

the formations equivalent in age to the Oldsmar are 

good sources of water. Special comments about the 

ground-water conditions in counties where studies 

have been made are described below. 

HIGHLANDS COUNTY 

Bishop ( 1956, p. 18) reports that the Lake City 

is a permeable, very productive water-bearing formation in Highlands County, Fla., and is utilized to a 

large extent wherever large quantities ( 500 to 1,500 

gpm) of ground water are needed for municipal and 

irrigation supplies. In Highlands County, the reported thickness ranges from about 200 to 350 feet. 

The top of the formation ranges from about 900 feet 

below sea level in the northern part of the county 

to about 1,100 feet below sea level in the southern 

part. The average dip is about 5 feet per mile to 

the south. According to Bishop, the permeability 

of the formation compared with overlying formations 

is indicated by pumping tests made by Briley and 

Wild, consulting engineers of Daytona Beach, during 

the drilling of well 403, 10 inches in diameter, 1,301 

feet deep at A von Park. Pumping tests show that 90 

feet of penetration into the Lake City Limestone, after 

the well had penetrated 915 feet of overlying waterbearing formations, increased the yield from 463 to 

636 gpm (gallons per minute) with a drawdown of 

25 feet for each test. At a depth of 1,301 feet with 
40 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

175 feet of the Lake City penetrated the yield was 

818 gallons with a drawdown of 35 feet. 

Bishop stated that in Highlands County the quality of water in the Lake City Limestone ranges from 

soft to hard, the hardness increasing toward the 

south end of the county. The chief constituents are 

calcium and bicarbonate. Locally there is more than 

0.3 ppm· of iron, some of which may be from well 

casings, but in general, the water is satisfactory. In 

seven samples reported by Bishop from wells 150 

feet to 1,550 feet deep using the Lake City Limestone 

as the principal source of water, the hardness of the 

water ranged from 50 ppm to 85 ppm. Only two of 

these contained iron, suggesting the iron is from the 

well casings. Both samples had 0.38 ppm iron. One 

sample had a color of 2, and two had a color of 7. 

As the wells are cased only to the top of the principal artesian aquifer, the samples are composites 

of the formations. The relatively low hardness suggests local recharge. The highest hardness is from 

the deepest well. As the color is present in the water 

with the greatest hardness, the color is apparently 

from peat in the Lake City Limestone instead of 

recharge of colored surface water. The temperature 

of the water from different wells ranged from 77° 

to 82°F. 

INDIAN RIVER COUNTY 

Wells penetrate the Lake City Limestone at a depth 

of about 600 feet in the southern part of Indian 

River County but do not penetrate the entire thickness (Bermes, 1958b, p. 10). Bermes showed several faults with small displacement in the Lake City 

and overlying Eocene limestones, but these faults do 

not extend upward into the Hawthorn Formation. 

These faults seem to have little or no effect on the 

piezometric surface of the artesian water. 

PUTNAM COUNTY 

Leve (1958, p. 7) reported that one well in Putnam County slightly more than 700 feet deep 

reached the Lake City Limestone at a depth of about 

550 feet. A current-meter survey of the velocities 

of the well when flowing showed that little or no 

water entered the bottom part of the well. Most 

of the water was from the overlying Avon Park 

Limestone. 

SEMINOLE COUNTY 

In the southwestern part of Seminole County as 

described by Barraclough (1962, p. 12-13), the top 

of the Lake City was penetrated about 600 feet 

below sea level. Only a few wells have been drilled 

into the Lake City in Seminole County because adequate supplies are obtained from the overlying Avon 

Park and Ocala Limestones of the principal artesian 

aquifer. However, the Lake City appears to be very 

productive. The largest yield pumped from a well 

in Seminole County was reported to be 8,100 gpm. 

The well penetrated more than 400 feet of Lake City 

Limestone and less than 200 feet of the overlying 

A von Park Limestone. Barraclough reported that 

the mineral content of the water from the Lake City 

is less than that from A von Park and Ocala in the 

southwestern part of Seminole County and the 

northern part of Orange County. He suggested that 

this difference may be due to the large percentage 

of dolomite in the limestone of the Lake City (the 

· dolomite being less soluble than the limestone). 

VOLUSIA COUNTY 

Wyrick (1960,.p. 17-18, table 1) reported six wells 

in. Volusia County that reached the Lake City Limestone. The deepest of these wells penetrated 380 

feet of the Lake City without passing through it. 

The Lake City is about 280 feet below sea level near 

De Land and about 315 feet below sea level near the 

coast. The top of the formation slopes toward the 

east at about 3 feet per mile. At some wells the unconformity separating th~ Lake City from the overlying A von Park Limestone is marked by a thin layer 

of rounded phosphatic pebbles, and the record of one 

well reveals a 6-foot layer of brown clay and peat. 

Tallahassee Limestone 

Applin and Applin (1944, p. 1688) proposed the 

, name Tallahassee for limestone penetrated by eight 

wells near Tallahassee, Fla. As described by Cooke 

(1945, p. 49), it consists chiefly of cream-colored, tan 

crystalline limestone and some soft clayey limestone. 

He regarded it as the equivalent of the Lisbon. It 

contains tan clay, chert, and gypsum. Its thickness 

ranges from about 75 feet in wells near its west edge 

to 650 feet in Jefferson County. The Tallahassee 

extends from Calhoun County ·on the west to Leon 

and Wakulla Counties on the east. Northward it 

extends to Decatur County, Ga. Eastward and southward it merges with nonfossiliferous limestone (Applin and Applin, 1944, p. 1690, fig. 4) and is present 

in the north half of the peninsula except along the 

east coast. The texture ranges from hard dense 

limestone to saccharoidal limestone. Gypsum and 

chert occur commonly. Thin streaks of carbonaceous 

clay are present. A 40-foot bed of lignite was penetrated at the base of the limestone in J. S. Cosden's 

Lawson well 1, Marion County. The limestone unit 

wedges out along the eastern and southern limits of 

the Tallahassee but in the central part of the penin-
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 41 

sula reaches a thickness of 1,200 feet in the Oldsmar 

well, Hillsborough County. It is 50 to 100 feet thick 

in northern Florida and 950 feet thick in Pierce 

County, Ga. 

As stated by Applin and Applin, the generally 

dome-shaped configuration of the nonfossiliferous 

limestone, its location over the Ocala uplift, and 

its lithologic character suggest that it may be an 

algal reef. The Tallahassee Limestone overlies the 

Lake City Limestone and underlies the Avon Park 

Limestone. The water-bearing properties of the 

Tallahassee Limestone apparently are similar to 

those of the A von Park Limestone. 

In recent geologic reports, including. one by Puri 

and Vernon ( 1959), the name Tallahassee Limestone 

has not been used. Apparently, the limestone has 

been included as part of the A von Park Limestone. 

However, in Levy County, Fla., Vernon (1951, p. 

88-89, 95) stated that 411 feet of dolomite penetrated by a well and assigned by Applin and Applin 

(1944, p. 1738) to the nonfossiliferous limestone, is 

part of the Lake City Limestone in which dolomitization may have destroyed fossils. 

Avon Park Limestone In Florida 

The name Avon Park Limestone was proposed by 

Applin and Applin (1944, p. 1680) for limestone of 

Claiborne age penetrated between depths of 600 and 

930 feet in a well drilled at the Avon Park Bombing 

Range (sec. 31, T. 32 S., R. 30 E.) in Polk County, 

Fla. At the type locality the formation is a creamcolored limestone that contains a very distinct microfauna of middle Eocene age. 

As described by Toulmin (1955, p. 223), the Avon 

Park is a cream-colored to brown chalky limestone 

and dolomite that is present in the eastern part of 

the panhandle of Florida from Gulf County eastward 

into southern Georgia and throughout the peninsula 

except in an area in Columbia and Suwannee Counties. Surface exposures of this formation have been 

found only on the Ocala uplift in Citrus and Levy 

Counties, Fla. (Vernon, 1951, p. 95). The Avon Park 

is 50 feet or less thick in the northern part of the 

peninsula, 150 to 300 feet in the central part, and 

450 to 650 feet thick in the southern part (Applin and 

Applin, 1944, p. 1687). However, H. G. Stewart 

(1959, p. 19) indicated a thickness of more than 845 

feet in Polk County. It lies unconformably on the 

Lake City Limestone in the Florida peninsula and is 

overlain unconformably by the Inglis Formation of 

the Ocala Group (Puri, 1953, p. 130). 

As described by Puri and Vernon (1959, p. 37), 

several general lithologic types, all carbonates, are 

present in the exposures in Citrus and Levy Counties 

and in wells that penetrate the formation. Three 

types as described by Vernon (1951, p. 96-98) are as 

follows: 

1. Marine limestone, cream to brown, highly fossiliferous, fragmental to pasty; weathers cream to 

white and is tinted purple. The bed contains abundant specimens of mollusks, foraminifers, and corals. 

Its permeability and fossils resemble a reef. It grades 

laterally and vertically through a tan to brown dense 

brittle thin lithographic limestone, a 4- to 6-inch layer 

of "fucoid-Cerithium" fragmental dolomite, an irregular lens of lignite and a dolomitic clay with 

foraminifers, and into the other rock types. 

2. Marine limestone (not exposed), cream to brown, 

pasty and fragmental, peat-flecked and seamed, very 

fossiliferous. Well-preserved bryozoans, foraminifers, and ostracods are abundant. The fossils are 

concentrated and somewhat deformed along thin beds 

that are interbedded with peat and pasty limestone 

seams which give the rock a laminated and mottled 

appearance, to which the term "molasses and butter" 

has been applied by some geologi~ts. 

3. Marine dolomite, tan to brown, finely crystalline. 

Molds of characteristic A von Park foraminifers are 

common. The dolomite is composed of euhedral siltsized crystals of dolomite, interbedded with layers of 

lignite and carbonaceous plant remains, each layer 

being commonly one-sixteenth to one-fourth inch in 

thickness. The structure of the rock resembles varves. 

Poor consolidation and grain size cause the rock to 

resemble siltstone. 

Vernon reported that the A von Park Limestone 

has been . dolomitized since deposition and that any 

of the general types may be irregularly or completely 

dolomitized, although the original structures and 

composition of the rock have been preserved. Encircling Polk County and including most of Citrus 

and Levy Counties, the A von Park Limestone is a 

shallow-water marine deposit made of a coquina. The 

laminated dolomite appears to have been formed 

in a partially landlocked shallow marine basin in 

which the seaweed and other marine plants flourished. In western Florida the A von Park Limestone 

consists of glauconitic and calcareous sand, hard 

glauconitic sandstone, soft sandy glauconitic and 

cherty limestone, and fossiliferous bentonitic clay. 

These beds are correlated with the Gosport Sand 

and the Lisbon Formation in part, although they 

differ from the formations at the type sections. 

The A von Park Limestone is very permeable and 

cavernous in some areas. It is one of the most productive water-bearing formations of the principal 
42 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

artesian aquifer in Florida and southeastern Georgia. 

However, in some areas it is reported to be less productive than the underlying Lake City and overlying 

Ocala Limestones, as may be noted in the discussion 

of the Avon Park in Highlands County. In the Fernandina area, Florida, it appears to be less productive 

than in some other areas. 

BREVARD COUNTY 

D. W. Brown, W. E. Kenner, and Eugene Brown 

(1957, p. 22) reported that the Avon Park Limestone, 

more than 300 feet thick, is the principal source of 

water for the deeper artesian wells in Brevard 

County where the formation consists chiefly of white 

soft dense chalky limestone; it ranges in color from 

white to light brown or ash gray. Its composition 

ranges from chalky limestone to a loose coquina of 

foraminifers, echinoids, and other marine shells. In 

some places, the A von Park has been largely altered 

to dolomite. Such alteration of the limestone may 

have changed the. permeability of the formation. 

Some of the dolomite is hard and relati~ely impermeable. The A von Park Limestone is less than 300 feet 

below sea level in the central part of the county east 

of the St. Johns River but is more than 600 feet 

below sea level along a fault on the west side of the 

St. Johns River. 

Chemical analyses of artesian water from the 

Avon Park Limestone and the overlying limestone 

indicate a hard calcium bicarbonate water mixed 

with remnants of connate water. The chloride content of the water samples reported by Brown, Kenner, and Brown (1957, p. 85) ranged froin about 290 

ppm to more than 2,000 ppm. The carbonate hardness ranged from about 380 to more than 1,000 

ppm. The temperature of the water ranged from 

about 73° to 81 °F. 

HIGHLANDS COUNTY 

Bishop (1956, p. 19) reported that the Avon Park 

in Highlands County, Fla., is not an important source 

of large water supplies but is utilized locally in the 

vicinity of A von Park. In other parts of the county 

it yields some water to wells that reach the underlying Lake City Limestone. The A von Park Limestone in Highlands County ranges from about 200 

to 350 feet in thickness. The top of the formation 

slopes to the south about 10 feet per mile from about 

500 feet below sea level in the northern part of the 

county to about 900 feet below sea level in the southern part. Bishop (1956, p. 53) included analyses of 

one sample from the Avon Park from a well 750 

feet deep. The water is similar to that in Lake City 

Limestone with a hardness of only 66 ppm. 

HILLSBOROUGH COUNTY 

Peek (1959b, p. 13) reported that the Avon Park 

Limestone is the oldest formation penetrated by 

water wells in southwestern Hillsborough County, 

where the top of the formation ranges in depth from 

575 feet below sea level in the northern part of the 

area to about 900 feet in the southern part. The estimated thickness is 600 to 700 feet. Although the 

formation is permeable and contains solution cavities 

that yield large quantities of water, relatively few 

wells penetrate the formation in the coastal area 

because the water is salty. Water of better quality 

is obtained from the younger formations. at shallower 

depths in that area. The upper part of the Avon Park 

consists predominantly of white to tan soft chalky 

and granular limestone containing many foraminifers and other fossils. The lower part is principally 

a tan to dark-brown hard crystalline dolomite containing carbonaceous material but very few fossils. 

MAN A TEE COUNTY 

In Manatee County, the A von Park Limestone, as 

described by Peek (1958a, p. 16-17), is about 700 

feet thick and probably is a productive water-bearing 

formation throughout· the county because of extensive solution channels. It is the oldest formation 

penetrated by water wells in Manatee County. The 

water probably is salty in the coastal area. The formation ranges from white or tan fairly soft coquinoid 

or granular limestone to dark-brown hard crystalline 

dolomite. Most of the formation has been dolomitized 

to some extent. A northwest to southeast section 

from Tampa Bay to the southeast corner of the 

county by Peek indicates the top of the A von Park 

ranges from less than 1,000 feet to a little more than 

1,000 feet below sea level. 

The wells described by Stringfield (1933c, p. 222-

227) in Sarasota County, except one, are less than 

1,000 feet deep and probably do not reach the Avon 

Park. However, current-meter measurements of a 

few wells show that the Ocala Limestone which overlies the A von Park yields little or no water to wells. 

The water is from the Tampa Limestone and the 

lower part of the Hawthorn Formation. 

MARTIN COUNTY 

. As described by Lichtler (1960, p. 14, 15), the 

A von Park Limestone in Martin County is generally 

a cream to tan, hard to medium soft, rather pure 

chalky to finely crystalline limestone. No known 

wells pass through the A von Park in this county, but 

Lichtler estimated the thickness to be at least 400 

feet. Current-meter tests in wells show that very 

permeable zones are separated by less permeable 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 43 

zones. Where the salt content of the water is relatively low, the Avon Park is a source of water for 

irrigation. Judging from a contour map showing the 

top of the Ocala Limestone (Lichtler, 1960, p. 17), 

the top of the A von Par~ Limestone ranges from 

about 700 feet to more than 1,200 feet below sea 

level. The greate~t depth to the A von Park is in a 

belt about 5 miles wide along the coast, which is in 

the downthrown block of a northwestward- to southeastward-trending fault parallel to the coast with 

a vertical displacement of 300 to 400 feet. 

Chemical analyses (Lichtler, 1960, p. 52) of samples of the artesian water from the A von Park Limestone and the overlying limestones indicate a calcium 

bicarbonate water mixed with remnants of salt 

water. Lichtler (1960, p. 63) believed that connate 

water was flushed from the formation and that sea 

water entered the aquifer during Pleistocene time 

when the sea covered much of Florida. However, 

Pleistocene sea water ent~red aquifers in some parts 

of Florida, but in Martin County the A von Park 

Limestone is so deeply buried that it probably was 

not exposed to Pleistocene sea water, except at the 

edge of the Continental Shelf where the head in the 

aquifer probably was sufficient to prevent salt-water 

encroachment. 

The chloride content of samples of artesian water 

from the principal artesian aquifer, which includes 

the A von Park Limestone in Martin County, ranges 

from about 300 ppm to several thousand parts per 

million. In the eastern part of the county two samples had chloride contents of from 3,200 to 4,050 

ppm. The highest of these is from the deepest well1,315 feet deE:p. The degree of mineralization of 

the water differs in different parts of the county 

and in different zones within the water-bearing formations. As suggested by Lichtler (1960, p. 81), the 

zones of lowest mineralization probably correspond 

to the more permeable limestone where the greatest 

flushing of the salt water has occurred. 

POLK COUNTY 

In northwestern Polk County, Fla., H. G. Stewart' 

(1959, p. 17-19) described the Avon Park Limestone 

as the most productive formation in the area. It 

is a cream to dark-brown hard dense fine-grained, 

locally crystalline limestone, but in some places it is 

chalky, dolomitic, gypsiferous, or cherty. Many rock 

fragments from wells at depths of 400 to 900 feet 

contain many small solution cavities. About 6 miles 

northeast of Lakeland a large industrial well 26 

inches in diameter and 1,200 feet deep penetrated 

the top of the A von Park at a depth of 355 feet but 

apparently did not pass through it. This indicates a 

thickness of more than 845 feet, the maximum reported for this formation. 

A table by H. G. Stewart (1959, p. 14) showing 

solution cavities penetrated by wells in limestone in 

Polk County includes cavities with vertical dimensions that range from 2 to 20 feet in the A von Park 

Limestone at depths from 458 to 805 feet. The cavity 

at a depth of 805 feet is 6 feet in diameter. The 

20-foot cavity is at a depth of 482 feet. At a depth of 

700 feet in one well, the driller's log showed a honeycomb zone 20 feet thick. Only the upper part of the 

wells are cased, and generally more than one waterbearing formation yields water to a well. Under 

these conditions, samples of water from a well and 

the yields represent a composite of more than one formation. However, pumping tests on several deep· 

wells, in which the A von Park is the principal waterbearing formation, give some indication of the waterbearing capacity of the A von Park in Polk County. 

A 61f2-hour pumping test (Stewart, 1959, p. 39-

40) at a rate of 6,500 gpm on the well 26 inches 

in diameter and 1,200 feet deep with 292 feet of 

casing gave a transmissibility of 1,000,000 gpd per 

ft. (gallons per day per foot) for the Avon Park and 

the overlying limestone of the lower member of the 

Ocala Limestone. Because the well was cased to a 

depth of 292 feet and reached the top of the A von 

Park at 355 feet, only 63 feet of the Ocala Limestone 

may yield water to the well. During the pumping 

test at 6,500 gpm beginning with a static level of 

14.7 feet below the land surface, the drawdown was 

11.6 feet, or a specific capacity (yield in gpm per ft. 

of drawdown) of 560. 

Assuming equivalent efficiency of the wells, differences in the permeability of the limestone in different area:s are indicated by results of the pumping 

tests on three wells 24 inches in diameter having 

specific capacities of 73, 100, and 200. The wells 

having specific capacities of 73 and 100 were the 

deepest wells, 1,285 feet and 1,220 feet, cased to 

depths of 285 and 294 feet, respectively. The well 

having a specific capacity of 200 was 1,037 feet deep 

with 118 feet of casing. These results suggest not 

only differences in .the permeability of the A von Park 

Limestone but also that the overlying Ocala Limestone may yield a large part of the water in the 

well with the smallest amount of casing. Calcium 

and bicarbonate are the principal constituents of the 

water as shown by chemical analyses of samples from 

66 wells (Stewart, 1959, p. 43) from the northwestern part of Polk County. Samples of water show that 
44 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

the magnesium and sulfate are low, indicating the 

water is from relatively pure limestone. 

The hardness of samples from five wells ranged 

from 148 to 260 ppm. Three of the wells are more 

than 1,000 feet deep, and two were 811 and 824 feet 

deep. These w·ells may obtain a large part of their 

water from the Avon Park. Chemical analyses 

(Black and Brown, 1951, p. 94, 95) of samples of 

water from wells throughout the county show that 

the hardness of the water which may be from the 

Avon Park ranges from 92 ppm from a well 1,063 

feet deep having 950 feet of casing at Lake Wales 

to 314 ppm from a well 1,201 feet deep having 300 

feet of casing at Lakeland. The sample from the 

well at Lakeland has a sulfate content of 100 ppm. 

The low hardness of 92 ppm at Lake Wales indicates 

local recharge of the aquifer. The temperature of 

the water from the principal artesian aquifer ranged 

from 76°F in a well 108 feet deep to 81 oF in a well 

635 feet deep (H. G. Stewart, 1959, p. 44). 

PUTNAM COUNTY 

Leve (1958, p. 7) reported that the Avon Park 

Limestone is a predominantly tan dense hard finely 

crystalline dolomite in Putnam County. It is about 

235 feet thick in the central part of the county. Some 

of the water wells penetrate the Avon Park, but the 

chief. y.ield to wells- apparently is £rom· the overlying . 

Ocala Limestone. 

SEMINOLE COUNTY 

Barraclough (1962, p. 14) stated that the Avon 

Park Limestone is the shallowest formation of the 

principal aquifer that underlies Seminole County. 

It is the chief source of artesian water. The overlying Ocala Limestone is absent in part of the county. 

VOLUSIA COUNTY 

In Volusia County, Wyrick (1960, p. 20) described 

the A von Park Limestone as a tan limestone about 

280 feet thick, some of it chalky white to ash gray 

or light brown. Some beds, especially near the top, 

are composed of a loose coquina of cone-shaped 

foraminifers, small echinoids, and other fossils. The 

Avon. Park is generally dolomitized. Wyrick found 

that replacement of calcium in the limestone by magnesium changed the permeability of the limestone 

in many places. Dolomitization of loosely packed 

coquina makes it dense and less permeable. However, 

selective dolomitization of the limestone makes it 

very permeable with a spongy honeycomb appearance. 

. The A von Park is the principal source of water in 

the western part of the county where the overlying 

Ocala Limestone is thin or absent. Many of the 

deeper wells along the coast yield water from the 

Avon Park. Wyrick (1960, p. 21) reported that 

chemical analyses of water from different depths 

in the same well show that the hardness of water 

from isolated sections of the A von Park Limestone 

is less than that from the over lying limestone. He 

suggested that this may be due to the fact that dolomitic rocks are commonly less soluble in wa~er than 

limestone. The Avon Park, the underlying Lake City, 

and overlying Ocala contain hard dense layers that 

are relatively impervious. These layers retard upward or downward movement of the water. 

JACKSON AGE 

As described by Toulmin (1955, p. 224), the formations of Jackson age (late Eocene) are separated 

from those of the middle Eocene by an inconspicuous 

.disconformity. In southeastern Alabama, the formations include the Moodys Branch Formation at 

the bottom, overlain by the .Yazoo Clay and the Ocala 

Limestone (Cagle and Floyd, 1957, p. 12). The 

Moodys Branch Formation, maximum thickness 

about 55 feet, consists of greenish-gray to white 

fossiliferous glauconitic limestone and marl. It is 

relatively impermeable but may be the source of 

small quantities of water. The Yazoo Clay, maximum thickness about 75 feet, consists of greenishgray clay and fine to medium glauconitic sand. The 

sand beds are the source of small quantities of water. 

The Ocala Limestone, maximum thickness about 60 

feet, consists of light-gray limestone and clayey fossiliferous marl (John G. Newton, written commun., 

1962). Solution cavities in the limestone supply moderate quantities of water to wells. In the outcrop 

area in east-central Georgia, the Ocala merges laterally with the Barnwell Formation, a marine pebbly 

sand and sandy limestone. Downdip in Georgia and 

South Carolina, the Barnwell grades into the Ocala 

Limestone. 

The Cooper Marl, a finely granular olive-drab to 

brown marl in South Carolina, has been considered 

to be Eocene and Oligocene at different times by 

different investigators. Herrick and Vorhis (1963, 

p. 18) assigned it to the Eocene in Georgia. It is 

included as part of the early Oligocene in the present 

report. In southeastern Georgia and Florida, rocks 

of Jackson age are represented by the Ocala Limestone. 

The stratigraphic nomenclature in Florida and 

southern Georgia, as proposed by geologists of the 

U.S. G€ological Survey and the Florida Geological 

Survey (Peek, 1959b, p. 14), is as follows: 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 45 

U.S. Geological Survey Florida Geological Survey 

Cooke Applin and Applin 

(1945) (1944) 

Vernon (1951) Puri (1953, 1957) 

Ocala Ocala Upper Ocala Limestone Ocala Crystal Lime- Lime- mem- restricted Group River stone stone ber FormaLower Moodys Wilhston tion mem- Branch Mem- Williston 

ber Forma- ber Formation Inglis tion 

Mem- Inglis 

ber Formation 

The Florida Geological Survey uses Ocala as a 

group name as proposed by Puri (1953) and divided 

into three formations as shown in the preceding 

table. Cooke (1959, p. 3) proposed the use of Inglis 

Formation as the equivalent of the Inglis and Williston Formations of the Florida Geological Survey. 

Cole and Applin ( 1964, p. 1) found no faunal (foraminiferal) breaks between the Inglis Limestone and 

the underlying Avon Park Limestone and recommended that Inglis beds be included with the Avon 

Park Limestone. However, Vernon (1951) reported 

that the Inglis is separated from· the A von Park by 

an unconformity. 

In Jackson County, Fla., Moore (1955, p. 21) divided the Crystal River Formation into the Bumpnose Member and the lower member. In the southeastern part of the county, he called the Crystal 

River the Gadsden Limestone. However, these names 

have not been adopted by the Florida and U.S. Geological Surveys. The Ocala as a formati9n name, 

with an upper member and a lower member, is used 

in the present report, in accordance with the official 

nomenclature of the U.S. Geological Survey. 

Ocala Limestone in Florida 

The Ocala Limestone was divided into an upper 

and a lower member by Applin and Applin (1944, 

p. 1679) on the basis of lithologic and faunal differences. They found that at least in the Florida peninsula it was generally possible to separate the Ocala 

into two members. However, in western Florida 

where the Ocala is chiefly cream-colored chalky limestone, they could not recognize the two members. 

Vernon (1951, p. 111-171) separated the limestone 

unit into the Ocala Limestone (restricted to the upper 

part) and the Moodys Branch Formation. He divided 

the Moodys Branch into the Inglis Member at the 

bottom and the Williston Member at the top. Puri 

(1953, p. 130) changed the Ocala Limestone (as restricted by Vernon) to the Crystal River Formation. 

Later Puri (1957, p. 24-30) gave the rank of formation to the Williston and Inglis Members of the 

Moodys Branch and proposed that the name Ocala 

be used for a group consisting of the Crystal River, 

Williston, and Inglis Formations. 

The Ocala Limestone is about 100 to 300 feet thick 

in much of the panhandle of Florida but is much 

thicker in the Apalachicola embayment in western 

Florida. It is thin in most of the central and northern 

part of the peninsula but reaches a thickness of 400 

feet in the northeastern part. In the southern part 

of the peninsula, it is generally 200 feet thick or 

less and probably is absent in the vicinity of Miami 

and Key West. A map by Toulmin (1952, p. 1171) 

shows the extent and range in thickness of the Ocala 

Limestone in· Florida, Georgia, and adjacent parts 

of South Carolina ari-d Alabama. It is as much as 

575 feet thick in the Savannah area, Georgia (Counts 

and Donsky, 1959, p. 98; 1963, p. 24). A map by 

Herrick and Vorhis (1963, p. 21) shows that the 

upper Eocene deposits in Georgia increase in thickness from their area of outcrop to more than 500 

feet in some of the coastal counties and 700 feet 

in the southwestern part of the State. 

In addition to a belt of outcrops extending from 

Alabama into Georgia, the Ocala Limestone crops 

out in two large areas in Florida. The largest area· 

borders the gulf coast in the northwestern part of the 

Florida peninsula on the Ocala uplift. The other 

area is in western Florida in the northern half of 

Washington and Jackson. Counties and the eastern 

part of Holmes County. The Ocala extends from· this 

area into southeastern Alabama and southwestern 

Georgia. The Ocala merges with the Barnwell Formation in east-central Georgia. The Barnwell in the 

outcrop area and the Ocala downdip in Georgia extend into South Carolina. 

As indicated by Toulmin's map and by Vernon 

(1951, pl. 2), the Ocala in Florida is absent in small 

areas in northern Seminole County, Volusia County, 

southern Orange County, northern Osceola County, 

Lake County, Marion County, and southern Levy 

County. Applin and Applin (1944, fig. 2, p. 1684) 

showed that the upper member of the Ocala is absent 

in a large area extending from the Atlantic Coast 

to Lake County. North to south it is absent from 

St. Johns County to Osceola County. The central 

part of this area is on the New Smyrna arch extending from the Ocala uplift to the Atlantic Ocean. This 

area also is on the Sanford high and Kissimmee flexure as mapped by Vernon. 

In the peninsula and northern Florida, the Ocala 

overlies the eroded surface of the Avon Park Limestone except at Live Oak, Suwannee County, and at 

Lake City, Columbia County, where the Avon Park 

is absent and the Ocala rests on the nonfossiliferous 
46 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

lower unit of the late middle Eocene (Applin and 

Applin, 1944, p. 1683). In Duval and Clay Counties, 

the Ocala rest$ on the basal part of the A von Park. 

In western Florida, Applin and Applin reported that 

where late middle Eocene beds are absent the Ocala 

apparently was deposited on early middle Eocene 

beds. 

The upper member of the Ocala is the typical 

limestone at the outcrops on the Ocala uplift. It is 

the equivalent of the Crystal River Formation of 

Puri (1953, p. 130), which Vernon and Puri (1956, 

p. 35, 38) proposed for 108 feet of limestone exposed 

in the Crystal River Rock Company quarry in Citrus 

County, Fla. The Crystal River is synonymous with 

Ocala Limestone (restricted) of Vernon (1951). It 

is soft white chalky permeable coquina consisting 

chiefly of large foraminifers. It contains chert and 

silicified limestone. The basal part may contain a 

few beds of secondary dolomite, as much as 12 feet 

thick (Puri and Vernon, 1960, p. 12). The youngest 

part of the upper member of the Ocala Limestone 

has been removed by erosion in the area of outcrop. 

Puri (1957, p. 31) reported that 310 feet of the member was penetrated in a well in Polk County. The 

upper member of the Ocala is more than 300 feet 

thick in the subsurface in Jackson County in western 

Florida (Puri and Vernon, 1960, p. 12). In some 

wells in central Florida it rests directly on the A von 

Park. 

The lower member of the Ocala is cream-colored 

limestone, generally harder than the upper member, 

and is commonly very calcitic. In contrast to the upper 

member, the lower member contains specimens of larger foraminifers. In western Florida where the Ocala 

is chiefly cream-colored chalk, Applin and Applin 

(1944, p. 1684) did not recognize the two members. 

The lower member of the Ocala, which is regarded as 

the equivalent of the Inglis Formation and Williston 

Formation of Puri, is approximately the basal 80 

feet of the Ocala Limestone of Cooke (1945, p. 53). 

The Inglis Formation is 50 feet thick at the type locality, near Inglis, Levy County, Fla. The maximum 

thickness may be more than 100 feet. As described 

by Vernon (1951, p. 116), the Inglis is cream to tan, 

granular, rarely pasty, permeable, fairly hard, marine limestone containing an abundant and bizarre 

fauna, in part being a coquina of foraminifers, mollusks, and echinoids. The base of the bed has been 

dolomitized in some of the area of outcrops, but it 

is seldom completely dolomitized. The dolomite is tan 

to brown and very porous but with low permeability. 

Although Cole and Applin (1964, p. 1-47) found no 

faunal (foraminiferal) or lithologic break between 

the Inglis and the underlying A von Park, Vernon 

reported that the base of the Inglis is generally 

marked by a barnacle bed and rubble of pebbles, concretions, and soil eroded from the underlying Avon 

Park Limestone. 

The Williston Formation is almost 100 feet thick 

in Hillsborough and Pinellas Counties and conformably overlies the Inglis (Puri and Vernon, 1960, 

p. 11). It is predominantly marine limestone. Silicified limestone is common in outcrops and generally 

is near the contact with the Inglis. It is overlain 

conformably by the Crystal River Formation of Puri. 

Generally, the Williston thickens as the Inglis becomes thinner. In near-shore environment, deeper 

water facies of the Williston disappear, and shallow 

water facies of the Inglis appear. 

The Ocala Limestone is one of the major waterbearing formations of the principal artesian aquifer 

in Florida and southern Georgia. Some parts of the 

limestone are very permeable. Circulation of water 

through parts of the formation has formed cavities 

and caverns, especially where it is at or near the 

surface. In these areas sinkholes are numerous. 

Many cylindrical holes or natural wells (figs. 8 and 

9), ranging from a few feet to more than 50 feet in 

depth, extend downward from the surface and connect with underground passages in the limestone. 

Solution channels formerly occupied by water but 

now filled with sand and clay are exposed in some 

of the limestone quarries. An exposure of a small 

channel filled with clayey material is shown in figure 

10. One of the largest channels in Marion County observed by the writer, about 12 feet wide and 6 feet 

high, is filled chiefly with white sand and some gray 

FIGURE 8.-Exposure of a vertical section of about 120 feet of 

Ocala Limestone, showing vertical solution channels or natural wells in Crystal River Rock Quarry, Citrus County, Fla. 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 47 

FIGURE 9.-Mouth of natural well near Brooksville, Fla. Well 

is about 5 feet in diameter and 50 feet or more deep. 

clay. It has a fairly flat floor and an arched roof. 

Puri (1957, p. 32) showed an exposure of one cavern 

having a vertical dimension of 30 feet and stated that 

such caverns are common in the Ocala. 

Vernon (1951, p. 152) showed pinnacles of limestone of the lower member of the Ocala Limestone 

extending as much as 40 feet above the floor of a 

quarry through the Alachua Formation in the vicinity of Floral City in southeastern Citrus County. 

The chert and silicified limestone are relatively impervious and do not yield water to wells, but water is 

commonly found beneath these rocks. An exposure 

of the eroded surface of the Ocala Limestone is 

shown in figure 11. A chalky part of the formation 

is shown in figure 12. 

Fresh water of the Ocala Limestone enters the 

formation in areas where it is at or near the surface in outcrops. Also the limestone is recharged 

FIGURE 10.-Exposure of ·cavity, filled with stratified clayey 

material, in Ocala Limestone in a quarry south of Ocala, 

Marion County, Fla. 

FIGURE 11.-0cala Limestone showing old eroded surface 

about 5lh miles north of Ocala, Marion County, Fla. 

in some of the lake regions in Florida and Georgia 

where sinkholes filled with sand extend from the 

surface to the Ocala through relatively impervious 

beds of the Hawthorn Formation. 

BREVARD COUNTY 

D. W. Brown, W. E. Kenner, and Eugene Brown 

(1957, p. 23) described the lower member of the 

Ocala Limestone in Brevard County as the Inglis Formation at the bottom and the Williston Formation 

at the top. Rock cuttings from wells in the county 

show that the Inglis is a cream to white marine 

fossilferous granular limestone having a thickness of 

50 to 100 feet. The Williston is essentially a creamcolored fossiliferous marine limestone having an 

average thickness of 30 feet. It is fine-grained and 

contains fewer echinoids than the underlying Inglis 

Formation. 

The upper member of the Ocala Limestone (Crystal River Formation of Puri) is a white to cream 

FIGURE 12.-0cala Limestone showing chalky part of formation in a quarry about 5lh miles north of Ocala, Marion 

County, Fla. 
48 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

soft massive friable fossiliferous limestone. The 

lower part of the limestone is distinguished from the 

underlying lower member of the Ocala on the basis 

of the fauna and texture. The upper member has 

been removed by erosion in the northern part of the 

county. In the southern part of the county the thickness increases southward to as much as 100 feet at 

the Indian River County line. A structural contour 

map of the top of the Ocala (D. W. Brown and others, 

1957, fig .. 9) shows tpat it ranges from about 100 

feet below sea level in the western part of the county 

to about 300 feet below sea level in the southeastern 

part of the county. An east-to-west section through 

central Brevard County (Brown and others, 1957, 

fig. 10) shows a north-south fault, a short distance 

west of the St. Johns River, where the top of the 

Ocala Limestone is as much as 600 feet below sea 

level on the west side and about 100 feet on the east 

side. Brown, Kenner, Crooks, and Foster (1962, 

p. 73) believe the fault probably affects the direction 

of movement of the artesian water. The piezometric 

surface indicates discharge of artesian water in the 

northeastern part of the county which, as suggested 

by D. W. Brown; W. E. Kenner, and Eugene Brown 

(1957, p. 82), is through springs in Indian River and 

the Atlantic Ocean. The water-bearing properties of 

the different units of the Ocala, which have a total 

thickness of 200 or more feet in the southern part 

of the county, are similar and act as a hydrologic 

· unit with the other water-bearing formations of 

the principal artesian aquifer. Yields of water are 

lowest in the fine-grained limestone in the upper part 

of the lower member. 

HIGHLANDS COUNTY 

As described by Bishop (1956, p. 20), the lower 

member of the Ocala Limestone consists of cream 

to tan-gray slightly hard to soft granular to chalky 

foraminiferal limestone that locally contains some 

crystaiiin·e calcite. The limestone is so similar to 

that of the upper member that the contact is not 

clearly defined. The lower member is about 50 to 

150 feet thick. It dips south about 4 feet per mile 

from 500 feet below sea level in the northern part 

of the county to about 750 feet below sea level in the 

southern part. Bishop (1956, p. 22) reported that 

the lower member probably is not capable of produCing large supplies of water but that it contributes 

some water to wells that penetrate it. He described 

the upper member as a light-gray to cream soft 

chalky coquina limestone composed almost entirely 

of large foraminifers. The thickness apparently 

ranges from about 150 to 250 feet, and the top of the 

member slopes to the south from about 250 feet below sea level in the northern part of the county to 

650 feet in the southern part at an average rate of 

about 10 feet per mile. 

The upper member does not yield as much water 

as the limestone below the Ocala, but in the south-

. eastern part of the county it is capable of yielding 

large quantities. In the western part of the county, 

the Ocala is overlain unconformably by the Suwannee 

Limestone of Oligocene age. The Suwannee is absent 

in the eastern part of the county, and the Ocala is 

overlain unconformably by the Hawthorn Formation 

of Miocene age. 

HILLSBOROUGH COUNTY 

As described by Peek (1959b, p. 14), the Ocala 

Limestone is about 250 feet thick in southwestern 

Hillsborough County, Fla., and lies unconformably 

on the A von Park Limestone. The top of the formation is about 300 feet below sea level in the northern part of the county and slopes to about 600 feet 

below sea level·in the southern part. 

The upper part of the Ocala is a creamy white to 

tan soft somewhat granular chalky coquinoid limestone, composed of remains of foraminifers, mollusks, echinoids, and other fossils loosely cemented · 

in a fine granular chalky matrix. The lower part of 

the Oca1a is more granular and less chalky than the 

upper- part and contains fewer foraminifers. Apparently the Ocala is one of the more productive 

water-bearing formations of the principal artesian 

aquifer in Hillsborough County. However, in the 

coastal area the mineral content of the water generally is considerably higher in the Ocala than in the 

over lying limestone. 

INDIAN RIVER COUNTY 

Bermes (1958b, p. 13-14) reported that the lower 

member of the Ocala Limestone in Indian River 

County, Fla., probably ranges in thickness from 20 

to 100 feet and presumably lies unconformably upon 

the A von Park Limestone. It consists predominantly 

of cream-colored to tan hard to soft granular permeable limestone with calcite crystals. 

The upper member of the Ocala in Indian River 

County consists of cream-colored to light-gray hard 

to soft permeable glauconitic limestone. It contains 

many foraminifers along with other fossils-as mollusks, echinoids, ostracods, corals, and a species of 

small brachiopod. The thickness ranges from 20 

feet to about 380 feet, apparently the maximum reported for this part of the Ocala. The Ocala Limestone is overlain by limestone of Oligocene age in 

the eastern part of Indian River County. In the re-
GEOLOG.IC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 49 

mainder of the county, it is overlain unconformably 

by the Hawthorn Formation. The Ocala is one of 

the most productive water-bearing formations of the 

principal artesian aquifer in this, county. 

MANATEE COUNTY 

In Manatee County, Fla., the 0Gala Limestone is 

about 300 to 325 feet thick (Peek, 1958a, p. 16). The 

upper part consists predominantly of cream, tan, and 

grayish-tan soft chalky very fossiliferous limestone. 

The lower part is similar to the upper part but contains beds of brown and tan hard crystalline dolomite 

and dolomitic limestone. Only a few wells in the 

county penetrate the Ocala, the top of which probably is less than 600 feet in the northeastern part of 

the county and more than 700 feet in the southwestern part of the county .. Jt may be a productive source 

of artesian water, but the ·water along the coast has 

a relatively high mine.ral content. 

MARTIN COUNTY 

As described by (Lichtler, 1960, p. 16), the Ocala 

Limestone is generally less than 100 feet thick in 

Martin County, Fla., and the record of a well at one 

locality shows it is only 20 feet thick. The limestone 

is white to cream or slightly pink soft to medium 

hard and contains much calcite in some areas. Part 

of it is granular and in some places the limestone 

consists almost entirely of foraminifers. The Ocala 

unconformably overlies the A von Park and is overlain unconformably by· the Suwannee ·Limestone in . 

Martin County. 

As shown by a contour map of the top of the Ocala 

Limestone (Lichtler, 1960, p .. 17), the depth to the 

top ranges from about 615 feet on a dome in the 

north-central part of the county to about 800 feet 

in the southern part. 

Lichtler also reported that in the eastern part 

of the county the limestone is on the downthrown 

block of a fault with a vertical dispbicement of about 

300 to 400 feet. The fault is approximately parallel 

to and about 5 miles west of the coast~ Although the 

top of the Ocala is an. erosionaJ surface and the 

underlying formations do not have exactly the same 

shape, the major features of the structure are present in the underlying A von Park Limestone. 

The Ocala Limestone is one of the ·water-bearing 

formations of the principal artesian . aquifer in this 

county. The contour map representing the top of the 

Ocala shows the depth at which the first substantial 

artesian flow is obtained in wells that yield water 

from the aquifer. West of the fault, the Ocala generally provides the first substantial flow because the 

overlying Tampa Limestone and Suwannee Limestone are either thin or missing. East of the fault, 

the Suwannee Limestone is relatively thick and will 

yield small quantities of artesian water. Currentmeter ~urveys in wells west of the fault show that a 

large percentage of the. artesian water is from the 

Ocala Limestone. In one well nearly 100 percent of 

the water is from the Ocala (Lichtler, 1960, p. 36-

38). East of the fault, the water enters the wells at 

a more uniform rate from different parts of the aquifer than west of the fault. 

PINELLAS COUNTY 

Although. the Ocala Limestone underlies all Pinellas County, Fla., and may be a productive waterbearing formation in that county, Heath and Smith 

(1954, p. 10) reported that the formation is not . 

used because it is more than 300 feet beneath the 

surface and is overlain by productive water-bearing 

formations (Tampa and· Suwannee Limestones) of 

the principal aquifer. Also, the water is harder and 

has a higher mineral content than the .overlying 

limestone. 

POLK COUNTY 

H. G. Stewart (1959, p. 20) described the lower 

member of the Ocala Limestone in northwestern 

Polk. County, Fla., as the Inglis and w·illiston Formations. and the upper member as the Crystal River 

Formation. The Inglis is cream-colored hard gran-

. ular limestone, about 25 to 50 feet thick. The Williston is cream-colored to tan generally soft granular 

limestone, 15 to 30 feet thick. The Crystal River Formation is described as white to cream very soft 

coarse-grained limestone about 100 to 150 feet thick 

in northwestern Polk County. It is composed chiefly 

of shells of large foraminifers in a fine-grained matrix of limestone.· This met:nber of the Ocala grades 

vertically into the underlying lower member, a condition making the contact difficult to determine. The 

Ocala Limestone rests unconformably on the underlying A von Park Limestone and is overlain unconformably by the Suwannee Limestone, except in localities where the Suwannee Limestone is absent. 

In these areas the Tampa overlies the Ocala unconformably. A northeast-southwest section in northwestern Polk County (H. G. Stewart, 1959, p. 18) 

shows that the top of the Ocala Limestone ranges 

from about sea level to about 150 feet below sea 

level. 

Although H. G. Stewart (1959, p. 14) recorded two 

solution cavities, one having a vertical dimension 

of 2 feet and the other of 40 feet, in the upper member of the Ocala Limestone, he- reported that the 

yield of wells in this part of the Ocala. is small, and 
50 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

larger yields are obtained by drilling into the underlying limestone. 

PUTNAM COUNTY 

Leve (1958, p. 9) described the Ocala in Putnam 

County, Fla., as a cream to white granular soft 

permeable limestone. The thickness is 110 to 135 

feet in the central part of the county. It is very 

fossiliferous, and some zones are composed of loosely 

cemented shell fragments. A generalized geologic 

section (Leve, 1958, p. 8) shows the top of the Ocala 

ranges from approximately 25 feet below sea level 

in the western part of the county to 125 to 170 feet 

below sea level in the central and eastern parts. The 

surface of the Ocala was eroded before the younger 

formations were deposited on it, and the altitudes 

of the surface may therefore differ as much as 50 

feet within a few hundred yards. The Ocala unconformably overlies the A von Park Limestone and 

is overlain unconformably by Miocene or younger 

formations. The· Ocala is the chief water-bearing 

formation of the principal artesian aquifer in Putnam County. 

Analyses of water samples (Leve, 1958, p. 25; 

Black and Brown, 1951, p. 96) from artesian wells 

that penetrate the limestone, chiefly Ocala, show 

that the water having a low chloride content (less 

than about 20 ppm) is calcium bicarbonate water 

whose total hardness ranges from about 50 ppm to 

about 125 ppm. The samples having the lowest hardness are from wells in areas in which the limestone 

is recharged by water that moves from the surface 

to the limestone through sinkholes, most of which 

are now filled with permeable sand. Samples having 

relatively high chloride content, as much as several 

thousand parts per million, appear to be a mixture of 

fresh water in the limestone and remnants of Pleistocene sea water. 

SEMINOLE COUNTY 

As described by Barraclough (1962, p. 14-15),·the 

Ocala Limestone in Seminole County, Fla., consists 

of white-cream to tan-gray, soft to hard, granular, 

permeable foraminiferal marine limestone. In most 

places the upper member is white to cream; parts of 

it are composed almost entirely of remains of large 

foraminifers. The lower member is harder, more 

granular, and contains fewer large foraminifers than 

the upper member. 

The Ocala Limestone unconformably overlies the 

A von Park Limestone and is unconformably overlain by the Hawthorn Formation. Where the Hawthorn is absent, the Ocala is overlain by younger 

deposits. The Ocala has been removed by erosion in 

the northern part and in a small area in the southwestern part of Seminole County. The thickness 

ranges from 0 to about 190 feet. The top of the 

Ocala ranges from a few feet below sea level near 

the town of Lake Mary to about 113 feet below sea 

level at the village of Lake Monroe. The Ocala Limestone is a very productive part of the principal artesian aquifer in Seminole County. It ranks next 

to the underlying A von Park and yields more than 

500 gpm to some wells. 

VOLUSIA COUNTY 

Wyrick (1960, p. 22) described the lower .Part of 

the Ocala Limestone in Volusia County, Fla., as the 

Inglis Formation at the bottom and the Williston 

Formation at the top. The Inglis is cream to white 

limestone. Its average thickness is 50 feet but may 

. be as much as 120 feet in some parts of the county 

(Vernon, 1951, p. 117-122). The gray color is due to 

finely divided pyrite. The limestone is very permeable and yields a large part of the water obtained 

from wells in Volusia County. The Inglis has been 

removed from the crest of a geologic structural 

feature near De Land. 

The Williston Formation is a soft granular limestone. It is generally finer grained and less permeable than the Inglis. It has an average thickness of 

about 30 feet but has been entirely eroded from the 

structural high near De Land and thinned by erosion 

throughout the remainder of the county. However, 

it is an important part of the principal artesian 

aquifer in Volusia County. Along the coast many 

wells yield water from this part of the Ocala. The 

hydrologic properties of the Inglis and Williston, 

which form the lower member of the Ocala, are similar but are modified locally by dolomitization. The 

upper member of the Ocala Limestone (Crystal River 

Formation of Puri) has not been recognized in V olusia County and apparently has been removed by 

erosion. 

Ocala Limestone in Georgia 

SAVANNAH AREA 

In the northeastern part of the Savannah area, 

Georgia, Counts and Donsky (1959, p. 96; 1962, p. 

24) divided the Ocala Limestone into a lower unit 

and an upper unit on the bases of hydrologic properties and electric-log correlations. S. M. Herrick 

(written commun., 1959) suggested that the same 

division may be made on the basis of microfauna! 

evidence. The lower unit is a soft sandy limestone 

or marl, somewhat similar to the underlying Gosport 

Sand, which consists of limestone, in this area. Its 

maximum recorded thickness is 283 feet. The upper 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 51 

unit is a white calcitized crystalline limestone having 

a maximum thickness of about 283 feet. In the 

southern and western part of the area, the Ocala 

Limestone has not been divided into upper and lower 

units. The maximum thickness of the undifferentiated Ocala is 575 feet. The Ocala Limestone is the 

major part of the principal artesian aquifer in this 

area. The recorded yield of wells from this aquifer 

is as much as 4,200 gpm. 

Chemical analyses of four samples of water from 

the aquifer in this area (Warren, 1944, p. 138) 

showed that the chief constituents were silica, calcium, and bicarbonate. Its hardness ranged from 100 

to 113 ppm. The silica ranged from 25 to 127 ppm. 

The range in bicarbonate was only from 134 to 135 

ppm. 

CALHOUN COUNTY 

The Ocala Limestone in Calhoun County, Ga., 

(Wait, 1960c, p. 28) is a white to cream-colored fossiliferous limestone that ranges from about 16 feet 

at Morgan to about 100 feet at Leary. The limestone 

.is at or near the land surface throughout the county. 

Many sinkholes in the limestone serve as areas of 

recharge to the Ocala. 

CLAY COUNTY 

The Ocala Limestone is present only in southeastern Clay County, Ga., where it consists of red sandy 

residual clay that contains silicified limestone boulders (Wait, 1960b, p. 96). The thickness of the residual material probably averages 40 to 50 feet. 

CRISP COUNTY 

The Ocala Limestone is a white to cream-colored 

limestone underlying Crisp County, Ga. (Wait, 1958a, 

p. 45). It is at or near the surface in the western 

part of the county in Flint River valley. It is only 

a few feet thick in the northwestern part of the 

county but thickens to as much as 130 feet in the 

southeast corner. Springs in the Ocala Limestone 

flow into the Flint River and tributary streams in 

the western part of the county. The Ocala Limestone 

is one of the more productive water-bearing formations in this county. The yield of wells increases 

with the increase in thickness of the limestone toward the southeastern part of the county. 

DOUGHERTY COUNTY 

In Dougherty County, Ga., the Ocala is a pale 

orange to white pure very fossiliferous recrystallized 

limestone, which ranges in thickness from about 70 

feet in the northwestern part of the county to about 

270 feet in the southeastern part (Wait, 1958b, p. 

124; 1963, p. 37). It overlies the Lisbon Formation 

and is overlain by red to brown surficial sandy clay 

derived in part from weathering of the limestone. 

This residual material, called residuum by some geologists, has a maximum thickness of about 70 feet. 

Solution of the Ocala Limestone by water moving 

along joints and bedding planes formed many sinkholes in the county. Surface water that accumulates 

in these sinks recharges the Ocala. 

Although the Ocala Limestone yields large supplies of water in the county, some wells, as in the 

Albany area, have been drilled into the underlying 

formations to avoid possible surface pollution of 

the water. The water in the Ocala is a moderately 

hard calcium bicarbonate type, in contrast to the soft 

sodium bicarbonate water in some of the underlying 

Cretaceous sands. 

LEE AND SUMTER COUNTIES 

In Lee and Sumter Counties, Ga., the Ocala Limestone is a pure to somewhat sandy limestone (Owen, 

1958, p. 118) ranging in thickness from about 15 

feet in the northwest corner of the county to about 

150 feet in the southeast corner. It is overlain by 

surficial sandy clay which is as much as 60 feet 

thick. In valleys the Ocala is exposed at the surface. 

Water can be obtained from the Ocala throughout 

most of the county. More wells obtain water from the 

Ocala than any other formation in the county. The 

Ocala Limestone is the principal source of· domestic 

water supplies in part of southeastern Sumter 

County (Owen, 1963, p. 45). 

TERRELL COUNTY 

The Ocala Limestone is a white to pale-yellowish 

orange fossiliferous pure limestone (Wait, 1960d, 

p. 121). It underlies much of the southern part of 

Terrell county,. Ga., and thickens toward the southeast where the maximum is estimated at 75 feet. It 

is overlain by surficial sands and clays and is underlain by the Lisbon. The Ocala Limestone is an important water-bearing formation in the southeastern 

part of the county. Elsewhere in the county it is 

generally too thin to yield much water. 

SOUTHWESTERN GEORGIA 

tn southwestern Georgia, Wait (1960a, p. 13) described the Ocala Limestone as a white to pink 

pure to sandy limestone. The formation contains 

brown dolomitic limestone in the Valdosta area. The 

Ocala is at or near the surface in a broad belt extending from Florida and Alabama northeast into 

Georgia, where it grades into the Barnwell Formation. The limestone extends southeastward under 

the Tifton Upland in Georgia. It is one of the principal water-bearing formations of this area and con-
52 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

tains calcium bicarbonate water that is moderately 

hard to hard and slightly alkaline.- The sulfate content is only a few parts per million where the limestone is at or near the surface, in contrast to the high 

sulfate and magnesium content in dolomitic limestone of the Ocala at depths of 350 to 400 feet· at 

Valdosta, Lowndes County. 

Ocala Limestone in Escambia County, Ala. 

In Escambia County (Cagle and Floyd, 1957, p. 

12), the Ocala Limestone includes only the upper 

part of the Jackson group (late Eocene) which consists of the Moodys Branch Formation at the bottom, 

Yazoo Clay in the middle, and the Ocala at the top. 

The Moodys Branch consists of greenish-gray fossiliferous glauconitic limestone, which is relatively impermeable but may yield small quantities of water to 

wells. The Yazoo Clay consists of greenish-gray clay 

and fine to medium glauconitic sand, which may yield 

small quantities of water to wells. The Ocala Limestone consists of light-gray limestone and clayey 

fossiliferous marl. Solution cavities in the limestone 

yield water to wells. 

OLIGOCENE SERIES 

The Oligocene is represented in south-central and 

southeastern Alabama by the Chickasawhay Limestone, Byram Formatio:r1, undifferentiated Marianna 

Limestone, and Red Bluff Clay. In Florida the Oligocene Series consists of limestone. · The series thickens 

downdip to the niaximum of about 800 feet in the 

Apalachicola area (Toulmin, 1952, fig. 6). In the 

Florida panhandle the Oligocene is represented by 

the Suwannee Limestone, Byram Formation, and 

Marianna Limestone. In peninsular Florida and in 

Georgia the Oligocene is represented by the Suwannee Limestone. ·The Flint River Formation extends 

from Alabama across Georgia to South Carolina. In 

Georgia and South Carolina the Cooper Marl is included in the Oligocene in the present report. Herrick and Vorhis (1963, p. 18) described the Cooper 

Marl as late Eocene in Georgia. Counts and Donsky 

(1963, p. 26) treated the rocks of the Oligocene Series in the Savannah area as undifferentiated. The 

Oligocene rocks are not exposed in the Savannah 

area but crop out 'in the southwest and central parts 

of Georgia and near Charleston, S.C. The writer considers the Suwannee and Flint River as part of the 

principal artesian aquifer in Georgia. 

In Alabama, formations in the Oligocene Series 

are composed of limestone, marl, clay, and calcareous 

sand of marine origin (Cagle and Floyd, 1957, p. 

12-15; Cagle and Newton, 1963, p. 26-32). The 

Oligocene rocks overlie the Ocala Limestone of Jackson age and are overlain by undifferentiated deposits 

of Miocene age. The Oligocene Series in Escambia 

County in southeastern Alabama includes, from bottom to top, the. Marianna Limestone, with the Red 

Bluff Clay at its base, the Byram Formation, and the 

Chickasawhay Limestone. The Red Bluff Clay and 

the Marianna and Chickasawhay Limestones are not 

exposed in Escambia County. The Red Bluff Clay 

and Marianna Limestone undifferentiated consist of 

about 40 feet of light-gray fossiliferous limestone 

and clayey marl. Toulmin (1955, p. 226) considered 

the Red Bluff a faunal zone at the base of the Marianna in this area. Solution cavities in the limestone 

supply moderate quantities of water to domestic, industrial, municipal, and some irrigation wells. 

BYRAM FORMATION 

The Byram Formation in Alabama includes at the 

bottom the Glendon Limestone Member, a yellow to 

white irregularly indurated coquinoid and crystalline 

limestone; in the middle a gray to tan sandy glauconitic marl and marlstone member; and at the top 

the Bucatunna Clay Member consisting of a yellow 

sand and dark carbonaceous clay. In table 2 the 

members are undifferentiated. In Escambia County, 

Ala., Cagle and Floyd (1957, p. 15) described the 

Byram as a unit consisting generally of 80 to 90 feet 

of dark-gray to brown lignitic clay. It is generally 

not an important source of water in the county; how-

~ver, sand in 40 to 50 feet of the Byram yields 

small supplies of water to flowing wells in Brewton. 

The Byram has been recognized ( Puri and Vernon, 

1959, p. 88) in several outcrops in Jackson County 

in western Florida. Farther west in Washington 

and Holmes Counties, Vernon (1942, p. 59) assigned 

all beds between the Marianna Limestone and the 

overlying Tampa Limestone to the Suwannee Limestone. Good exposures of the Suwannee Limestone 

in the panhandle of Florida include Falling Water 

Sink, about 72 · feet . deep, in Washington County 

(Puri and Vernon, 1959, p. 100; Vernon,ll942, p. 

60-61). 

CHICKASAWHAY LIMESTONE 

The Chickasawhay Limestone in Alabama consists of about 70 feet of fossiliferous dolomitic greenish-gray limestone and a few beds of fine glauconitic 

sand. The sand and solution cavities yield small 

quantities of water to wells. In Escambia and Santa 

Rosa Counties in western Florida, Marsh (1962a, 

p. D59-D60) reported that the Chickasawhay Limestone underlies the entire area and that it thickens 

from about 30 feet to 130 feet toward the Gulf of 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 53 

Mexico. The Chickasawhay consists of vesicular 

limestone and dolomitic limestone and some lightbrown dolomite. It underlies the Tampa, which is 

dark to light gray to grayish white and generally 

is not dolomitic. The Tampa is less vesicular and 

contains more clay than the Chickasawhay. 

The age equivalents of the Byram and Chickasawhay are not easily differentiated. However, the 

Bucatunna Clay Member of the Byram has been described by Marsh (1961, p. 224; 1962b, p. 243-251) 

in Santa Rosa and Escambia Counties, where it consists chiefly of a relatively impervious clay ranging 

in thickness from 45 feet in the northeast corner of 

Santa Rosa County to 215 feet in the area just north 

of Escambia Bay. It dips about 30 feet to the mile 

toward the southwest and separates the principal 

aquifer into two parts. The clay is overlain by 

Oligocene limestone, which Marsh (1962a, p. D60) 

refers to as Chickasawhay Limestone. 

COOPER MARL 

The Cooper Marl, a finely granular olive-drab to 

brown marl as much as 200 feet thick~ containing 

glauconite and phosphatic nodules in the lower part, 

crops out in a broad belt extending northeastward 

from Allendale County on the Savannah River to 

the Santee River in Berkeley County. The marl is 

soft in fresh exposures. Cooke (1936, p. 163) assigned the marl to the Jackson Group of Eocene 

age and reported that in the vicinity of Charleston 

the Cooper Marl and the underlying Santee Limestone of late Eocene age had a thickness of about 

440 feet. 

Later Cooke and MacNeil (1952, p. 27) and MacNeil (in Malde, 1959, p. 19) found fossils in the 

formation, and they as·signed the marl to the Oligocene Series. The marl is at or near the land surface 

in the Charleston area, where the permeability is 

so small that an unlined tunnel in the marl has been 

used for many years to conduct the municipal water 

supply· of Charleston many miles from a surface 

reservoir to the city. It. yields little or no water to 

wells and, therefore, is not important as a source of 

water in South Carolina and Georgia. 

SUWANNEE LIMESTONE IN FLORIDA 

As described by Toulmin (1955, p. 226), the Suwannee is a cream-colored granular permeable thinbedded coquinoid limestone. The bottom part of th.e 

formation contains some thin-bedded dense hard 

limestone. The maximum thickness in Georgia is 

about 200 feet in the south-central part near Florida. 

As described by Applin and Applin (1944, p. 1682), 

at Tallahassee the thicknes-s is 300 to 350 feet and 

is 450 feet in a well at Key West. The Suwannee 

lies unconformably on the Byram Limestone or, 

where that is absent, on the Ocala. It is overlain unconformably by the Tampa Limestone or by the Hawthorn Formation (Cooke, 1945, p. 88). The Suwan-

·nee is absent in southeastern Georgia and throughout the eastern and central parts of the Florida 

peninsula, as far south as Indian River County on the 

Atlantic coast. In north-central Florida, it is absent 

from coast to coast. 

As shown by Toulmin (1952, p. 1172) and Applin 

and Applin (1944, p. 1682), the Suwannee is also 

absent in southwestern Georgia and adjacent parts 

of Georgia and Alabama. In the Flint River valley 

in southwestern Georgia, the Oligocene is represented 

by the Flint River Formation described by Cooke 

(1943, p. 77-84). The Suwannee crops out in the 

Suwannee River valley in Florida and in all or parts 

of several counties bordering the river. It also is 

at or near the surface in the west-central part of 

the peninsula, chiefly in Pasco and Hernando Counties; it extends eastward into adjacent counties and 

northward into Citrus County. 

The Suwannee Limestone !s not as extensive as the 

underlying Eocene formations; however, where .it is 

present, it is one of the most productive waterbearing formations of the principal artesian aquifer. 

The limestone contains many cavities formed by 

solution. These cavities yield large quantities of 

water to wells. Parts of the limestone, consisting 

chiefly of shells of foraminifers, are very permeable. 

Many solution cavities in the limestone are exposed 

along the Suwannee River where water from the 

river enters the limestone during high stages of the 

river. During low stages large quantities of water 

flow from the limestone into the river. The east-west 

flow in the limestone, with its reversal of flow, may 

be observed at Falmouth Spring, 0.2 mile west of 

Falmouth and 3.5 miles southeast of the Suwannee 

River at Ellaville. 

Highlands County 

The Suwannee Limestone in Highlands County, 

Fla., (Bishop, 1956, p. 23) is predominantly creamcolored slightly permeable and soft chalky to slightly 

crystalline limestone. Its maximum thickness is 

about 80 feet. It is present only in the western part 

of the county where it rests unconformably on the 

Ocala Limestone and is unconformably overlain by 

the Hawthorn Formation. The top of the formation 

slopes from about 200 feet below sea level in the 

northern part of the county to about 500 feet below 

sea level in the southern part, an average of about 
54 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

6 feet per mile. The Suwannee is not an important 

water-bearing formation in Highlands County although it is used for small domestic supplies. 

Hillsborough County 

Peek ( 1959b, p. 15) reported that the upper part 

of the Suwannee Limestone in the southwestern part 

of Hillsborough County, Fla., is creamy white to 

tan soft granular fossiliferous limestone. Some beds 

are crystalline, dolomitic, and partly silicified. The 

lower part of the Suwannee is generally a tan to 

brown soft to hard granular to dense limestone, 

which is harder, more crystalline and dolomitic, and 

less fossiliferous than the upper part. The Suwannee 

has a fairly uniform thickness of about 200 to 225 

feet. As shown on a map by Peek (1959b, p. 16), the 

top of the limestone ranges in depth from about 75 

feet below sea level in the vicinity of Tampa to 400 

feet below sea level in the southwestern part of the 

county. 

Martin County 

Lichtler (1960, p. 17) reported that the Suwannee 

Limestone in Martin County, Fla., is cream-colored 

and soft. Its thickness ranges from 20 to 60 feet 

on the west side of a fault, which is parallel to 

and about 5 miles west of the coast. The thickness 

is 100 to 170 feet on the east (downthrown) side 

of the fault. These differences in thickness indicate 

that movement along the fault probably started 

during late-Oligocene or post-Oligocene time and 

continued when the Suwannee was exposed to erosion. The thickness of the Suwannee on the east 

side of the fault is greater than on the west side 

because the downthrown block was protected from 

erosion. Lichtler also suggested that some move- · 

ment along the fault probably occurred during Miocene time and that the faulting, as discussed by 

Vernon (1951, p. 54-63), was probably associated 

with crustal movements which formed the Ocala 

uplift. The Suwannee is underlain unconformably 

by the O~la Limestone and is overlain unconformably by the Tampa Limestone or by the Hawthorn 

Formation where the Tampa is absent. The Suwannee Limestone is part of the principal artesian aquifer, but its permeability is generally less than that 

of the underlying limestone. The chloride content of 

the water is generally larger than in the more permeable rocks because ground-water circulation has 

removed more salt water in the permeable rocks than 

in those less permeable. 

Pinellas County 

In Pinellas County, Fla., (Heath and Smith, 1954, 

p. 12) the Suwannee Limestone is predominantly 

white to cream colored, hard, and generally fossiliferous. A well penetrated 180 feet of the limestone 

north of Tarpon Springs. Although the well did not 

pass through the formation, Heath and Smith suggested that the limestone is not much thicker than 

180 feet. In Pinellas County the Suwannee is underlain by the Ocala and is overlain by the Tampa 

Limestone. The Suwannee is very permeable and a 

good source of water in coastal areas where salt 

water has not entered it. 

Polk County 

In a report on the northwestern part of Polk 

County, Fla., H. G. Stewart (1959, p. 21) described 

the Suwannee as a light- to dark-cream granular 

detrital soft very pure fossiliferous limestone as 

much as 100 feet thick. Some parts are so fossiliferous that well drillers usually call it coquina. In 

some places the limestone contains extremely hard 

masses of dark-brown chert, commonly 1 inch to 

2 feet thick, but in a few places they may be as 

much as 10 feet thick. The Suwannee unconformably 

overlies the upper member of the Ocala Limestone. 

In the southern part of the area, it is overlain unconformably by limestones of Miocene age, and in 

the northern part, by unconsolidated sand and clay, 

which may range in age from Oligocene to Recent. 

Solution cavities penetrated by a well in the Suwannee Limestone range in vertical dimensions from 

2 to 5 feet. One spongy honeycomb zone has a thickness of 43 feet. 

SUWANNEE LIMESTONE IN SAVANNAH AREA, GEORGIA 

In the Savannah area, Counts and Donsky (1959, 

p. 98; 1963, p. 14) reported that undifferentiated deposits of Oligocene age consist of as much as 205 

feet of loosely consolidated gray to buff limestone 

containing thin stringers of dense white sandy and 

cherty limestone. The limestone is part of the principal artesian aquifer and yields as much as 500 

gpm to wells .. 

FLINT RIVER FORMATION 

As described by Cooke (1945, p. 104-106; 1943, 

p. 77-84), the Flint River Formation extends from 

Covington County, Ala., across Georgia to Allendale 

County, S.C., a distance of nearly 350 miles. Its belt 

of outcrop is nearly 65 miles wide in southwestern 

Georgia, where the formation is broken into two 

parts by an inlier of Ocala Limestone. The Flint 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 55 

River grades southward into the Suwannee Limestone and westward into the Chickasawhay Limestone. In its original condition the Flint River Formation probably consisted chiefly of sandy and 

pebbly limestone and calcareous sand. Solution and 

weathering have removed the lime from the exposed 

parts of the formation. Solution of the limestone 

was accompanied by silicification, which locally retained the original form but elsewhere produced 

dense vitreous chert or jasper. Some of the cavities 

in the chert are studded with drusy quartz crystals. 

The original thickness of the formation may have 

been more than 100 feet, but the residual products 

now exposed are probably less. 

Southwestern Georgia 

Recent reports on Calhoun, Clay, Crisp, and Terrell Counties in southwestern Georgia include brief 

statements on the water-bearing properties of the 

Flint River Formation. Wait (1960c, p. 27) reported 

that in Calhoun County the Flint River Formation 

is siliceous limestone and sandy clay. The formation 

occurs only in the northwest corner of the county. 

It may yield small amounts of water locally to dug 

wells. In Clay County, Wait (1960b, p. 95) described 

the Flint River as sandy clay and silicified limestone 

boulders restricted to hilltops in the southern part of 

the county. It is not important as an aquifer but may 

yield some water to dug wells. The Flint River Formation in Crisp County (Wait, 1958a, p. 44) is 

siliceous and sandy limestone. It is present in the 

eastern two-thirds of the county, where it supplies 

water to dug ·wells and shallow drilled wells. In the 

east half of the county, the Flint River Formation 

underlies the Hawthorn Formation. It is at or near 

the surface in a broad north-south belt 3 to 5 miles 

east of the Flint River. In Terrell County Wait 

(1960d, p. 121) reported that the Flint River consists chiefly of dark-red sandy clay intermixed with 

si1iceous boulders. It may yield small amounts of 

water to dug wells. 

MIOCENE SERIES 

As described by Cooke (1945, p. 109), Miocene 

time may be divided into three parts, each of which 

began by an expansion of the sea upon the land. In 

Florida and Georgia the early Miocene is represented by the Tampa Limestone, which lies on the 

eroded surface of the Suwannee Limestone and the 

Flint River Formation of Oligocene age or . upon 

older limestones. The Tampa seems to be contemporaneous with the Catahoula Sandstone and Paynes 

Hammock Sand in southeastern Alabama. In middle 

Miocene time, the sea may have spread out over all 

the Floridian Plateau, which had been partly above 

sea level, and covered parts of Georgia and South 

Carolina. However, Vernon (1951, p. 181) believed 

that the Miocene seas never extended across the Ocala 

uplift in the Florida peninsula. The Hawthorn Formation was deposited in the eastern region. In western Florida the Chipola Formation and the overlying 

Shoal River Formation, including the Oak Grove 

Sand Member, were deposited. Cooke (1945, p. 137) 

included the Hawthorn (east of the Apalachicola 

River) and the Chipola and Shoal River (west of 

the Apalachicola) in the Alum Bluff Group. After 

the Hawthorn was deposited, the sea withdrew presumably beyond the present shoreline. In late Miocene time the sea advanced and deposited the Duplin 

Marl. 

In southeastern Florida, the late Miocene is represented by the Tamiami Formation (Parker and others, 1955, p. 84-88), which apparently is the age 

equivalent of the Choctawhatchee Formation of the 

Florida Geological Survey. 

The Alachua and Bone Valley Formations described by Cooke (1945, p. 199-210) as Pliocene are 

regarded by Puri and Vernon (1959, p. 9, 160-174) 

as Miocene. In the present report, these formations 

are included in the Pliocene. 

The Miocene is divided by Puri and Vernon (1959, 

p. 9) ·into three time-rock units as follows : Tampa 

stage, Alum Bluff stage, and Choctawhatchee stage. 

The lithostratigraphic and biostratigraphic divisions 

are subdivided into facies. 

Tampa, Shoal River, Chipola, Hawthorn, Tamiami, 

Alachua, and Bone Valley are used as formation 

names in the present report. The Choctawhatchee 

is regarded (Cooke, 1945, p. 168) as part of the 

Shoal River, which is equivalent in age to the Tamiami. The Al.um Bluff Group includes the Chipola 

and Shoal RiVer Formations. The Oak Grove Sand 

is a basal member of the Shoal River. The Hawthorn 

Formation represents the Alum Bluff Group east of 

the Apalachicola River in Florida. The distribution 

of these units on the surface and in the subsurface 

in Florida are shown by Puri and Vernon ( 1959, 

pls. 2-7). 

Goodell and Yon (1960, p. 75-113) included the 

Miocene formations in composite lithofacies and 

isopach maps of post-Eocene formations and also 

included lithostratigraphic cross sections of postEocene strata in Florida. 

TAMPA LIMESTONE IN FLORIDA 

As described by Cooke (1945, p. 113-114), the 

Tampa Limestone is commonly a fairly hard dense 
56 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

FIGURE 13.-Tampa Limestone showing bedding in portland 

cement quarry about 11 miles west of Brooksville, Hernando County, Fla. 

light-colored to yellowish limestone in Hillsborough, 

Pasco, and Pinellas Counties, Fla. Its composition is 

much more variable than either the Suwannee or the 

Ocala, both of which are much purer limestone. Bedding is distinct (fig. 13), in contrast to the Ocala 

(fig. 12). Some weathered exposures reveal small 

pockets of clay, as in a quarry in Hernando County, 

Fla. (fig. 14). 

Cooke and Mossom (1929, p. 78-79) changed the 

name Tampa Formation to Tampa Limestone because 

the formation is chiefly limestone in outcrops. They 

redefined it to include the Chattahoochee Formation. 

Vernon (1942) revived the original term Tampa Formation because the Tampa consists of sand, silt, 

marl, subordinate limestone, and fuller's earth downdip. In the present report the name Tampa Limestone is used. 

The Tampa Limestone is at or near the surface in 

two general areas in Florida. One area, which inFIGURE 14.-Tampa Limestone showing weathered limestone 

and pockets of clay in portland cement quarry about 11 

miles west of Brooksville, Hernando County, Fla. 

eludes the type locality at Tampa, is in the Florida 

peninsula in Hillsborough and Pasco Counties and 

adjacent parts of Pinellas County. The area in the 

panhandle extends westward from the Apalachicola 

River valley in western Gadsden and Liberty Counties to the west side of Holmes County. Well records 

indicate that the Tampa is absent in the eastern and 

northeastern parts of the peninsula. It extends from 

Florida into Georgia and is present as far north as 

South Carolina in the Savannah area (Counts and 

Donsky, 1959, p. 98; 1963, p. 28). The outcrop in 

Georgia, as shown on a geologic map (Cooke, 1943, 

pl. 1), extends as a narrow belt from southwestern 

Decatur County northeastward into Worth County 

near Sylvester. The thickest exposure reported by 

Cooke (1945, p. 114) is at Chattahoochee in Gadsden 

County, Fla., where the limestone rises from river 

level to 117 feet above low water level in the Apalachicola River. 

Wells in southern Florida penetrate as much as 

250 feet of the limestone. The Tampa unconformably 

overlies the Oligocene limestones and, according to 

Cook (1945, p. 115), merges upward gradually into 

the Hawthorn Formation with an indefinite boundary 

between them. However, according to Vernon (1951, 

p. 183) there is an unconformity between them in 

the west-central and southwestern parts of the peninsula. Heath and Smith (1954, p. 14) reported that 

the Hawthorn unconformably overlies the Tampa in 

Pinellas County, Fla. 

In the area between Hernando and Hardee 

Counties in the west-central part of the Florida peninsula, Ketner and McGreevy (1959, p. 59-65) described the Tampa in three units as follows : a phosphorite unit in the northern part of the area having 

a maximum thickness of about 10 feet; a clay unit 

overlying the phosphorite unit having a maximum 

thickness of 25 feet; and a limestone unit in the 

southern part of the area having a maximum thickness of 25 feet. The phosphorite unit consists of 

clay, fine quartz sand, and sandy clay containing 

clay-sized particles of apatite. Although nonfossiliferous, the unit probably is early Miocene in age. 

It is underlain unconformably by the Suwannee and 

Ocala. It is overlain with apparent conformity by 

clay of early Miocene age. Rubble of Suwannee 

Limestone and sand- to boulder-sized concretions of 

apatite, known as hard-rock phosphate, are scattered 

in the unit. The limestone unit consists of clayey 

sandy limestone containing a few phosphorite nodules of sand size. Ketner and McGreevy reassigned 

the clay and phosphorite units from the Alachua to 

the Tampa because the clay contains marine inverte-
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 57 

brate fossils, and both units are probably weathered 

Tampa. 

In the west-central part of the Florida peninsula 

Carr and Alverson (1959, p. 21-32) reported that 

the Tampa contains both marine and fresh-water 

limestone. Phosphate nodules occur in the Tampa 

Limestone at a few ·localities. The formation contains lenses of limestone conglomerate, green and 

gray clayey sand, sandy clay, and clay-pebble conglomerate. Chert is common. In Escambia and 

Santa Rosa Counties in western Florida, Marsh 

1962a, p. 60) reported that the Tampa Limestone 

is present in the south half of the area. Its maximum 

thickness is 270 feet. The ·limestone generally is 

not dolomitic. It resembles the underlying Chickasawhay Limestone of Oligocene age but is less vesicular and contains more clay than the Chickasawhay. 

Although· the Tampa as a whole is relatively impure, it contains much pure limestone. Samples range 

from 73 to 96 percent calcium carbonate. The quantity of heavy minerals in the Tampa is small but is 

much larger than in the Suwannee. Pink garnet is 

relatively common and may exceed 40 percent of the 

heavy fraction. Analyses of rock samples of the 

Tampa reported by Cooke (1945, p. 113) show that 

the formation ranges from 20 percent to about 70 

percent silica ( Si Oz) . The silica commonly is very 

fine sand. In the silex bed, first described at the 

type locality at Tampa, silica has replaced the carbonates in the limestone or shells within it. 

Highlands County 

In the northern part of Highlands County, Fla., 

Bishop (1956, p. 25) included in the Hawthorn Formation material that may· be equivalent to the sandy 

limestone of the Tampa. 

Hillsborough County 

Peek (1959b, p. 15-18) described the Tampa Limestone in the Ruskin area in Hiiisborough County, 

Fla., as a white, gray, or tan hard dense sandy limestone. Some parts are crystalline and dolomitic. It 

is generally fossiliferous. The top of the Tampa 

rang~s in depth from a little below sea level in the 

lr"orthern part of the area to about 250 feet below 

sea level in the,southern part. The Tampa Limestone 

is a productive source of artesian water in the Ruskin 

area. Most of th~ water is from relatively thin zones 

of high permeability containing many interconnecting solution channels. Current-meter explorations in 

wells show that much of the artesian flow is from 

the Tampa Limestone (Peek, 1959b, p. 24). 

Manatee County 

The Tampa Limestone in Manatee County, Fla. 

(Peek, 1958a, p. 18), is white, gray, or tan hard 

dense sandy limestone which contains fine-grained 

phosphorite in some places. Part of the limestone 

is crystalline and dolomitic and contains thin beds 

of chert. The formation generally is fossiliferous. 

The thickness of the Tampa ranges from about 125 

feet in the northeastern part of the county to about 

235 feet in the southeastern part. The top of the 

limestone ranges from about 200 feet below sea level 

in the northern and northeastern parts to more than 

350 feet below sea level in the southeastern part. The 

limestone has .many solution cavities and is a productive source of artesian water. 

Martin County 

In Martin County, Fla. (Lichtler, 1960, p. 18), the 

presence of Tampa Limestone has not been definitely 

established, but 10 to 15 feet of sandy limestone underlying the Hawthorn Formation about 2 miles south 

of Stuart belongs to the Tampa. 

Pinellas County 

The Tampa is generally a white to tan hard sandy 

limestone in Pinellas County, Fla. Chert fragments 

are abundant in some well cuttings. A north-south 

geologic section through Pinellas County (Heath 

and Smith, 1954, fig. 4) shows that the thickness of 

the Tampa ranges from about 100 feet in the northern part to more than 150 feet in the southern part. 

A map, figure 5 of that report, shows that the surface 

is irregular and stopes from sea level in the northern 

part of the county to 120 feet below sea level in the 

southern part. The irregular surface in the southern 

part of the county is due chiefly to erosion that preceded the deposition of the Hawthorn. However, the 

map is too general to show the numerous pinnacles 

and sinkholes that might be expected on an eroded 

surface of limestone in which solution has taken 

place. Numerous solution cavities in the limestone 

yield large supplies of water to wells. 

The chief chemical constituents of the water in 

the Tampa are calcium and bicarbonate, except in 

areas along the coast where the ground water is 

mixed with sea water. Away from the coastal areas 

the chloride of some samples is less than 10 ppm. The 

hardness ranges from about 150 ppm to about 250 

ppm. Th.e water from underlying formations is 

harder than that in the Tampa. Water samples having a chloride content ranging from 148 to 309 ppm 

were erroneously reported (Black and Brown, 1951, 

p. 93) for three wells 300 feet' deep in the Cosme 

Odessa well field in northwestern Hillsborough 
58 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

County near Pinellas County. These samples were 

actually from the old city wells in St. Petersburg 

near Tampa Bay and not from the Cosme Odessa well 

field. 

Polk County 

H. G. Stewart ( 1959, p. 23) described the Tampa 

in Polk County, Fla., as a dark-gray to white generally hard sandy limestone having black and brown 

granules of phosphates. The thickness ranges from 

less than 1 foot to about 60 feet. Although the contact with the underlying Suwannee Limestone is unconformable (Cooke, 1945, p. 109; Vernon, 1951, 

p. 179), it is difficult to detect and generally is regarded as the contact of the pure limestone of the 

Suwannee with the sandy limestone of the Tampa. 

In northwestern Polk County, Stewart reported that 

a blue-gray or blue-green and cream silty sandy clay 

3 to 15 feet thick overlies the limestone. In some 

places this part of the Tampa is shaly and contains 

less sand than where it is clayey. This bed is relatively impermeable, but it yields small quantities of 

water to some wells. Stewart (1959, p. 14) lists 

solution cavities in different formations including 

one in the Tampa Limestone that has a vertical 

dimension of 5 feet. 

TAMPA LIMESTONE IN GEORGIA 

Savannah Area 

Although the Tampa Limestone is absent in northeastern Florida and southeastern Georgia as indicated by Cooke (1945, p. 112, 115), Counts and 

Donsky (1963, p. 28) reported that the limestone 

is present in the subsurface in the Savannah area, 

Georgia, where it is as much as 130 feet thick. In 

that area it is gray sand and marl, interbedded with 

dolomitic limestone. It has a thin brecciated unit at 

the base which unconformably overlies Oligocene 

limestone. From place to place the Tampa ranges 

from broken shelly sandy limestone to hard dolomitic limestone to sandy silty limestone. In part 

of Hampton County in southeastern South Carolina, 

both the limestone of Oligocene age and the Ocala 

Limestone of late Eocene age are absent, and the 

Tampa overlies the Gosport Sand of middle Eocene 

age. 

The Tampa is part of the principal artesian aquifer. In the Savannah area, Counts and Donsky 

(1959, p. 100; 1963, p. 14) reported that hydrogen 

sulfide is noticeable in the water from the Tampa. 

Commonly, this water is cased out of the well, and 

water is obtained from the underlying limestone. 

In other parts of the report area, however, the artesian water from other formations of the principal 

aquifer contains small quantities of hydrogen sulfide, which seem to be most abundant some distance 

from recharge areas. 

Southwestern Georgia 

A sandy facies of the Tampa in northwestern 

Florida, formerly called the Chattahoochee Limestone (Cooke, 1945, p. 87), extends into Decatur 

County in southwestern Georgia. Wait ( 1960a, p. 3, 

15) reported a sandy facies in the Tifton Upland area 

which extends northeastward from Decatur and 

Grady Counties into east-central · Georgia. The 

Tampa yields abundant water where it is present 

as part of the principal artesian aquifer, as at 

Valdosta. 

ALUM BLUFF GROUP 

As described by Cooke (1945, p. 137), the Alum 

Bluff Group consists predominantly of micaceous 

sand, sandy clay, fuller's earth, and limestone. Cooke 

included the Hawthorn (east of the Apalachicola 

River) and the Chipola and Shoal River Formations 

(west of the Apalachicola) in the Alum Bluff Group. 

The name Hawthorn Formation was first applied 

to rocks of Miocene age exposed in Alachua County, 

Fla. (Dall and Harris, 1892, p. 107). According to 

Cooke, at the end of Tampa time, the shoreline 

advanced inland beyond the shores of the Tampa 

sea, and the Hawthorn was deposited unconformably 

on the old land surface. In the area of the Tampa 

sea, the Hawthorn and Chipola Formations were deposited conformably on the Tampa Limestone. The 

Hawthorn east of the Apalachicola River in Florida 

and in southern Georgia represents different lithologic facies of the Chipola Formation and possibly 

part of the Shoal River Formation in western Florida. The contact of the Chipola with the overlying 

Shoal River probably is conformable. Vernon (1942, 

p. 75) regards the Chipola and Shoal River as contemporaneous ecologic facies. Cooke (1945, p. 138) 

saw some justification for this belief but considered 

that more probably the two formations are in chronological sequence. The Chipola is represented by UTIfossiliferous sand and clay west of its type locality. 

Hawthorn Formation in Florida 

The Hawthorn Formation is extensive, covering a 

large part of the area of this report. In Florida the 

formation consists of as much as several hundred 

feet of imbedded clay, sand, limestone, and sandy 

phosphatic limestone and marl. Lenses of fuller's 

earth are widely distributed in the Hawthorn. Extensive deposits in the east half of Gadsden County 

in western Florida have been mined for many years. 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 59 

Fuller's earth is also extensively mined near Attapulgus, Decatur County, Ga. Fine sandy phosphatic 

limestone forms a large part of the formation in 

Florida and South Carolina. In Georgia phosphatic 

limestone is less conspicuous (Cooke, 1943, p. 90), 

an'd dolomitic limestone containing as much at 35 

percent magnesium carbonate (MgCOa) is near the 

base in the southern part of the State. 

The maximum thickness reported for the Hawthorn is about 650 feet in Highlands County, Fla. 

(Bishop, 1956, p. 27). Cole (1944, p. 23) assigned 

cuttings from depths of 90 feet to almost 500 feet 

to the Hawthorn in Hilliard well 1, 4 miles northwest of Hilliard in northeastern Florida. In southeastern Florida, Lichtler (1960, p. 18) reported a 

maximum thickness of 550 feet. 

A well at Quincy in western Florida penetrated the 

Hawthorn Formation from the surface to a depth of 

210 feet where it passed into the Tampa (Cole 1944, 

p. 13). One of the thickest exposures described by 

Cooke (1945, p. 147) is in the Devils Mill Hopper, a 

sinkhole, about 6 miles northwest of Gainesville in 

Alachua County, Fla., that passed through more than 

100 feet of Hawthorn to the underlying Ocala Limestone, which is not far below the water level in the 

sink. A description of the section at the Devils Mill 

Hopper by Pirkle (1956, p. 215, 216) includes 120 

feet of the Hawthorn. Puri and Vernon (1959, p. 

122) described a section of the Hawthorn, including 

Devils Mill Hopper and one 96.9 feet thick at the 

fuller's earth mine of the Floridin Co., Quincy, Gadsden County, Fla. 

The Hawthorn grades westward into the Chipola 

Formation and probably includes equivalents of the 

Shoal River Formation. It apparently overlies the 

Tampa conformably but rests unconformably, in part 

of the area, on Ocala Limestone and older formations on which it was deposited. 

Espenshade (1958, p. 208) reported that solution 

pipes 5 to 10 feet deep in the Ocala Limestone in a 

limestone quarry about 1112 miles south-southeast 

of Bellview in Marion County are filled with phosphatic clay of the Hawthorn. 

The Hawthorn is overlain unconformably by the 

Duplin Marl and younger formations (Cooke, 1945, 

p. 143). In southeastern Florida, its contact with 

the overlying Tamiami Formation apparently is conformable (Lichtler, 1960, p. 18). As described by 

Puri and Vernon (1959, p. 119), the Hawthorn in 

part of Florida was deposited under continental and 

deltaic environments. The continental sediments are 

east of Marianna and north and northeast of Talla,.. 

hassee in Leon County. The deltaic deposits are in 

Gadsden, Jefferson, and Madison Counties. Puri and 

Vernon concluded from exposures at Rock Bluff and 

at Alum Bluff 71/2 miles south on the Apalachicola 

River in Florida that the Hawthorn Formation is 

contemporaneous with the Chipola and Shoal River 

Formations and that both the bottom and top of the 

Hawthorn are marked by a distinct disconformity, 

erosional, at least in places. 

Between the Withlacoochee and Manatee Rivers in 

the west-central part of the Florida peninsula, Carr 

and Alverson (1959, p. 34-36) reported that the 

Hawthorn is exposed in northeastern Pasco County, 

in the phosphate district of Hillsborough, Polk, 

Hardee, and Manatee Counties, and in western Sarasota County. In southern Hillsborough and Polk 

Counties, the formation is about 100 feet thick, but 

it thickens southward to more than 300 feet near 

Sarasota. According to Stringfield (1933c, p. 142), 

the thickness ranges from about 450 to 500 feet in 

Sarasota County. In west-central Florida, Carr and 

Alverson divided the Hawthorn into lithologic units 

as follows: ( 1) A lower limestone unit, containing a 

fauna like that of the Oak Grove Sand Member of 

the Shoal River Formation in western Florida, (2) 

an upper limestone containing fauna similar to the 

Shoal River above the Oak Grove Sand Member, (3) 

a surficial phosphorite unit in the central and southern part of the area, and ( 4) a surficial gray to red 

sand unit in the northern part containing a few middle Miocene fossils. The surficial phosphorite and 

sand units are from the weathering of the underlying 

limestone. 

Within the Hawthorn Formation are permeable 

water-bearing beds of sand, limestone, and marl, 

above and below which are less permeable beds. In 

some localities the water-bearing limestone contains 

solution channels that yield water to wells and 

springs. In general the lower part of the formation 

yields the most water, but wells usually supplied by 

water from the Hawthorn h~ve only. moderate yields. 

Where large supplies are required, the wells are 

drilled into the underlying limestone. If there is 

adequate development, however, relatively large supplies of water can be obtained from the formation. 

Much of the water in the Hawthorn is under artesian 

pressure, and the pressure in the lower part of the 

formation is comparable with that in the underlying 

limestone of the principal artesian aquifer. Under 

these conditions, the lower part of the Hawthorn 

constitutes the top of the principal artesian aquifer, 

and the relatively impervious clay and marl beds in 

the formation prevent or retard upward movement 
60 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

of artesian water as reported by Clark, Musgrove, 

Menke, and 'Cagle (1962, p. 68). 

Fresh water enters the ·formation where it is exposed at or near the surface and in areas where it is 

overlain by permeable material. Recharge also occurs through sinkholes, some of which are filled with 

permeable sands. The water in general is similar to 

that in the underlying limestone but is softer. Water 

from the limestone or marl at the bottom of the formation may be of the same quality as that in the underlying limestone. Some parts of the formations 

which contain phosphatic material yield water that 

almost everywhere contains fluoride in concentrations in excess of 1.0 ppm and which may be as much 

as 2.5 ppm (Black and Brown, 1951, p. 15). 

BREVARD COUNTY 

In Brevard County; Fla. (D. W. Brown and others, 

1957, p. 24-31) the Hawthorn is composed of greenish-gray calcareous clay, sandy phosphatic limestone, 

black and brown phosphorite, and light-green to 

white phosphatic radiolarian clay. The formation 

ranges in thickness from 10 feet in the northern 

part of the county to about 220 feet in the southern 

part. It contains many beds of relatively impervious 

marl and clay that prevent or retard upward movement of artesian water. The more permeable sands, 

shells, marls, and limestones yield water to wells 

and springs. The permeable beds in the lower part 

of the formation in contact with the underlying limestone form the top of the principal artesian aquifer. 

In an east-west section through central Brevard 

County, D. W. Brown, W. E. Kenner, and Eugene 

Brown (1957, p. 29, 31) postulated that the Hawthorn is several hundred feet thick on the west side 

of a fault with a north-south course in the St. Johns 

River valley. The Hawthorn probably is less than 

50 feet thick east of the fault. They believed that the 

fault probably affects the direction of movement of 

the water. 

COLLIER COUNTY 

In the Naples area in Collier County, Fla., Klein 

(1954, p. 9) described the Hawthorn as gray-green 

clay, silt, and fine sand interbedded with limestone 

and shell marl. He reported that the formation is 

about 4~0 feet thick. McCoy ( 1962, p. 11) stated 

that the Hawthorn Formation and the overlying Tamiami Formation are very difficult, if not impossible, 

to differentiate. However, he estimated that the 

thickness of the Hawthorn is from 250 to 300 feet. 

The top is present at depths between 40 and 50 feet 

below the land surface at Fort Myers. At Goodlane, 

south of Naples, the top of the Hawthorn is between 

150 and 270 feet below the land surface. Permeable 

limestone and shell beds in the lower part of the formation are regarded as the uppermost part of the 

principal artesian aquifer. That part of the formation probably is the source of the artesian water in 

deep wells in Naples. The overlying clay and silt are 

relatively impermeable and separate the water of the 

principal artesian aquifer from the shallow artesian 

water in the Naples area. 

HIGHLANDS COUNTY 

As described by Bishop (1956, p. 24-28), in Highlands County, Fla., the Hawthorn consists of marine 

and deltaic deposits. The marine deposits consist 

chiefly of dark-green to white phosphatic clay and 

lenses of white to cream dense sandy phosphatic limestone, phosphorite pebbles, and quartz sand. The 

deltaic deposits consist of quartz ranging from fine 

sand to pebble gravel and some phosphorite, mica, 

and kaolinite. The marine deposits, which underlie 

all the county, rest unconformably on the Suwannee 

in the western part of the county and on the Ocala 

Limestone in the eastern part. In the northern part 

of the county, sandy limestone of the Tampa may be 

present. 

According to Bishop the deltaic beds grade horizontally into typical marine beds and are overlain 

unconformably by surficial Pleistocene deposits. 

Bishop concluded that the Citronelle Formation 

(Cooke, 1945, p. 233) grades downward and laterally 

into the Hawthorn Formation and therefore is Miocene instead of Pliocene. In a section Bishop showed 

that the Tamiami Formation of Miocene age wedges 

out against the deltaic deposits in eastern Highlands 

County. The Hawthorn ranges in thickness from 300 

feet in the northern part of the county to about 650 

feet in the Lake Placid area in the southern part of 

the county. 

Bishop believed that a large part of Highlands 

County was above the sea at the beginning of Haw-

_ thorn time. As the sea rose and covered the county, 

shifting currents deposited phosphatic clay having 

lenses of limestone, sand, and phosphorite in a small 

area. Before the end of Hawthorn time, a finger 

of a large delta moved ·southward across the county. 

The remnant of the delta is the core of the topographic ridge in Highlands County. 

The unconsolidated sands which Bishop assigned 

to the deltaic beds of the Hawthorn are an important 

source of water for wells cased and finished with 

screens or slotted casing, at depths generally less 

than 200 feet. A 12-inch well near Avon Park, 180 

feet deep having 120 feet of slotted casing, yields 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 61 

1,800 gpm. In contrast, the limestone and sand in 

the lower part of the Hawthorn yield small quantities 

of water to wells. 

In general the chief constituents of the water from 

the Hawthorn are calcium and bicarbonate with 

hardness of less than about 75 ppm, except in the 

limestone near the bottom of the form~tion, which 

yields water similar to that in the underlying formations. Chemical analyses of samples of water reported by Bishop ( 1956, p. 53) from wells in Highlands County show that most of the samples have 

small quantities of fluoride, ranging from 0.1 to 

0.5 ppm. As the fluoride content of water in Florida 

is associated with phosphatic material in the Hawthorn and other deposits of Miocene age or younger, 

it seems that the Hawthorn yields some water to most 

of the wells. 

HILLSBOROUGH COUNTY 

As defined by Peek (1953; 1959b, p. 18) for the 

Ruskin area in the southwestern part of Hillsborough 

County, Fla., the Hawthorn includes all marine deposits of middle Eocene age. It consists· chiefly of 

gray, blue-gray, and gray-green sandy calcareous 

phosphoritic clay interbedded with thin layers of 

gray, white, and tan sandy phosphoritic limestone 

and thin beds of sand and shells. The limestone is 

silicified and dolomitic and contains some fossils. 

The thickness· of the formation ranges from less than 

10 feet in the northern part of the area to more than 

150 feet in the southern part. It is at or near the 

surface in several places in the Ruskin area. The 

top of the formation slopes to the south from about 

25 feet above sea level to about 50 feet below sea 

level. 

The Hawthorn apparently rests unconformably on 

the Tampa Limestone and is overlain unconformably 

by unconsolidated deposits, ranging in age from late 

Miocene to Recent. Thin beds of sand and limestone 

yield artesian water to some wells in the area, but 

generally weJis are drilled into the underlying limestone for large yield. Clay beds and other relatively 

impervious beds prevent or retard upward movement 

of artesian water in the Hawthorn Formation and 

the underlying limestone. The temperature of water 

from the Hawthorn (Peek, 1959b, p. 46) generally 

ranges between 74° and 76°F. 

Chemical analyses (Peek, 1959b, p. 57-58) of 

water from wells show a few samples which had a 

fluoride content ranging from 0.4 to 1.2 ppm. All 

these samples appeared to be a composite of two 

or more water-bearing formations. The samples 

containing fluoride indicate that some of the water is 

from the Hawthorn. A few of the composite samples 

had a chloride content of about 35 to 270 ppm. The 

others had smaller amounts of chloride. Calcium, 

magnesium, bicarbonate, and sulfate were the principal constituents of the samples having low chloride 

content. The hardness ranged from about 500 to as 

much as 1,000 ppm. All samples were alkaline with 

pH ranging from 7.3 to 8.1. 

INDIAN RIVER COUNTY 

Bermes (1958b, p. 15) described the Hawthorn 

Formation in Indian River County, Fla., as a thick 

section of green to brown phosphatic sandy clay 

and marl and interbedded lenses of hard sandy limestone, chert, and phosphorite pebbles. The limestone is most abundant in the middle and upper parts 

of the formation. The formation underlies the entire 

county and ranges in thickness from about 115 feet 

in the northern part of the county to about 225 feet 

in the central part. The Hawthorn unconformably 

overlies Oligocene limestones in the eastern part of 

the county and the Eocene Ocala Limestone in the 

other parts of the county. 

MANATEE COUNTY 

Peek (1958a, p. 21) described the Hawthorn in 

Manatee County, Fla., as gray, bluish-gray, and 

greenish-gray sandy calcareous clay interbedded 

with white, gray, and tan sandy limestone and thin 

beds of sand and shells. The clay and limestone 

layers contain different amounts of chert, dolomite, 

sand, and phosphorite grains and pebbles. The thickness of the Hawthorn ranges from about 150 feet in 

the northeastern part of the county to more than 

350 feet in the southern part. The sand and limestone yield water to many domestic and some irrigation wells. Clay beds and other relatively impervious beds in the Hawthorn Formation prevent 

or retard upward movement of artesian water in the 

Hawthorn and the underlying limestone. The mineral content of the water generally is less than that 

in the underlying limestone. The quality of water is 

similar to that discussed under the Hawthorn in 

Hillsborough County, except that. some of the high 

chloride water in Manatee County is more concentrated than sea water. 

MARTIN COUNTY 

The Hawthorn Formation in Martin County, Fla., 

is dark-green to white phosphatic clay containing· 

thin beds of phosphatic limestone and chert, especially in the lower part (Lichtler, 1960, p. 18). Lenses 

of phosphatic sand and shells are common in some 

· places. The formation underlies all the county and 

probably rests conformably on the Tampa Lime-
62 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

stone where present or unconformably on the Suwannee or older limestone. Its contact with the 

overlying Tamiami Formation probably. is conformable. The thickness of the Hawthorn ranges from 

350 to 550 feet. Relatively impervious beds retard 

or prevent upward movement of artesian water in 

the Hawthorn and underlying limestones. Lichtler 

reported that the formation does not yield significant 

amounts of water to wells in Martin County.· 

PINELLAS COUNTY 

The Hawthorn Formation is present in the Pinellas 

peninsula south of Clearwater, Fla. (Heath and 

. Smith, 1954, p. 15). Its composition ranges from 

gray sandstone to sandy gray clay_ containing black 

and brownish phosphate grains and angular chert 

fragments. In some places the sandstone is calcareous. The thickness of the Hawthorn ranges 

from about 50 feet in the vicinity of ·Clearwater to 

90 feet in the south end of the county. It unconformably overlies the Tampa Limestone and is overlain 

unconformably by surficial sands. In Pinellas County 

sand beds of the Hawthorn yield water to domestic 

wells. 

POLK COUNTY 

H. G. Stewart (1959, p; 23) reported that the Hawthorn in the northwestern part of Polk County, Fla., 

consists of light-cream to tan sandy phosphatic limestone interbedded with clay or silts. Locally the 

limestone is silicified. The limestone beds are generally separated by 1 to 6 feet of brown sandy gritty 

clay. A geologic section (Stewart, 1959, p. 18) shows 

the Hawthorn is absent in the northern part of the 

county. It has a thickness of about 100 feet in the 

vicinity of Lakeland. The Hawthorn unconformably 

overlies the Tampa Limestone and is unconformably 

overlain by the Bone Valley Formation. Stewart 

(1959, p. 15) listed records of solution cavities in the 

Hawthorn whose vertical dimensions ranged from 

2 to 19 feet. In most places the limestone yields sufficient water for domestic supplies. Large quantities 

of water may be obtained from solution cavities. 

Locally, artesian ·water in the Hawthorn -Formation is separated from artesian water in the underlying Tampa Limestone by a clay bed 3 to 15 feet 

thick, which was assigned to the Tampa Limestone 

by Stewart. Clay beds in the upper part of the Hawthorn or lower part of the Bone Valley Formation 

prevent or retard upward movement of its artesian 

water. East and northeast o{ Lakeland in the lowland of Saddle Creek, wells ranging .from 114 to 6 

inches in diameter and only 30 to 75 feet in depth 

yield artesian water from limestone. of the Hawthorn. The casing in the wells generally is seated in 

·the uppermost part of the limestone. The water 

level in the wells in the underlying limestone of the 

principal artesian aquifer is 5 to 15 feet below the 

level in wells in the Hawthorn of that area. In parts 

of the area the difference in water levels is not great. 

The levels appear to have been approximately the 

same before they were affected by withdrawal of 

water from wells. 

Chemical analyses of samples of water included by 

H. G. Stewart (1959, p. 43-46) show that the composition of the water from the Hawthorn Formation, 

in general, is similar to that in the underlying lime-

. stones which form the principal artesian aquifer. 

However, other analyses indicate that relatively 

small quantities of fluoride are present in water associated with phosphatic material in the Hawthorn 

and younger formations (Black and Brown, 1951, 

p. 15). The principal constituents of the water from 

the Hawthorn and the underlying limestone are calcium, magnesium, and bicarbonate. The sulfate 

ranged from 1.0 to 11 ppm, in contrast to the high 

sulfate in artesian water in the eastern and southern 

parts of Florida. 

SEMINOLE COUNTY 

Heath and Barraclough (1954, p. 14) described the 

Hawthorn in Seminole County, Fla., as beds of blue 

to gray calcareous clay, alternating with beds of 

sand and white to gray .sandy limestone con:taining 

many. grains of blac1< to cream phosphate rock and 

fragments of chert. A geologic section (Heath and 

Barraclough, 1954, p. 29) indicates that the Hawthorn is about 75 feet thick in the southwestern part 

of the country. It has been removed by erosion in the 

St. Johns River valley in the northern and eastern 

part of the county. The Hawthorn is also absent in 

some· of the sinkholes and sinkhole lakes. The Hawthorn rests unconformably on the Ocala Limestone 

and the A von Park Limestone. It is overlain unconformably by younger surficial deposits, which may 

be as much as 100 feet thick in some areas. The limestone and sand beds in the Hawthorn Formation yield 

small supplies of water to wells. Clay beds and other 

relatively impervious beds prevent or retard upward 

movement of artesian water in the underlying limestone. 

SOUTHEASTERN . FLORIDA 

Parker, Hoy, and Schroeder (in Parker and others, 

1955, p. 67, 83-85) described the Hawthorn in southeastern Florida as sandy phosphatic marl, interbedded with clay, shell marl, silt, and sand. Its maximum thickness is about· 500 feet. The formation 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 63 

includes beds of flattened weJl-worn quartzite and 

phosphate pebbles as much as half an inch in diameter. Near Clewiston on the south side of Lake Okeechobee, the zone of pebbles is 51 feet thick; its top is 

76 feet below sea level. About 63 miles south of Clewiston, the zone is 52 feet thick; its top is 214 feet below sea level. This indicates a dip of 2.2 feet per mile 

toward the south. The Hawthorn is underlain by the 

Tampa Limestone and is overlain by the Tamiami 

Formation which has a maximum thickness· of about 

150 feet and includes all upper Miocene deposits in 

southeastern Florida. 

Hawthorn Formation in Georgia 

The Hawthorn extends from Florida into Georgia 

and South Carolina. The bulk of deposits above the 

principal artesian aquifer in Georgia (fig. 25) is represented by the Hawthorn Formation. 

As described by Counts and Donsky (1959, p. 98; 

1963, p. 14) in the Savannah area, Georgia, the 

Hawthorn consists of green silt and sand interbedded 

with clay, marl, and limestone. It has a maximum 

thickness of about 300 feet in the area. The formation thickens toward the south to more than 400 feet 

and thins toward the north in South Carolina where 

the maximum is about 150 feet. 

Wait (1958a, p. 45) described the Hawthorn in 

Crisp County in southwest Georgia as pale to darkgreen phosphati~ sandy clay interbedded with sand 

and sandy limestone. It is present in the east half of 

the county where it supplies water to shallow and 

drilled wells. The Hawthorn overlies the Tampa 

where that formation is present. Elsewhere, the 

Hawthorn unconformably overlies Oligocene formations (Flint River or Suwannee) or the Ocala Limestone of Eocene age. 

TAMIAMI FORMATION 

As described by Parker and Cooke ( 1944, p. 65) in 

southeastern Florida, the Tamiami Formation was 

regarded as Pliocene in age and the equivalent of the 

Caloosahatchee Marl. It included permeable limestone, which is the principal source of ground water 

in the Miami area. However, Parker (1951, p. 821) 

and Hoy and Schroeder ( 1952, p. 283-286) assigned 

the Tamiami to late Miocene deposits in southern 

Florida having a maximum thickness of about 150 

feet. The upper part includes not more than about 

15 feet at the base of the shallow permeable limestone 

aquifer in the Miami area. The beds below this permeable limestone consist of sand, marl, and impure 

limestone containing relatively itnpervious beds similar to the underlying Hawthorn Formation. The 

Caloosahatchee Marl was retained in the Pliocene. 

In the Miami area the upper part of the Tamiami, 

as revised, is an important source of water (Parker 

and others, 1955, p. 88). That part of the limestone 

and the overlying permeable limestone of Pliocene 

and Pleistocene age contain many solution cavities 

· filled with permeable sands, forming one of the most 

productive aquifers in the area of this report. 

The permeable part of the Tamiami yields fresh 

water except in: ( 1) the coastal area where sea water has entered the aquifer, and (2) in parts of the 

Everglades where residual salt water has not been 

flushed out of the formation. The less permeable 

part of the formation, as well as the Hawthorn Formation and the underlying artesian limestones which 

constitute the principal artesian aquifer, yield water 

having a relatively high chloride content. 

Klein (1954, p. 10) reported that the Tamiami 

may be more than 125 feet thick in the Naples area 

in Collier County, Fla. The top of the formation is 

about 15 to 20 feet below sea level. The upper part is 

relatively impermeable marl below which is permeable sandy limestone containing many solution cavities filled with fresh artesian water. The limestone 

of the Tamiami Formation forms the principal shallow aquifer in Collier County, Fla. (McCoy, 1962, 

p. 13). 

DUPLIN MARL AND CHOCTAWHATCHEE MARL 

Cooke (1936, p. 117) recognized the Duplin Marl 

in South Carolina as sandy shell marl containing 

clay of late Miocene age. Later he assigned the upper 

two faunal zones (Ecphora and Cancellaria zones) 

of the Alum Bluff Group to the Duplin (1945, p. 

181). Cooke (1945, p. 168) considered these two 

zones as part of the Choctawhatchee Marl. He also 

proposed that the A rca and Y oldia zones of the Choctawhatchee be transferred to the Shoal River. With 

these transfers, he considered it inadvisable to retain the nam.e Choctawhatchee. However, Puri and 

Vernon (1959; p. 9) retained the name Choctawhatchee for the four zones mentioned. 

Cooke (1945, p. 14) indicated that the late Miocene sea in which the Duplin was deposited, covered 

all Florida, except the northern part of the panhandle and the coastal areas of Georgia and South 

Carolina. The thickness of the beds assigned to the 

Duplin at Alum Bluff, Fla., is 46 feet, but the top of 

the formation has been eroded. In Georgia the few 

exposures are only 5 to 16 feet thick. The greatest 

thickness recorded in South Carolina is 50 feet. It 

thickens to the north, reaching its maximum in 

North Carolina. The formation lies unconformably 

on older beds ranging from the Late Cretaceous 

Black Creek Formation in the Carolinas to the middle 
64 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Miocene Hawthorn. It overlies the Hawthorn in 

Georgia and east of the Apalachicola River in Florida. 

West of the Apalachicola in Florida, it overlies the 

Chipola and Shoal River Formations. Locally the 

Duplin yields small supplies of hard water to shallow 

wells. 

In the Savannah area, Georgia, Counts and Donsky (1959, p. 100; 1963, p. 31) recognized the Duplin 

only in the Savannah River valley where it is chiefly 

marl with some shells and sand. Locally it may be a 

source of small supplies of nonartesian water. The 

relatively impervious beds in the marl prevent or retard upward movement of artesian water in the underlying limestone. The water-bearing properties 

are similar to those of the Hawthorn Formation. 

PLIOCENE SERIES 

In a discussion of the geology of Florida, Cooke 

(1945, p. 197) included the following formations in 

the middle Pliocene: Alachua Formation, Bone Valley Formation, Buckingham Marl (of former usage), 

Caloosahatchee Marl, Charlton Formation, Citronelle 

Formation, and Tamiami Formation. Puri and Vernon (1959, p. 9) included the Citronelle Formation 

and the Caloosahatchee Marl in the Pleistocene Series. In the present report the Alachua and Bone 

Valley Formations, Caloosahatchee Marl, Charlton 

Formation, and Citronelle Formation are regarded 

as Pliocene. The Pliocene and younger formations 

are· less than 50 feet thick or absent in a large part of 

the region. In small areas as in central and southeastern Florida the total thickness may be more than 

150 feet (fig. 15). 

ALACHUA AND BONE VALLEY FORMATIONS 

The Alachua and Bone Valley Formations are 

present in the west-central part of the Florida peninsula. Cooke (1945, p. 199-210) described them as 

middle Pliocene. He stated that the fossil bones of 

Miocene animals attributed to the Alachua probably 

were buried in sinkholes during Miocene time. Puri 

and Vernon (1959, p. 9, 160-172) described the formations as Miocene. Vernon (1951, p. 190) believed 

that the Alachua may have accumulated throughout 

Miocene time to Pliocene. 

Pirkle (1956, p. 230) cited evidence to support his 

conclusion that the Hawthorn Formation is the immediate source of the phosphate in the hard rock deposits of the Alachua Formation a:r:1d therefore that 

the Alachua is post-Hawthorn in age-late Miocene 

or Pliocene. 

Bergendahl (1956, p. 70, 83) indicated that the 

Bone Valley Formation is late Miocene and Pliocene 

in age. Also he reported that F. S. MacNeil (written 

commun., 1954) considered the Bone Valley Formation of marine origin and equivalent stratigraphically to the unnamed sand of late Miocene that he 

described in De Soto and Hardee Counties. Altschuler and Young (1960, p. 202) regard the Bone Valley 

as Pliocene. Also Cathcart (1963a; 1963b) considered the Bone Valley as Pliocene in Hillsborough and 

Polk Counties. 

The Alachua consists chiefly of weathered, collapsed, and compacted residue of the Hawthorn Formation in place together with accumulations in sinkholes and ponds, some of which contain bones of 

Pliocene animals (Cooke, 1945, p. 200). The part of 

the formation to which the name was originally applied by Dall (1892, p. 127) consists chiefly of clay in 

sinks and ponds. Much of the formation consists of 

sand with some phosphate .. The lower part contains 

phosphate rock as plates or large boulderlike masses. 

The formation contains a varied vertebrate fauna, 

ranging from middle Miocene to Pleistocene. According to Sellards and Gunter (1913, p. 30-31), the 

Alachua is as much as 75 to 100 feet thick in Citrus 

County, Fla., though it usually is thinner. The formation extends from the northern part of Gilchrist 

County into Hernando County. In this area the 

Withlacoochee River has cut through the Alachua 

into the Ocala Limestone. The formation is present 

in a few areas in the southwestern part of Lafayette 

County, the western part of Hamilton County, and 

in Alachua and Marion Counties. 

The Alachua overlies an irregular eroded surface 

of the Ocala and older Eocene limestone, on which 

there are residual pieces of the Suwannee Limestone. 

In Gilchrist County, Puri and Vernon (1959, p. 160) 

reported that in some quarries the eroded surface of 

the Ocala Limestone has pinnacles of limestone as 

much as 25 feet in height. The clays and phosphatic 

sands deposited on such an irregular surface have 

an irregular thickness. This solution-pitted erosion 

surface probably was formed before the Hawthorn 

and Alachua were deposited. Pleistocene terrace 

sands unconformably overlie the Alachua. The Alachua Formation contains the valuable hard-rock 

phosphate deposits of Florida. Although the Alachua 

Formation probably would yield water to wells, it is 

not known to be an important aquifer. Clark, Musgrove, Menke, and Cagle (1962, p. 70) reported that 

in north-central Florida it may be a source of water 

for domestic supplies. 

The Bone Valley Formation extends from Lake 

County southward to De Soto ·and Hardee Counties, 

south of the area of the Alachua Formation. As described by Cooke (1945, p. 204-205) and Matson 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 

0 

30o -------------1-------~~=:::~~~.r~~~-P~~~~~~---P~~--~----~--~-E---f~~--'~~~~--~---C)­

G U L 

p 

27°1----J------1---- EXPLANATION 

26° 

50 

25° 

---------300---------

Isopach 

Shows thickness of Pliocene, Pleistocene, 

and Recent deposits combined; interval 

50 feet 

0 50 100 MILES 

., 

t'=l 

~ 

'Z. 

FIGURE 15.-Isopach map of Pliocene, Pleistocene, and Recent Series. (From Toulmin, 1952, fig.-8.) 

65 
66 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

(1915, p. 21) the Bone Valley consists of rounded 

pebbles of phosphate embedded in a matrix of sand or 

clay overlain by loose semi-indurated sand. The 

maximum thickness seems to be about 50 feet. Cooke 

suggested that the typical part of the Bone Valley 

Formation was deposited in a broad delta of a stream 

that flowed southward into the ocean and that some 

parts of the formation may be from the Hawthorn 

weathering in place. Locally, permeable sands of the 

Bone Valley may yield water to wells. It is the source 

of the pebble phosphate deposits in Florida. 

CALOOSAHATCHEE MARL 

The Caloosahatchee Marl of Pliocene age consists 

chiefly of sand and shells along the Caloosahatchee 

River in southern Florida (Cooke, 1945, p. 214). In 

some places the shells form most of the formation. In 

southeastern Florida, Parker, Hoy, and Schroeder 

(in Parker and others, 1955, p. 88-89) described the 

Caloosahatchee as a silty, sandy shell marl with interbedded layers and lenses of sand, silt, clay, and 

marl. In some places in the Everglades it contains 

carbonaceous zones of roots, stems, and other organic 

material. The Caloosahatchee Marl discontinuously 

underlies the Everglades and Big Cypress Swamp on 

the west side of the Everglades. It extends northward beneath Pleistocene terraces in the Kissimmee 

River valiey: From the Caloosahatchee River and 

Lake Okeechobee, where the formation is at or near 

the surface, the Caloosahatchee Marl dips south and 

southeast under the Everglades and Atlantic Coastal 

Ridge. It is absent in many places in southeastern 

Florida. In the Miami area, lenses of the formation 

are preserved in depressions in the unconformable 

contact with the underlying Tamiami Formation. 

The maximum thickness apparently is less than 50 

feet. 

Stringfield (1933a, p. 7) gives a log of a well 

(Florida Geol. Survey No. W-20) at Belle Glade, 

Fla., indicating that the Caloosahatchee is present at 

depths of 52 feet to 175 feet and has a total thickness 

of 123 feet. If current correlations are used, however, the lower part probably should be assigned to 

the Tamiami or Hawthorn of Miocene age. 

Puri and Vernon (1959, p. 178) included the Caloosahatchee in the Pleistocene Series after DuBar 

(1958, p. 129-155) who assigned the formation to 

the Pleistocene on the basis of ( 1) a late Pleistocene 

horse in the upper shell bed, (2) stratigraphic details, and (3) molluscan evolution. In his detailed 

study, DuBar divided the Caloosahatchee into three 

members. Two of these members are subdivided into 

several units. 

Permeable sand and shell beds of the Caloosahatchee yield water to wells in the Lake Okeechobee area 

(Stringfield, 1933a, p. 17), but some of the water is 

salty. In some areas on the south side of Lake Okeechobee all the ground water, including that in the 

shallow formations, has a relatively high chloride 

content. The investigation in 1933 caused the writer 

to conclude that the salt water in the shallow formations is the remnant of sea water which covered the 

area during Pleistocene ( Pamlico) time when the 

sea stood about 25 feet above its present level. 

If the Caloosahatchee is Pleistocene as reported by 

DuBar (1958), the salt water could be sea water in 

which the formation was deposited. However, the 

absence of salt water in the Caloosahatchee more 

than 25 feet above sea level suggests that the Caloosahatchee was deposited before the Pleistocene sea 

stood at the 25-foot level. 

CHARLTON FORMATION 

As described by Cooke (1945, p. 227), the Charlton 

Formation consists chiefly of light-colored calcareous clay and· impure limestone. Cooke and Mossom 

(1929, p. 129) reported a thickness of 15 feet for the 

Charlton and suggested that the maximum is about 

20 feet. Cole (1944, p. 22-23) recommended that 

the name Charlton be discarded in favor of Caloosahatchee because the two formations are contemporaneous. He assigned to the Caloosahatchee 60 feet 

of the material penetrated in a well 4 miles northwest of Hilliard. Cooke ( 1945, p. 228) stated that 

the upper part of that unit consists of gray-green 

sandy clay like the Charlton but that the lower 40 

feet is loosely consolidated sandstone with shell fragments similar to the Caloosahatchee. S. M. Herrick, 

(written commun., July 1962) doubted the presence 

of the Charlton in Georgia. He suggested that the 

deposits regarded as the Charlton may represent the 

Duplin Marl. 

According to Cooke (1945, p. 228) exposures of 

the Charlton Formation in Florida are confined to the 

bluffs along St. Marys River in Nassau County above 

Orange Bluff. Eastward beyond the river it probably merges into the Caloosahatchee Marl. There are 

a few exposures near Satilla River in Charlton and 

Brantley Counties, Ga. Probably small quantities of 

water can be obtained from the Charlton Formation. 

However, information is not available on its properties as an aquifer. 

CITRONELLE FORMATION 

The name Citronelle Formation was applied by 

Matson (1916, p. 168) to sediments of Pliocene age, 

chiefly nonmarine, that occur near the seaward mar-
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 67 

gin of the Gulf Coastal Plain, extending from western Florida to Texas. The formation as much as 400 

feet thick consists of yellow and red sands and clays, 

locally gray where unweathered. Much of the gravel 

is near the landward margin and in the valleys of the 

principal streams. The Citronelle Formation in the 

area of the present report consists chiefly of sand, 

gravel, and clay. Much of the sand is red or orange, 

and the clay is stained with iron where it is mixed 

with the sand and gravel. It is underlain unconformably by older formations and is overlain unconformably by Pleistocene sands. It occurs as a discontinuous blanket paralleling the Fall Line across 

southern Alabama, northern Florida, and Georgia 

into South Carolina. It was mapped by Cooke (1945, 

p. 230) in the central ridge section in the Florida 

peninsula where it extends from Clay County to 

Highlands County. 

Its thickness is as much as 140 feet in Escambia 

County, Ala. (Cagle and Newton, 1963, p. 37). In 

Escambia and Santa Ros'a Counties, Fla. (adjacent 

to Escambia County, Ala:), Marsh (1962a, p. D61) 

reported that the formation probably is as much as 

800 feet thick. The thickness may be more than 250 

feet in southern Alabama according to Matson (1916, 

p. 178). In his geologic map and geologic sections of 

the formation in the southern part of the Atlantic 

Coastal Plain, Doering (1960, p. 182-200) ind~cated 

a maximum thicl\ness of about 100 feet. The sections 

indicate that in some places in the .Coastal Plain the 

Citronelle is overlain by Pleistocene terraces, showing that the Citronelle is older than the terraces. 

This, together with the fact that according to Matson the formation contains Pliocene flora, suggests 

that the Citronelle is Pliocene. However, Doering 

(1960, p. 199) believed that this ~vidence does not 

preclude a pre-Nebraskan Pleistocene age. After 

Roy (1939, p. 1553-1559) and otper investigators 

concluded that the flora found at the type locality of 

the Citronelle near Citronelle, Ala., was not from 

the Citronelle, Stringfield and LaMoreaux (1957, p. 

7 42-7 46) called attention to the locality near Red 

Bluff, Ala., where the flora studied by Berry (1916) is 

unquestionably from the Citronelle. 

Miss Estella Leopold,. U.S. Geological Survey, reported (written commun., June 14, 1960) that th~ 

pollen from Red Bluff is similar to that in the Pascagoula Formation of Miocene age. However, the pollen in western Florida is young~r than Pliocene. As 

the Citronelle rests unconformably on the. Miocene 

and is overl.ain unconformably by the Pleistocene, 

the Miocene pollen in the Citronelle in Alabama 

could 6·e :firom reworked . Miocene materiaL,·.· The 

Pleistocene pollen in the Citronelle in Florida could 

be from Pleistocene deposits that were reworked 

and mixed with Citronelle deposits. 

In Highlands County, Fla., Bishop (1956, p. 26) 

concluded that the Citronelle red sand and gravel 

mapped by Cooke (1945, p. 233) as Pliocene, grade 

downward and laterally into the Hawthorn Formation of Miocene age. Clark, Musgrove, Menke, and 

Cagle ( 1964, p. 25) described the deposits in Clay 

and Bradford Counties as unnamed coarse clastics 

having a maximum thickness of 90 feet. Goodell 

and Yon (1960, p. 99) considered the sands and 

·gravels as genetically related to the uppermost beds 

of. .. similar lithology in the western panhandle of 

Florida and therefore probably of post-Miocene age. 

Pirkie (1960) and Pirkle, Yoho, and Allen (1964) 

have reported that the Citronelle in the Florida 

peninsula overlies shell beds of late Miocene age. 

They concluded that the Citronelle is post-Hawthorn. 

The fact that the solution-pitted Hawthorn underlies 

the Citronelle indicates that the two formations 

are separated by an unconformity formed under 

subaerial erosion. As suggested by Pirkle, Yoho, 

Allen, and Edgar (1963, p. 130) and Bishop (1956), 

the Citronelle in the Florida peninsula is believed to 

be :alluvial and other terrestrial materials deposited 

as a prograding delta built southward into Florida. 

However, there is not agreement on the age of the 

delta. Bishop reported the formation as part of the· 

Hawthorn, but Pirkle reported it as post-Hawthorn. 

In Texas, Tipsword (1962, p. 22) correlated the Citronelle with the Goliad. Wilson (1962, p. 34&) . 

stated that the Goliad is Pliocene; Judging from 

available information, the writer finds insufficient 

evidence to justify assigning the Citronelle ·to the 

Pleistocene or Miocene, and in the present report it 

is therefore regarded as Pliocene, possibly contemporaneous with the marine Pliocene deposits. · 

The sand and gravel in some parts of the Citronelle are very permeable and will yield water to 

wells where·the permeable parts of the formation are 

below the water table. It is a very productive aquifer 

in many parts of the Gulf Coastal Plain. The water . 

has a low mineral content but in some places contains some iron. 

QUATERNARY SYSTEM 

PLEISTOCENE AND RECENT SERIES · · ~ 

·cooke (1945, p. 197-312): includ'ed the follo~ing in ··~ 

the Pleistocene Series in Florida: Fort Thompson ·· 

Formation, Miami Oolite, Key Largo Limestone, ··' 

Anastasia Formation, Lake Flirt Marl, ,and the sands 

that underlie seven marine terraces. · 
68 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

During the Pleistocene Epoch, the Coastal Plain 

remained stable relative to the continent, but the 

level of the sea repeatedly rose and fell in response 

to the alternate withdrawal from and return to the 

sea of large quantities of water, which formed the 

continental ice caps that gave the name Great Ice 

Age to··that epoch (Cooke, p. 245). The accumulation and melting of the continental ice caps alone 

would account for an oscillation of sea level of about 

200 or 300 feet. In addition, as suggested by Cooke, 

increases in the capacity of the ocean basins by a 

post-Pliocene sinking of the bed of the ocean in the 

North Atlantic, in the Indo-Pacific region, in the 

region off the coast of California, or at some other 

unstable part of the world would increase the 

capacity of the ocean and cause a worldwide lowering of sea level even though large parts of the 

continent remained stationary. 

During the Pleistocene, several advances and retreats of continental ice sheets took place. The sea 

stood at different levels that corresponded to the 

advances and retreats of the glaciers. Rivers cut 

and scoured deeper channels during the retreats of 

the sea and deposited terrace materials along the 

sides of streams during the advances of the sea. 

Cooke (1939, p. 34) postulated the fluctuations of 

sea level as follows : an intermittent drop from 270 

feet above the present to 230 or 300 feet below ; a 

-·rise of 1 (:)0 feet ·above, and an intermittent fall to 

60 feet below ; an intermittent rise to 25 feet above, 

and a drop to an undetermined low; and a rise to 

the present level. Later this postulate was modified 

as shown in his revised table of oscillation of sea 

level in the following section on "Marine terraces." 

Cooke's illustrations of the Pleistocene shorelines 

are shown in figures 16, 17, 18, 19, and 20. According to Cooke, the major stands of low sea level correspond to the Nebraskan, Kansan, Illinoian, and Wisconsin Gl;:~.ciations. 

The development of the surface and subsurface 

features of southern Florida was influenced by the 

relations of land and sea. During early Pliocene 

time, southern and eastern Florida were submerged. 

During late Pliocene time much of the Floridian 

Plateau emerged and was eroded. During each major 

stage of low sea level, in Pleistocene time the shoreline lay offshore from its present location, and subaerial erosion and subterranean solution became active. Fresh-water lakes and marshes occupied the 

Lake Okeechobee-Everglades depression. In Florida 

the major stages of low sea level are indicated by 

erosion surfaces, solution holes, soil zones, and freshwater limestones and marl. 

MARINE TERRACES 

The marine terrace formations, consisting chiefly 

of sand, were named by Cooke ( 1945, p. 248) after 

the shorelines. The highest terrace is the oldest ; the 

lowest is the youngest. Detailed maps of the terraces in local areas are given in many of the county 

reports on Florida. A report by Bermes, Leve, 

and Tarver (1963) includes a map showing the distribution of terraces in Flagler, Putnam, and St. 

Johns Counties, Fla. 

Cooke's latest interpretation (written commun., 

1963), shown in the following table, is a revision of 

that given in previous reports. 

Present Quaternary 

altitude geologieMarine of shore- climate terrace line elassifi- Oscillations of sea level 

(feet) cation 

Nebraskan Emergence caused by the aeeu- mulation of continental ice. 

Hazlehurst 270 Afton ian Submergence to a height of 270 

ft a.t. (above present tide 

level) caused by the melting 

of continental ice. 

Kansan Emergence caused by the aeeu- mulation of continental ice, 

permitting the formation of 

sinks in rock now standing 

150 ft a.t. 

Coharie 215 Yarmouth Submergence to a height of 215 

Sunderland 170 ft a.t. caused by the melting 

Okefenokee 150 of continental ice, followed by 

Wicomico 100 intermittent emergence of at Penholoway 70 least 170 ft caused by downTalbot 42 warping of oceanic basins. 

TIIinoian Emergence caused by the aeeu- mulation of continental· ice. 

Pamlieo 25 Sangamon Submergence to a height of 25 

ft a.t. caused by the melting 

of continental ice. 

Early Emergence caused by the aeeu- Wisconsin mulation of continental ice. 

Silver Bluff 6 Middle Submergence to a height of 6 ft 

Wisconsin a.t. probably caused by the 

partial melting of the Wiseonsin ice sheet. 

Late Emergence caused by the aeeu- Wisconsin mulation of continental ice. 

Recent 0 Submergence to the present sea level probably caused by the 

melting of continental ice. 

As described by Cooke (1945, p. 248--312), the 

shoreline and terraces may be divided into groups, 

three of which formed during the three interglaciations (Afton ian, Yarmouth, and Sangamon) . Later 

Cooke (written commun., 1963) revised the groups 

as shown in table above. The first group in his 

revised table consists of the Hazlehurst, the highest 

and oldest of the Pleistocene shorelines, formed at 

an elevation of about 270 feet during the Aftonian 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 69 

..,.,,,------

--------\-----------7..'' I '-

\ \ I \ 

\ I ' "\ \ -~ I 

\ 

50 0 

FIGURE 16.-Early Pleistocene shorelines in the Southeastern 

States, much generalized and in part conjectural. (After 

Cooke, 1939, fig. 12.) 

Interglaciation after the Nebraskan Glaciation. The 

name Hazlehurst was proposed by Cooke (in 

LaForge and others, 1925, p. 29). He rejected the 

name in favor of Brandywine but later restored the 

name Hazlehurst. The second group consists of the 

Coharie, Sunderland, Okefenokee, Wicomico, Penholoway, and Talbot terraces at altitudes from about 

215 to 42 feet, as shown in the table. These terraces 

formed in the Yarmouth Interglaciation after the 

Kansan Glaciation. Cooke included the Okefenokee 

shoreline at an altitude of about 150 feet above sea 

level. The name for this shoreline was revived by 

MacNeil (1950, p. 101). The third group includes 

the Pamlico, formed during the Sangamon Interglaciation after the Illinoian Glaciation. The fourth 

group includes the Silver Bluff, apparently formed 

during a recession in middle Wisconsin time. From 

studies in the Miami area, Florida, Parker and Cooke 

(1944, p. 22) recognized and named the Silver 

Bluff terrace, about 6 feet above present sea level. 

A terrace at about that altitude is present in other 

areas along the Atlantic and Gulf coasts. Cooke 

(1954, p. 200-202) recognized the terrace in Maryland and Virginia. 

MacNeil (1950, p. 104-105, pl. 19) showed _the 

Silver Bluff terrace along the coast of Florida and 

Georgia and indicated that the toe of the scarp is 

about 6 or 8 feet above sea level. Parker (in Parker 

and others, 1955, p. 146-147) described the Silver 

Bluff terrace and concluded that it was formed during Recent time in the interval known as climatic 

optimum, which is believed to have occurred about 

5,000 B.C. when the sea rose to 5 and perhaps 8 

feet above its present level (Brooks, 1949, p. 364). 

Parker, Hoy, and Schroeder (in Parker and others, 

1955, p. 125) estimated that, before returning to the 

present level, the sea stood at the higher elevation 

for 2,000 to 3,000 years-long enough to cut the 

Silver Bluff terrace and to fill the discharge channels 

..,.,--------~--.. 

--------\-----------(,- ', ___ ---,,, 

I '-

\ \ 

\ \ \ ',"\ 

\ -\ 

\ '"\ I 

\ 

', 

( 

I 

I 

\ 

50 0 50 MILES 

.......... _._. _.__, .L..J' '---..J' 

FIGURE 17.-Shoreline of the Wicomico sea in the Southeastern States. (After Cooke, 1939, fig. 13.) 
70 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Qc. 29° 0 

<~ " 0 

\ t'l 

> ~ J oz·· 

' 28° ~ \ '¢. \ 0 

0 \ 27° 

\ 

I 

I 

26° 

I 

I 50 0 50 MILES _)f 

- J 25° 

.. · .;' 

.... .,. . 

FIGURE 18.-Shoreline of the Penholoway sea in the Southeastern States. (After Cooke, 1939, fig. 14.) 

with sand through the Atlantic Coastal Ridge as 

far south as Miami. Parker, Hoy, and Schroeder 

(in Parker and others, 1955, p. 109) reported that 

the peat and muck, as much as 8 to 10 feet thick 

near Lake Okeechobee in the Everglades, formed 

after the high level of the sea during the climatic 

optimum. He also reported that the age of three 

samples of peat, as determined by the carbon-14 

method, ran.ged from 3800±200 to 5050±200 

years. Subsequently, however, Parker (written 

commun., Jan. 21, 1963) concluded that the Silver 

Bluff terrace is late Pleistocene. Also Scholl (1963, 

p. 145) reported evidence that during the last 5,000 

years sea level never rose above its present position. 

When the Hazlehurst shoreline was at 270 feet · 

above the present sea level, the Pleistocene sea 

covered a large part of the Coastal Plain in Georgia 

· and South Carolina and the northern parts of west-· 

ern Florida. The Hazlehurst sea advanced from a 

lower level over the Citronelle :and older formations. 

The Coharie shoreline apparently was formed in 

Yarmouth time when the sea rose from an undetermined lower level to a height of 215 feet above 

its present level (Cooke, 1945, p. 277). The Coharie 

deposits consist chiefly of sand and appear to have 

a maximum thickness of 50 feet in Florida west of 

the Apalachicola River, where there was an abundant source of sediments brought down to the sea 

by rivers. Later in the Yarmouth Interglaciation, 

the Sunderland shoreline was formed when the sea 

stood at about 170 feet above the present level. The 

Okefenokee shoreline was formed when the sea was 

about 140 to 150 feet above its present level. The 

Wicomico, Penholoway, and Talbot shorelines and 

terraces formed when the sea stood 100, 70, and 42 

feet, respectively, above the present level, before the 

sea withdrew to a low stand during the Illinoian 

Glaciation. In the Sangamon Interglaciation after 

the Illinoian Glaciation, the sea rose to a height of 

25 feet above its present level, formed the Pamlico 

_,,-------~,.., 

--------,-----------7'• I 

'. ' \ '-\ 

I \ 

\ 

I 

I 

\ 

I 

I 

\ \, ( ' {,l -~ f '" 

: ( 

\ I 

: ) 

~· ~· f ---t------f\31. 84. 83° 8 1 1,7----4---~~~G_!_:'._~ \ 

50 . 0 50MILES LJI •_LI ..LI .L.J' !1-___JI 

FIGURE 19.-Shoreline of the Talbot sea in the Southeastern 

'· t States. (After Cooke, 1939, fig. 15.) .. 
GEOLOGIC FORMATIONS AND THEIR WATER-BEARING PROPERTIES 71 

~-------~.-. 

____ ~/ ' , '------,, --------~-------- ,I .... ~ ,_ -,, 

\ 

I 

I 

\ 

\ 

' ' \ 

I 

I 

\ 

I 

( 

I 

I 

) 

50 0 It I I I I 50 MILES 

I 

\ 

'""" '· 

FIGURE 20.-Shoreline of the Pamlico sea in the Southeastern States. (After Cooke, 1939, fig. 16.) 

shoreline, and then fell below its present level in 

early Wisconsin time. The se~ rose to about 6 feet 

above the present level in middle Wisconsin time, 

then fell below its present level, and then rose in the 

]ate Wisconsin to its present level. 

Flint (1940, p. 757-787) reviewed the reports giving results of investigations on the Atlantic Coastal 

Plain and expressed doubt about the marine origin 

of terraces that have no seaward-facing scarps. He 

expressed the opinion that only two scarps had been 

proven to be marine in the central Atlantic region 

but that there was a possible third and higher scarp 

in Georgia and Florida. Cooke (1941) called attention to the fact that seaward-facing scarps are absent from some coastlines, one of which is the present shoreline of the Atlantic coast. 

The chronology and nomenclature as given in the 

table by Cooke are used in this report. The Pleistocene terrace formations are described by Cooke 

(1936, 1937, 1943, 1945) in Florida, Georgia, and 

South Carolina. However, in the present report, the 

formations are not differentiated. They consist 

chiefly of sands and clays having a. total maximum 

thickness of not more than 100 feet. Locally, the 

thickness may be greater where the deposits fill sinkholes or stream channels. Surficial sands of Pleistocene and Recent age are present throughout most of 

the area and are a common source of water for domestic supply. One of the largest supplies obtained 

from these sands is the public supply of Pensacola, 

Fla. The water generally has a low mineral content, 

except in some places along the coast where it is 

exposed to salt water. 

Ewing, Richards, Fray, and Craig (1962, p. 148) 

suggested that the maximum lowering of the Pleistocene sea in Wisconsin time was possibly as much as 

450 feet below its present level. According to Donn 

and others (1962, p. 206-214), the lowering of sea 

level during Illinoian time was greater than that 

during Wisconsin time. In discussing the age of the 

fauna and the age as determined by carbon-14 tests 

on fossil shells from the Continental Shelf off Argentina, Richards (1963, p. 145) stated that it is 

mo.:te than probable that some warping or subsidence 

ha;s · taken place during and since Wisconsin time, 

thus accounting for the greater depth of a sample 

from 86 fathoms with a carbon-14 date of 18,700+ 

500 years before present time. However, Fray and 

Ewing (1963, p. 113) believed that the uniformity 

of the depth of the upper shell layer in cores in the 

same depth of water suggests that there has been 

little, if any, warping of the Argentine Continental 

Shelf since late Wisconsin time. 

Sinkhole topography in the Flint River valley in 

Georgia, at altitudes of as much as 170 feet above 

sea level, shows evidence of having been submerged 

by a high stand of the Pleistocene sea after a lower 

stand during which the sinkholes formed. The deep 

buried channel of the Apalachicola River with its 

terraces (Hendry and Yon, 1958, p. 12-20) also 

indicates that the Pleistocene sea rose to a high level 

after a lower stand. Correlation of altitudes of the 

river terraces with older marine terraces indicates 

'that the low stand of the sea during which the 

channel was cut was pre-Wisconsin. 

ANASTASIA FORMATION 

The Fort Thompson Formation, Miami Oolite, 

Key Largo Limestone, Anastasia Formation, and 

Lake Flint Marl are present in southeastern Florida. 

The Anastasia Formation consists of coquina, shells, 

sand, sandy limestone, and calcareous sandstone. 

As described by Parker, Hoy, and Schroeder (in 

Parker and others, 1955, p. 100-102) and Cooke 
72 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

( 1945, p. 266) , the Anastasia extends along the east 

coast from Anastasia Island, St. Johns County, to 

the south boundary of Broward County where it 

merges with the Miami Oolite. The formation extends westward into the Lake Okeechobee-Everglades depression, where it forms the marine members of the Fort Thompson Formation. Klein (1954, 

p. 12) reported that the Anastasia is composed of 

light-gray sandy limestone and shelly sandy marl in 

the Naples area in Collier County. Like the Miami 

Oolite, it is thickest under a ridge bordering the 

Atlantic coast and thins to the west. The maximum thickness may exceed 100 feet. Along the Atlantic Coastal Ridge, it yields water to many wells, 

and in some parts of the ridge, as in Brevard County, 

it is a principal source of fresh water for wells. The 

Anastasia is the most important component of the 

shallow aquifer in the Pompano Beach area, Broward County (Tarver, 1964, p. 9). Parker reported 

that the Anastasia Formation yields potable water 

to wells in southern Florida. From southern Palm 

Beach to central St. Lucie County, it contains a considerable amount of swamp deposits, which yield 

only small quantities of water of poor quality. 

MIAMI OOLITE 

After its combination with the Anastasia Formation in Broward County, the Miami Oolite extends 

southward beyond Florida City. Tarver (1964, p. 9) 

reported that the oolite overlies the Anastasia Formation in northeastern Broward County. The Miami Oolite forms the floor of the Bay of Florida and 

reappears above sea level in the Florida Keys from 

Big Pine Key to Key West. The maximum thickness 

is under the Atlantic Coastal Ridge where it may be 

as much as 40 feet. The bottom of the formation is 

seldom more than 20 feet below sea level. It becomes 

thin in the Everglades and disappears at the east 

edge of the Big Cypress Swamp on the west edge of 

the Everglades, as described by Parker, Hoy, and 

Schroeder (in Parker and others, 1955, p. 102) and 

Cooke (1945, p. 256). The typical Miami Oolite is a 

soft white oolitic crossbedded to massive limestone 

containing as much as 95 percent calcium carbonate. Many vertical and horizontal solution channels 

are filled with fine to medium quartz sand (fig. 21). 

It yields large quantities of water to wells and 

forms the upper part of the shallow aquifer, the 

principal source for the Miami area and other parts 

of southeastern Florida. 

FORT THOMPSON F O RMATI ON 

brackish-water marls, limestones, shell beds, and 

sand at the type locality near LaBelle on the Caloosahatchee River (Parker and others, 1955, p. 90). 

Parker, Hoy, and Schroeder reported that the Fort 

Thompson underlies the Everglades and extends to 

the coast. Its thickness averages less than 10 feet in 

the Lake Okeechobee area; but in the Miami area 

the thickness averages about 80 feet, and the maximum may be about 200 feet. Parker, Hoy, and 

Schroeder showed that the formation merges with 

the Anastasia Formation at Fort Lauderdale. In the 

Miami area, the Fort Thompson consists chiefly of 

sandy limestone and calcareous sandstone containing 

beds and pockets of quartz sand and thin beds of 

dense hard fresh-water limestone. Like the overlying Miami Oolite, the Fort Thompson has many vertical and horizontal solution channels, most of which 

are filled with permeable sands. The Fort Thompson 

is one of the principal sources of fresh ground water 

in southeastern Florida. 

KEY LARGO LIMESTONE 

The Key Largo Limestone is chiefly a fossil coral 

reef. It interfingers with the Miami Oolite and the 

Fort Thompson Formation in the Miami area and 

underlies the Florida Keys. As described by Parker, 

Hoy, and Schroeder (in Parker and others, 1955, p. 

99), the reef, about 90 miles long, has a maximum 

width of about 3 miles at sea level. It is known to be 

at least 60 feet thick. As reported by Cooke (1945, 

p. 263), the reef grew along the outer edge of the 

Floridian Plateau, contemporaneous with the Miami 

Oolite. The Key Largo Limestone is very permeable, 

but sea water fills the formation below the water 

table, except locally where there may be sufficient 

The Fort Thompson Formation consists of only FIGURE 21.-Natural wells or solution tubes in t he Miami 

about 6 feet of alternating fresh-water, marine, and Oolite near Miami, F la. 
GEOLOGIC STRUCTURE 73 

fresh-water recharge to provide limited supplies of 

potable water. 

LAKE FLIRT MARL 

The Lake Flirt Marl consists chiefly of gray calcareous mud containing fresh-water shells. It is 

present in many parts of the Everglades. The maximum thickness of about 6 feet is in the basin of Lake 

Flirt on the Caloosahatchee River east of LaBelle. 

It generally underlies the peaty accumulations in the 

Everglades and overlies the Pamlico Sand, Fort 

Thompson Formation, and the Miami Oolite (Parker 

and others, 1955, p. 108). The marl is interbedded 

with peat or muck, suggesting that it may have been 

deposited in Recent time. The marl is relatively impervious and is not an aquifer. However, it prevents 

or retards vertical movement of the water. 

GEOLOGIC STRUCTURE 

MAJOR FEATURES 

The regional structure is that of a wedge of sediments thickening to the southeast and south. These 

sediments have a gentle homoclinal dip except where 

modified by special structural conditions. Major 

structural features shown on figure 22 are: (1) Peninsular arch, {2) Ocala uplift, (3) Chattahoochee 

anticline, ( 4) Apalachicola basin, which extends into 

Georgia and forms the southwestern Georgia basin, 

( 5) southern Florida basin, and ( 6) the southeastern 

Georgia basin. 

The peninsular arch extending about 275 miles 

from southern Georgia to the vicinity of Lake Okeechobee, forms the axis of the north two-thirds of the 

Florida peninsula (Applin, 1951, p. 3-5). Its crest 

of Paleozoic sedimentary rocks lies about 60 miles 

west of Jacksonville (Toulmin, 1955, p. 210). The 

crest was above sea level in . Early Cretaceous and 

part of Late Cretaceous time. Sediments of Austin 

age (Late Cretaceous) were deposited across the 

crest of the arch. However, throughout the remainder of the Late Cretaceous and during the early Tertiary, sedimentation in Florida was interrupted only 

by short periods of land emergence. During Miocene 

time the northern part of the peninsula was uplifted, 

causing the complete removal of Oligocene rocks 

from a broad area and the irregular erosion of the 

upper part of the Eocene Series. 

Reports by Vernon (1951, p. 53) and Applin 

(1951, p. 3-5) show that the axis of the Tertiary 

structure, the Ocala uplift, does not coincide with 

the peninsular arch. Vernon believed that there is 

no close structural relationship between them. How-

, ever, Meyer (1962, p. 22) suggested that in Columbia 

County the Ocala uplift is probably related to movements of the peninsular arch. Both structures have a 

parallel trend, but the crest of the Ocala uplift in 

Levy and Citrus Counties is about 60-70 miles southwest of the peninsular arch. In one of the earliest 

discussions of the structure of ·Florida, Johnson 

( 1888, p. 230-236) described the peninsula as a 

broad anticline or arch with the apex in the vicinity 

of Gainesville. The crest of the arch was located by 

the sinkhole topography, which was thought to indicate the presence of Eocene limestone less than 100 

feet below the surface. The dip of the limestone away 

from the central part of the peninsula is indicated 

by the presence of younger formations at the surface 

and by the attitude of Eocene limestones in wells at 

different points. 

In a discussion of the structure, Matson (Matson 

and Sanford, 1913, p. 163-166) referred to a paper 

·by Johnson (1888, p. 230-236) and recognized two 

distinct axes of the uplift which extends northsouth in the Florida peninsula. He also recognized 

the uplift west of the Apalachicola River which 

Veatch and Stephenson (1911, p. 63) described as 

the Chattahoochee anticline. In reviewing the literature on the Chattahoochee anticline, Hendry and 

Yon (1958, p. 20, 21) reported that the structure 

has been called the Decatur arch. 

This anticline extends along the Alabama-Georgia 

boundary into Florida. Like the peninsular arch, it 

was buried beneath a considerable thickness of 

Cretaceous sediments before the beginning of Tertiary time. East of the anticline is the southwestern 

Georgia basin, which forms the northern part of the 

Apalachicola basin. Herrick and Wait (in Thomson 

and others, 1956, p. 287) referred to part of the 

basin as the Tallahassee syncline. 

In relation to oil possibilities the structure in the 

Tertiary rocks of the Florida peninsula was described by 0. B. Hopkins (U.S. Geol. Survey, press 

release, Apr. 19, 1920) as an anticlinal fold which 

trends south-southeast and forms the axis of the 

Florida peninsula, which has two high areas. He 

called the highest part of the structure the Ocala 

uplift in eastern Levy County. The other high area 

in the vicinity of Live Oak was called the Live Oak 

uplift. Subsequent investigations have shown that 

the Ocala uplift centers around outcrops of Ocala 

Limestone (upper Eocene) and A von Park Limestone (middle Eocene) in Citrus, Dixie, and Levy 

Counties on the west coast of Florida. On some 

parts of the crest; the Ocala Limestone is as much 

as 120 feet above sea level. The Ocala and A von 
74 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

G U L 

p 

NORTH GULF COAST O -5'~ '< 

SEDIMENTARY PROVINCE ..t0 <)/. 01> 

w ~~ r---------r---------~--------~----~1-~~ ---------~--~~~ 

-1~~A. )- ·v/ 

~~~~<1 '<""" C'~ 

27"r------r-------+-------+-------+-------1--

50 0 50 100 MILES 

25"~-----t-------,~~------~--------r----------,------~ 

FIGURE 22.-Major structural features and sedimentary provinces in southeastern Alabama, Florida, and southeastern 

Georgia. (After Toulmin, 1955, fig. 2.) 
GEOLOGIC STRUCTURE 75 

Park dip under the younger formations exposed on 

the flanks of the fold. 

The general features of the Tertiary structure in 

Florida are shown on a contour map· by Mossom 

( 1926, p. 256) representing the top of the Ocala 

Limestone. The map shows two distinct structural 

uplifts : one is the Ocala area and the other the 

Marianna-Chipley area. Mossom includes the Live 

Oak area as part of the Ocala uplift. The MariannaChipley area is part of the Chattahoochee anticline. 

The map also shows an arch extending from the 

east flank of the Ocala dome to an area on the east 

coast between Melbourne and St. Augustine where 

Mossom (1926, p. 233) reported Eocene limestone 

at a depth between about 100 and 200 feet below 

sea level. At New Smyrna the limestone is at a depth 

of 105 feet below the land surface, about 90 feet 

below sea level. Some investigators have referred to 

the structure as the New Smyrna arch. The lime-:-

stone dips to the north and is about 500 feet below 

sea level at Jacksonville. It also dips to the south 

where it is about 1000 feet below sea level in 

southern Florida. 

L. C. Johnson ( 1888, p. 230-236) recognized the 

New Smyrna arch and the Ocala uplift. With that 

information and an estimate of the dip on the northeast flank of the Ocala uplift, about 1885 he correctly estimated the depth to the top of the Ocala 

Limestone, the artesian aquifer at Jacksonville, 

Fla. Although the top of the Ocala Limestone is 

an eroded surface, it shows the general structural 

features. 

Later studies of the stratigraphy and paleontology enabled the investigators to subdivide the 

Ocala Limestone and learn other details of the 

geology. A structure contour map by Vernon (1951, 

pl. 2) based on some of these studies shows additional details of the structure. Vernon (1951, p. 53) 

stated that the structural deformation of the Ocala 

uplift probably began during the early Miocene. Applin and Applin (1965, p. 15) described the uplift 

as a faulted and folded structure in the Eocene a.nd 

younger rocks on the southwest flank of the older 

and dominant peninsular arch. 

Vernon's structure map of the Ocala uplift shows 

that the north side is composed of two well-defined shallow folds which converge southward in 

Levy and Citrus Counties, Fla., where they are sep-

~rated by only a few miles and their crests are extensively fractured and faulted. In Citrus County the 

structure includes the Bronson graben (Vernon, 1951, 

fig. 15) with small displacement. Yon and Puri 

(1962, p. 678) extended the structure northward in 

Gilchrist County. However, the writer believes that 

the topographic feature, Waacasassa Flats, in Gilchrist County is due to surface and underground 

solution of the limestone prior to the deposition of 

the Alachua Formation. On the southeast flank of 

the uplift in Lake, Orange, Seminole, and Osceola 

Counties, the map shows the Kissimmee faulted 

flexure, a wedge-shaped block approximately 90 

miles long, 54 miles wide on the northwest border, 

and 17 miles wide on the southeast margin. This 

faulted flexure is the northwest boundary of a 

downfaulted triangular block which Vernon named 

the Osceola low, in Osceola County. The apex· of 

the triangle formed by the fault on the northwest 

and east side of the block is in the northeast corner 

of Osceola County. The downward displacement of 

the block is about 300 feet at the apex with no 

movement on the southwest side. 

East of the Kissimmee faulted structure in Seminole and Volusia Counties is a structure that Vernon 

named the Sanford high, which apparently is part 

of the New Smyrna arch. 

The southern Florida basin (Pressler, 1947, p. 

18-56, fig. 1) is the regional structure that extends 

from the south side of the Ocala uplift to the Straits 

of Florida just south of the Florida Keys. The 

southeastern Georgia basin is on the northeast flank 

of the uplift. 

On some parts of the crest of the Ocala uplift, the 

principal artesian aquifer is as much as 120 feet 

above sea level. The aquifer and overlying formations on the flanks of the uplift dip at low angles 

away from the crest of the fold. The formati'ons 

crop out on the floor of the Atlantic Ocean and the 

Gulf of Mexico some distance offshore, and some of 

them probably crop out on the edge of the Floridian 

Plateau which, as described by Cooke and Mossom 

(1929, p. 39) and Vaughan (1910, p. 99-185), is 

a peninsula that separates the deep water of the 

Gulf of Mexico from the deep water of the Atlantic 

Ocean. The plateau includes not only the State of 

Florida but also the parts of the adjacent ocean 

floor less than 50 fathoms ( 300 ft.) below sea level. 

The outline of the· plateau is shown in figure 4. 

Beyond a depth of 50 fathoms, the ocean floor slopes 

abruptly to depths of more than 400 fathoms in the 

Straits of Florida and the Atlantic Ocean and more 

than 2,000 fathoms in the Gulf of Mexico. The edge 

of the plateau in the gulf lies somewhat less than 

75 miles to more than 100 miles west of the present 

coast of the Florida peninsula. Along the southern 

and eastern coasts of the peninsula from Key West 

to Palm Beach, the edge of the plateau is not more 
76 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

than 10 miles off the coast. In much of the area 

from Miami to Palm Beach, the plateau is within a 

few miles of the coast as shown on the Key West, 

Miami, and West Palm Beach quadrangle maps 

(scale, 1 : 250,000) by the U.S. Geological Survey. 

Submarine topography of the Pourtales Terrace 

(G. F. Jordal), 1954, p. 1810) in the western Straits 

of Florida and the Tortugas ·Terrace (Kofoed and 

Jordan, 1964, p. 69-77) on the continental slope approximately 45 miles west of Dry Tortugas indicates normal block faulting in these areas. J. E. 

Johnston and others (1959, p. 1-7) described the 

general features of the emerged and submerged 

Atlantic Coastal Plain, including the major known 

structural features north of Florida. Pirkle and 

Yoho (1961, p. 244-276) described local folding and 

warping resulting from solution in north-central 

Florida. 

JOINTS AND FRACTURES 

In addition to faulting, fracture patterns in the 

northern part of the peninsula were first described 

and mapped by Vernon (1951, p. 47-48, fig. 11). 

The mapping of the fracture patterns was based on 

physiographic features and on mosaics and contact 

prints of aerial photographs, available for each 

county·except Orange, ·Taylor, ·and· pa:rt of Marion; 

Vern on checked the geology of these features in 

cores and records of core holes along the proposed 

ship-canal route across the peninsula. The core holes 

extend from the Gulf of Mexico along the Withlacoochee River, along the Citrus-Levy County line, 

and across southern Marion County to the Oklawaha River. 

The regional pattern consists of two fracture systems, one trending northwest-southeast, parallel to 

the axis of the Ocala uplift, and the other northeast-southwest, according to Vernon (1951, p. 47). 

He stated that geologic sections crossing the Ocala 

uplift show that the fractures paralleling the axis 

of the uplift are faults but that sufficient data are 

not available to determine displacement along the 

transverse fractures. The two fracture systems 

form approximately a rectangular pattern where 

they intersect. Fractures trending northeastward 

are poorly formed along the crest of the Ocala uplift 

but are well formed and numerous along the northwest flank of the uplift in Jefferson,. Madison, Hamilton, and Suwannee Counties, where they delineate 

the northwest limit of the crest. The southeast 

flank of the crest of the Ocala uplift is not so 

conspicuously marked by these systems of fractures, 

which Vernon states can be traced from county to 

county throughout the State. 

Vernon (1951, p. 50) mapped two other systems 

of fractures, one in Union County over the crest 

of the peninsular arch and the other in Osceola 

County over the Osceola low. The pattern in Union 

County is radial, resembling the fracturing over 

structural domes. The fractures in Osceola County 

trend northwest-southeast and northeast-southwest 

similar to those on the Ocala uplift, but the northwest trend is more westerly than those on the uplift. These trends are over an area of Precambrian 

igneous and metamorphic rocks which are more 

than 6,000 feet below sea level (Applin, 1951, figs. 1, 

2) . As discussed by Vern on, if these fracture patterns in Union and Osceola Counties reflect the 

pre-Mesozoic rocks, it must be through several 

thousand feet of Cretaceous, Tertiary and younger 

sediments. Vernon suggested that adjustment of 

these relatively unconsolidated sediments over the 

stable pre-Mesozoic rocks may have formed the 

fractures. 

As described by Vernon, the regional fracturing 

associated with the Ocala uplift is believed to reflect 

structural movement during the late Tertiary. 

Stream patterns and sink alinement generally parallel both the northwest and the northeast systems 

of fractures. The valleys of the Oklawaha, Withlacoochee, and Kissimmee Rivers are given as examples of the streams having rectangular trends northeast-southwest and northwest-southeast. In the area 

of Albany, Ga., Wait (1962a) reported alinement 

of sinkholes in two directions, one about N. 60° W. 

and the other about N. 10°-30°E. Moore (1955, p. 

15) recognized a rectangular joint pattern on aerial 

photograph mosaic in Jackson County, Fla. He 

suggested that the· angular stream pattern of the 

Chipola River and Dry Creek is probably caused by 

jointing. 

SOLUTION IN LIMESTONE 

Calcium carbonate, the chief constituent of pure 

limestone, is relatively insoluble in pure water. Only 

0.014 gram of calcium carbonate is dissolved by 1 

liter of distilled water at 25°C (Foster, 1949, p. 

648). Calcium bicarbonate, however, formed by the 

reaction between calcium carbonate and water containing carbonic acid and other acids is much more 

soluble. The amount of calcium carbonate or magnesium carbonate taken into solution depends both 

on carbon dioxide content of the water and the calcium and magnesium content of the water. The 

carbon dioxide content of the water is from the 

atmosphere and oxidation of organic matter in the 
GEOLOGIC STRUCTURE 77 

soil and in the geologic formations. Swinnerton 

(1949, p. 659) stated that under ordinary conditions when air exerts a pressure of 1 atmosphere, 

the partial pressure due to carbon dioxide is 0.0003 

atmosphere. Under this pressure, at 16°C, about 

63 ppm of calcium carbonate can be dissolved. The 

partial pressure of carbon dioxide required to dissolve 400 ppm is approximately 0.065 atmosphere. 

The rate of solution of limestone depends upon 

many factors including the chemical composition, 

permeability of the limestone, the rate of circulation 

of the ground water, time, volume of solvent, area 

of contact, the concentration and partial pressure 

of carbon di'oxide, and natural acids in the water. 

Swinnerton (1949, p. 659) reported that the temperature factor in the ordinary range of ground 

water is complicated but is not very significant. 

Above the water table, howeve~, the variation in 

temperature may be large enough to be significant. 

Carson (1964, p. 5) observed that in Tolleys Cave, 

Va., the ratio of solution to deposition varies with 

seasons. During the winter, water entering the cavern is cold and contains a large amount of calcium 

carbonate in solution. As the water becomes warmer 

ins-ide the cavern, carbon dioxide is released and 

travertine is deposited. Burdon and Papakis (1963, 

p. 61-62) discussed amount and rate of solution of 

carbonate rocks and cited results of studies by 

Corbel (1959, p. 117) that indicate the rate of 

erosion from cold rain is greater than that from 

warm rain. 

Swinnerton ( 194;9, p. 660) stated that the common ion effect, as that produced by calcium sulfate 

in solution with calcium bicarbonate in the presence of limestone, sh9uld depress the solubility of 

calcium carbonate. In southwestern Florida, as in 

Sarasota County, where the artesian water has a 

relatively high content of calcium sulfate, there 

appear to be fewer solution cavities, and the lower 

part of the aquifer yields very little water. This condition may be due in part to the common ion effect 

in addition to the depth and distance from a recharge area. 

In addition to solution or chemical action, physical 

action or corrasion caused by running water erodes 

carbonate rocks. Some evidence of that action is 

present in some of the underground cavities and 

caverns. However, this action appears to be small 

in comparison with solution which may occur both 

in the zone of aeration and in the zone of saturation. 

Calcareous rocks differ appreciably with respect 

to their strength to resist fracture and with respect 

to their solubility as stated by Piper (1932, p. 73). 

Welder and Reeves (1962, p. 36) concluded that 

solution channels in limestone in Uvalde County, 

Tex., are larger than those in dolomite because calcium carbonate dissolves more readily than the 

magnesium carbonate. 

Fox (1941, p. 334) found that in boulders exposed in the Tennessee River for 25 years the purer 

limestone was more soluble than the impure limestone. Siliceous limestone was the least soluble. 

The purer limestone dissolved from one-fourth to 

three-fourths inch faster than the impure limestone. 

From this he estimate-d that limestone continually 

washed by the river will dissolve at a rate of approximately half an inch in 25 years. 

Some of the Eocene formations of the principal 

aquifer contain anhydrite and gypsum which may 

be dissolved by water without the presence of natural acids. The water-bearing capacity of limestone, 

marl, dolomite, anhydrite, and gypsum depends in 

part on the original permeability of the formation 

and on the secondary permeability which is formed 

by fracturing, solution, and other processes after 

the beds have been formed. The permeability that 

is due to solution of limestone accounts for much of 

the large yield of the Tertiary and Quaternary limestones. 

SOLUTION CAVITIES 

Solution cavities are numerous in the aquifers 

and also are reported in older Eocene and Cretaceous formations penetrated by oil wells. The log 

of Cory well 1 of Peninsular Oil arid Refining Co., 

Monroe County, Fla., shows cavities 18 feet high between 2,846 and 2,864 feet deep, 4 feet high between 

2,959 and 2,963 feet deep, and 11 feet high between 

2,986 and 2,997 feet deep (R. H. Jordan, 1950, 

p. 264). 

The log of well W -820 of the Humble Oil Co. in 

Collier County, Fla., shows a cavity 40 feet high at 

a depth of 6,100 feet. Vernon (in Ferguson and 

others, 1947, p. 21) reported that cavities have been 

penetrated at depths of 8,000 feet in oil wells and 

that circulation of mud in the well has been lost at 

greater depths. Hughes (1944, p. 75) reported that 

the oil-producing horizon at depths of 11,613 to 

11,626 feet in the Sunniland field in Collier County 

in southern Florida is cavernous limestone of Early 

Cretaceous age. 

There may be solution by deep circulation of 

artesian water in areas where there are favorable 

structural conditions, such as recharge of the 

aquifers at high altitudes on the flank of an anticline or discharge ·from a deep basin at a lower altitude. For example, at Parris Island, S.C., fresh 

water and the relatively high artesian head indicate 
78 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

circulation at a depth of as much as 2,600 feet in 

water-bearing sands of the Tuscaloosa Formation 

of Cretaceous age. Where hydrologic and structural 

conditions are not, however, favorable for circulation 

of the ground water, deep cavities such as those in 

the older Eocene and Cretaceous limestone would 

have to form before the formations are deeply 

buried. 

The writer found no evidence of circulation of 

water below the Lake City Formation of middle 

Eocene age in Florida in Recent time. The deep 

circulation of artesian water in the Lake City and 

the younger formations depends on ( 1) recharge 

and (2) the opportunity for discharge at submarine 

outcrops or through springs and upward leakage 

into overlying formations. The discharge at submarine outcrops is controlled by the relation of the 

fresh-water head and the back pressure from the 

salt water. In areas where the pressure of the salt 

water is greater than the artesian head at the submarine outcrop, no discharge occurs. Upward leakage depends on the permeability and thickness of 

the overlying beds and the hydrostatic head of water in the aquifer in the overlying formations. 

After deposition in the sea, most of the waterbearing formations of the principal artesian aquifer 

were raised above sea level, and solution cavities 

formed in the limestone and other carbonate rocks 

before they were resubmerged in the sea and covered by overlying formations. Many of these solution cavities probably were filled by the overlying 

formations. Shallow sinkholes in the Hawthorn 

Formation in central Florida are filled with deposits 

of Bone Valley Formation (Cathcart, 1963b, p. 22). 

If the Bone Valley is Pliocene in age, this relationship would indicate erosion and solution in the Hawthorn began in late Tertiary time. It appears that 

sinkholes in the Hawthorn in some upland areas 

formed after the Citronelle Formation was deposited. The solution cavities which exist today in 

the principal artesian aquifer ·and younger formations apparently formed chiefly if not entirely during Pleistocene and Recent time. 

Even though solution is continuous where there is 

cir~ulation of artesian water as at the present time, 

it seems that much of the solution in the deeper 

water-bearing formations of the principal artesian 

aquifer of Tertiary age occurred during Pleistocene 

time when sea level was at least 300 feet below the 

present level. At that time, the land area extended 

to the edge of the Continental Shelf, and the highest 

areas in Florida were at least 600 feet above sea 

level. The solution channels in the shallow aquifer 

in the Miami area also formed during a low stand 

of the Pleistocene sea. 

Although sinkholes are formed and solution cavities are enlarged above the water table, a solution 

cavity in the zone through which the water table or 

water level in the limestone fluctuates is enlarged 

both by water in the zone of saturation and by water 

in the zone of aeration. The opportunity for maximum solution, however, appears to be in the upper 

part of the zone of saturation where the limestone 

is in continuous contact with the water. Many cavities penetrated by wells in the principal aquifer at 

different depths appear to have formed in the upper 

part of the zone of saturation when that zone was 

at various levels in accordance with different stands 

of the Pleistocene sea. Records of cavities throughout the extent of the aquifer, such as those given 

in the following discussions, may show some correlation with the levels. at which the sea stood long 

enough for the ground-water circulation to adjust 

to the new sea level. Such correlation, however, is 

obscured because solution occurred not only with 

the lowering of sea level but also during the rise. 

Zones of solution cavities in the limestone exposed 

in channels of streams cut into the aquifer, as along 

the Suwannee River in Florida and the Flint River 

in Georgia, are examples of zonation of cavities 

where the opportunity for the solution of the limestone is favorable.· The channel that connects Falmouth Spring with the Suwannee River is an illustration of a shallow solution channel in the aquifer. 

The spring is in a sinkhole formed by the local collapse of the roof of an underground stream. If there 

were a lowering of sea level, the base level of the 

streams would be lowered along with the lowering 

of water level in the limestone. If there were sufficient lowering of the water level, the solution channels-such as the one connecting Falmouth Spring 

with the Suwannee River-and the zone of cavities 

exposed in the river would be left above the zone 

of saturation in the limestone, and enlargement of 

the channel and cavities. would occur only when surface water flowed into them. 

The origin of caves or caverns in limestone, as 

described by Davis (1930, p. 475-628), is a twocycle process jn which the first cycle is solution in 

the zone of saturation which forms cavities below 

the water table. This cycle is related to regional 

peneplanation. The second cycle takes place with 

an uplift of the cavern opening or lowering of the 

zone of saturation and removal of ground water. 

In the second cycle, the caverns are modified by 

the action of water above the water table. 
GEOLOGIC STRUCTURE 79 

Bretz (1942, p. 675-811; 1956, p. 10-38) accepted 

almost completely the two-cycle theory of Davis and 

inserted another cycle that consists of cave filling 

with very fine red clay before the removal of ground 

water. Roger Baker, U.S. Geological Survey (written commun., Nov. 1962) recognized three cycles in 

the solution of limestone on the Edwards Plateau 

in Texas. Herrick and LeGrand (1964, p. 29-35) 

described the karst cycles of erosion in the Flint 

River valley in southwestern Georgia. Their study 

indicates that concepts of the karst cycle are useful 

if considered in terms of both time and space. The 

cycle represents a sequence of topographic features 

to which a corresponding sequence of time may be 

applied only when referring to a restricted part of 

a limestone terrane. 

Swinnerton (1932, p. 663-693) proposed a single 

cycle in which the initial openings in the limestone 

form in the zone of saturation but the most active 

formation is near the water table. Vern on pointed 

out (in Ferguson and others, 1947, p. 19, 20) that 

artesian water is under pressure and any solution 

of the principal artesian aquifer must be in the 

zone of saturation. 

Back ( 1963, p. 43) reported that water at depths 

of several hundred feet in the aquifer in central 

Florida is undersaturated with respect to calcite; 

therefore, solution of the deep limestone can occur. 

Although solution may occur at great depths, if 

there is circulation of artesian water, it seems that 

most of the solution would occur in the upper part 

of the zone of saturation, in the part of the aquifer 

where continuous circulation is the most vigorous. 

In recharge areas of the artesian aquifers, the piezometric surface merges . with the water table, and 

water-table conditions are present. Solution in the 

aquifer may therefore occur under water-table or 

artesian conditions. 

Piper (1932, p. 73) suggested that where ground 

water in limestone has a free upper surface or water 

table, the limestone is presumably dissolved most 

rapidly in the zone between the highest and lowest 

positions occupied by the water table in its seasonal 

fluctuations. In that zone the water circulates most 

rapidly and is most likely to contain natural acids. 

In a discussion of the solution cycle in limestone in 

south-central Tennessee, Theis (1936, p. 44) reached 

the conclusion that the greatest amount of solution 

takes place near the water table. Other conditions 

being the same, the large solution passages are 

formed near the water table. From observations of 

the patterns and rates of solution on the surface of 

small limestone blocks immersed in dilute acid, 

Kaye (1957, p. 45) concluded that the rate of solution is considerably affected by agitation and that 

the rate varies with the relative movement. 

At the present time, there is movement of water 

through the principal artesian aquifer to springs, 

rivers, and lakes, such as those in the St. Johns 

River valley and to the Atlantic Ocean and the Gulf 

of Mexico. Solution is shown by the chemical composition of the water. In Citrus and Levy Counties 

on the gulf coast of Florida, the top of the limestone 

of the principal aquifer is at or near the surface, 

and large quantities of artesian water discharge into 

the Gulf of Mexico, although the gradient of the 

piezometric surface is small. If sea level were lowered, the opportunity for discharge into the Gulf of 

Mexico would be increased, and a new hydraulic 

gradient would be established, which eventually 

would be parallel to the old gradient, except for factors such as changes in the area of the cross section 

through which the water flows, diversion of flow, 

and increase in recharge. These factors would cause 

the new gradient to be steeper than the older one 

until new or enlarged solution channels formed at 

a lower level. As stated by Kaye ( 1957, p. 45) , if 

recharge of the aquifer is not increased, the enlargement of solution channels would lower the water table and thereby expose caverns formed in· the 

z·one of saturation. This process initiates the second 

cycle of Davis without diastrophism, eustatic 

changes of sea level, or marked changed in topography; but this would not be sufficient to explain 

the cavernous zones at different levels. However, 

in the report area eustatic changes of sea level during Pleistocene time were a controlling factor in the 

karst cycles and the formation of solution channels 

at different depths in the aquifer. 

Theoretically water moves in arcuate paths following lines of flow that have their origin at the 

top of the zone of saturation in recharge areas 

(Swinnerton, 1949, p. 665). The flow lines curve 

downward for some distance and then rise to an 

outlet or point of discharge. Diagrammatically 

these flow lines can be represented by a family of 

curves, the spacing of which is closest near the area 

of outlet and widest along the top of the zone of 

saturation as the distance from the outlet increases. 

In uniformly permeable material where geologic 

structure does not control the direction of movement, the water may be expected to have an arcuate 

pattern of flow. In the initial stages of groundwater circulation in limestone and other carbonate 

rocks, the lines of flow are modified. The concentration of flow lines in the discharge area, together 
80 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

with the greater velocities in that area, will result 

in an enlargement of the outlet and a consequent 

shallowing of the more remote arcuate paths. The 

more direct paths will become larger than the less 

direct paths and will permit progressively larger 

flows at the expense of other passageways. 

As stated by Rhoades and Sinacori (1941, p. 794), 

the initial flow both at great and at shallow depths 

causes solution, which is quantitatively more pronounced in the upper zone because of greater circulation in that zone. Progressive concentration in 

the upper part of the zone of saturation produces 

master conduits and causes eventual diminution 

of flow and solution at greater depths. 

In general, the solution cavities and channels 

form with vertical and lateral circulation of the 

water; however, there are exceptions as reported by 

Olsen (1958, p. 396--403). The main solution and 

flow channel of Wakulla Spring, Fla., is at a 45° 

slope 100 feet below the land surface (Nevin Hoy, 

written commun., 1962). The vertical pipes and 

natural wells are formed by vertical movement, 

chiefly above the zone of saturation. The horizontal 

cavities and channels are formed in the zone of 

saturation. 

Information on solution cavities in the principal 

artesian aquifer and the overlying Hawthorn Formation, as reported by H. G. Stewart (1959, p. 14) 

in Polk County, Fla., shows that the vertical dimensions of the cavities penetrated by wells in that 

area range from 2 to 40 feet at depths ranging from 

112 feet above sea level in the Hawthorn Formation 

to a depth of 805 feet, or 584 feet below sea level, in 

the Avon Park Limestone. The largest cavity, 40 

feet in diameter, is in the Crystal River Formation, 

360 feet below the land surface or about 228 feet 

below sea level. One "honeycomb" zone 43 feet 

thick, 13 feet below sea level, was penetrated in the 

Suwannee Limestone. 

Altitudes, with reference to sea level, are given 

for some of the cavities. Some altitudes were estimated and therefore are approximate. However, 

they give information on the vertical distribution 

of the cavities. Seventeen of these cavities are in 

the A von Park Limestone, 206 to ·685 feet below sea 

level. Two cavities are in the Crystal River Formation, and the remainder are in the overlying Suwannee and Tampa Limestones and the Hawthorn Formation. The cavities in the Avon Park Limestone 

and the Crystal River Formation apparently are in 

zones which slope to the southwest in the same general direction as the slope of the piezometric surface 

at the present time. If these zones represent solution 

in the upper part of the zone of saturation, the hydraulic gradient of the piezometric surface was 

probably two to three times as large as the steepest 

natural gradient at the present time. The cavities 

in the formation above the Crystal River appear to 

form a zone from about 100· feet above sea level to 

about 25 feet below sea level. This zone appears to 

have a slight slope to the southwest. 

In the Orlando area (Orange County) in central 

Florida where the surface altitude is generally about 

100 feet, W. F. Lichtler (written commun., 1963) 

recorded cavities penetrated by wells in the limestone of the principal artesian aquifer, as follows: 

Depth below mean sea level 

(feet) 

0-100 

100-200 

200-300 

300-400 

400-500 

500-1,000 

1,10(l-1,200 

1,200-1,300 

1,300-1,400 

Number of reported cavities 

At least 1 foot in 

vertical dimension 

14 

12 

11 

23 

5 

0 

2 

2 

1 

At least 10 feet in 

vertical dimension 

5 

2 

3 

2 

1 

0 

0 

0 

0 

The zone, 300 to 400 feet, where most of the 

smaller cavities are reported consists chiefly of hard 

brown dolomitic layers with softer intervening layers. All cavities had a vertical dimension of at least 

1 foot. Thirteen had vertical dimensions of at least 

10 feet. All the cavities having dimensions of at 

least 10 feet were less than 400 feet below sea level 

except one between 400 and 500 feet. An unusual 

exception not given in the preceding table is a 90-

foot cavern 468 to 558 feet below sea level and penetrated by a well (Primrose) drilled 885 feet deep in 

1963. 

The principal artesian aquifer in Florida probably has caves and solution channels comparable in 

size and extent to those in Mammoth Cave in Kentucky. From reports on cavities penetrated by water 

wells and a report by Olsen (1958, p. 396--401) on 

Wakulla Cave through which Wakulla. Spring flows, 

the largest and most extensive caves are filled with 

water. Wakulla Cave was explored through a distance of 1,100 feet and a depth of about 250 feet 

below the surface and about 240 feet below sea 

level. 

The caves above the water in the aquifer at present are not as large as those in the zone of saturation. Some of the caves in the Marianna Limestone 
GEOLOGIC STRUCTURE 81 

of the principal artesian aquifer near Marianna, 

Fla., are above the water level in the limestone and 

have been explored. Those at the Florida Caverns 

State Park near Marianna are open to the public. 

Olsen ( 1959, p. 73) referred to two caves in Citrus 

County and one south of Ocala in Marion County, 

Fla. He stated that many of the limestone caves in 

the central part of the peninsula and in the panhandle of Florida have been visited by persons 

searching for vertebrate fossils. 

Two of these in the peninsula are Iron Ladder 

Cave and Saber-Tooth Cave in Citrus County. Access to Iron Ladder Cave is by a metal ladder 

through a hole in the cave ceiling, which is 60 feet 

above the floor of the cave. The pile of bones beneath the opening, including one human skeleton, 

probably Indian, indicates this opening was a natural· deathtrap similar to the exposure of natural 

wells, as shown in figure 9. Animals falling through 

the hole were killed on impact on the rocks below. 

Some water wells in the areas where the aquifer 

is at or near the surface penetrate air-filled cavities 

above the water in the limestone. One of these in 

the De Land area in Volusia County contained air 

under several pounds of pressure, which apparently 

was caused by a rise in the water level in the limestone and in a cavity not directly connected with 

atmospheric pressure. 

Throughout most of the areas of artesian flow 

many water-well drillers report cavities at different 

depths and increases in artesian flow immediately 

below relatively impervious lenses of hard silicified 

limestone or chert that locally may retard upward 

movement of artesian water in the aquifer. These 

relatively impervious layers apparently are not continuous over large areas except in western Florida, 

where the Bucatunna Clay Member of the Byram 

Formation of Oligocene age separates the upper part 

of the aquifer from the lower part. Cavities are 

most numerous and largest in natural recharge and 

discharge areas. 

In the Hawthorn Formation overlying the principal artesian aquifer, relatively impervious beds may 

retard vertical movement of water and control to 

some extent the lateral movement. The vertical 

movement of the water in the Hawthorn Formation 

and the principal artesian aquifer are not, however, 

retarded as much as that in some of the limestones 

of Paleozoic age in central Tennessee and the Blue 

Grass region of Kentucky. In part of the Blue Grass 

region, solution of the limestone has occurred from 

the surface to a depth of about 80 feet. Underlying 

beds of bentonite and shale prevent downward 

movement of water, as described by Hamilton ( 1948, 

p. 39-52). Near Lexington, Ky., the relatively 

impervious beds are so effective in preventing percolation of water that a limestone mine under these 

beds is dry. 

As stated by Piper (1932, p. 82-83) a bed of impermeable shale or other impervious material that is 

not readily soluble or is not jointed may prevent 

downward circulation, as in north-central Tennessee, where the Chattanooga Shale underlies Mississippian limestone. If the restraining bed is, however, thin and breached, channeling may take place 

at a lower level. The lower system of channels 

may drain the upper system through natural wells 

and pipes. 

In southern Florida, solution is dominant where 

limestone and other calcareous deposits are at or 

near the surface and where the surface water contains relatively large amounts of organic acids. Solution in the shallow aquifer, which consists chiefly 

of cavernous limestone and marl ranging from late 

Miocene to Recent in the Miami area in southeastern 

Florida, was most active when sea level was below 

its present level. Solution occurs through vertical 

movement of the water from the land surface to the 

bottom of the aquifer, which overlies relatively 

impervious Miocene marl and clay. Thousands of 

vertical channels are now filled chiefly with permeable sand. They range in diameter from a fraction 

of a foot to several feet. Horizontal channels were 

formed by lateral movement of the water to the 

Atlantic coast. Later, . when the sea covered the 

area, most of these cavities and vertical channels 

were filled with sand. 

Parker and Cooke (1944, p. 29) reported that in 

large areas in southern Florida at least one-fourth 

of the total volume of limestone of the shallow aquifer, once mostly solid rock, is now occupied by solution holes, generally filled with sand. Some of the 

horizontal solution channels have vertical dimensions of as much as 11 feet. In some places the channels are within a few feet of the surface. The largest 

channel recorded at shallow depths is between 10 

and 21 feet below the land surface in the Silver 

Bluff area in Miami. Some solution is active at the 

present time, although the cavities are filled with 

sand. If sea level were below the bottom of the 

aquifer for a sufficient length of time for water to 

remove the sand from the cavities, surface drainage 

would be underground, and the water table would 

decline to the bottom of the aquifer. Water would 

flow freely through the aquifer, and the zone of saturation would be temporary. At the .present time, 
82 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STA'rES 

however, the cavities in the aquifer are filled with 

permeable sands, and sea level is near the top of the 

aquifer. Therefore, the water table ranges from sea 

level along the coast to a maximum of about 10 feet 

above sea level in areas several miles inland. 

Although many vertical solution channels occur 

along joints and fractures or the intersection of 

joints, solution may begin in a small depression on 

the surface of the limestone. The water ·stands in 

the depression and dissolves the limestone until it 

is flushed from the depression by rain or water flowing over the surface during and after rains. Parker 

and Cooke (1944, p. 27) reported that on some of 

the limestone surfaces in southern Florida, the first 

effects of solution appear as small surficial pits resembling raindrops in mud. These gradually become deeper, without visible outlet along the sides 

and bottom. They later become tubes, which enlarge 

into holes of different shapes and sizes. Some of the 

holes observed were several feet deep. 

Solution in the shallow limestone in the Miami 

area has been intense, . but typical sinkhole or karst 

topography has not resulted. Solubl~ limestone extends to the land surface, and solution has occurred 

throughout the aquifer in relatively small channels 

instead of concentrating in large channels which 

would cause sinkholes. The vertical movement of 

the water from the surface to the aquifer is through 

many vertical shafts or natural wells of small diam-

. eters instead of large sinkholes. 

SINKHOLES AND NATURAL WELLS 

Sinkhole topography, or karst topography has 

formed in the area of this report where limestone 

is at or near the surface and the overlying Hawthorn 

Formation has been removed by erosion, or where 

sinkholes and natural wells extend through the Hawthorn to the underlying limestone. 

R. H. Jordan (1950, p. 262) believed that the 

karst geomorphic cycle, which is typical of many regions underlain by limestone or other soluble rock, 

does not apply in Florida. The writer is of the 

opinion that both karst and cave cycles in the 

Tertiary limestone in the southeast are similar to 

those in other regions, as Mammoth Cave, Ky., except that the cycles were affected by eustatic 

changes of the Pleistocene sea. Von Engeln (1949, 

p. 563-585) discussed the karst geomorphic cycle 

and g:;tve definitions of some of the foreign words 

used to designate features of karst topography. In a 

comparison of Florida limestone with the London 

Chalk in England, he indicated that, because of its 

large permeability and ~bility to hold water, the 

chalk is not cavernous; but Florida limestone is cavernous because of its small permeability and inability to hold water. Actually, Florida limestone is 

permeable and holds large volumes of water. Some 

parts of the limestone are chalky but are also permeable. The permeability of the London Chalk is 

small, and the water occurs chiefly in joints and 

fractures as indicated in the large seasonal fluctuations of water level, which may be more than 100 

feet. Chalk may have a high porosity, as the Selma 

Chalk of Cretaceous age in Alabama, but the permeability is so small that excavations in the chalk 

have been used as cisterns. The permeability of the 

chalky part of the Cooper Marl of Oligocene age in 

South Carolina also is so small that an unlined tunnel in the marl is used to pipe the municipal water of 

. Charleston, S.C., from a surface reservoir to the 

city. Apparently, joints and fractures that may occur in the Selma Chalk· and Cooper Marl do not remain open long enough for the formation of solution 

channels. 

Sinkholes and natural wells, or vertical shafts, are 

natural openings that generally extend from the 

land surface to a permeable or cavernous zone in the 

limestone. The sinkholes, in general, are caused by 

solution arid by collapse of the roof of underground 

channels or caverns. Formation of a sinkhole by 

solution commonly originates at a vertical joint or 

fracture or the intersection of two joints, the 

·crevice being enlarged by the. solvent action of water that descends from land surface to a lower level 

or to the zone of saturation. In Tennessee, Piper 

(1932, p. 72) stated that at first the descending water is largely depleted in solvent power before it percolates far· below the surface and, therefore, the 

deeper part of the joint is not likely to be enlarged 

appreciably. This process results in a conical depression in the limestone, the base of the cone being 

at the land surface and its apex pointing downward. 

As this depression increases in diameter and depth, 

the relatively insoluble soil subsides, giving the first 

indication of the sink. Piper reported that both 

cone-shaped sinks and natural wells, or vertical 

shafts, also form underground between solution 

channels at different levels in Tennessee. 

Natural wells, or vertical shafts, that may be 

approximately cylindrical and about the same diameter at the top and bottom are formed by solution 

along joints above the zone of saturation in the limestone. The solution rate is approximately the same 

from the top to the bottom of the wells. As described by Pohl (1955, p. 10), the vertical shafts in 

Kentucky caves range from a few feet to more than 
GEOLOGIC STRUCTURE 83 

30 feet in diameter and 10 to 200 feet in height. 

Merrill (1960, p. 107) reported that the deepest 

shaft in central Kentucky is '240 feet. There is no 

uniform relation between· height and diameter except that the shafts of large diameter are taller. 

The shafts usually have a cup-shaped base that is 

no larger in diameter than most of the cylinder. 

The top is an irregular dome. In caves, the shafts 

are called domes and pits, or dome pits. 

One of the well-known examples of a natural well 

in Florida is Falling Water Sink about 4 miles 

south of Chipley in Washington County, which is 68 

feet deep and about 20 feet in diameter (Cooke, 

1945, p. 134) . It penetrates the Tampa Limestone 

and the underlying Suwannee Limestone. A small 

stream from surficial sands above the Tampa flows 

into the cylindrical shaft and flows out through ~ 

small cavern at the bottom. Figure 9 shows the 

mouth of a natural well about 5 feet in diameter in 

the Suwannee Limestone near Brooksville, Hernando County, Fla. At a depth of 50 feet, the well 

was dry. The boards on the ground are remnants of 

a fence built to prevertt persons and animals from 

falling into the well. 

In a discussion of caves in northern Alabama, W. 

D. Johnston (1933, p. 53) described a feature in 

Madison County known as Natural Well, 186 feet 

deep. The sides of the well are fluted but have circular sections ranging from 25 to 40 feet in diameter. From the bottom of the well a spiral opening, 

sloping steeply, descends into a high narrow corridor 

with fluted walls. At the end of the corridor is a low 

crawlway which ends in a pit 30 feet deep. The 

total depth to which Johnston explored was 352 feet 

below the surface. Mohr (1964, p. 803~837) reported 

that a "vertical pit" in Fern Cave in northern Alabama is 426 feet deep and that the Devils Sinkhole 

in Texas is 407 feet deep. Lobeck (1939, p. 143) 

reported that some sinkholes in the karst topography in the Causses region in southern France are as 

much as 700 feet deep; 

In Florida, sinks and natural wells are known to 

be as much as several hundred feet· deep. H. G. 

Stewart (1959, p. 16) reported that the original 

depth of a sinkhole in Polk County may have been at 

least 300 feet, the surface elevation being about 230 

feet above mean sea level. Meyer (1962, p. 24) indicated that Alligator Lake at Lake City occupies a 

large solution basin in which rocks slumped from a 

surface elevation of more than 100 feet above sea 

level to almost 100 feet below sea level. One of the 

deepest sinkholes reported (W. S. Wetterhall, written commun., 1961) is 480 feet deep at an elevation 

of 94 feet above sea level in Pasco County, Fla. The 

sink is filled with unconsolidated sediments. 

As may be seen in caves, many of the natural 

wells, known as vertical shafts or dome pits in caves, 

terminate at the level of a lateral channel which 

formerly was in the zone of saturation, but a few of 

the wells extend to two or more levels of lateral 

channels. Although some of these lateral channels 

are .now above the zone of saturation in the limestone, the writer believes that they formed in the 

upper part of the zone of saturation. The lowest 

position of the water table in the limestone is indicated by the deepest natural wells. 

Where the Hawthorn Formation is present, the 

first cycle of solution probably was started by water 

in the permeable beds of the Hawthorn moving 

downward to the limestone below. The solution of 

limestone along vertical intersecting joints and fractures enlarged these vertical openings from mere 

tubes to large shafts. The domelike ceiling of many 

of the shafts in caves shows the effects of solution 

caused by the thin films of water which seep in 

from above and move along the ceiling from the 

center of the dome to the walls of the shaft. The 

downward movement of the film of water on the 

walls of the shaft dissolves the limestone, causing 

vertical fl1uting. 

As described by Bretz (1956, p. 23) in Mammoth 

Cave and other caves, descending water may cling to 

the vertically grooved surface all the way down the 

vertical shaft. In some shafts, as shown by McGrain 

(1954, p. 29) in a cave in the Cascade Park of 

eastern Kentucky, a continuous underground stream 

of water from a solution cavity at the top of the 

shaft forms a waterfall that plunges down the shaft 

to a pool at the bottom, which may be the top of the 

zone of saturation in the limestone. In describing 

the vertical shafts which he called dome pits, Bretz 

(1956, p. 21-22) showed how dome pits may form 

by a coring mechanism. Water moves downward 

from a system of anastomosing horizontal solution 

channels at one level in the zone of aeration to large 

chambers at a lower level. After a vertical shaft has 

been formed between the upper channel. and the 

chamber, solution enlarges the shaft along the 

channel until it completes the circuit and the core 

drops to the chamber below. Bretz (1956, p. 337) 

reported three vertical shafts (dome pits) in the 

Mystery Cave in Missouri, which appear to have 

been formed by a retreating waterfall underground. 

Pohl (1955, p. 14) stated that the shafts in the 

Mammoth Cave region are exclusively the' result of 

solution. In some shafts Pohl has found many fossil 
84 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

shells attached to the shaft walls by fragile pedestals showing the action of solution rather than corrasion. In a few places, such as the underground 

waterfall in eastern Kentucky and the waterfall in a 

shaft in Washington County, Fla., water flowing 

over the side of the shaft may remove some limestone by erosion. In the dome of the shafts, layers of 

the ceiling may fall as solution removes the limestone until the shaft has reached a bedding plane or 

unconsolidated bed that will drop into the shaft. 

Pohl showed that in the Mammoth Cave area all 

but a few of the vertical shafts are at or near the 

edges of the Mammoth Cave Plateau and near the 

heads of the surface valley where some of the sandstone overlying the limestone has been removed. In 

exceptions to this rule, the shafts are related to 

small sinkholes or arms of larger sinkholes on the 

tops of the ridges or the surface of the plateau. 

Pohl (1955, p. 23) showed how the headward erosion of streams removes the sandstone overlying the 

cavernous limestone and exposes the limestone forming the Pennyroyal Plateau, which is at a lower level 

and is dotted with thousands of sinkholes ( McFarlan, 1958, p. 46). 

As part of the Hawthorn Formation was removed 

by erosion in Florida and Georgia, more and more 

of the surface drainage went underground into solution channels. After complete removal of the Hawthorn in Citrus and Levy Counties, th~ Ocala Limestone of the principal aquifer was exposed at the 

surface with sinkhole topography. There was little 

or no surface drainage in parts of the area. Probably the removal of the Hawthorn began at the 

coastline and along streams where the aquifer was 

nearest the surface. An escarpment, formed by the 

more resistant Hawthorn, retreated from the coasts 

and streams. For example in Leon, Wakulla, and 

Jefferson Counties in Florida, the Hawthorn escarpment, now at the south edge of the Tallahassee Hills, 

apparently retreated inland from the Gulf of Mexico. Wave action along the shoreline probably contributed to this retreat during higher stands of the 

sea. 

In a study of Baker and Mitchell Counties in 

southwestern Georgia, Herrick and LeGrand (1964, 

p. 25) concluded that the Flint River had cut a channel through the Hawthorn Formation to the Ocala 

Limestone of the principal artesian aquifer. The 

Hawthorn escarpment which parallels the river 

retreated from the river to its present position some 

miles to the southeast. Solution at the base of the 

escarpment formed gullies at right angles to the 

scarp, which contributed to the retreat of the scarp. 

These gullies with vertical head and sidewalls and 

a nearly flat floor are called pocket valleys by Von 

_ Engeln (Engeln, 1942, p. 569). They occur chiefly 

along the Hawthorn escarpments in Georgia and 

Florida. · The steep heads which V 9n Engeln calls 

pocket valleys in the Holt quadrangle in western 

Florida are not, however, related to the solution of 

limestone. The origin of these features is discussed 

· under the section on topography of the Western 

Highlands physical division in western Florida. 

The pocket valleys at the edge of the escarpment 

and shallow sinkholes filled with the Bone Valley 

Formation were covered and buried by a high stand 

of the Pleistocene sea, according to subsurface data 

reported by Cathcart (1963a, p. 37; 1963b, p. 1, 

24) in Hillsborough County, Fla. Although an arm 

of this sea covered part of the Flint River valley 

and filled many of the sinkholes, much of the drainage is underground. However, the Flint River receives water from the limestone. In flood stages, 

water from the river flows into the aquifer through 

solution openings in the stream channel. 

The erosion of the Hawthorn and the formation 

of solution openings in the Hawthorn and the underlying limestone are comparable to the conditions 

described by McFarlan (1958, p. 46-70) and Pohl 

(1955, p. 10) in the Mammoth Cave region of Kentucky where sandstone overlies limestone. Water 

moving downward from the surface through the 

sandstone to the zone of saturation in the limestone 

formed the solution cavities. The surface of the 

limestone, pitted with sinkholes, is exposed as the 

Dripping Springs escarpment of the more resistant 

overlying sandstone retreats. A ·north-south section 

through the vicinity of Mammoth Cave (McFarlan, 

1958, p. 46) shows the Mammoth Cave Plateau 

where the upper part of the sandstone has been removed. Water moving from the sandstone into the 

underlying limestone formed the vertical solution 

tubes and shafts in the zone of aeration. The water 

moves chiefly in a lateral direction after it reaches 

the zone of saturation. 

Karst topography (similar to that in Kentucky) 

developed in Florida and Georgia in areas where the 

Hawthorn Formation was removed, but the topography has been modified by invasions of the Pleistocene sea. In the areas where the Hawthorn is 

present and the top of the principal artesian aquifer 

is relatively high as on part of the Ocala uplift, 

sinkholes extend from the surface through the Hawthorn into the underlying limestone. Most of these 

sinks are now partly filled by unconsolidated material, some of which is relatively permeable. In 
GEOLOGIC STRUCTURE 85 

the areas where the Hawthorn was overlain by unconsolidated sands, the sands slumped into the sinks 

and formed the sloping walls of the sink. The slope 

depends to a large extent on the thickness and angle 

of repose of the unconsolidated material. In exploring the Devils Pit, a steep-sided sinkhole in northcentral Florida, Pirkle and Brooks (1959, p. 315) 

noted that it has a funnel shape in the surficial 

sands overlying the Hawthorn. This funnel shape 

appears to be common in sinks in areas where the 

Citronelle Formation or other unconsolidated sands 

overlie the Hawthorn. Where the sands are absent 

and consolidated rocks are at the surface, a new sink 

forms vertical walls. 

In some areas, as in Orlando in Orange County, 

Fla., some lakes that occupy sinkholes are narrow 

and long, indicating that they were formed by collapse of the roof of a meander of an underground 

stream. Some large lake basins along the St. Johns 

River valley and in northern Florida resulted from 

solution of the limestone and collapse of solution 

channels. 

In the upland regions of Florida, Sellards (1914, 

p. 156) reported that sinks have broken through as 

much as 100 feet of material, a large part of which, 

however, is calcareous and phosphatic. Some of the 

material may have been removed by solution and 

caving before the material at the surface collapsed 

into the underlying solution cavity. 

As stated by Sellards, sinks are not known to form 

in areas of artesian flow. The artesian aquifer is 

overlain by relatively impervious beds, and the water in cavities is under artesian pressure. Along the 

border between the flowing and nonflowing areas, 

the artesian water forms artesian springs in some 

places where the aquifer is at or near the surface 

and the artesian pressure is sufficient to force water 

to a point of discharge at the surface. Most of these 

springs flow through channels and sinkholes apparently formed when the sea stood at a lower level 

and when the top of the zone of saturation in the 

limestone was at a lower level. The areas in which 

sinks are forming today are generally those in which 

(1) the limestone is near the surface, (2) the water 

level in the limestone is near the surface, and (3) 

the material overlying the limestone is too weak to 

prevent collapse into the underground stream. When 

the water level in the limestone is high, as in a rainy 

season, a cavity having a weak roof may be filled 

with water, which will give some support to the 

roof. During prolonged drought, however, when the 

water level declines, the support is withdrawn, and 

the roof of the underground cavity may collapse. 

Sometimes a similar collapse occurs because of heavy 

rains after a dry spell. 

Some information on the depth and other features 

of open sinkholes has been obtained by divers in 

lakes and springs in sinks. Brandle ( 1959) and 

Stephens (1959) reported that divers penetrated to 

a depth of 210 feet in the sinkhole through which 

Little Salt Spring in Sarasota County, Fla., flows. 

They reported that stalactites and dripstones were 

found on protected ledges in the sink. Two ledges 

with stalactites are at depths of 25 to 90 feet. In 

nearby Warm Mineral Springs (same as Warm Salt 

Spring), Stephens reported that a charred log from 

a ledge 40 feet deep is 10,000±200 years old, according to radiocarbon dating by the Scripps Institution 

of Oceanography. 

These results indicate that the sinkholes were 

formed during a low stand of the sea in Pleistocene 

time. The sink might have been filled later with 

sand during a high stand of the sea but was reopened during a later low stand. The location of 

the log on a ledge of the Hawthorn Formation 40 

feet below present sea level suggests that the log 

might have entered the sink when the water in the 

sink stood at that level, or that the log became 

lodged on the ledge when surface water flowed into 

the sink at a lower level. If the water stood at 40 

feet, it would indicate sea level probably was about 

60 feet below its present level. At the present time, 

the head of the spring is estimated to be about 20 

feet or less above sea level ; if the sea were lowered 

about 60 feet, the water level would stand about 40 

feet below present sea level in the sinkhole now 

occupied by the spring. The pre-Pamlico shoreline, 

as shown by Cooke (1939, p. 39; 1945, p. 299), was 

60 feet below present sea level. However, the age of 

the log indicates that it entered the sink in postPamlico time. 

The presence of partial skeletons of more than a 

hundred humans under a ledge 30 to 40 feet below 

the surface in Little Salt Spring causes W. R. Royal 

and others to conclude that the caves of that depth 

were occupied by humans when the water stood below that level in the limestone, as reported by 

Stephens (1959, p. 6, 7). Royal also concluded that 

the charred log 1Vas the remains of some prehistoric 

campfire in the cave where it was found. Upson, 

Leopold, and Meyer (1964, p. 121-132) and Scholl 

(1963, p. 145) reported evidence which indicates that 

the sea has risen from a lower level since the end of 

Pleistocene time. Under these conditions, the log 

in Warm Mineral Springs could have been carried 

into the cave during the last low stand of the sea. 
86 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Shumway, Dowling, Salsman, and Payne (1962, 

p. 271) reported a buried forest (pine stumps about 

20 em in diameter standing vertically with tops at 

level of sandy sea floor) on the Continental Shelf off 

Panama City, Fla., at a depth of 18 meters, apparently at the edge of a terrace about 60 feet below 

sea level. A radiocarbon age of 36,500 years was 

reported for a specimen of wood from one of the 

stumps. Another sample had a radiocarbon age of 

37,500 years. A sample of peat was dated older than 

40,000 years. These facts suggest that the sea stood 

at least 60 feet below its present level about 35 to 40 

thousand years ago. Stearns (1935, p. 1955) gave 

evidence of submarine shorelines at 60 and 300 feet 

below sea level along the coast of Hawaii. 

Olsen (1958, p. 402) reported mastodon bones 

and 600 bone spear points in Wakulla Cave several 

hundred feet from the entrance of the cave and 

about 210 feet below sea level. The spear points are 

similar to those found with Florida's prehistoric 

inhabitant, the Vero man. Although Olsen pointed 

out that some objects, such as crescent-shaped tusks 

weighing several hundred pounds, could not have 

been easily rolled by water down the sloping floor 

of the cave, he concluded that Wakulla Cavern has 

never been dry at this depth and thus could not 

have been visited by land animals and early man. 

However, a study of Pleistocene chronology and 

submarine terraces indicates that it is entirely possible that Wakulla Cave formed during a low stand 

of the Pleistocene sea and that the water level in 

the limestone dropped below the cave during the 

lowest stand of the sea several hundred feet below 

the present level. Under these conditions, both animals and men could have entered the cave. This 

suggested history of the cave seems to be supported 

by the submarine terraces described by Logan (1965, 

p. 101) at approximately 96 to 120 feet, 168 feet to 

190 feet, and 300 to 360 feet below sea level along 

the coast of Yucatan, Mexico. The Wakulla Cave 

could have formed when the higher submarine terraces were formed and could have been drained of 

water wheri the sea stood about 300 to 360 feet below 

the present level. 

As the Citronelle Formation was not deposited 

in sinkholes in northern Florida, it seems that sinks 

formed in that area after the deposition of the 

Citronelle Formation. This fact suggests that many 

of the sinkholes, natural wells, solution channels, 

and other cavities that are open or filled with unconsolidated sand in the· Tertiary limestone and 

younger formations in the area of this report 

formed during Pleistocene and Recent time. AIthough Bretz (1949) and Horberg (1949) believed 

that the caves in the Carlsbad area in New Mexico 

probably are older than the Ogallala Formation of 

Pliocene age, the consensus of Gardner ( 1935, p. 

1270) and others is that most of the world's caverns 

in limestone and associated rocks formed during 

Pleistocene time. 

Erosion and solution of the Hawthorn Formation 

seems to have started in late Miocene and early 

Pliocene in north-central Florida, where the Bone 

Valley Formation is deposited in shallow sinks in the 

Hawthorn Formation in Polk and Hillsborough 

Counties (Cathcart, 1963a, p. 20; 1963b, p. 22) 

Sinkholes were also formed after the deposition of 

the Bone Valley and prior to the deposition of 

Pleistocene sand. 

Advances and recessions of the sea have affected 

the sinkhole topography and solution in the limestone to such an extent that it is difficult to interpret 

the history and the present conditions. Vern on 

(1942, p. 30) recognized this effect in Holmes and 

Washington Counties, Fla., where an embayment of 

the Pleistocene sea and a line of drainage appear to 

have affected the present distribution of the sinkholes. 

Elliptical shallow depressions, called Carolina 

Bays, as described by Cooke ( 1936, p. 7, pl. 17 ; 1954, 

p. 195-207) on the Pamlico terrace and higher 

terraces, apparently are surficial features formed 

by tidal currents on the terraces when the sea 

stood at higher levels. LeGrand (1953, p. 263) reviewed the hypotheses given by the principal authors 

on the subject and concluded that the Carolina Bays 

resulted from solution in a shallow artesian aquifer. In some areas where the limestone is near the 

land surface as in the Beaufort area, South Carolina, circular depressions as shown by Siple (written commun., 1960) are believed to be circular sinkholes which were filled with sediments when the 

sea covered the area. After the retreat of the sea, 

there has been enough settling of the sediments in 

the sinks to form the circular depressions. 

In addition to the circular lake. basins, there are 

large solution basins formed by the collapse of the 

roof of underground channels and coalescing of 

sinkholes which formed along the courses of underground streams. Examples of these are the basins 

occupied by the following lakes : Lake Apopka, Lake 

Harris, and Lake Eustis in the Central Highlands 

of Florida; Lake Jessup, Lake Harney, and Lake 

Monroe in the St. Johns River valley; and Lake 

Iamonia, Lake Jackson, Lake Lafayette, and Lake 

Miccosukee near Tallahassee in the Tallahassee Hills 

in Leon and Jefferson Counties, Fla. 
GEOLOGIC STRUCTURE 87 

LAKE BASINS DUE TO SOLUTION OF 

LIMESTONE 

Lake basins due to solution of limestone are 

chiefly in areas where the limestone is at or near 

the surface. In the upland ridge section of southern 

Florida, as in Polk and Highlands County, sinkholes 

that later became lake basins, however, formed in 

areas where the limestone is as much as several 

hundred feet below the land surface. The basins 

range from a few feet in diameter to several miles 

in diameter. Some of the basins are as much as 6 

miles in length in the Tallahassee Hills. The depths 

range from a few feet to more than 200 feet. 

Many smaller lakes occupying solution basins 

and some larger solution basins are more or less 

circular in outline, ranging from a few feet to a 

mile or more in diameter. These circular lakes are 

most common in the lake regions in the uplands in 

Florida and Georgia. Circular shallow depressions 

only a few feet deep and as much as several hundred feet in diameter are common on the Pamlico 

terrace and may also be present on some of the other 

low terraces. Although they have been called solution depressions, they apparently are surficial features that formed in tidal marshes and other shallow 

water along the coast during the last time the sea 

advanced over that area. At the present time, these 

circular depressions are forming on tidal marshes 

such as those in the salt marshes near the mouth of 

the St. Johns River near Mayport, Duval County, 

Fla., as shown by Harper· (1910, pl. 17). The sediments in this area are not calcareous, and limestone 

of the principal artesian aquifer is as much as 500 

feet below the surface. · 

As stated by Cooke ( 1945, p. 9), lakes of the Central Highlands indicate the occurrence of soluble 

limestone not far below the surface. Where the 

Ocala Limestone of the principal artesian aquifer is 

not too deeply buried, a lacy pattern of innumerable shallow lakes such as Lake Tsala Apopka forms. 

The lake region of the Central Highlands contains 

innumerable lakes, which range in size from mere 

ponds to bodies of water 9 or 10 miles wide, like 

Lake Apopka (Cooke, 1939, p. 102). · 

The largest lake basin is that occupied by Lake 

Okeechobee, which. appears to have originated during late Pleistocene time as a slight depression on 

the floor of the Pamlico sea (Cooke, 1939, p. 101). 

The oval lake has a maximum width of about 36 

miles north and south and 29 miles east and west. 

The water is very shallow near the shore. The bottom slopes gently to a maximum depth of about 15 

feet near the center. Although this basin did not 

form like the large solution basins in the principal 

artesian aquifer, probably solution of the surface 

of the Pleistocene limestone and marl that forms 

the bottom of the lake accounts in part for the basin. 

The limestone of the principal artesian aquifer 

under Lake Okeechobee and southeastern Florida is 

separated from the surficial formations by as much 

as 500 feet of the Hawthorn Formation, which 

contains relatively impervious beds. Although there 

are sinkholes in areas where the artesian aquifer is 

near the ·surface, there is no evidence of such sinks 

extending to that aquifer in southeastern Florida. 

In southwestern Florida, however, there was sufficient circulation and solution in the Hawthorn to 

form a few natural wells or sinkholes as shown by 

Still Lake on the sandy flatland, about 16 miles east 

and slightly south of Fort Myers, and· Deep Lake in 

the Big Cypress Swamp, about 10 miles north of 

the Tamiami Trail and 200 yards east of Florida 

Route 29. 

Most of the lakes are relatively shallow except 

those in natural wells and sinkholes which remained open. Pirkle and Brooks (1959, p. 315) 

reported that Devils Pit in Putnam County was explored by divers to a depth of 135 feet and 45 feet 

below sea level. Dismal Sink about 10 mil.es southeast of Tallahassee is another example of a deep 

sinkhole lake. As reported by R. H. Jordan (1950, 

p. 265), it is approximately 60 feet in diameter at 

the water surface, about 100 feet below the rim of 

the sink. The depth of the water is about 75 feet. 

Deep Lake in southwestern Florida is 97 feet deep 

and 300 feet in diameter. Still Lake is about 208 

feet deep and 600 feet in diameter (Parker and 

Cooke, 1944, p. 30). Nevin Hoy and Robert 0. 

Vernon (written commun., 1963) reported that 

Emerald Spring, a sinkhole lake, in the vicinity of 

Orlando, Fla., was 390 feet deep, the water level 

being 56 feet below land surface, July 12, 1950. The 

sink is about 20 feet in diameter from the surface 

to 20 feet below sea level where it connects with a 

large cavern, the bottom of which is 280 feet below 

sea level as reported by W. F. Lichtler (written 

commun., 1963). 

Many of the sinkhole lakes in Florida have no 

surface outlets. Some lakes, however, are connected 

with one another and drain into surface streams. 

The aquifer is recharged in the area of lake basins, 

and the artesian head of wells in the limestone is 

generally below the water table in the surficial material. 

Some of the large shallow lakes vary greatly in 

size with seasonal fluctuations; some of them are 
88 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

intermittent. Paynes Prairie, also called Alachua 

Lake, south of Gainesville in Alachua County, is an 

example of an intermittent lake which drains 

through Alachua sink into the underlying Ocala 

Limestone. When the sink through which it drains 

became clogged, the prairie was covered by a lake 

at least 9 miles long and 11j2 miles wide (Cooke, 

1939, p. 102). Lake Iamonia near Tallahassee drains 

intermittently through a sink in the underlying 

limestone as described by Gunter (1934). 

A sketch by Sellards (1914, p. 156, fig. 39) shows 

the relation· between · ground-water levels in the 

Ocala Limestone of the principal artesian aquifer 

in sinks and in lake basins in central Florida, from 

the vicinity of Gainesville passing through Paynes 

Prairie and Orange Lake and following the Oklawaha to the St. Johns River. Espenshade and Spencer (1963, p. 12) contrasted the drainage systems 

in the areas of the Ocala with those of the Hawthorn. No surface drainage is present in the areas 

where the Ocala is at or near the surface in the 

western part of Alachua County, but streams, ponds, 

and lakes are present in the area north of Gainesville, where the Hawthorn has not been removed. 

In a description of the origin and hydrology of 

lakes of north-central Florida, Pirkle and Brooks 

(1959, p. 302-317) included (1) a block diagram of 

Alachua County and vicinity, (2) section showing 

relationships of piezometric surface to lakes, and 

(3) a diagram showing the altitudes of some of the 

typical lakes in northeastern. Alachua County and 

adjacent Clay County, along with logs of test 

borings. Their section and block diagram show 

the Hawthorn escarpment and its relation to the 

underlying Ocala Limestone. The Hawthorn Formation forms an upland surface 150 to 200 feet 

above sea level in the north-central and much of the 

northeastern parts of Alachua County. One of the 

large basins occupied by Santa Fe Lake is on that 

upland. The western part of the county, where the 

Ocala Limestone is at or near the surface, ranges 

from about 80 to 90 feet above sea level. The southcentral part of the county is characterized by flatbottomed lakes and prairies and erosional remnants 

of the Hawthorn Formation. 

Lakes and their relation to the principal artesian 

aquifer in Alachua, Bradford, Clay and Union Counties, are discussed by Clark, Musgrove, Menke, and 

Cagle (1962). A section of Brooklyn Lake in southwestern Clay County shows a sinkhole that extends 

to the principal artesian aquifer (Clark and others, 

1963). The sink is on the edge of the large solution 

basin occupied by Brooklyn Lake. The sinkhole 

was apparently more than 400 feet deep before it 

was filled with unconsolidated material. It appears 

to be a satellite sink such as those commonly present 

near large solution basins. 

Pirkle and Brooks (1959, p. 309) recognized the 

formation of these basins through the solution of 

the limestone in north-central Florida but believed 

the solution is most rapid in the zone of aeration. 

The present author, however, believes that the evidence in caves in many limestone areas shows that 

the solution which formed the caves is chiefly in the 

zone of saturation. There are a few exceptions, such 

as Cliff Cave in St. Louis County, Mo., which Bretz 

(1956, p. 437) reported as having been formed almost entirely in the zone of aeration (vadose zone) 

and as being enlarged today by downcutting of the 

floor. He reported that on the walls and floor about 

500 feet from the entrance of the cave is the finest 

showing of solution faceting and fluting which he 

has observed in Missouri caves. Yet, on another part 

of the rock floor, a cascade 3 feet high, almost a 

waterfall, is receiving the heaviest deposit of flowstone. 

In addition to the large lake basins in north-central Florida, Sellards (1910, p. 47-76) described 

large lake basins in western Florida, including 

Lakes Iamonia, Jackson, Lafayette, and Miccosukee 

near Tallahassee (1917, p. 87-139). As suggested 

by Sellards and also by Cooke (1939, p. 103), the 

dendritic shorelines of these lakes suggest that they 

were originally surface streams which have been 

ca.ptured by underground drainage. Sellards showed 

by maps (1917, p. 134, 135) the St. Marks drainage 

system at the present time with Lake Miccosukee 

and the drainage system reconstructed as it may 

have existed. before the drainage went underground. His map of the Wakulla drainage system, 

including Wakulla Spring, shows that the headwater streams are surface streams but sink underground in the limestone and reappear as a spring 

which forms a surface stream. White (1958, p. 67) 

believed that the lake basins antedated the dismemberment of the streams. Formation of this drainage system and large solution basins, however, as 

suggested by Sellards, seems to be in accord with 

the history of limestone solution as interpreted by 

the present writer. 

During Pleistocene time, surface streams were 

active in removing the Hawthorn Formation in the 

area between the coastline and the Tallahassee Hills. 

As the Hawthorn escarpment retreated to its present 

position at the south edge of the Tallahassee Hills, 

the Tampa Limestone of the principal artesian aqui-
GEOLOGIC STRUCTURE 89 

:fer was exposed. Surface streams cut deep enough 

into the Hawthorn Formation to permit water to 

pass through to the underlying limestone,_ thus 

starting the solution channels and sinkholes that 

formed the farge lake basins.· It seems entirely 

possible that large areas above underground channels collapsed and that smaller sinks formed adj acent to the large sink, as may be seen at the northeast edge of Lake Iamonia. 

If the basins in the Tallahassee Hills were formed 

before surface streams cut into the Hawthorn, as 

suggested by White, it would seem plausible to 

expect an area of many circular sinkholes such as 

those in the southern part of Washington, Putnam, 

and Polk Counties and other areas where the location of many of the sinks is independent of the surface drainage. In some parts of the area in Washington County, the location of the sinks (Vernon, 

1942, p. 30) appears to have been influenced by 

surface streams and embayments of the Pleistocene sea. Some of the sinks that formed independent of surface streams are, however, now drained by 

surface streams which formed after the sinks, as 

may be seen at the head of some tributaries of Pinelog Creek in Washington County. 

ARTESIAN WATER 

PRINCIPLES OF OCCURRENCE 

Part of the water absorbed by the soil or surficial 

rocks percolates downward until it reaches a level 

where the rocks or soils are saturated. This saturated zone constitutes the zone of ground water 

that yields water to wells and springs, and its upper 

surface (except where that surface is formed by an 

impermeable body), which is at atmospheric pressure 

and is free to rise and fall, is known as the water 

table (Meinzer, 1923a, p. 22; 1923b, p. 32). The 

water table (the top of the zone of saturation) 

generally lies at a level which is the resultant of the 

relation between the rate at which water can drain 

downward and laterally and the rate at which water 

is added from above. Thus the water table fluctuates 

within a range depending on the geology, hydrology, 

and climate of the area. It may sink to a low level ; 

it may rise to the land surface. The water table 

begins to lower as soon as recharge diminishes and 

to rise when local recharge exceeds the rate of 

discharge. Artesian aquifers are under water-table 

conditions in some areas where they are at the surface. 

The water table, in general, is an undulating surface sloping toward nearby streams, lakes, or the 

ocean, where ground water discharges. Ground water moves downgradient under the influence of gravity from areas of recharge to areas of discharge, 

such as a spring or a well. The material in which 

the water occurs and moves is known as a waterbearing formation, or aquifer. The zone above the 

water table, not saturated with water, is known as 

the zone of aeration. As water from the surface percolates slowly downward to the zone of saturation, 

part of it is held in the zone of aeration by molecular 

attraction to the walls of the open spaces through 

which it passes. Although water in the zone of 

aeration is not available to wells, much of it is withdrawn by transpiration and by evaporation from 

the soil. 

In the coastal areas where the differences in altitude of the land surface are small and surface drainage is poor, the water table is generally only a few 

feet below the land surface. In areas of little relief, 

as in the Florida Everglades and the Okefenokee 

Swamp in Georgia and Florida, the water table may 

rise to the land surface. Inland where topographic 

relief is greater, the water table is at various depths. 

In places of maximum relief in the report area, the 

water table may be as much as 100 feet below the 

surface. 

Rocks that will not transmit water are said to be 

impermeable. In some areas, water that percolates 

downward reaches relatively impermeable material and, therefore, does not reach the main zone 

of saturation. The water table thus formed is 

known as a perched water table. For example, beds 

of clay intervening in generally permeable sand and 

gravel may cause a perched water table. Above the 

main water table there may be one or more perched 

water bodies. A perched body indicates a place 

where water is· added from above faster than it can 

drain through or off from the perching bed. 

Where artesian aquifers are at or near the surface, the water generally is under water-table conditions ; the water level in wells represents the water table. In areas of recharge through sinkholes 

and sinkhole lakes, where the artesian aquifer is not 

near the surface, as in the upland lake regions of 

Florida and Georgia, water levels in wells in the 

artesian aquifer normally are below the lake level 

and below the water table. Generally, the water 

table at the lake is ·approximately the same as the 

lake level. Water tables in north-central Florida 

are described by Clark, Musgrove, Menke, and Cagle 

(1962, p. 73, 76--85; 1963, p. 15--32). Outside the 

recharge areas, water levels or artesian heads of 

wells in the artesian aquifer may be above or below 

the water table. 
90 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Where relatively impermeable beds restrict the 

vertical movement of water in a completely saturated aquifer, the water occurs under artesian conditions, and the surface described by the levels to 

which water will rise in wells tapping the aquifer 

is referred to as the piezometric surface. Artesian 

conditions exist when the water is under greater 

than atmospheric pressure or when the water will 

rise above the top of the aquifer when tapped. 

Where the piezometric surface is lower than the 

water table, the water may move downward from 

the nonartesian aquifer into the artesian aquifer. 

Where the water table is lower than the piezometric surface, water may nwve upward from the 

artesian aquifer into the nonartesian aquifer or to 

flowing wells and springs. 

Artesian water is ground water that is confined 

between beds of low permeability and is under sufficient pressure to rise in a well above the level at 

which it is found. Water moving downdip under the 

force of gravity may eventually become confined between beds of low permeability ; it is then under 

hydrostatic pressure. This pressure is caused by the 

weight of water in updip parts of the aquifer and is 

also affected by the degree of confinement of the 

overlying beds. Where ground water completely saturates an aquifer that is overlain by relatively impermeable strata and the water is under sufficient 

hydrostatic pressure to rise above the top of the 

aquifer in a well, the water is said to be :under artesian pressure. The height to which water will rise in 

tightly cased wells in an artesian aquifer is the 

pressure head, often called merely head. The head is 

represented by water levels in nonflowing artesian 

wells. In flowing artesian wells, the position or the 

height at which the water level would stand in a 

well if the casing were extended may be determined 

by measuring the shut-in pressure. Where referred 

to common datum, water levels represent the pressure-indicating surface, or piezometric surface, 

which is the equivalent of the water table for nonartesian conditions. The position of the water table 

is within the nonartesian aquifer, but the piezometric surface of the artesian water is above the top 

of the artesian aquifer. If the artesian pressure declines and the piezometric surface falls below the 

top of the artesian aquifer, conditions change from 

artesian to nonartesian, and the water level in the 

aquifer will be the water table. Artesian wells will 

flow in areas where the piezometric surface is above 

the ground. 

Water enters an artesian aquifer in areas of relatively high altitude where the impervious confining 

beds that overlie the aquifer and prevent or retard 

vertical movement of the artesian water are absent, 

where sinkholes penetrate the confining beds, and 

where the aquifer is at or near the land surface or is 

overlain by permeable material. From such intake 

or recharge areas, the water reaches the permeable 

rocks and gradually moves laterally downgradient in 

the aquifer under the confining beds in response to 

pressure produced by recharge; The hydrostatic 

head of the column of water extending from the 

water table in the recharge area through the aquifer causes the water to move to points of discharge. 

The term "confined water" adapted from German 

usage (Tolman, 1937, p. 316) is used by some investigators instead of artesian water. Also, the terms 

"aquiclude" and "aquifuge" are used in some reports on artesian water. Tolman (1937, p. 36-37) 

defined aquiclude as a formation which, although 

porous and capable of absorbing water slowly, will 

not transmit it fast enough to furnish an appreciable supply for a well or spring. The term "aquifuge," as used by Tolman, is a rock that is impervious to water. Granite, quartzite, and completely 

cemented sedimentary rocks are given as examples. 

W. M. Davis (in Tolman, 1937, p. 37) originally 

suggested the term to include both aquifuge and 

aquiclude but approved the restricted use by Tolman. 

In the present report the term artesian water is used 

instead of confined water. The use of the terms 

"aquiclude" and "aquifuge" is considered unnecessary in this report. 

As first adapted and used by the U.S. Geological 

Survey (Fuller, 1906, p. 9-15), the term "artesian" 

was applied to water under sufficient hydrostatic 

pressure to rise above the level at which it was 

penetrated by a well but which did not necessarily 

rise to or above the ground surface. Later, Meinzer 

(1923a, p. 39) defined artesian water as water that 

would rise above the zone of saturation, or water 

table. Tolman (1937, p. 316) and others adopted 

Meinzer's definition. In many artesian areas the 

height to which water rises in wells is not, however, 

directly related to the water table, which fluctuates 

with local recharge and discharge. In general, the 

position of the water table is affected by topography, 

being highest under hills where there is recharge 

and lowest in valleys and other areas where the 

ground water discharges to the surface. In these 

areas the piezometric ·surface may be relatively 

smooth and may show no relation to the ground surface. In areas of topographic relief of even only a 

few feet, the piezometric surface may be below the 
ARTESIAN WATER 91 

water table where the land surface is high, and it 

may be above the water table where the land surface is low, although there is no difference in the 

artesian aquifer. Because of th1s problem with the 

definition of artesian water, the Geological Survey 

returned to Fuller's definition which is now generally 

used, expressed as water that will rise above the top 

of the artesian aquifer in wells that penetrate it. 

All aquifers are both reservoirs and conduits. 

However, under artesian conditions, aquifers function chiefly as conduits in which water may move 

literally many miles from the intake to the discharge 

areas. Under water-table (nonartesian) conditions, 

aquifers generally function chiefly as reservoirs in 

which the water does not move laterally many 

miles. There are exceptions as on the High Plains 

in New Mexico and Texas, where water under watertable conditions may move many miles before reaching a point of discharge. These two functions of 

aquifers must be recognized and differentiated in 

the understanding of the geology and hydrology of 

artesian aquifers. 

Aquifers are recharged naturally by precipitation, underground percolation, and in some cases by 

streamflow. Discharge occurs as springs, seeps, 

underground leakage, evaporation, and transpiration. If the water table is near the land surface, 

water may be discharged by evaporation from the 

soils and by transpiration from plants. Although 

evaporation and transpiration may be as much as 

the precipitation in humid regions, there is generally sufficient recharge to form springs and seeps 

that feed the streams and maintain their flow during 

dry seasons. Where the artesian aquifers are deeply 

buried, there is no discharge from them by evaporation and transpiration. 

Artesian aquifers are generally inclined. Upward 

leakage of the water may take place through the 

relatively impervious formations overlying the 

aquifer. A reduction of artesian pressure due to. 

withdrawal of water may reduce the upward leakage 

and permit the pressing out of water from overlying 

beds into the permeable parts of the aquifer. Although this may be a relatively small amount for 

each square foot of area, the total is considerable in 

large areas in which the piezometric surface has 

been lowered such as that in the Fernandina area, 

Florida. Soon after pumping begins, the water table or piezometric surface around a pumped well 

assumes a form which is comparable to an inverted 

cone. Where the aquifer is homogeneous, the cone 

of depression will be circular if the original water 

table or piezometric surface had been horizontal, 

but elliptical if the initial water table had been 

sloping. 

Slight differences in geology may cause significant differences in the _hydrologic properties of an 

aquifer (Stringfield and Cooper, 1951a, p. 804). 

Two of these properties, the hydraulic permeability and the specific yield, are among the most important factors affecting the perennial yield. Hydraulic permeability of an aquifer is its capacity to 

transmit water. The quantity of water that will 

flow through a permeable formation is directly proportional to the cross section through which the water percolates, the hydraulic gradient, and the coefficient of permeability. The quantity is inversely 

proportional to the viscosity of the water. The field 

coefficient of permeability (Meinzer, 1936, p. 702; 

Wenzel, 1942, p. 7) as used by the U.S. Geological 

Survey represents the quantity of water in gallons 

per day that will flow through a cross section of the 

aquifer 1 mile wide and 1 foot thick, under a hydraulic gradient of 1 foot per mile, at the prevailing 

temperature. This unit, known as a meinzer, may 

be expressed as the rate of flow, in gallons per day, 

through a cross section of 1 square foot under a 

hydraulic gradient of 100 percent. The coefficients 

determined in the laboratory are for 60°F. Corrections for temperature must be made in comparing 

permeability in different areas and in laboratory 

tests. Wenzel (1942, p. 10) gave a conversion table 

for changing meinzers at 60°F to other permeability units at 60° and 68°F. 

The field coefficient of permeability multiplied by 

the saturated thickness of the aquifer, in feet, may 

be . defined as the coefficient of transmissibility 

(Wenzel, 1942, p. 10; Theis, 1935, p. 520). It represents the quantity of water, in gallons per day, 

that will flow through a cross section of the aquifer 

1 mile wide under a hydraulic gradient of 1 foot 

per mile. An aquifer having a saturated thickness 

of 200 feet and a coefficient of permeability of 500 

would have a transmissibility of 100,000. In other 

words, a vertical section of this aquifer 1 mile 

wide having a hydraulic gradient of 1 foot per mile 

would transmit 100,000 gpd. If the hydraulic gradient were 10 feet per mile, it would transmit 1 

mgd (million gallons per day) . If there were a 

cone of depression having a gradient of 100 feet per 

mile at a certain distance from the well, the aquifer 

having a saturated thickness of 100 feet and· coefficient of permeability of 500 would transmit, through 

a cylindrical section 1 mile in circumference, 5 mgd 

(500x100x100). 

A family of curves of the leaky-aquifer type was 
92 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

developed by H. H. Cooper, Jr., and was used by 

Bermes, Leve, and Tarver (1963, p. 65-67) to determine the coefficient of leakance (commonly 

known as coefficient of leakage), for the principal 

artesian aquifer in several parts of Flagler, Putnam, 

and St. John Counties, Fla. The curves are based 

upon equations that assume a permeable aquifer 

overlain by semipermeable confining beds through 

which water, under a constant head, can infiltrate 

to recharge the aquifer. The coefficient of leakance 

is defined as the number of gallons that will pass 

through each cubic foot of a semipermeable confining bed in 1 day under a unit hydraulic gradient. 

It is equal to the vertical permeability of the confining bed in meinzers divided by the thickness of 

the beds. 

The specific yield (Meinzer, 1923b, p. 51) of an 

aquifer is the proportion of its volume that is occupied by water which it ultimately yields by gravity. 

For example, 100 cubic feet of saturated material 

having a specific yield of 25 percent will yield 25 

cubic feet of water when drained by gravity. The 

term "effective porosity" has been used by groundwater investigators to mean approximately the 

same as specific yield. Students of agriculture prefer to use "effective porosity"· in another way, and 

petroleum geologists use it in a more general sense. 

In ground:..water studies, however, loose use of the 

term "porosity" may be misleading. A saturated 

clay that will yield little or no water to wells may 

have a higher porosity and contain more water than 

a productive water-bearing sand, but its effective· 

porosity, or specific yield, is much less than that of 

sand. The specific yield indicates the storage capacity of nonartesian aquifers, expressed as the coefficient of storage. As used by the U.S. Geological 

Survey (Theis, 1940, p. 277), the coefficient of storage is the number of cubic feet of water released 

from storage in a saturated vertical column of the 

aquifer 1 foot square when the water table declines 

1 foot. 

Under artesian conditions, the coefficient of storage is the number of cubic feet of water released 

from storage in a vertical column of the aquifer 1 

foot square when the piezometric surface declines 

1 foot. In nonartesian aquifers the coefficient of 

storage is much larger than in artesian aquifers because water is drained from pores and interstices 

as the water table declines. Under artesian conditions, however, all pores and interstices remain 

saturated with water as the piezometric surface declines, and the aquifer releases water from storage 

only by contracting in proportion to its volumetric 

compressibility as the artesian pressure decreases. 

A nonartesian aquifer might have a coefficient of 

storage or specific yield of 0.25; lowering the water 

table 1 foot in a cubic foot of such an aquifer would 

release 0.25 cubic foot of water from storage. Ferris, Knowles, Brown, and Stallman (1962, p. 76-78) 

gave a range of 0.05 to 0.30 for storage coefficients 

of water-table aquifers and a range of about 0.00001 

to 0.001 for storage coefficients of artesian aquifers. 

Under artesian conditions, the aquifer might have 

a storage coefficient of 0.00025 cubic foot of water 

from storage in a vertical column of 1 square foot 

of the aquifer. This quantity may seem insignificant, but in an artesian aquifer extending over many 

square miles the quantity is appreciable. Available 

data (Meinzer and Hard, 1925, p. 90-93) on artesian 

water in the Dakota Sandstone led Meinzer (1936, 

p. 719) to the conclusion that the great quantity of 

water discharged by several thousand flowing wells 

supplied by the sandstone in the last half century 

was in considerable part derived from storage 

through compression of the aquifer, rather than 

from recharge or lowering of the water table in the 

outcrop area. 

Lohman (1961, p. B47-B49), beginning with 

Meinzer's work, briefly reviewed the concepts of the 

occurrence of water in artesian aquifers ; he derived 

an equation for determining the amount of elastic 

compression of artesian aquifers from known declines in artesian pressure and known hydrologic 

properties of the aquifers. 

In a study of the coefficient of storage in a region 

of major subsidence caused by compaction of an 

aquifer system, Poland (1961, p. B52-B54) found 

that the stored water released by compression or 

compaction of clayey beds is about 50 times as great 

as the water released by elastic expansion of the 

water and elastic compression of the aquifer. The 

stored water yielded by clayey beds would be large 

only during the first decline of artesian pressure. 

The yield as determined from a short-term pumping 

test, however, would be only about one-fiftieth of the 

yield from storage during a period of 15 to 25 

years. Poland also found that, if the pressure recovered and then was drawn down again through the 

same interval, the compression of the clayey beds, 

if mostly preconsolidated during the first drawdown 

phase, would be only a small fraction of that of the 

first phase of pressure decline, probably less than 10 

percent. Meinzer stated (1928, p. 263~291; 1936, 

p. 718) that cones of depression produced under 

artesian conditions involve the transfer of much 

more water than would be required merely by ex-
ARTESIAN WATER 93 

pansion of the water as a result of its . volume 

elasticity. The coefficient of storage is a function of 

the elasticity of an artesian aquifer (Ferris and 

others, 1962, p. 88). 

The difference in the amount of water· obtained 

from storage accounts for some of the differences 

between the behavior of wells in artesian aquifers 

and those in nonartesian aquifers. For example, 

under water-table conditions, the cone of depression of a producing well forms slowly because it involves the removal of much water from storage. 

Under artesian conditions the cone of depression 

forms rapidly because removal of less water from 

storage is involved for a given area and the transmittal of pressure effects is rapid. 

In tests made by Leggette and Taylor (1934, p. 

409-413) in the artesian basin of Ogden Valley, Utah, 

the effects of pressure changes were transmitted at 

different rates according to varying conditions. 

However, in all cases the transmission occurred at~ 

much more rapid rate than in the elaborate tests 

made by Wenzel (1936, p. 37-38) under nonartesian 

conditions in Platte Valley, Nebr., where the rim of 

the cone of depression reached 500 feet from the 

producing well in 2 hours, 900 feet in 6 hours, and 

about 1,200 feet in 12 hours. In the Utah tests the 

opening of an artesian well affected the artesian 

pressure head in an observation well 2,850 feet distant in 7 minutes; the opening of another well 3,850 

feet distant affected the head in the observation well 

in 57 minutes. In other tests, changes of pressure 

were transmitted a distance of 2 miles in 3 to 13 

hours. The rate of progress of pressure effects in 

water in a permeable but perfectly rigid rock formation encased in perfectly rigid and impermeable 

confining beds would doubtless be very rapid although not instantaneous. 

Investigations by Warren (1944, p. 24-77) on 

artesian water in the Tertiary limestone in the 

coastal area of Georgia showed that large changes 

in rates of withdrawal caused measurable fluctuations in artesian pressure for approximately 17 miles, 

and wells as much as 25 miles away appe.ared to be 

affected. In one test in the Savannah area, change 

in rate of pumping required about 2 days to affect 

the artesian pressure in a well about 6 miles distant. 

Warren ( 1944, p. 60-64) found that the pressure 

effects of recharge of the principal artesian aquife-r 

in the coastal area of Georgia required several 

months to extend 90 miles. 

The amount of water discharged naturally from 

an aquifer not affected by wells is equal to that entering in the recharge area, except for temporary 

differences due to changes in the amount stored in 

the aquifer. The average discharge rate for a long 

period is approximately equal to the average re-

~harge rate. Withdrawal of water from wells is 

balanced by a decrease of water in storage, a decrease in discharge, an increase in recharge, or a 

combination of these changes. 

Water first withdrawn from wells is largely from 

storage, but as withdrawal continues and the piezometric surface declines, the withdrawal consists of 

increasing amounts of water that would have been 

discharged naturally~ or water that would have 

been rejected from recharge. Removal of water 

lowers the water level and creates a hydraulic 

gradient. The shape of the piezometric surface or 

water table where a hydraulic gradient has formed 

toward a well or group of wells is known as the cone 

of depression. The extent and shape of a cone of 

depression depends in part on the coefficient of 

transmissibility of the aquifer and the distance to 

recharge and discharge areas. When the effects of 

withdrawal reach the intake or recharge areas, the 

rate of recharge is increased if there is any rejected 

recharge prior to the development of wells. 

When the effects of withdrawal reach an area of 

discharge, the rate of discharge will be decreased. 

As stated by Cooper (19.44, p. 179), increase in recharge and decrease in natural discharge may be 

regarded as salvage. Water will be removed from 

storage and water levels will decline until the rate 

of salvage equals the rate of ·withdrawal from 

wells. The time required for water levels to reach 

equilibrium, other conditions being equal, is more 

or less proportional to the coefficient of storage. If 

the rate of withdrawal exceeds the maximum rate 

of salvage, the perennial yield will be exceeded, and 

water levels in wells in the area of withdrawal will 

decline persistently. Water levels and artesian head 

in wells are used to determine the cones of depression and other features of the piezometric surface. 

The fluctuations of water levels and artesian head 

also give essential information in determining the 

yield of an aquifer. 

The drawdown, or lowering of water level in a 

pumped well, is usually limited in the development 

of an area. In some places, water may be withdrawn 

at a rate that exceeds the perennial yield, although 

the entire area may not be overdeveloped. The practical limits to which water levels can be lowered in 

wells, as stated by Cooper ( 1944, p. 179), may be 

the bottom of the aquifer, or the limit beyond which 

salt water might be drawn into wells. In some 

areas of thick deep aquifers, where water levels are 
94 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

deep, the practical limit is an economical one beyond which pumping of water would be too expensive to justify its use. Although the pumping costs 

are not generally regarded as a limiting factor in 

obtaining water supplies from wells in the area of 

this report, the economical use of the artesian. water 

for irrigation in some areas in Florida depends on 

the artesian head. It is economical to use artesian 

wells that flow, but the cost of pumping water is 

not justified for some crops in some areas. 

Spacing wells as far apart from one another as 

practicable and as near to areas of recharge or 

natural discharge as feasible will help keep the 

drawdown to a minimum. If a thick aquifer consists of relatively productive zones, a larger quantity of water for the same drawdown may be obtained by drilling through more of the productive 

zones, thereby increasing the· amount available to 

wells. This method increases the yield of the wells, 

which generally is expressed as gallons per minute 

without reference to the drawdown in the well. 

The yield has more significance when expressed as 

specific capacity, which is the ·yield in gallons per 

minute per foot of drawdown. 

ARTESIAN AQUIFERS IN TERTIARY LIMESTONE 

Artesian aquifers in the Tertiary limestone of the 

southeastern States consist of many local aquifers 

and one principal aquifer. The principal aquifer underlies Florida, southern Georgia, and adjacent parts 

of South Carolina and Alabama. · 

Many local artesian aquifers consist of sand and 

· limestone in the Hawthorn Formation. In some 

places, sand and other permeable material overiying 

the Hawthorn yield water under artesian pressure. 

All these aquifers are shallow and overlie the principal artesian aquifer of Tertiary age. Clark ( 1964, 

p. 7-12) described two shallow aquifers in the· upper 

part of the Hawthorn Formation in the southwestern part of Sarasota County. In northwestern Polk 

County, Fla., two shallow artesian aquifers, one 

in the Hawthorn and the other in the overlying 

Bone Valley Formation, are described by H. G. 

Stewart (1959, p. 29-31). 

Bermes ( 1958b, p. 29-32) described an artesian 

aquifer in the Hawthorn Formation in Indian River 

County, Fla. Parker (in Parker and others, 1955, p. 

193) described .a Pleistocene artesian aquifer 16 to 

35 feet below land surface· overlain by hardpan at 

Indiantown, Martin County, Fla. Permeable limestone in the Tamiami Formation in the Naples area 

in Collier County (Klein, 1954, p. 18) forms an 

artesian aquifer. The upper part of the Tamiami, 

with its· top 15 to 20 feet below mean sea level, is 

relatively impervious and prevents or retards upward movement of artesian water from the aquifer. 

These shallow artesian aquifers generally do not 

yield large .quantities of water. When large supplies 

are required, wells are therefore drilled into the underlying principal artesian aquifer, except in areas 

where the deep artesian water is too highly mineralized to be satisfactory for use. One of the most productive aquifers is the Biscayne aquifer in southeastern Florida extending from the surface to a 

depth of about 100 feet or more along the coast in 

the Miami area. Schroeder, Klein, and Hoy (1958, 

p. 5) reported that the Biscayne aquifer is as much 

as 200 feet thick in the vicinity of Fort Lauderdale 

in Broward. County. Tarver (1964, p. 39) reported that the aquifer extends from the surface 

to a depth of about 400 feet in the Pompano Beach 

area only a few miles north of Fort Lauderdale. A 

brief description of the Biscayne aquifer is given 

here because it is in part artesian and in part of 

Tertiary age. Parker (in Parker and others, 1955, 

p. 160-162) named the unit the Biscayne aquifer 

and described it as consisting of the following formations : ( 1) A thin layer of very permeable limestone of the Tamiami Formation of Miocene age, 

(2) insignificant erosional remnants of Caloosahatchee Marl of Pliocene age, (3) Fort Thompson 

Formation, ( 4) Anastasia Formation, ( 5) Key 

Largo Limestone, and ( 6) Pamlico Sand-the last 

four of Pleistocene age. The principal part of the 

Biscayne aquifer is the Fort Thompson Formation. 

This· shallow aquifer consists chiefly of cavernous 

sandy limestone and calcareous sandstone. Most of 

the cavities are filled with permeable sand. Many of 

the vertical solution channels filled with sand extend to the land surface. Some of these areas are 

covered by a thin blanket of permeable sand through 

which the precipitation moves downward to the 

water table. 

In 1908 the Miami public. water supply was from 

four flowing artesian wells in the shallow aquifer. 

They ranged in depth from 73 to 95 feet (Parker 

and others, 1955, p. 585). Although there is no 

record of the height to which the artesian water 

rose, it could not have been more than a few feet 

above sea level. Later after the wells stopped flowing and pumps were installed, the wells were 

plugged at a depth of 40 to 45 feet to avoid inflow of 

water from the lower part of the aquifer which had 

become contaminated with salt water. 

The capacity of the Biscayne aquifer to yield water to wells is very large. The transmissibility of the 
PRINCIPAL ARTESIAN AQUIFER 95 

aquifer in the Miami area (Parker and others, 1955, 

p. 270) ranges from 4 to 15 mgd per ft. Transmissibility represents the quantity of water (gpd) that 

will move through a cross section of the aquifer 1 mile 

wide under a hydraulic gradient of 1 foot per mile. 

As the flow is directly proportional to the hydraulic 

gradient, the quantity would be twice as much under 

a gradient of 2 feet per mile. Where the aquifer is 

about 100 feet thick, the permeability would. range 

from 40,000 to 150,000 gpd per sq ft. Results of 

pumping tests on wells penetrating the Biscayne 

aquifer in the Greater Miami area showed that the 

aquifer behaves as an unconfined or water-table 

aquifer and that the coefficient of storage is essentially equal to the specific yield. 

In comparing this shallow Biscayne aquifer in the 

Miami area with the principal artesian aquifer 

(Floridan) , Warren and Parker (in Parker and 

others, 1955, p. 270) reported that a well 18 inches 

in diameter penetrating less than 100 feet of the Biscayne aquifer would yield 5 mgd with a drawdown 

of 2 to 3 feet. A typical well of the same diameter 

penetrating the Floridan aquifer in the Jacksonville area would have a drawdown of about 50 feet 

with a yield of 5 mgd. As determined by Warren. 

(1944, p. 103-104) the principal artesian aquifer has 

an average transmissibility of 250,000 gpd per ft 

at Savannah, Ga. At Brunswick, Ga., the transf!1iSsibility ranges from 750,000 to 1,000,000 gpd per ft. 

The average permeability of the aquifer where it is 

500 feet thick is computed as 500 meinzers at Savannah and 1,500 to 2,000 at Brunswick. 

PRINCIPAL ARTESIAN AQUIFER 

The principal artesian aquifer, which is the source 

of nearly all the artesian water in Florida and southeastern Georgia, consists chiefly of limestone ranging in age from middle Eocene to middle Miocene. 

The aquifer also yields water to many wells in adj acent parts of Alabama and South Carolina. It includes the following formations or equivalents from 

bottom to top : Lake City Limestone, Tallahassee 

Limestone, and A von Park Limestone of middle Eocene age; Ocala Limestone of late Eocene age ; Marianna Limestone, Suwannee Limestone, and Flint 

River Formation of Oligocene age ; and the Tampa 

Limestone and lower part of the Hawthorn Formation of Miocene age. In some places the Oldsmar 

Limestone or its age equivalent of early Eocene age 

may form part of the aquifer. Some formations in 

southwestern Georgia and southeastern Alabama act 

as separate aquifers where the Tertiary limestones 

merge into sandy formations. These have been designated as Paleocene and Eocene · limestone-sand 

aquifers by Herrick (Thomson and others, 1956, p. 

271). Most of the limestones grade laterally into 

sandy and clayey deposits in western Florida, southeastern Alabama, southwestern Georgia, east-central 

Georgia, and South Carolina. After the principal 

artesian aquifer of Tertiary age was defined (Stringfield, 1953, p. 28), Applin and Applin (1944, p. 

1683-1703) divided the Ocala Limestone and older 

Eocene limestone into several formations on the 

b~ses of micropaleontology and named these .formations Ocala, Avon Park, and Lake City. The limestones of the aquifer act as a hydrologic unit, as was 

demonstrated when the pressure surface of the artesian water was mapped in the Flor1da peninsula 

in 1933 (Stringfield, 1936, pl. 12). 

Parker (in Parker and others, 1955, p. 189) proposed tha.t the aquifer· be named Floridan. That 

name is commonly used in Florida. In Georgia, Warren (1944) used the terms "the principal artesian 

limestone aquifer" and "the principal artesian aquifer." Counts and Donsky (1959, p. 96-102; 1963, 

p. 23) referred to the aquifer as the principal artesian aquifer in the Savannah area, Georgia and 

South Carolina. In this and some other reports, 

the term "principal artesian aquifer" is used because 

it is the principal aquifer in Florida and southeastern Georgia as defined in 1933. Where the discussion of artesian water relates chiefly to the principal 

artesian aquifer, in some parts of this report it is 

merely designated as the aquifer. In South Carolina 

and in parts of Georgia and Alabama, where the 

underlying Cretaceous formations consisting chiefly 

of sand are the source of artesian water locally, the 

principal artesian aquifer is differentiated from the 

Cretaceous by referring to it as the principal limestone aquifer or Tertiary artesian aquifer. 

EXTENT AND THICKNESS 

The principal artesian aquifer is one of the most 

extensive limestone aquifers in the United States. 

It underlies Florida, ·southeastern Georgia, and adjacent parts of South Carolina and Alabama. It is at 

or near the land surface in areas where the Tertiary limestones crop out in a broad belt extending 

from western Florida through southeastern Alabama, Georgia, and into southeastern South Caro:-

lina, approximately paralleling the Fall Line. The 

aquifer also is at or J)ear the surface in a large area 

in north-central Florida, where the Tertiary limestones are exposed on the· Ocala uplift. The top of 

the aquifer in. Florida and southeastern Georgia is 

shown in figure 23. The extent of the aquifer in 

Georgia is shown in figure 24. The oldest exposed 
96 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

0 ~ 

29"r---------i-----------}---------~----------~----·------~_: 

27r-----------~-----

26"r-----:--+----

25"r-----~-

50 

EXPLANATION 

Sinkholes breaching 

-

Hawthorn Formationor younger Miocene. deposits 

Aquifer at or 

.. 

near the land surface 

Structure contou.rs 

Drawn on top of aquifer; dashed 

where approximate. Ticks indicate 

depression. Contour interval 100 

feet; datum is mean sea level 

0 50 lOOMILES 

? 

FIGURE 23.-Contour map of top of principal artesian aquifer. (Florida, from Vernon, 1955; Georgia, from Warren, 1944.) 
PRINCIPAL ARTESIAN AQUIFER 97 

85' 84' 83' 

""\-·~ 

\Rom~ 

I 

32' 

82' 

50 0 50 100 MILES 

FIGURE 24.-Extent of the chief artesian aquifers in the 

Coastal Plain in Georgia. (From S. M. Herrick and R. L. 

Wait, 1956, fig. 2.) 

formation of the aquifer in Florida is the A von Park 

Limestone. The underlying Lake City Limestone is 

not exposed. Formations believed to be its equivalent in age, however, as shown in the correlation 

chart (table 1, p. 28), are exposed in the areas extending from Alabama to South Carolina where the 

Tertiary formations are at the surface. The thickness of the aquifer in a section across Florid~ and 

Georgia is shown in figure 7. Figure 25 shows several sections in Georgia. 

The aquifer north and south of the Ocala uplift in 

Florida is as much as 1,500 feet thick. In addition to 

the wells in figure 7, the log of a well 1,455 feet deep 

reported by Bishop (1956, p. 84-86) 2 miles south of 

De Soto City in Highlands County, 135 feet above 

sea level, indicates that the top of the Oldsmar Limestone which forms the bottom of the aquifer in this 

area is at a depth of 1,375 feet. The depth, thickness, and correlations at De Soto City based on that 

record are as follows: 

Formation 

Hawthorn ................................... . 

No sample ................................... . 

Suwannee Limestone ................ . 

Ocala Limestone ........................ . 

A von Park Limestone ............... . 

Lake City Limestone ................. . 

Oldsmar Limestone ................... . 

Depth below 

land surface 

(feet) 

20-515 

515-541 

541-610 

610-900 

900-1150 

1150-1375 

1375-1455 

Thickness 

(feet) 

495 

26 

69 

290 

250 

225 

80 

If we consider the Oldsmar Limestone as the bottom of the principal artesian aquifer in this area, 

the total thickness of the aquifer up to the Hawthorn 

is 860 feet. Where present, the limestone in the 

lower part of the Hawthorn generally is part of the 

aquifer. If we judge from the log, the limestone 

present in the Hawthorn below depths of about 400 

feet may be part of the aquifer. Inclusion of the 

limestone from depths of 400 to 1,375 feet in the 

aquifer would make a total thickness of 975 feet. 

In northwestern Polk County, H. G. Stewart (1959, 

p. 29-31) reported that the limestone of the Hawthorn is locally separated from the principal aquifer. 

The limestone is confined above the clay in the upper part of the Hawthorn or the lower part of the 

Bone Valley Formation. The deepest well reached 

the A von Park at a depth of 355 feet and apparently 

had not passed through it at a depth of 1,200 feet. 

Thus the A von Park is at least 845 feet thick. At that 

locality, the A von Park is overlain by about 200 feet 

of the Ocala and about 75 feet of the Tampa-a total 

thickness of 1,120 feet for the aquifer, exclusive of 

the lower part of the Hawthorn. 

In the Cosme-Odessa well field in the northwestern 

part of Hillsborough County, Fla., a well 1,200 feet 

deep ended in the A von Park Limestone. A log of 

that well (Florida Geol. Survey W-5423) prepared 

by C. W. Hendry, Jr., of the Florida Geological Survey, showed the following: 

Depth below Thickness 

Formation land surface (feet) 

(feet) 

Post-Miocene .............................. 0-40 40 

Tampa Limestone (Miocene) ... 40-110 70 

Suwannee Limestone 

(Oligocene) .............................. 110-380 270 

Ocala Limestone (Eocene) ........ 

Upper member ..................... 380-420 40 

Lower member ..................... 420-640 220 

A von Park Limestone 

(Eocene) .................................. 640-1200 560 

Hendry refers to the Ocala Limestone as the Ocala 

Group, composed of the Crystal River, Williston, and 

Inglis Formations. The Crystal River is shown as 

the upper member in the preceding log. The Williston and Inglis, each 110 feet thick, are shown as the 

lower member. According to that log, the aquifer is 

at least 1,160 feet thick in the area. 

In western Florida the thickness of the aquifer 

appears to be as much as 800 feet (Marsh, 1962b, 

fig. 2). In southern Florida and the coastal area 

south of St. Augustine, where the artesian water 

has a relatively high chloride content, the maximum 
98 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

thickness of the aquifer is not known. However, 

available records indicate that the thickness probably ranges from about 500 to at least 1,000 feet. 

The deeper water is generally more highly mineralized, and, therefore, most of the water wells are not 

drilled to the bottom of the aquifer. In the coastal 

areas from St. Augustine to South Carolina, the aquifer generally ranges from 500 to 800 feet thick. In 

northeastern Florida and southeastern Georgia, the 

bottom of the aquifer is about 1,000 feet below sea 

level, and the top is 450 to 550 feet below sea level. 

Cooper (1944, p. 171) reported that in Duval and 

Nassau Counties in northeastern Florida the depth 

to the top of the aquifer ranges from about 250 feet 

in southwestern Duval County to 550 feet below sea 

level in Nassau County. Leve (1961a, p. 9) showed 

the top· of the Ocala Limestone (Crystal River For-

.m~tion) at a depth of 570 feet in a well at Jacksonville and at a depth of 5.50 feet at Fernandina. The 

well at Jacksonville reached the top of the Lake City 

Limestone at a depth of 935 feet but did not pass 

through it. The well at Fernandina reached the 

Lake City at a depth of 1,280 feet and the Oldsmar 

at a depth of 2,130 feet. 

In the Savannah area, Georgia, the top of the 

Ocala Limestone, the upper part of the aquifer at 

that .locality, is about 250 feet below sea level; part 

of the aquifer in that area is the Gosport Sand and 

Lisbon (McBean) Formation of middle Eocene age. 

The Lisbon (McBean) Formation is the lowest part 

of the principal artesian aquifer in the western part 

of the Savannah area (Counts and Donsky, 1959, p. 

99; 1963, p. 22). The formation becomes less permeable in the eastern part of the area and forms part 

of the relatively impervious barrier that separates 

the aquifer from the underlying water. The Tallahatta Formation underlying the Lisbon is the principal barrier separating the aquifer from the salt 

water in the Tallahatta and underlying formations 

in the Savannah area. 

In a fence diagram, figure 25, of the artesian aquifers in the Coastal Plain in Georgia, Herrick (in 

··. Thomson and others, 1956, pl. 2) showed the relation of the principal artesian aquifer to the limestonesand aquifers of Paleocene and Eocene ages into 

which it merges in southwestern Georgia and to the 

underlying Cretaceous aquifers. ··The principal artesian aquifer underlies about two-thirds of the Coastal 

Plain.i~ Georgia. 

,,; RI<;CHAHGE AND DISCHARGE 

Recharge of the principal artes'ian aquifer by surface water occurs in areas in which the aquifer is at 

or near the surface. Also some recharge occurs in 

areas in which the aquifer is overlain by relatively 

impervious beds of the Hawthorn Formation. Recharge through the Hawthorn in amounts sufficient 

to be revealed by the piezometric surface, however, 

occurs where sinkholes extend from the surface 

through the Hawthorn to the aquifer. Many sinks 

are now almost completely filled with relatively permeable unconsolidated sands through which water 

may move downward. Lakes occupy many of these 

sinkholes forming the upland lake regions in Florida 

and Georgia. 

The rate of recharge through sinkholes ranges 

from zero in sinks filled with relatively impervious 

material to 100 percent in open sinks. In some areas 

where the sinks were covered by the Pleistocene sea, 

they were completely filled with relatively impervious material, but later compaction and settling in 

the sinks formed surface depressions that are now 

occupied by ponds and lakes. Probably many sinks 

filled with sediments on the coastal terraces are not 

detectable at the surface. 

In a study of water-level fluctuations of ponds in 

depressions of old sinkholes and the water table in 

an area in Baker and Early Counties in southwestern 

Georgia, Hendricks and Goodwin (1952, p. 210) concluded that the effect of these ponds upon recharge 

of ground-water aquifers is minor. In other parts of· 

southwestern Georgia and in the Valdosta area, recharge through sinks is large. 

Clark, Musgrove, Menke, and Cagle (1962, p. 28, 

83) reported evidence of recharge through sinkholes 

in part of north-central Florida, described in the 

present report as the Putnam County area of the 

piezometric surface. In discussing lakes in the northwestern part of Putnam and the southwestern part 

of Clay Counties, they stated that the large range 

in stage of the sinkhole lakes without surface outlets 

may be due partly to the fact that an open sinkhole 

is taking water when the lake level is above the piezometric surface or water table. Also, it is possible 

that the sinkhole is· filled with very permeable material through which water moves downward to the 

underlying aquifer as shown in sections of Brooklyn 

Lake in the southwestern part of Clay County (Clark 

and others, 1963, figs. 13-16). Northeast of the area 

of sinkholes that reach the principal artesian aquifer, there is a sinkhole about 85 feet deep occupied by 

Kingsley Lake in western Clay County. Clark, Musgrove, Menke, and Cagle (1962, figs. 17, 18) included 

a section and depth contour map. As the water table 

and water level in the lake are about 100 feet above 

the piezometric surface, they concluded that if the 

\: 
1-

MILES L_ 

. 800 FEET 

JO HORIZONTAL SCALE O 

DATUM IS LAND SURFACE 

-~ ... >.:\L 

' T u sea loosa 

Formation 

SL indicates sea level 

- --~o_uJ'II c4Jlo 

"-----~--- 131 ce;;;;;;-.~""' 1

"' ~- ----211 

---~-

366 

108 

~~ 

EillJ 

Miocene and younger 

deposits 

Ocala and 

-

associated limestones (Eocene, Oligocene, 

and Miocene) 

1=.=:.::1 

~ 

McBean Formation 

(Eocene) 

EXPLANATION 

~ WWL+I ~ Tuscahoma Formation 

~ (Eocene) I-

<( 

::I 

0 

0 

I-

~ 

0::: 

<( 

i= 

0::: 

w 

INanafalia 

~ Formation 

(EOcene) 

L2J 

Clayton Formation 

(Paleocene) 

~ ~ \ ~ Post-Cu~~~~ Formation 

I-w EJ•'··· .. ..;. VI <( . : ·.:.. ::I 

i5 Cusseta Sand 8 

o prw;;}~tl ~ 

~ Bluffto~; ~nd Eutaw I ~ ~ Formations u i= . 

0::: W []]'•• '1• 'J' I- ...... 

Tuscaloosa Formation 

FIGURE 25.-Fence diagram showing principal artesian aquifer in southeastern Georgia (Herrick and Wait, 1956). For logs of wells see report by Herrick (1961). 

'i:l 

~ 

z 

Cl 

-., 

~ 

> 

~ 

1-3 

l:.%j 

U2 

-> z 

> A) 

~ 

~ ~ 

(.0 

(.0 
100 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

bottom of the sink originally extended to the aquifer, 

it is now partly filled and sealed. They also concluded 

that if the water table were as much as 100 feet 

above the piezometric surface, millions of gallons of 

water per day probably would recharge the principal 

artesian aquifer by seeping downward through relatively impervious beds of the Hawthorn Formation 

into the aquifer. However, if such recharge occurs, it 

apparently is not sufficient to have a detectable effect on the piezometric surface~ 

In areas where the sinkholes are open or filled with 

permeable sand and are connected to the underlying 

limestone, large quantities of surface water flow directly into the aquifer. Rainfall percolates rapidly 

through the sand into the permeable limestone in 

areas in southern and western Alachua County 

where the Hawthorn Formation is thin or absent 

and the Ocala Limestone of the principal aquifer is 

at or near the surface. Although the amount of water entering the aquifer in that area is not known, 

Clark, Musgrove, Menke, and Cagle (1962, p. 84) 

concluded that it doubtless averages at least millions 

of gallons per day. This average rate of recharge 

probably is one of the highest, if not the highest, for 

this aquifer. Pride, Meyer, and Cherry (1961, p. 

86-87) recognized recharge through sinkholes in the 

Green Swamp area in Polk and Lake Counties in 

central Flo"rida:. · 

In a study of the relation of lakes to the principal 

artesian aquifer in the Lake Placid area in Highlands County, Fla., Kohout and Meyer (1959, p. 64) 

estimated that the average downward leakage to the 

principal artesian aquifer caused the level of Lake 

Placid to decline an average of 2 to 3 inches a month 

from January to July 1956. This decline is equivalent to a rate of recharge to the aquifer of 6,400,000 

to 9,500,000 gpd. That amount multiplied by the 

large number of lakes and sinkholes through which 

recharge occurs in the lake regions of Florida and 

Georgia gives some indication of the volume of recharge. However, additional studies of recharge 

through other lakes and sinks will be needed to give 

reliable estimates of the total recharge in the lake 

regions. Lakes that do not occupy sinkholes or solution basins in the areas underlain by the Hawthorn 

Formation do not recharge the principal artesian 

· aquifer, as has been shown by Kohout (in Kohout 

and Meyer, 1959, p. 15-25) in a study of Lake Istokpoga east of Lake Placid, Fla. 

During flood stage, water in surface streams 

enters the aquifer locally, as along the Flint River 

in Georgia and the Suwannee and Santa Fe Rivers 

in Florida. However, the recharge by these streams 

in a humid climate is not a significant source of 

artesian water in comparison with recharge by 

streams that cross the outcrops of aquifers in arid 

and semiarid areas, such as the Coastal Plain in 

Texas. 

Although recharge from rivers in the area of this 

report returns to the surface streams, such transfer 

of water is of value in storing water in the aquifer 

during floods. Such recharge also reduces the 

amount of discharge from the aquifer into the 

rivers during floods. In the event of the development 

of a large water supply from the aquifer near the 

stream, the withdrawal of water from the stream 

would salvage some of the floodwater in the aquifer 

and reduce the discharge to the river. If the withdrawal of water reversed the hydraulic gradient between the river and the area of withdrawal, that part 

. of the aquifer would be recharged by the river. · 

Although artificial recharge of the principal aquifer through wells or other methods has not been 

practiced to increase the supply, wells are used in 

some areas to drain surface water into the aquifer 

where the surface drainage is not adequate, as dis-. 

cussed under drainage wells. Such wells effectively 

recharge the aquifer in areas where water level in 

the limestone is not near the land surface. Some 

recharge and discharge of the aquifer may occur in 

the subsurface by exchange of water between the 

aquifer and overlying and underlying formations. 

Natural discharge from the aquifer in quantities 

sufficient to be detected on the piezometric surface 

of the artesian water or by direct observation occurs 

as springs, where the aquifer is near the surface, 

a11d at submarine outcrops. At the submarine outcrops, discharge occurs where the artesian pressure 

exceeds the back pressure of the salt water. Many 

large springs on land and some submarine springs 

discharge through sinkholes and solution basins. 

Some sinkholes extend from the surface through 

several hundred feet of the Hawthorn Formation 

into the principal aquifer. 

WATER-BEARING PROPERTIES 

Water-bearing properties are discussed in the 

descriptions of the geologic formations of the aquifer. As a unit, the principal artesian aquifer is 

unusual in its great thickness and areal extent. It 

is the source of the large limestone springs in 

Florida and Georgia. Silver Springs in the northcentral part of Florida near Ocala is one of the 

largest limestone springs in the world, having had 

an average discharge of 809 cfs for 26 years (U.S. 

Geol. Survey, 1960b, p. 69). The aquifer yields water 
PRINCIPAL ARTESIAN AQUIFER 101 

to thousands of artesian wells that are the source 

of water for some of the largest ground-water supplies in the country. 

Some parts of the aquifer consist chiefly of soft 

masses of foraminifer or coquina, which are very 

permeable. Part of the Ocala ·Limestone is soft and 

chalky without apparent bedding planes. Before the 

limestones were altered by solution, water moved 

through permeable parts, particularly joints and 

fractures. Apparently, most of these joints and 

fractures are now closed, except where water has 

enlarged them. Many of the vertical solution channels formed at intersections of two joint systems. 

Joints and bedding planes, differences in lithology, 

and original permeability of the water-bearing formations were factors in the origin of the horizontal 

solution channels in these formations. However, the 

zoning of these channels and cavities was controlled 

to a large extent by the position of the points of discharge with reference to sea level. 

A large part of the ground water is in cavities 

and solution channels, many of which are filled 

with permeable sands. In general, the cavities are 

largest and most numerous in the areas where the 

aquifer is at or near the surface, as on the crest of 

the Ocala uplift in north-central Florida and in 

regions where sinkholes extend from the surface to 

the aquifer. Downdip from the Ocala uplift, as in 

southern Florida where there are fewer solution 

cavities and where the limestone contains calcite 

and anhydrite and gypsum, the permeability is much 

less. In some areas, as in Sarasota County, the lower 

part of the aquifer yields little or no water. 

The aquifer contains, at different depths, lenses 

of relatively impervious chert and silicified limestone. These affect the vertical movement of the 

water locally, but they are not extensive enough to 

separate the limestone into different aquifers, except 

in western Florida and southwestern Georgia. Most, 

if not all, wells drilled into the aquifer yield water. 

A well drilled into the aquifer near Parrish in Manatee County, Fla., was reported to yield no water. 

(D. W. Dansby, oral commun., 1932). However, it 

is not known whether the well was deep enough to 

test the total thickness of the aquifer. 

In some areas, as in northwestern Polk County, 

the lower part of the Hawthorn Formation is separated from the underlying limestone by a bed of 

clay (H. G. Stewart, 1959, p. 29). Locally in that 

area, only the lower part of the Hawthorn is an 

aquifer. Where the clay bed is absent, relatively 

impervious beds in the limestone prevent or retard 

upward movement of the artesian water in the principal artesian aquifer. Where the Hawthorn Formation is absent, surficial clay and other relatively 

impervious deposits ranging in age from Miocene to 

Recent may confine the water locally. Several different formations ranging from middle Eocene to late 

Eocene form the bottom of the aquifer. 

FLORIDA 

Alachua, Bradford, Clay, and Union Counties 

The water-bearing properties of the principal artesian aquifer and the relation of the aquifer to 

surface streams and lakes in these counties were 

described by Clark, Musgrove, Menke, and Cagle 

(1962). The area is underlain by a series of limestones and dolomites to depths of several thousand 

feet. The limestones and dolomites are generally 

overlain by relatively thick beds of clay, sandy clay, 

and: limestone of the Hawthorn Formation. A series 

off.high terrace deposits forms most of the land surface. The water-table aquifer consists of shallow 

sand or clayey sand. The artesian aquifers consist 

of limestone layers. The source of the largest supplies is the principal artesian aquifer. 

Brevard County 

Reports (D. W. Brown and others, 1957, 1962) 

have described the geologic format{ons and waterbearing properties of the principal artesian aquifer. 

The development of adequate supplies and the prevention of flooding in the St. Johns River valley are 

the principal water problems in Brevard County. 

The mineralization of the artesian water prevents 

its use as a public water supply in the area east of 

the St. Johns River. Nonartesian water occurs in 

the sediments of Pleistocene and Recent age ; artesian water is in the underlying limestones of 

Eocene age. The piezometric surface of the artesian 

aquifer is higher than the land surface over most 

of the county. Wells drilled into the aquifer overflow at the surface. 
102 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Collier County 

The upper part· of the principal artesian aquifer 

consists of the Tampa · Limestone and permeable 

limestone and shell beds in the lower part of the 

overlying Hawthorn Formation (Klein, 1954, p. 22); 

In the. Naples area the Hawthorn is about 400 feet 

thick with its top 170 feet below the land surface. 

At depths of 200 to 250 feet, limestone in the Hawthorn Formation yields artesian water that rises 

approximately to the land surface in wells. The 

artesian head in the principal aquifer was about 18 

feet above land surface in 1938. 

Columbia County 

Meyer (1962, p. 37-38) described the geologic 

formations and the water-bearing properties of the 

principal artesian aquifer. A pumping test on a 

well in the Lake City area indicated a transmissibility of 270,000 gpd per ft and a coefficient of storage 

of 0.0008 for the upper part of the aquifer. 

Duval and Nassau Counties 

For the vicinity of Jacksonville, Cooper (1944, 

p. 178) computed that the coefficients of transmissibility of the aquifer ranged from about 50,()00 to 

1,000,000 gpd per ft. The smallest coefficient was 

obtained from a well that penetrated only 250 feet 

of the aquifer, and the largest was from a well that 

penetrated 700 feet of the aquifer. Thus, the coefficient of permeability was only about 200 gpd per sq 

ft for the upper 250 feet of the aquifer and about 

1,430 for 700 feet. Much of the water was from cavities in the limestone. Cooper reported that, during 

the deepening of municipal well 22 at the McDuff 

pumping station at Jacksonville, the artesian flow 

was reported to have increased almost instantaneously from 500 to more than 1,500 gpm, when the 

well penetrated a cavity whose vertical dimension 

was 2 feet at a depth of 1,260 feet. According to a 

log by Leve (1961a, p.' 9), the Lake City Limestone 

is at this depth. Because the aquifer consists of 

zones of permeable limestone interbedded with relatively impervious limestone or chert, the coefficient 

of transmissibility represents approximately that 

part of the aquifer that :yields water to the well. 

The transmissibility computed from a well that 

penetrated 555 feet of the aquifer ·at Fernandina, 

Nassau County, is about 150,000 gpd per ft. This 

value gives a permeability of about 260 gpd per sq 

ft, only slightly more than the upper 250 feet of the 

aquifer at Jacksonville. The transmissibility of the 

total thickness of the aquifer may be larger than 

that indicated for 555 feet. However, the shape of 

the piezometric surface of artesian water in the 

aquifer in local areas also shows significant differences in the transmissibility of the aquifer in different areas (Stringfield and others, 1941, p. 698-

711). The shape of the piezometric surface, together 

with the quantity of water from wells, indicates 

that the transmissibility is much greater at Jacksonville than at Fernandina. 

The coefficient of storage of the aquifer as determined by Cooper (1944, p. 178) by pumping tests 

on wells was only 0.00025 at Fernandina. Pumping 

tests ·on wells indicated coefficients of storage of 

0.017 at Jacksonville and 0.021 in Duval County, 6 

miles southwest of Whitehouse. A well 12 inches in 

diameter, drilled near Yukon, Duval County, in November 1942, flowed 6,500 gpm when first completed. 

The initial flow of two other wells measured by 

Cooper ( 1944, p. 17 4) near Yukon was 3,200 and 

4,000 gpm. 

In the log of a well 2,130 feet deep at Fernandina, 

in Nassau County, Leve (1961b, p. 8) showed the 

following formations : 

Formation 

Post-Hawthorn ---------------------------------------------------------- Hawthorn ----------------------------------------------------------------- Ocala Limestone 

Upper member -------------------------------------------------- Lower member -------------------------------------------------- A von Park Limestone ---------------------------------------------- Lake City Limestone ------------------------------------------------ Oldsmar Limestone --------------------------------------------------

Depth 

(feet) 

0-40? 

40?-550 

550-840 

840-1,028 

1,028-1,280 

1,280-1,756 

1,756-2,130 

Leve showed the upper member of the Ocala as 

the Crystal River Forma~ion from 550 to 840 feet. 

The 'iower. member of the Ocala is spown as the 

Williston Formation from 840 to 930 feet and the 

Inglis Formation from 930 to 1,028 feet. The Inglis 

contains relatively impermeable peds of hard dense 

crystalline dolomite and limestone that restrict vertical mov~me~t of the water. 

The lower part of the Hawthorn represents the top 

of the principal artesian aquifer in the Fernandina 

area. Although not shown by Leve, it appears that 

the bottom. of the aquifer is at a depth of about 

1,400 feet in the Lake City Limestone; below this 

depth are dense relatively impervious beds separating the aquifer from the relatively highly mineralized water in the lower part of. the Lake City and 

the Oldsmar Limestones. The chloride content of 

water from wells more than 1,400 feet deep ranged 

from 50 to 1,060 ppm, and water from wells less 

than 1,400 feet deep ranged from 26 to 41 ppm 

(Leve, 1961b, p. 16-17). However, chloride content 

of eight samples of water collected over a period of 

about 3 years from one well 1,700 feet deep ranged 

from 52 to 38 ppm. The bottom of the well is near 
PRINCIPAL ARTESIAN AQUIFER 103 

the unconformable contact of the Lake City Limestone and the overlying Oldsmar Limestone. A comparison of the log of a well at Fernandina with a 

well near Jacksonville as given by Leve (1961a, p. 

9) shows significant differences in the geology, 

which may explain some of the differences in permeability. Apparently at Fernandina, the upper part 

of the Lake City Limestone which is productive at 

Jacksonville, Fla., was removed by erosion, and dense 

dolomite of the A von Park was deposited. 

Flagler, Putnam, and St. Johns Counties 

A report by Bermes, Leve, and Tarver ( 1963) 

described the geology and ground-water resources of 

Flagler, Putnam, and St. J obns Counties and included maps showing the distribution of the members of the Ocala Limestone and the areas in which 

the formations contain water having a relatively 

high chloride content. 

They computed the transmissibility, storage coefficient, and leakance coefficient for the upper part 

of the aquifer in several places in Flagler, Putnam, 

and St. Johns Counties (Bermes and others, 1963, 

table 5, p. 67). The transmissibility ranged from 

173,000 to 360,000 gpd per ft; the storage coefficient 

ranged from 1.9 X 10-" to 9.4 X 10-4, and the leakance coefficient ranged from 1.5 X 10- 3 to 1.75 X 

10-~. Judg-ing from the thickness of the -part of 

the aquifer penetrated by the wells tested, the average permeability ranged from about 850 to 2,500 

gpd per sq ft. 

Highlands County 

The Lake City Limestone, consisting of crystalline 

dolomite and permeable limestone and dolomitic 

limestone, is one of the most productive formations 

of the aquifer in Highlands County, according to 

Bishop (1956, p. 18). Apparently, it forms the 

lower part of the aquifer in Highlands County. The 

overlying Avon Park Limestone consists of about 

200 to 350 feet of granular to chalky limestone containing considerable secondary calcite and some dolomitic limestone. Bishop reported that it is not an 

important source of large water supplies in Highlands County. The Ocala Limestone, which unconformably overlies the Avon Park, consists of about 

200 to 400 feet of granular to chalky foraminiferal 

limestone; some beds consist almost entirely of 

foraminifers. The yield from the Ocala apparently 

is not as large as th~t from the Lake City Limestone. 

The Suwannee Limestone which unconformably 

overlies the Ocala is present in the western part of 

Highlands County. Its maximum thickness is about 

80 feet. The Suwannee consists chiefly ·of slightly 

permeable soft chalky to slightly crystalline limestone. Although it is used for small domestic water 

supplies, the Suwannee is not an important part of 

the aquifer in Highlands County. 

The Hawthorn Formation unconformably overlies 

the Suwannee Limestone and Ocala Limestone in 

Highlands County. In the northern part of the 

county, Bishop (1956, p. 25) included, in the Hawthorn, sandy limestone which may be part of the 

Tampa if that formation is present in this area. 

The sandy limestone may form the top of the principal artesian aquifer in this area. The Hawthorn 

ranges in thickness from about 300 feet in the 

northern part of Highlands County to about 650 feet 

in the Lake Placid area. 

Hillsborough County 

Peek (1959b, p. 12) stated that the Suwannee 

Limestone and Tampa Limestone are the chief 

sources of water in the aquifer in the Ruskin area of 

Hillsborough County, although the underlying Ocala 

Limestone and A von Park Limestone may be productive. Because the beds thicken and dip to the 

southwest, wells of similar bottom altitude will penetrate older formations in the northeast than in the 

southwest. Most of the deep wells in the southwestern part of the county produce water from the 

Tampa and Suwannee, whereas those in the centraleast and northeast produce from the A von Park. 

The Tampa and Suwannee yield 1,000 gpm. The 

A von Park yield exceeds 5,000 gpm ~n some wells. · 

Wetterhall (in Menke and others, 1961, p. 72) reported that the Suwannee and Tampa Limestones, 

partly dolomitized and having . high permeability 

and solution channels, are more productive than the 

underlying Ocala and Avon Park Limestones in Hills- ~ 

borough County. He stated that throughout most of 

the county all the limestone acts as an aquifer, but 

where there is large discharge from the Tampa and 

Suwannee Limestones, these formations act as an 

aquifer separate from limestones below the Ocala 

Limestone. Recharge to or discharge from an aquifer will cause differences in water levels at different depths within the aquifer. Therefore, differences in water levels at different depths in the 

same aquifer may be expected in recharge and discharge areas. The presence of solution cavities in 

the Oldsmar and Cedar Keys Limestones caused Wetterhall to include these formations as part of the 

principal artesian aquifer. In the absence of evidence that these formations are hydrologically connected with the principal artesian aquifer, the writer 

does not, however, regard them as part of the 
104 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

aquifer. Solution cavities in the Eocene and Cretaceous formations underlying the principal aquifer 

probably were formed before the formations of the 

principal aquifer were dep0sited. Some of the cavities remained open while the limestone was being 

buried by the younger formations. 

The principal artesian aquifer penetrated by a 

well (Florida Geol. Survey W-5423) 1,200 feet 

deep in the northwestern part of Hillsborough 

County is chiefly limestone to the top of the A von 

Park Limestone at a depth of 640 feet, according to 

the log of well W-5423 by C. W. Hendry, Jr. (written commun., 1962). The Avon Park Limestone, 

which was penetrated from 640 feet to the bottom 

of the well, consists chiefly of dolomite containing 

gypsum in the lower part. 

In a study of the movement of water in the Tampa 

and Suwannee Limestones, Wetter hall (in Menke 

and others, 1961, p. 73-74) concluded that solution 

channels in the limestone formed along joints, 

faults, and bedding planes. In his investigation of 

Sulphur Springs, a sodium fluorescein dye test indicated that the water moved in a pattern similar to 

that of the regional joint systems mapped by Vernon 

(1951, p. 47-48). Wetterhall suggested that both· 

vertical and lateral movements probably occur along 

faults. However, the writer is unable to find evidence to support this suggestion. 

Sands and Hmestone in the Hawthorn Formation 

are the source of water for many domestic supplies 

and small irrigation supplies. The formation contains relatively impervious beds which retard or prevent upward movement of artesian water in the 

lower part of the Hawthorn and the underlying 

limestone of the principal aquifer. Peek (1959b, p. 

23-24) reported that the artesian pressure in the 

Hawthorn is considerably less than that in the underlying limestone. However, a current-meter survey by Peek in part of the area seemed to indicate 

that the lower part of the Hawthorn is part of the 

principal aquifer. Results of a pumping test (Peek, 

1959b, p. 54) on well 40-27-7 in the aquifer near 

Sun City gave a transmissibility of 114,600 gpd per 

ft and a storage coefficient of 0.0006. 

Manatee County 

The Tampa and underlying Suwannee Limestones 

are the chief water-bearing formations of the principal artesian aquifer in Manatee County, as described by Peek ( 1958a, p. 26-34) . Few wells in 

the county penetrate the Ocala Limestone and underlying A von Park Limestone. Current-meter surveys 

in wells by Peek showed that the lower part of the 

Suwannee Limestone below a depth of about 600 

feet yielded little or no water. The most productive 

part of the aquifer is the Tampa Limestone. The 

lower part of the Hawthorn apparently forms the 

top of the aquifer. A survey of one well showed 

that permeable beds in the upper part of the Hawthorn at depths of 60 to 70 feet are under lower 

artesian head than that of the principal aquifer. 

Water from the aquifer enters the wells, moves upward, and flows into the uncased part of the Hawthorn Formation. South of Manatee County in adjoining Sarasota County, Stringfield (1933c, p. 205-

214) found that the lower part of the Hawthorn 

Formation and the upper part of the Tampa Lime-

. stone ·are the chief water-bearing formations of the 

aquifer. No artesian flow was detected· in wells below about 675 feet. 

Martin County 

As described by Lichtler (1960, p. 14-20, 35-36) 

the principal artesian aquifer in Martin County includes the A von Park Limestone at the bottom, overlain by the Ocala Limestone and the Suwannee 

Limestone. About 10 to 15 feet of the Tampa Limestone may be present. A well 1,800 feet deep north 

of Indiantown may have penetrated the Lake City 

Limestone. The water was reported too salty for irrigation, and the well was sealed off at 1,100 feet 

before the initial depth could be checked. 

The A von Park Limestone, estimated to be about 

400 feet thick, is a good source of water for irrigation where the water is not too salty. The overlying 

Ocala Limestone is generally permeable and is an important part of the principal artesian aquifer, although it generally is less than 100 feet thick and 

only 20 feet thick in one well. 

A fault having a vertical displacement of 300 to 

400 feet parallels the coast about 5 miles inland. 

The Suwannee Limestone, overlying the Ocala-20 

to 60 feet thick on the west ( upthrown) side of the 

fault and from 100 to 170 feet thick on the east 

(downthrown) side-yields moderate amounts of 

water to artesian wells. The permeability is generally lower than that of the underlying formations, 

and the chloride content of the water is higher. 

Limestone, about 10 to 15 feet thick, may represent 

the Tampa, about 2 miles south of Stuart. This 

limestone has moderate permeability and yields some 

water to artesian wells. The chloride content, like 

that in the underlying Suwannee, is higher than 

that from more permeable parts of the Ocala Limestone and A von Park Limestone. 

The Hawthorn Formation, 350 to 550 feet thick, is 
PRINCIPAL ARTESIAN AQUIFER 105 

generally relatively impervious and does not yield 

significant amounts of water to wells in Martin 

County. It prevents or retards upward movement 

of artesian water in the underlying limestone. The 

top of the aquifer is about 600 to 1,000 feet below 

sea level. An appreciable artesian flow begins in 

wells drilled to about 660 to 800 feet below sea level 

on the west side of the fault. On the east side, wells 

bE.gin to flow at depths of 800 to 1,000 feet below sea 

level. 

Current-meter surveys (Lichtler, 1960, p. 38) in 

several wells show the depth at which water enters 

the wells. Two miles west of Palm City, in a well 

773 feet deep and cased to 400 feet, the estimated 

flow is about 300 gpm. About 30 percent of the 

water enters the well between depths of 660 and 

675 f-eet, about 25 percent between 700 and 720 feet, 

about 25 percent between 7 40 and 760 feet, and the 

remaining 20 percent between 760 feet and 773 feet. 

About 80 percent of the water is obtained from 

about 55 feet of the Ocala Limestone and A von Park 

Limestone. Twelve miles west of Palm City, in a 

well 696 feet deep having an estimated flow of 190 

gpm, nearly 100 percent of the water enters the 

well between depths of 685 and 696 feet. 

East of the fault, in a well 1,315 feet deep having 

an estimated flow of 300 gpm, 18 percent of the 

water enters between depths of 960 and 970 feet, 18 

percent between 1,235 and 1,245 feet, and the remainder almost uniformly between 1,245 and 1,315 

feet. The limestone section through which the water 

moves laterally is about 355 feet thick, about three 

times the thickness on the west side. This increase 

in thickness is chiefly in the Suwannee Limestone. 

The fault apparently has little or no effect on the 

hydraulic gradient of the artesian water or the direction of movement of the water laterally, even 

though the formations on the east side of the fault 

are 300 to 400 feet deeper than those on the west 

side. The faulting apparently occurred prior to the 

deposition of the Hawthorn Formation in Miocene 

time, and therefore the relatively impervious beds of 

the Hawthorn, which prevent or retard upward 

movement of the water, have not been faulted. Only 

the water-bearing formations of the aquifer ( Suwannee, Ocala: and A von Park Limestones) have 

been displaced. Under these conditions relatively 

impervious beds which might form barriers such as 

those in the Hawthorn Formation have not been 

faulted against water-bearing formations. During 

the low stand of the sea in Pleistocene time there 

was an opportunity for solution channels to form on 

both sides of the fault and to cross it. 

Pinellas County 

The Tampa Limestone, which is cavernous in 

Pinellas County, forms the upper part of the artesian 

aquifer. It overlies the Suwannee Limestone, which 

is also an important water-bearing formation of the 

aquifer in this county (Heath and Smith, 1954, p. 

12-18). The underlying Ocala Limestone is not used 

as much as the overlying formations because it is 

more than 300 feet deep and yields water that is 

harder than that from the overlying limestone. 

Along the coast some of the water has a relatively 

high chloride content. 

The Tampa Limestone is near the surface in the 

northern part of Pinellas County. West of Lake 

Tarpon, water in the Tampa and the Suwannee is 

under water-table conditions. East of Lake Tarpon 

and south of Palm Harbor, it is under artesian conditions. 

Polk County 

In the Lakeland area in northwestern Polk County, 

the coefficient of transmissibility of the aquifer, as 

computed by H. G. Stewart (1959, p. 39) from a 

pumping test on a well 1,200 feet deep, is 1,000,000 

gpd per ft. The top of the aquifer was at a depth of 

180 feet; the well penetrated 1,120 feet of the aquifer. However, the well was cased to a depth of 292 

feet, 908 feet being open to the aquifer. At this 

thickness, the average permeability of the aquifer is 

about 1,100, about 330 less than the highest average 

permeability recorded at Jacksonville, even . though 

the aquifer appears to be more cavernous in the 

Lakeland area than in the Jacksonville area. This 

difference in permeability in the aquifer in the two 

areas may arise because many cavities in the Lakeland area may be filled with sand and clay that entered through sinkholes in Pleistocene time when the 

sea stood lower than its present level. The transmissibility is appreciably less in the upper part of the 

. aquifer than in the lower part ; it differs considerably from place to place. 

In the Lakeland area, a 26-inch well, 1,200 feet 

deep with 292 feet of casing, yielded 6,500 gpm with 

a drawdown of 11.6 feet during a 6.5-hour pumping 

test, which gives a specific capacity of 560 gpm per 

ft of drawdown. The maximum specific capicity reported (Stringfield, 1936, p. 159, 173, 186) is 833, 

for a well 18 inches in diameter, 852 feet deep, 

cased to a depth of 324 feet. The yield of that well 

was 7,500 gpm with 9 feet of drawdown. 

H. G. Stewart (1959, p. 19) reported that the 

A von Park Limestone is the most productive part· of 

the principal artesian aquifer in Polk County. Although the upper part of the overly'ing Ocala Lime-
106 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

stone is soft permeable limestone containing many 

shells of large foraminifers, the yield to wells is reported to be small. The Suwannee Limestone above 

the Ocala has permeable beds of limestone containing foraminifers. Locally, at or near the top of the 

Suwannee, are masses of chert, commonly 1 inch to 

2 feet thick, but in a few places they may be as much 

as 10 feet thick. The Suwannee generally supplies 

enough water for domestic supplies. The Tampa 

Limestone forms the top of the principal aquifer. 

Locally in northwestern Polk County, the overlying 

Hawthorn Formation is separated from the Tampa 

by a clay bed 3 to 15 feet thick which H. G. Stewart 

referred to the Tampa Limestone. H. G. Stewart 

listed many solution cavities whose vertical dimensions ranged from 2 to 43 feet at depths from 102 

feet above sea level to 584 feet below sea level. 

Putnam County 

In Putnam County (Leve, 1958, fig. 2) the principal aquifer consists of the Lake City, A von Park, 

and Ocala Limestones. It apparently is more than 

700 feet thick in the western part of the county and 

somewhat less in the St. Johns River valley. However, only a few of the wells penetrate the Avon Park 

Limestone and the underlying Lake City Limestone. 

The Ocala, about 100 feet to 135 feet thick, is the 

principal source .of water. The top of the -Ocala is 

about 25 feet below sea level in the western part of 

the county and 125 to 170 feet below sea level in the 

central and eastern parts. Because of the irregular 

surface of the Ocala, these depths may differ as 

much as 50 feet within a few hundred yards. The 

Hawthorn Formation and younger deposits unconformably overlie the Ocala. 

Discontinuous limestone beds of the Hawthorn 

form the upper part of the principal artesian aquifer 

(Leve, 1958, p. 11). Relatively impervious beds of 

the Hawthorn and younger formations prevent or 

retard upward movement of the artesian water in 

the underlying aquifer. In the western part of the 

county, sinkholes extend from the surface through 

the Hawthorn into the Ocala. In the southeastern 

part of the county in the St. Johns River valley, the· 

Hawthorn is thin or absent, and the unconsolidated 

Pleistocene deposits overlie the Ocala. 

Seminole County 

In Seminole County, the principal artesian aquifer 

includes the Lake City Limestone, as shown by 

Heath and Barraclough (1954, fig. 2). However, few 

wells have been drilled into the Lake City, the top 

being as much as 600 feet below sea level in the 

southwestern part of the county~ Water supplies 

can generally be obtained from the overlying Avon 

Park and Ocala Limestones. 

The Lake City Limestone generally consists of alternating layers of crystalline dolomite and chalky 

dolomitic limestone. Where the aquifer does not 

contain salt water, the water in the Lake City is less 

highly mineralized than that in the overlying Avon 

Park and Ocala (Barraclough, 1962, p. 12). Heath 

and Barraclough (1954, p. 13) suggest that this difference may be due to the dolomitic limestone in the 

Lake City, which is less soluble than pure limestone. There is also the possibility that silicification 

of the limestone has made that part of the aquifer 

less soluble. 

The A von Park Limestone consists of as much as 

500 feet of chalky limestone, some of which has 

been dolomitized since it was deposited. The limestone forms the top of the aquifer in the northeastern part of the county, where the Ocala has been 

removed by erosion. It is the principal water-bearing formation of the aquifer in Seminole County. 

The Ocala Limestone consists of chalky limestone 

in the upper part and dolomitic limestone in the 

lower part. It is as much as 75 feet thick in the 

southern part of the county and thins toward the 

north where it has been eroded. The Ocala is one 

of the most productive formations of the aquifer and 

yields water to hundreds of irrigation and domestic 

wells. 

The Hawthorn Formation consists of sandy limestone interbedded with clay and marl, which prevents or retards upward movements of the artesian 

water. It is about 75 feet thick in the southwestern 

part of the county but has been removed by erosion 

in the northern part and along the St. Johns River 

valley. In the northern part of the county, deposits 

consisting of clay in the upper part and sandy shell 

beds at the base (Heath and Barraclough, 1954, p. 

14) overlie the Hawthorn where present and the 

limestones of Eocene age where the Hawthorn is absent. These deposits were assigned to the Pliocene 

(Caloosahatchee Marl) by Stubbs (1938, p. 30-31) 

and Cooke (1945, p. 225). Vernon (1951, figs. 13, 

33) assigned these beds to late Miocene. Heath and 

Barraclough reported that the head and quality of 

water in the sandy shell beds is similar to that in the 

underlying limestone. Under these conditions, the 

shell beds are a part of the principal artesian aquifer-an exception to the general condition in which 

the lower part of the Hawthorn Formation is the 

youngest part of the aquifer. 

A surficial blanket of deposits, as much as 50 feet 

thick, chiefly sand of Pleistocene and Recent age, 
PRINCIPAL ARTESIAN AQUIFER 107 

covers the county. These deposits . contain some 

shelly sand and thin beds of clay in the St. Johns 

River valley. In some places these deposits contain a 

layer of sand generally less than 2 feet thick, cemented with iron oxide and other cementing. agents. 

This relatively impervious layer, known locally as 

hardpan, underlies most of the level lowlands at a 

depth of 3 to 5 feet and retards downward percolation of water, making it possible to irrigate celery 

an~ other crops through drain tile buried about 3 

feet deep. In some places hardpan may retard or 

prevent upward movement ·of water in the underlying sands. Water having sufficient artesian pressu,re 

to overflow at the surface in shallow wells may be 

present in such areas. 

Barraclough (1962, p. 18) and Wyrick (1960, p. 

24) stated that the aquifer is faulted along the north 

edge of Seminole County and south edge of Volusia 

County. A downthrown block of the westward-striking fault underlies part of the St. Johns River valley 

and the north end of Lake Monroe. Barraclough 

suggested that a surface expression of this fault 

block is probably shown by the westerly offset of the 

St. Johns River along the northern part of the 

county. 

However, the writer believes that Lake Monroe, 

Lake Jessup, and Lake Harney occupy large basins 

formed by solution of limestone of the principal 

aquifer. These basins formed along with the numerous sinkholes in this area. The course of the St. 

Johns River was controlled in part by these large 

lake basins and by conditions along the coast when 

sea level was higher than at the present time. 

Volusia County 

Limestone underlies Volusia County at a depth of 

40 to 100 feet and extends to a depth of several 

thousand feet. The limestone is overlain by sand, 

clay, and shell sediments, which are overlain by a 

sand blanket to a depth of 30 to 70 feet. Beds of 

relatively impermeable clay of Miocene or Pliocene 

age overlie the artesian aquifer and confine the water in the aquifer. 

As described by Wyrick (1960, p. 13-19), the 

Lake City Limestone is the lower part of the principal aquifer in Vol usia County. The overlying A von 

Park and Ocala Limestones are the middle and upper parts of the aquifer. In some places a thin 

layer. of well-rounded phosphatic pebbles is present 

at the unconformity separating the Lake City from 

the overlying Avon Park Limestone. At one place a 

layer of clay and peat 6 feet thick separates the two 

formations. 

The Lake City Limestone was not included in a 

report by Wyrick and Leutze (1956, p. 22), but areexamination of the well cuttings (Wyrick, 1960, p. 

16) showed that zone B of the Avon Park Limestone 

(Wyrick and Leutze, 1956) is the Lake City Lime-· 

stone, th~ top of which is reached by several wells at 

depths of 290 to 385 feet below the land surface. 

The deepest of these wells, 511 feet, penetrated 126 

feet of the Lake City Limestone but apparently did 

not pass through it. 

The Avon Park Limestone. is about 280 feet thick 

where it is overlain by the Ocala Limestone. The top 

of the A von Park Limestone ranges in depth from 

about 580 feet below the land surface in the central 

part of the county to about 200 feet below along the 

east coast. Some of the limestone, especially near 

the top, is a loose coquina of foraminifers, small 

echinoids, and other marine shells. Wyrick reported 

that the A von Park Limestone is almost everywhere 

dolomitized in Volusia County and that the dolomitization generally changes the permeability of the 

limestone. Dolomitization of the permeable loosely 

packed coquina generally makes it dense and less 

permeable. Dolomitization, however, has made 

other parts of the limestone more permeable. The 

A von Park Limestone is the principal source of water in the artesian aquifer in the western part of 

the county, where the Ocala Limestone is thin or 

absent. The A von Park also yields water to many of 

the deeper wells along the coast. The top of the 

Ocala ranges from about 50 feet below the land 

surface in the central part of the county to 100 feet 

below on the coast. A thickness of about 40 to 60 

feet of shelly sand and clay beds of Miocene and 

Pliocene age overlies the Eocene limestone. 

The top of the aquifer is an eroded surface, 

ranging from about sea level in the western part of 

the county to about 100 feet below sea level in the 

southeastern part of the county, as shown by Wyrick 

(1960, fig. 4). The top of the limestone is domed in 

the northwestern part of Volusia County near Pierson. Wyrick showed two faults-one having an east~ 

west strike through the north end of Lake Monroe 

and the other striking north-south through DeLeon 

Springs. The top of the limestone is displaced vertically 60 to 100 feet near Lake Monroe and about 

80 feet near DeLeon Springs and Lake Beresford. 

Wyrick believed that the east-west fault forms th~ 

north side of a graben which includes Lake Monroe. 

The writer believes that Lake Monroe was formed 

by solution of the limestone and collapse of the surface in the same way as many lakes and sinkholes formed in north-central Florida and in the 
108 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Tallahassee area in western Florida (Sellards, 1910, 

p. 43-76). 

Wyrick (1960, p. 44) reported that movement of 

artesian water along the north-south fault permits 

salt water to move upward from the lower part of 

the aquifer. However, the upward leakage of artesian water in part of the St. Johns River valley, 

as shown on the map of the piezometric surface, is 

in the area where the relatively impervious beds 

above the aquifer are absent. 

The Lake City and A von Park Limestones contain 

relatively impervious layers of dense indurated limestone at different depths in Volusia County. Some 

of the thicker layers, such as one between 220 

and 240 feet, seems to be parallel to the bedding 

planes. The thick layers are continuous over large 

areas. These layers retard vertir""~J movement of 

the water in the aquifer as shown in current-meter 

surveys in wells (Wyrick, 1960, p. 13-15). 

In well 911-104-4 in the eastern part of the 

county, the survey showed that the upward flow in 

the well was probably between 150 and 200 gpm 

when it was not pumped. Most of the water entered 

the well below a depth of 430 feet in the Lake City 

Limestone, moved upward and entered the A von 

Park Limestone between depths of 150 to 160 feet 

in. the. upper. part .of the .aquifer .. The .flow- entered 

another well at depths of 395 to 485 feet in the Lake 

City Limestone when it was not being pumped. A 

small quantity of water probably left the well in the 

Avon Park Limestone between 300 and 310 feet. 

Most of the flow entered the A von Park Limestone 

between depths of 225 and 230 feet. The remainder 

entered the Avon Park between depths of 165 to 180 

feet. This difference in pressure apparently is 

caused by withdrawal of water through wells in the 

upper part of the aquifer in the Daytona Beach area. 

Wytick reported that a current-meter survey in well 

909-106-1, about 3 miles west of well 911-104-4, 

showed that water entered the well from the A von 

Park Limestone 150 to 160 feet below the land surface, moved downward, and entered the lower part 

of the A von Park and the upper part of the Lake 

City at depths below 225 feet. 

In the Daytona Beach area pumping tests on 

wells (Wyrick, 1960, p. 56-62) indicated that the 

tra_nsmissibility of the upper part of the aquifer 

above the relatively impervious layer, 235 to 245 feet 

deep, is about 300,000 gpd per ft with a storage coefficient of about 0.0007. This represents about 150 

feet of the aquifer, including the Ocala Limestone 

and the upper part of the underlying A von Park. 

With a transmissibility of 300,000 gpd per ft and a 

thickness of 150 feet, the permeability is 2,000 gpd 

per sq ft, which is one of the highest recorded for 

the aquifer. Tests in other parts of the county indicate that the transmissibility may be as low as 

28,000 and as high as 370,000 gpd per ft. 

GEORGIA 

The principal artesian aquifer yields nearly 70 

percent of the ground water used in Georgia, as reported by Herrick (in Thomson and others, 1956, · p. 

271, 277). The aquifer underlies all the Coastal 

Plain in Georgia (fig. 24), except in the area of outcrop of the Cretaceous formations paralleling the 

Fall Line and in a small area in southwestern Georgia where some limestone formations of the aquifer 

grade into sand and form separate aquifers. Herrick 

designated these as the Paleocene and Eocene limestone-sand aquifers. 

The Lisbon Formation in southwestern Georgia, 

the Lake City Limestone in southern Georgia and 

Florida, and the McBean Formation in the northeastern part of the Coastal Plain in Georgia and 

southeastern part of South Carolina form the bottom 

part of the aquifer. Herrick showed the McBean 

(fig. 25) as the bottom for the entire area in Georgia. In the Savannah area, Counts and Donsky 

(1959, p. 96; 1963, p. 22) used the name Lisbon 

F-ormation' instead--of McBean ·and reported ·that· the 

Lisbon is part of the aquifer in the western part of 

the Savannah area. However, in the eastern part, 

its permeability is low, and the formation acts as a 

confining bed separating the water of the aquifer 

from that of the underlying limestone. 

The top part of the aquifer is generally the lower 

part of the Hawthorn Formation. The top of the 

aquifer (fig. 23), as shown by Warren (1944, p. 

17a), ranges from more than 100 feet above sea 

level in the area of outcrop and slopes southeastward to more than 550 feet below sea level on the 

coast. As described by Herrick (in Thomson and 

others, 1956, p. 277), the top of the aquifer is as 

much as 600 feet below the surface in the vicinity of 

Darien in Mcintosh County, Ga. This depth is the 

maximum recorded along the coast of Georgia and 

northeastern Florida. The aquifer rises toward the 

north, south, and west from that low area. South of 

St. Augustine, Fla., on an arch on the east fhtnk of 

the Ocala uplift, the aquifer rises to less than 100 

feet below sea level. It rises from about 150 feet below sea level in the Savannah area to less than 80 

feet below sea level at Parris Island and Hilton Head 

Island, S.C. 

Pumping tests and flow-net analyses reported by 

Counts and Donsky (1959, p. 100; 1963, p. 41-42) 
PRINCIPAL ARTESIAN AQUIFER 109 

show that the transmissibility of the aquifer has a 

wide range, averaging 220,000 gpd per ft. It is 

higher in the northeastern and. eastern parts of the 

Savannah area than in the city. Pumping tests on 

wells by Warren (1944, p. 103-104) give an· average 

transmissibility of about 250,000 gpd per ft. and a 

coefficient of storage of about 0.0003 for the aquifer 

in the immediate vicinity of Savannah. A test at 

Camp Stewart (now Fort Stewart), near Hinesville, 

Liberty County, 35 miles southwest of Savannah indicates the coefficient of transmissibility to be about 

780,000 gpd per ft. Farther south in the Brunswick 

area in Glynn County the results of tests show a 

range of 750,000 to 1,000,000. In the St. Marys area 

in Camden County near the Florida State line, the 

tests by Warren show the transmissibility ranges 

from 104,000 to 177,000, averaging 140,000. Counts 

and Donsky (1959, p. 100; 1963, p. 44) reported that 

the specific capacity of wells in the Savannah area 

ranges from 45 to 65 gpm per foot of drawdown. 

Specific capacities of 47 wells penetrating the aquifer in different parts of the coastal area of Georgia, as determined by Warren (1944, p. 83-87), 

ranged from 1.1 to 240 gpm per foot of drawdown. 

Only 50 feet of the aquifer was penetrated in the 

well with a capacity of 1.1. Most of the wells had 

penetrateg more than 100 feet of the aquifer and 

had capacities of more than 50. These capacities, 

however, which correlate in a general way with the 

range in the transmissibility determined from pumping tests, indicate considerable differences in permeability of the aquifer. For example, one of the 

highest of the capacities was 206 for a well that 

penetrated 365 fe.et of the aquifer at Fort Stewart 

where the transmissibility was about 780,000 gpd 

per foot, the highest obtained in Georgia, except at 

Brunswick. A comparison of the specific capacity of 

112 for a well that penetrates 500 feet of the aquifer 

at Brunswick with the results at Fort Stewart indicates that the average permeability of the aquifer 

is higher at Fort Stewart than at Brunswick, even 

though the maximum transmissibility is at Brunswick. 

RATE OF MOVEMENT OF WATER 

In open channels of the aquifer, as in the channel 

exposed at Falmouth Spring, Fla., the flow may be 

turbulent, and the rate of movement may be com=-

parable to a surface stream with a similar gradient. 

Generally, however, ground-water flow is laminar, 

and the movement is much slower than that of a 

surface stream under a similar gradient. Laminar 

flow, which is proportional to the hydraulic gradient 

and to the permeability and effective porosity of the 

aquifer, may be only a few feet a year. The results 

of tests indicate that the permeability of the aquifer 

ranges from about 500 to 2,000 gpd per sq ft. 

As stated by Warren ( 1944, p. 126), in a study of 

the movement of water in the artesian aquifer in the 

area of Savannah, Ga., having a permeability of 

500 and an effective porosity of 20 percent, the 

average velocity with which the water would move 

through the aquifer for each foot of hydraulic gradient to the mile would be 0.063 foot a day, or 23 

feet a year. At a permeability of 1,500 gpd per 

sq ft and effective porosity of 20 percent, the movement would be three times as fast but only about 

70 feet a year. If the effective porosity were 10 percent, the velocity would be twice as much, or about 

140 feet a year. As the velocity is proportional to 

the hydraulic gradient, the rate of movement would 

be five times as much, or 700 feet a year if the 

gradient were 5 feet per mile. However, the rate 

probably is less than that except in a few recharge 

and discharge areas. In cavernous limestone in a 

discharge area, tests (Wetterhall, 1965, p. 24) indicate a velocity of as much as 500 feet per day. 

ARTESIAN HEAD AND WATER LEVELS 

The artesian head, sometimes called pressure head 

or merely head, is the height, with reference to 

some datum, to which water will rise in a tightly 

cased well penetrating an artesian aquifer. The 

imaginary surface that represents the level to which 

water will rise in artesian wells is known as the 

piezometric, or pressure-indicating, surface. It is 

also known as the potentiometric surface. The piezometric surface may be represented by contours, or 

lines that pass through points where the head is at 

equal altitude above a given datum. The contours of 

equal head are known as equipotential lines (Ferris and others, 1962, p. 139) . 

Differences in head and artesian flow at different 

depths may be expected in various parts of the report area. The head in the lower part of the Hawthorn Formation generally is the same as that in the 

underlying limestone of the principal artesian aquifer, but it is different from that in the middle and 

upper parts of the Hawthorn and overlying formations, which may locally yield water under artesian 

pressure. In the coastal counties and in the southern part of Florida where wells in the principal 

artesian aquifer will overflow (fig. 28), the head in 

the aquifer is higher than that in the middle and 

lower parts of the Hawthorn and younger formations. Although the principal artesian aquifer contains relatively impervious beds that prevent or 

retard vertical movement of the water locally, the 
110 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

head generally is the same throughout the aquifer, 

except in recharge and discharge areas where the 

vertical and lateral movement of water in the 

aquifer may not be in equilibrium. 

In some areas, increases in head and artesian flow 

have been observed with increased depth. According to Sellards and Gunter (1913, p. 146-147) a 

record of well 10 of the city water supply of Jacksonville, Duval County, showed that the artesian 

water had a pressure head of 27.72 feet with reference to the ground surface when the well reached 

a depth of 680 feet and a pressure head of 34.65 

feet when it reached a depth of 900 feet. The flow 

was about 5 gpm from a depth of 270 feet in the 

Hawthorn Formation, 900 gpm from a depth of 

900 feet, and 1,500 to 2,000 gpm from a depth of 

980 feet. The well penetrated about 500 feet of 

the Hawthorn Formation and entered the Ocala 

Limestone at a depth of about 510 feet. 

As described by Cooper (1944, p. 181), wells 

in Duval and Nassau Counties in northeastern Florida penetrate alternate layers of hard and soft 

limestone, ranging from a few feet to more than 

100 feet in thickness. The hard layers are less 

permeable than the soft limestone and locally prevent or retard vertical movement of the water. In 

the Jacksonville area withdrawal of water from 

wells penetrating the upper part of the aquifer 

caused the pressure to be considerably less than that 

in the lower part. Cooper. reported that well 7, 

1,250 feet deep, of the city of Jacksonville, in the 

apex of the cone of depression of the piezometric 

surface, had a head of 55 feet above mean sea level 

in 1940 when the head of wells in the upper part of 

the aquifer was less than 40 feet. The well was 

apparently cased only to the top of the Ocala Limestone, as are other wells in the vicinity. Therefore 

the ·head in the wells is a composite of the aquifer. 

If the well had been cased to 1,250 feet, the pressure would have been more than 55 feet above sea 

level, possibly as much as 60 feet, which is almost as 

high as the original piezometric surface. 

An incomplete log (Matson and Sanford, 1913, 

p. 396) of the well at the Ponce de Leon Hotel, at 

St. Augustine, Fla., reported as well 27, St. Johns 

County, by Stringfield (1936, p. 135), indicates that 

the artesian water had a pressure head of 32 feet 

above the land surface when the well reached a 

depth of 170 feet. The head was 38 feet when the 

well reached a depth of 350 feet, and 42 feet at a 

depth of 520 feet. The Ocala was penetrated at a 

depth of about 170 feet .. The pressure of that well in 

1930 (Stringfield, 1936, p. 135, 173, 187) was about 

30 feet above the surface of the ground. That pressure head was about the average for wells penetrating the aquifer in the vicinity of St. Augustine. 

These observations indicate that where wells penetrate water-bearing beds at several horizons having 

different artesian pressures, there may be an equalization of pressure in the beds at different horizons 

in the vicinity of the wells, unless the wells are· so 

cased that they will prevent such leakage, as discussed under "Subsurface leakage in wells." 

Generally in recharge areas, as recorded by Bishop 

(1956, p. 47) in Highlands County, Fla., the depth 

of water levels below the land surface may increase 

with the depth of the well. In areas of artesian flow, 

the head may increase with increased depth ~s described for the wells at Jacksonville, St. Augustine, 

and Daytona Beach, especially if the artesian pressure has been reduced in the upper part of the aquifer by withdrawal of water from wells, natural discharge, or upward leakage. 

In the local recharge area west of the Daytona 

Beach area in Volusia County, Wyrick (1960, p. 28) 

reported that a current-meter survey in a well 

showed that water entered the well from the upper 

part of the aquifer and moved downw~rd through 

the well to lower parts of the aquifer. 

The head in water-bearing formations below the 

principal artesian aquifer generally is higher . than 

that in the aquifer. For example, a test well for oil 

drilled to a depth of 2,130 feet in 1920, at Cherokee 

Hill, 21.5 feet above sea level, 7 miles northwest of 

Savannah, Ga., flowed salt water from a depth of 

1,980 to 2,035 feet (Warren, 1944, p. 127). Warren 

stated that in July 1939 the piezometric surface of 

the artesian water in the principal aquifer at Cherokee Hill was about 2 feet above sea level. In Dade 

County, Fla., a well penetrating the Cedar Keys 

Limestone had an artesian head equivalent to 99 

feet of fresh water (Nevin Hoy, written commun., 

1962). . 

At Parris Island, S.C., the artesian water in the 

Tuscaloosa Formation of Cretaceous age had a pressure of about 60 to 65 psi (pounds per square inch) 

at the land surface, the land being about 10 feet 

above sea level. This pressure is equivale:Qt to 138 

to 149.5 feet of water and is the maximum height 

to which water would rise above th~ land surface 

in a tightly cased well in the area covered by this 

report. 

LOSS OF ARTESIAN HEAD AND FLOW 

The loss of artesian head is a normal process that 

invariably accompanies withdrawal of large amounts 

of artesian water. In a few areas of original flow 
PRINCIPAL ARTESIAN AQUIFER 111 

withdrawal of water has lowered the artesian head 

to an extent that pumps are installed on wells. 

After further reduction in head due to pumping, 

wells no longer overflow at the surface. The loss of 

head due to pumping is more than 100 feet in a few 

areas. With the lower head, loss of water formerly 

through uncontrolled flow of artesian wells and subsurface leakage in wells is stopped. However, loss of 

head not only increases the cost of pumping the water but may permit highly mineralized water to enter 

the aquifer in some areas. 

In addition to loss of flow due to loss of head in 

the aquifer, loss of flow may occur because of subsurface leakage in wells and clogging of walls of 

wells by the accumulation of sand or other material 

in the well. If the wells are not adequately cased, 

unconsolidated material may cave into it and stop 

the flow completely. Sellards and Gunter (1913, p. 

151) observed that although clogging of pores of 

the walls of wells is likely to be caused by material 

mechanically transported, the clogging may also be 

due to chemical deposition. 

H. H. Cooper, Jr. (written commun., 1962) has 

recorded loss of flow without loss of head in wells 

in Duval and Nassau Counties. After underreaming 

the wells, the flow increased, indicating the pores in 

the walls of the wells were clogged. As suggested by 

Cooper and by Sellards and Gunter, some of this 

clogging appears to be due to chemical deposition 

from the water as its pressure is reduced when it 

enters the well. 

FLUCTUATIONS OF ARTESIAN HEAD AND WATER LEVELS 

Artesian head and water levels in wells fluctuate 

continuously. Fluctuations in wells that do not 

overflow at the land surface are determined by continuous or intermittent measurements of water 

levels in these wells. The fluctuations in a flowing 

well are determined by measuring the shut-in pressure in pounds per square inch or in feet of water. 

The pressure in pounds per square inch may be 

multiplied by 2.3 to convert to feet of water, or the 

height to which the water would rise in a tightly 

cased well. By referring these measurements to sea 

level or some other common datum, it is possible to 

determine the piezometric surface or the height to 

which water would rise with reference to that datum 

in wells. . 

In order that the character of the piezometric 

surface can be interpreted and the effects of recharge and discharge of water can be determined, 

the causes and amounts of these fluctuations must 

be determined. One of the earliest reports on the 

causes of fluctuations of water levels in wells is by 

Veatch (1906). Some of these causes are discussed 

in the following sections. 

FACTORS AFFECTING FLUCTUATIONS OF ARTESIAN HEAD 

AND WATER LEVELS 

Rainfall in Recharge Areas 

In areas in which the aquifer is recharged, such 

as Marion County, Fla. (Stringfield, 1936, p. 136), 

the water levels in wells may rise as much as 10 

feet within a period of a few weeks, and much of 

the rise may be attributed to rainfall that enters 

the aquif~r. The effect of rainfall in the recharge 

area is transmitted to other parts of the aquife!, 

but this transmission is usually slow, requiring 

weeks or perhaps months, the time depending on 

the distance and the hydrologic conditions. Moreover, as distance increases, the magnitude of the 

effect decreases. 

Between October 1941 and March 1942, Warren 

(1944, p. 60-66) observed the pressure effects of 

recharge on the artesian head in the principal aquifer in an area apout 55 miles wide and 90 miles long 

northeast of the Valdosta recharge area in southeastern Georgia, where the aquifer is overlain by 

confining beds of the Hawthorn Formation. During 

the 6-month period, the rise in artesian head 

ranged from 2.5 feet a few miles from the recharge 

area to 0.5 foot and less at a distance of 90 miles 

downgradient toward Savannah, where the effects 

were not large enough to be measured. If there is 

a storage coefficient of 0.0003, as determined in the 

Savannah area, the amount of water going into 

storage when the head rises 1 foot in 1 square mile 

is 62,559 gallons. Using that coefficient and an average rise of 1. 7 feet of head in the area 90 by 55 

miles, Warren computed the amount of water required to go into storage is approximately 

62,599 X 90 X 55 X 1. 7 or about 526 million gallons. 

Warren's estimate of the recharge in the Valdosta 

area indicates that the rech~rge was sufficient to 

furnish that quantity of water.· 

Matson (Matson and Sanford, 1913, p. 238-239) 

pointed out that rainfall may cause some increase 

in the artesian head by means of the added weight 

that may accumulate in the formations overlying 

the artesian aquifer. This weight may be transmitted to the underlying aquifer and thereby cause 

an increase in artesian head. Increases of pressure 

after rains have been reported by owners of wells in 

Seminole County, Fla. However, these wells are in 

irrigation districts, and the changes in head may be 

caused by opening and closing artesian wells. Moreover, in Seminole County there may be local recharge 

of the artesian aquifer. Veatch (1906, p. 7) sug-
112 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

gests single showers may, by transmitting pressure 

through the air in soil, produce instantaneous and 

noticeable rises in the water 1n wells. Robert 

Schneider, U.S. Geological Survey (written commun., 

1963) has observed rises in water levels in wells 

over large areas after rains. As discussed under 

fluctuations caused by changes in atmospheric pressure, some of the changes after heavy rains may 

be due to changes in barometric pressure . 

. Surface Drainage Into Wells 

In some parts of Florida, as in Orange and Dade 

Counties, and in the Valdosta area, Georgia, where 

the static water level in wells penetrating permeable limestone is below the land surface, water is 

drained into the aquifer through the wells in order 

to dispose of it. The wells drain into the principal 

artesian aquifer, except in Dade County where the 

wells drain into the shallow aquifer near the coast 

in the Miami area. 

Water levels in wells near drainage wells may 

rise several feet during and after periods of heavy 

rains. The record of a continuous water-level recorder on a well near Ocoee, Orange County, shows 

the marked influence of drainage wells in that vicinity. Although no water entered the mouth of the 

recorder well, there was a rise in water levels after 

each rain, and the maximum rise was about 6 feet 

during a 3-day period (Stringfield, 1936, p. 142). 

At Orlando, Orange County, where there are numerous drainage wells, water levels in wells rise as 

much as 10 feet after periods of heavy rainfall. 

Drainage wells are used to dispose of surface 

water in areas of poor surface drainage. The wells 

are effective in recharging the aquifer as described 

by Unklesbay and Cooper (1946, p. 299). Warren 

(1944, p. 64) estimated that several million gallons 

of water per day enter the aquifer through drainage 

wells in the Valdosta area. The effects of that recharge together 'with the natural recharge were 

observed over a distance of 90 miles northeast of the 

Valdosta area. The aquifer consisting of the Ocala 

Limestone and older Eocene limestones is so cavernous that the wells seldom become clogged, although 

some trash passing the screens (fig. 26) around the 

mouth of the wells enters the aquifer. 

As described by Sellards (1910, p. 72) and Unklesbay and Cooper (1946, p. 305), some drainage 

wells spout water at intervals like a geyser. The 

spouting is caused by an outrush of air that has 

been carried into the well by surface-water drainage. The air accumulates in cavities in the aquifer 

and is compressed by the water until the air pressure exceeds the weight of the column of water in 

FIGURE 26.-Manhole over drainage well. Screen which fits 

over mouth of well is on edge of manhole. 

the well, at which time the spouting occurs. One of 

the well-known spouting wells described by Sellards and by Unklesbay and Cooper on the south side 

of Lake Fairview northwest of Orlando drains water 

from the lake when the lake level is above the mouth 

of the well (fig. 27). At times the well spouts water 

more than 100 feet above its mouth. As the flow 

from the lake to the well can be controlled, spouting 

is produced when desired as a tourist attraction. 

However, spouting of a well generally is a nuisance 

and reduces the effectiveness of the well for draining surface water or recharging the aquifer. Also, 

the spouting may be a hazard to nearby structures. 

Consequently, some wells are equipped with devices 

designed to deflect the spouting or decrease its force. 

FIGURE 27.-Drainage well spouting water at Lake Fairview, 

northeast of Orlando, Orange County, Fla. 
PRINCIPAL ARTESIAN AQUIFER 113 

Unkles bay and Cooper ( 1946, p. 305) reported that 

at some places in the Orlando area, air is trapped 

over a wide area, within which wells cased to comparatively shallow depths will contain air under 

pressure. They observed that the air in one well had 

a pressure equivalent to 54 feet of water or about 

23 psi at the surface. In one area, flammable gas 

from citrus pulp and skins, which had been injected into a well, accumulated to such an extent 

that it was used locally for fuel. 

Rivers 

In parts of their courses some rivers flow on the 

aquifer where it is at or near the surface. In the 

northwestern part of the Florida peninsula along 

the Suwannee River and the lower course of the 

Santa Fe River and in the west-central part of the 

peninsula along the lower course of the Withlacoochee River changes in the stage of the rivers may 

affect the ground-water level in the aquifer. Groundwater levels are also affected by changes in the 

stage of the Flint River in Georgia. 

Ground-water level near the streams is generally 

about the same· as the water level in the rivers, but 

during the flood stages the rivers lose water to the 

formations and thereby cause the ground-water levels to rise in adjacent areas. In Florida, such fluctuations have been noted in a well at High Springs in 

Alachua County, in a well at Branford in Suwannee 

County, and in Falmouth Spring near Falmouth in 

Suwannee County. At Falmouth Spring, an exposed part of an underground stream in the aquifer, 

the movement of the water is toward the east when 

the river is high enough to recharge the aquifer and 

toward the west when the aquifer discharges into 

the river. During the flood ~tage of the river, when 

the spring is flowing toward the east, the spring water is the color of tea because of the colored water 

from the river. During the low stage of the river 

when the spring flows toward the west, the water is 

clear, indicating that either the water has lost its 

organic color in contact with limestone or it is 

ground water from a part of the ~quifer that was 

not recharged with colore~ water. 

Changes in Atmospheric Pressure and Wind 

Variations in atmospheric pressure may cause 

fluctuations of head in most if not all artesian wells 

and some nonartesian wells, but these fluctuations 

may be masked by larger fluctuations due to other 

causes, chiefly variations in withdrawal of water. 

Fluctuations of head or water levels in nonartesian 

wells in response to changes in atmospheric pressure 

may occur when water in the zone of aeration is 

I 

frozen, as reported by Stringfield (in Meinzer and 

Wenzel, 1937, p. 84), or when part of that zone above 

the water table is saturated with water after heavy 

rains. These temporarily saturated or frozen zones 

prevent the full effect of atmospheric pressure from 

being transmitted to the ·water table. Also, the water table responds to changes in atmospheric pressure under conditions such as that cited below in the 

Grand Prairie region, Arkansas. 

As explained by Meinzer (1932, p. 141-142), a 

well will act as a barometer if it ends in an aquifer 

overlain by relatively impervious beds having sufficient strength to resist deformation by slight 

changes in pressure at the surface. The fluctuation 

of the water level will have about the same range as 

a water barometer, or 13.5 times the range in a mercury barometer because the specific gravity of mercury is 13.5 times that of fresh water. The movement of the water level in the well is in the opposite 

direction from that of an ordinary barometer. For 

example, as the atmospheric pressure transmitted 

through the mouth of the well increases or rises, the 

water level in the well is depressed. As the atmospheric pressure decreases, the water level in the well 

rises. 

If an aquifer consists of unconsolidated sand and 

sandy clay overlain by clay beds that are relatively 

impervious but yield to slight pressure, water-level 

fluctuations in wells in response to changes in atmospheric pressure will be smaller than those of a water barometer. When atmospheric pressure changes 

are expressed in terms of a column of water, the 

ratio of water level changes to pressure changes expresses the barometric efficiency of an aquifer ( J a-:-

. cob, 1940, p. 582; Todd, 1959, p. 159). Most observations give values which range from 20 to 75 percent. 

In the Grand Prairie region, near Stuttgart, in 

the Coastal Plain of Arkansas, D. G. Thompson (in 

Engler and others, 1945, p. 27) observed wells in 

which the water-level fluctuations due to changes 

in atmospheric pressure ranged froin a fraction of 

a foot to about 1 foot. The maximum fluctuation, 

with a barometric efficiency of 100 percent, is in an 

area where the artesian pressure in the aquifer has 

been lowered to the extent that water-table conditions are present. Under these conditions, the atmospheric pressure on the confining beds is not 

transmitted to the water table because it is some 

distance below the bottom of the confining bed, but 

the atmospheric pressure is transmitted to the water through wells. 

The principal artesian aquifer in the area of the 
114 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

present report apparently has a barometric efficiency that ranges from less than 50 to 75 percent. 

In Sarasota County (Stringfield, 1933c, p. 160-161), 

the range of water-level fluctuations due to changes 

in atmospheric pressure in a well in the principal 

artesian aquifer was about 50 to 75 percent of that 

of a barometer in Sarasota about 7 miles west of 

the well. However, the ratio was about 50 percent 

much of the time, and it appears that the barometric 

efficiency was actually about 50 percent. The higher 

range apparently was due to higher atmospheric 

pressure at the well than at the barometer in Sarasota. The record also appears to have been affected 

by earth tides. In Flagler, Putnam, and St. Johns 

Counties, Bermes, Leve, and Tarver (1963, p. 70) 

computed that the aquifer has a barometric efficiency of about 30 to 40 percent. Odom (1961, p. 

29) showed that the water level in a well in the 

Savannah area, Georgia, rose more than a foot in 

response to the low barometric pressure caused by 

a tropical storm. 

Changes of air pressure resulting from variation· 

in the velocity of wind, as it blows across the top of 

the casing or past the structure housing the recorder, cause small fluctuations of water levels in 

both artesian and nonartesian wells. As gusts of 

wind blow over the top of the casing or past the well, 

the air pressure in the well is lowered, and the water 

level rises. Observations made at Miami (Parker 

and Stringfield, 1950, p. 453) showed that these 

fluctuations seldom exceed 0.03 foot. Such fluctuations of water levels have also been observed by 

Elmer Rexin, chief engineer, Nunn-Bush Shoe Co., 

in a well in the basement of the Nunn-Bush factory 

at Milwaukee, Wis. As the wind did not have access 

to the well, the gusts of wind apparently affected the 

atmospheric pressure in the building. Although such 

small fluctuations may. not be as significant as other 

fluctuations of water levels in showing characteristics of an aquifer, they should be understood and 

recognized when studying records that have small 

but significant fluctuations. 

Ocean Tides and Earth Tides 

Ocean tides may cause fluctuations of water levels 

in wells in aquifers along the coasts, but earth 

tides (Robinson, 1939, p. 656-666) may occur in 

wells not only in coastal areas but in the interior. 

Fluctuations of head or water levels in wells caused 

by ocean tides may be due to ( 1) the result of actual 

transfer of water from the ocean to the aquifer and 

(2) alternate compression and expansion of an artesian aquifer by the added weight of water transmittE;;d in the vicinity at high tide and removal of 

the weight at low tide. Transfer of water between 

the ocean and the aquifer may occur in the principal 

artesian aquifer along the gulf coast where the 

aquifer is at or near the surface, from Pinellas 

County to western Florida. It may also occur in 

submarine outcrops of the aquifer many miles offshore, but these effects are not known to extend to 

the mainland. The tidal fluctuations in wells due to 

transfer of water are significant in studying saltwater encroachment. 

However, in most of the coastal areas of this 

report, conditions causing tidal fluctuations in wells 

in the principal artesian aq~ifer are similar to conditions. in the vicinity of Atlantic City, N.J., where 

Thompson (1928, p. 27-30, 57, 113) and Barksdale, 

Sundstrom, and Brunstein (1936) demonstrated that 

the tidal fluctuations in the head of water in wells 

drawing from an aquifer at a depth of 800 feet are 

due to the alternate tidal loading and unloading in 

the immediate vicinity and not to transfer of water 

or pressure change transmitted from the submarine 

outcrop of the aquifer. Observations by Warren 

( 1944, p. 72) on the rate at which pressure effects 

are transmitted through the artesian aquifer at 

Savannah indicated that days would be required 

for the pressure effect of the tide to be transmitted 

through the formation from the submarine outcrop. 

The maximum fluctuation of artesian pressure that 

can be definitely attributed to tidal loading amounts 

to about 1 foot in wells near the Gulf of Mexico and 

2 feet in wells near the Atlantic coast in Florida. 

From the nearest tidal water body, the farthest 

point inland at which tidal fluctuations in head 

were definitely observed in the principal aquifer 

was about 0.2 mile in Florida and more than 1 mile 

in Georgia. Well 7 in Effingham County, Ga., 5 miles 

from the nearest tidal water is reported to be affected by tides (Odom, 1961, p. 29). However, it 

seems entirely possible that the fluctuations attributed to ocean tide may be caused by earth tides and 

barometric flt1ctuations. At Miami, Fla., lateral 

transfer of pressure effect of high tides in Biscayne 

Bay on water levels in wells in the shallow aquifer 

is 6,680 feet inland (Parker and Stringfield, 1950, 

p. 448). Continuous records on a well on the Atlantic coast at Jacksonville Beach show a semidiurnal 

variation of 1 to 2 feet in the artesian head of the 

principal aquifer. The fluctuations on the Atlantic 

coast are about half the magnitude of the tides. 

Warren (1944, p. 74) recorded in December 1942 

a tidal fluctuation of 4.35 feet in well 328 at Fort 

Screven, Ga., 600 feet west of the Tybee Lighthouse, 

when the tidal fluctuation was 9.7 feet in the Atlan- · 
PRINCIPAL ARTESIAN AQUIFER 115 

tic Ocean at the Tybee Light, about 1,000 feet 

northeast of the well-a tidal efficiency of about 

50 percent. The smallest tidal efficiency observed 

along the coast was about 20 percent in Glynn 

County. 

In estimating the tidal efficiency of an aquifer 

along an irregular shoreline where there are tidal 

marshes and flats, consideration must be given to 

the area inundated at different stages of the tide. 

At the Tybee well, for example, where a larger 

land area is flooded during spring tide than during 

neap tide, the fluctuation of water level is about 

7 percent larger in proportion to the range of the 

tide during spring and neap tides. If the area covered were always the same, it would be expected 

that the tidal fluctuations of water levels would be 

a certain percentage of the fluctuations of the tide 

during the spring and neap tides (Warren, 1944, p. 

77). 

As stated by Jacob (1940, p. 582) barometric 

and tidal fluctuations may be taken as an index of 

the elasticity of the aquifer. The barometric efficiency is a measure of the competence of the aquifer 

and confining beds to resist pressure changes. The 

tidal efficiency is a measure of the incompetence 

of the aquifer and confining beds to resist pressure. 

The tidal efficiency plus the barometric efficiency 

of the aquifer equals unity (Ferris and others, 

1962, p. 86) ~ Jacob (1940, p. 582-585) and Todd 

(1959, p. 165-168) described a method of using the 

barometric efficiency or tidal efficiency to compute 

the coefficient of storage. 

Small fluctuations of water levels in artesian 

wells r~sulting from the attraction exerted on the 

earth's crust by the moon, and to a lesser extent 

by the sun, have been described (Robinson, 1939, 

p. 656-666; Richardson, 1956, p. 461-462; J. W. 

Stewart, 1961, p. 107; and Ferris and others, 1962, 

p. 86). Thomas Cramer of the U.S. Potash Co., 

working with Robinson, called attention to tidal 

fluctuations in a well in New Mexico (C. V. Theis, 

written commun., 1962). Veatch (1906, p. 69) mentioned the possibility of earth-tide fluctuations in 

wells but did not recognize them in wells which he 

described. 

As stated by Todd (1959, p. 168), ·Robinson's 

observations show "(a) two daily cycles of fluctuations occur about 50 minutes later each day, as 

does the moon ; (b) the average daily retardation 

of cycles agrees closely with the moon's transit; (c) 

the daily troughs of the water level coincide with 

the transits of the moon at upper and lower culmination; and (d) periods of larger fluctuations coincide with periods of new and full moon, whereas 

periods of small, irregular fluctuations coincide with 

periods of first and third quarters of the moon." 

At times of new and full moon when the tideproducing forces of the moon and sun act in the 

same direction, the ocean tides have a range greater 

than average. The ocean tides are smaller than 

average when the moon is in the first and third 

quarters and the forces producing the tides act 

perpendicularly to one another. 

Theis (1939) and Todd (1959, p. 169) suggested 

that the earth tides are lowest at time of the 

moon's transit because the overburden load on the 

aquifer is reduced, allowing the aquifer to expand 

slightly when the tidal attraction is maximum. 

Ferris (1962, p. 86-87) quoted the following from 

Theis ( 1939) : 

As the crust of the earth in any given area rises and falls 

with the deformation of the earth caused by the tidal forces 

the crust is most probably alternately expanded and compressed late.rally-expanded when the earth bulges up and 

compressed when it subsides. Water in an artesian aquifer 

making up 'part of the crust shares in this deformation. In 

localities distant from points. of outflow of the water, it is 

in effect confined without possibility of outflow within the 

period of tidal fluctuations. The slight hydraulic gradient 

imposed by the tidal distortion is too small to cause effective 

release of pressure. Hence the aquifer is essentially sealed 

with respect to its included fluid. With 'the expansion of the 

aquifer incident to the tidal bulge the hydrostatic pressure 

falls and with its compression incident to tidal depression the 

hydrostatic pressure rises. 

The records of artesian wells in the principal 

artesian aquifer have not been studied to determine 

the earth tides. However, tidal fluctuations due to 

earth tides are probably present in most if not all 

of tl!e artesian wells in Florida and adjacent 

States. Careful study of the earth tides in the aquifer probably would give significant information on 

its water-bearing properties. Although the best 

known earth tides are in sedimentary artesian aquifers, J. W. Stewart (1961, p. 109) reported earth 

tides in three of four wells 400 feet deep in metamorphic rocks near Dawsonville, Ga. 

Loads Such as Railroad Trains and Ships 

Compression and expansion of artesian aquifers 

by addition and removal of loads, such as railroad 

trains, have been observed in many ground-water 

investigations. As the train approaches, the water 

levels rise in the observation wells ; then the water 

levels decline to normal as the train passes. The 

record of such fluctuations in a well in the shallow 

aquifer in the Miami area, Florida, shows that 

heavy freight trains cause the largest fluctuat~ons, 
116 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

which are a maximum of about 0.045 foot, and the 

short, light trains cause the smallest (Parker and 

Stringfield, 1950, p. 459). 

Jacob (1939, 666-674) described the effect of the 

load of a train on the water level in an observation 

well on Long Island, N.Y. The water level reached 

its maximum (about 0.02 foot) when the train 

stopped. Within seconds the water level declined, 

first rapidly and then more slowly, returning to its 

original level. After a few seconds when the train 

started again, the water level declined rapidly, about 

0.03 foot, and then slowly rose toward the original 

level. Jacob's record is also included and discussed 

by Todd (1959, p. 170) and Meinzer (1939, p. 

212, 220). 

Odom (1961, p. 28) gave a record of the effects 

of passing ships in the Savannah River on the water 

level in a well near the river. He concluded that as 

the ship· moves through a body of water, it forces 

water ahead and aside in the form of a wave, 

thereby causing a temporary rise in the level of the 

river. This temporary rise causes a temporary load 

which is transmitted to the riverbed and to the 

underlying confining beds of the aquifer. 

Earthquakes 

Fluctuations of water levels ranging from a fraction of a foot to several feet in wells in artesian 

aquifers have been caused by shocks from earthquakes. The fluctuations are sudden and range above 

and below the water level before the shock. Apparently, the maximum fluctuation recorded was 7 feet 

or more on March 27, 1964, in wells in a broad 

belt extending southeastward from Wisconsin 

through Illinois and Indiana to Georgia and Florida, at the time of th~ Alaskan earthquake (Waller and Thomas, 1964, U.S. Geol. Survey mimeo. 

memo.). The maximum fluctuation in the Southeastern States was about 17 feet in a well in the 

principal artesian aquifer near Perry, Fla. (Waller 

and others, 1965, p. 123-131). The maximum fluctuation recorded in Florida prior to the Alaskan 

earthquake was 4.5 feet in a well at Miami, Fla., 

where records (Parker and Stringfield, 1950, p. 459) 

also show many very small fluctuations, ranging 

from 0.006 to 0.038 foot, not reported by regular 

seismological stations. Apparently, these minor 

shocks represent small adjustments of the earth's 

crust, possibly along the margin of the Floridian 

Plateau. 

One of the most detailed records obtained is for 

an observation well in the basement of the NunnBush shoe factory in Milwaukee, Wis. Elmer Rexin, 

chief engineer of the Nunn-Bush Shoe Co., designed 

and built the recorder with an expanded time scale 

which gives more detail than the conventional 

recorder. One of these records given by Vorhis 

(1955, p. 47-52) and Todd (1959, p. 170) shows the 

effect of an earthquake centered on the ArgentinaChile border, nearly 5,000 miles from the well. The 

maximum fluctuation was less than 2 inches. As 

stated by Todd (1959, p. 171), although the quantitative effects of earthquakes on ground water are 

not fully understood, the fluctuations of water levels 

in the response of wells to earthquakes apparently 

are due to compression and expansion of artesian 

aquifers by the earthquake waves. 

Natural Artesian Flow or Pumping From Wells 

The most noticeable fluctuations of head are due 

to withdrawal of water from wells, either by natural flow or pumping. When a well begins to discharge, the head of the water in the well imme-· 

diately drops, and at the same time the head of the 

water in the aquifer around the well drops. The 

decline in head is greatest in the discharging well 

and decreases · with increased distance from that 

well. The piezometric surface is nearly vertical at 

the well, but with increasing distance from the 

well the gradient gradually becomes more gentle 

until, generally within a few hundred or a few 

thousand feet, it becomes nearly horizontal. The 

rate of decline in head is at first rapid but becomes 

slower and slower until finally there may be no further apparent decline. The time required to reach 

the point of stability is generally at· least several 

hours and may be several days or weeks. The conical depression in the piezometric surface is called 

the cone of depression. 

When the discharge ceases, the head increases 

immediately. The rate of increase is at first rapid 

and then slower until, when sufficient time has 

passed, the water will recover its original head unless some other influence has caused the head to 

change. The time required to reach a stable head 

after discharge has ceased is approximately as long 

as the time required to reach a stable head during 

discharge. The difference between these two heads 

is known as the drawdown. 

When water is pumped from a well, the pressure 

in the aquifer is decreased, and a cone of depression 

is established around the well. The cone of depressi{)n may be large or small, according to the amount 

of water removed, the rate at which it is removed, 

and the ability of the rock to transmit water. If 

large amounts of water are pumped for a long 

period of time, the resulting cone of depression 
PRINCIPAL ARTESIAN AQUIFER 117 

may be extensive. When several wells discharge in 

a locality, their cones of depression may coalesce 

and form a single large irregular depression. Under 

artesian conditions in some areas, as at Fernandina, 

Fla., and Savannah, Ga., the cone of depression 

may extend many miles from the center of draft. 

R. L. Wait (1963, p. 44) stated that the cone of 

depression at Savannah, Ga., is more than 60 miles 

in diameter. The distance from the deepest part of 

the cone of depression to the zero contour is greater 

to the east than it is to the west in the Savannah 

area, Georgia (Counts and Donsky, 1963, p. 56). 

The distance is about 8 to 10 miles on the west 

side of Savannah, about 18 miles on the south side, 

and about 25 miles on the northeast side, where the 

cone reaches its maximum extent in the vicinity of 

Hilton Head, S.C.; the cone slopes more steeply on 

the west side than on the east side. 

The maximum fluctuation in a flowing well is 

limited by the difference in shut-in head and the 

altitude of the top of the well. When a well flows, 

the pressure at the mouth is almost zero, so that 

the shut-in head is almost equal to the drawdown 

or loss in head resulting from discharge of water. 

AREAS OF ARTESIAN FLOW 

The general areas in which the artesian water 

is under sufficient pressure to rise to the surface and 

produce flowing wells in the Coastal Plain from 

North Carolina to Mississippi, inclusive, are shown 

by Stringfield ( 1953, p. 32) . The areas in Florida, 

Georgia, and adjacent parts of Alabama and South 

Carolina are represented in figure 28. They include 

three principal areas: the Atlantic coast, southern 

Florida, and the gulf coast. The map indicates the 

limits of the areas of flow only approximately. 

More detail is shown in reports cited in the following discussion. 

Within areas of flow there are relatively high districts in which wells will not flow. In some areas 

shown as nonflowing areas, flows may be obtained 

in some of the relatively low districts where the 

pressure is relatively high. Along the borders of 

areas of artesian flow where the piezometric surface is near the land surface, wells may flow intermittently in response to changes in barometric pressure, tides, and other forces which cause water-level 

fluctuations in wells. 

In the larger river valleys, the areas of flow extend 

beyort.d the area underlain by the principal aquifer 

of Tertiary age into the Cretaceous area almost to 

the Fall Line, as shown by LeGrand (1961a) in 

the Macon area. The artesian water between the 

Fall Line and the Tertiary aquifer is from formations of Cretaceous age. The Cretaceous aquifers 

underlying the Tertiary are a source of artesian 

water in southwestern Georgia, in southeastern Alabama, and in a broad belt extending from Alabama 

across Georgia into South Carolina. 

ATLANTIC COAST 

The area of flow along the Atlantic coast extends 

from Savannah area, Chatham County, Ga., to the 

Florida Keys. The area of flow in Georgia in 1914 is 

shown by Stephenson and Veatch (1915, p. 123). 

. Originally, flows co~ld be obtained in wells in the 

principal aquifer in most of Chatham County and 

in the southern part of Effingham County and adj acent parts of South Carolina. However, in 1942, as 

described by Warren (1944, p. 22), withdrawal of 

water from wells in the Savannah area had reduced 

the area of artesian flow in Chatham County to approximately the southwestern quarter of the county 

and in Effingham County to the lowlands near Meldrim and Eden. Within the area of artesian flow in 

the eastern part of Bryan, Liberty, and Mcintosh 

Counties, there are small relatively high areas in 

which wells would not flow in 1942. Warren reported that one area is 10 miles southeast of Richmond Hill in Bryan County, another js in the vicinity of Dorchester in Liberty County, and the third 

is just west of Crescent in Mcintosh County. All 

nonflowing areas have become enlarged as a result 

of the increase in consumption of water and the decline of the piezometric surface. They have not 

been mapped recently, but a comparison of the altitude of the piezometric surface with the land surface 

will indicate approximately the area in which wells 

will flow. 

In the coastal area of northern Florida, the area of 

flow of the principal artesian aquifer includes a 

large part of Nassau and Duval Counties and extends westward along the valleys of the St. Marys 

River into Baker County. The withdrawal of water 

from wells at Fernandina has lowered the pressure 

in the principal artesian aquifer and the overlying 

Hawthorn to the extent that wells no longer flow in 

that vicinity. 

The area of flow includes the valleys of the St. 

Johns River and some o.f its tributaries, such as 

Black Creek and the Oklawaha and Wekiva Rivers. 

The area of flow along Black Creek and its tributaries extends into western Clay County. Details of 

the areas of flow in Clay County in 1961 are shown 

by J. B. Foster (1962, fig. 2). The area in which 

wells will flow along the Oklawaha River extends 

into the east-central part of Marion County almost 

to Silver Springs, which has the largest artesian 
118 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

G U .l 

p 

27·r---------t-----------~--------~~--------~-----------+-----~ 

EXPLANATION 

.. 26·r----~~--- Areas of artesian flow 

50 0 50 100 M LES 

., 

FIGURE 28.-Areas of artesian flow. (Florida, from Healy, 1961; Georgia, after Warren, 1944; Alabama, after Smith, 1907.) 
PRINCIPAL ARTESIAN AQUIFER 119 

flow in the area. At the headwaters of the Oklawaha River, on the borders of some of the lakes in 

Lake County, the artesian water levels in wells are 

near the surface of the ground. There are flowing 

wells in the lowland bordering the southeast, south, 

and west sides of Lake Apopka, but on the north and 

northeast sides· of the lake, the artesian head is too 

low to produce flowing wells because the piezometric 

surface slopes to the northeast and is below the surface of the ground. 

Details of the areas of flow are given by Leve 

(1958, p. 20) for Putnam County, Bermes (1958a, 

p. 7) for Flagler County, and Wyrick (1960, p. 35) 

for Volusia County. Bermes, Leve, and Tarver 

(1963) included a map showing the areas of artesian 

flow in Flagler, Putnam, and St. Johns Counties. 

Barraclough (1962) showed in detail the area of 

flow in Seminole County. D. W. Brown (1957, p. 81) 

reported that the area of flow includes all Brevard 

County, except the top of high areas in the coastal 

ridge. 

SOUTHERN FLORIDA 

The area of artesian flow in southern Florida 

merges with the Atlantic coast and gulf coast areas. 

It covers all the southern part of the peninsula and 

extends along the Kissimmee River valley into northern Osceola County and along the Peace Creek valley 

to the southern part of Polk County. In a relatively 

few high areas, such as that in northern Collier 

County, wells do not flow. Lichtler (1960, p. 35) 

reported that flowing wells may be obtained 

throughout Martin County, except at the tops of 

high sand hills in the eastern part of the county 

where the land surface is more than 50 feet above 

sea level. Wells in the principal aquifer on the 

Florida Keys are apparently nonflowing, although 

the altitude of the land surface is only a few feet 

above sea level. 

GULF COAST 

The gulf coast area of artesian flow is chiefly a 

narrow strip along the Gulf of Mexico. It extends 

inland along the valley of the Myakka River in Sarasota and Manatee Counties and the larger valleys in 

Manatee and Hillsborough Counties. Details of the 

area of artesian flow are shown by Peek (1958a, fig. 

27) for Manatee County and by Heath and Smith 

(1954, fig. 13) for Pinellas County. In Pasco, Hernando, and Citrus Counties, flows may be expected 

only where the land surface is near sea level. The 

area of flow extends westward from Wakulla County 

along the coast to Alabama. From the coastal belt, 

the area of flow extends many miles inland along 

some of the larger stream valleys. It extends up the 

Apalachicola and Chattahoochee Rivers into Georgia 

and Alabama. From the Chattahoochee River it extends up the Flint River and its tributaries in Georgia. Areas of flow include the Choctawhatchee and 

Escambia Rivers and their tributaries in Alabama. 

The artesian flow north of the region underlain by 

the principal artesian aquifer is chiefly from the 

Cretaceous aquifers. Wells in shallow aquifers overlying the principal artesian aquifer will flow in the 

valleys of the Escambia and Perdido Rivers. 

PIEZOMETRIC SURFACE OF WATER 

The piezometric surface, or pressure-indicating 

surface, shown by means of contour lines on figure 

29 represents the height to which water would rise 

in wells with reference to mean sea level in 1961. 

The piezometric surface is above sea level except in a 

few areas such as Panama City and Fernandina, 

Fla., and Savannah, Ga., where pumping has lowered the artesian head. The piezometric surface is 

above the land surface in areas of artesian flow. 

Because of fluctuations of the pressure head, the position of the piezometric surface is changing almost 

constantly, and the representation at any one time 

shows only approximately the condition at any other 

time. However, except in areas of heavy withdrawal 

of water, there has been no detectable net rise or 

decline of the piezometric surface, and the major 

features remain the same. The fluctuations in head 

are generally less than a foot in areas where changes 

caused by recharge and discharge are small or not 

detectable. In the areas where large quantities of 

water are withdrawn from the aquifers, as in the 

coastal counties of Georgia and northeastern Florida, the piezometric surface is based on measurements which show the effects of pumping in 1961. 

A comparison of the original piezometric surface 

prior to 1885 (fig. 30), prepared by Warren (1944, 

p. 26), with the piezometric surface of 1940 (fig. 31) 

shows the changes caused by withdrawal . of water 

through 1940. A comparison of figures 29 and 31 

shows the changes between 1940 and 1961. 

Except for those areas of heavy withdrawal of 

water, most of t~e major features of the piezometric 

surface of 1961 are essentially the same as those 

mapped by Stringfield (1936, pl. 12) in the Florida 

peninsula, by Warren (1944, p. 18) in southeastern 

Georgia, and by V. T. Stringfield and F. C. Westendick in 1936 in Florida west of the Suwannee River. 

These maps were combined and included in reports 

by Warren (1944, p. 18), Stringfield (1950, p. 219), 

Stringfield and Cooper (1951a, p. 528), and Black, 

Brown, and Pearce (1953), and in many subsequent 
120 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

G U .l 

p 

0 

AREAS OF THE PIEZOMETRLC. 

SURFACE IN FLORIDA 

1 Jackson County area 

2 Wakulla County area 

3 Madison County area 

4 Suwannee River area 

5 Putnam County area 

6 Marion County area 

7 Volusia County area 

8 Citrus County area 

9 Pasco County area 

10 Hillsborough County area 

11 Polk County area · 

12 Southern Florida 

0 

EXPLANATION 

---40__.1._LLLL. 

Piezometric contours 

Represent the height to which water 

would rise in tightly cased wells in 

1961. Ticks indicate depression. 

Contour %'nterval 20 feet; datum 

is mean sea level 

50 0 50 

? 

1--.< 

tl 

0 

("). 

t_:l:1 

~ 

'Z. 

FIGURE 29.-Piezometric surface of water in the principal artesian aquifer, 1961. (From Healy, 1962; Stewart and 

Croft, 1960; and Warren, 1944.) 

31° 

30° 

25° 
PRINCIPAL ARTESIAN AQUIFER 121 

82" 

32" 

31" Piezometric contour , 

V

Represents . the height to which water would rise 

in the first wells drilled 

into the principal aquifer. 

Contour interval 10 feet; 

datum is mean sea level 

0 10 MILES 

FIGURE 30.-0riginal piezometric surface of water in the 

principal artesian aquifer in the coastal area of Georgia 

and northeastern Florida about 1885. (By Warren in 

Stringfield and others, 1941, p. 706, and Warren, 1944.) 

reports on artesian water. Profiles of the piezometric 

surface across northern and north-central Florida 

and Marion County are shown in figures 32 and 33. 

Details of the piezometric surface as mapped in 

local areas, in the reports cited, were used in the 

revised map for 1961 in the present report, figure 29, 

insofar as the scale would permit in Florida and 

Georgia. In Florida, the contours are based on a map 

prepared by Healy ( 1962a) . Some features shown 

FIGURE 31.-Piezometric surface in the principal artesian 

aquifer in the coastal area of Georgia and northeastern 

Florida in 1940. (From Stringfield and others, 1941.) 

by the contours, as drawn by Healy, may be caused 

by conditions of the observation wells, such as subsurface leakage from the well, rather than being 

caused by natural conditions of the aquifer. For example, in southern Florida, the 50-foot contour as 

drawn by Healy in Okeechobee and Highlands and 

Glades Counties indicates a slight depression in the 

piezometric surface, which may be due to subsurface leakage from the observation wells measured 

rather than conditions in the aquifer. 
122 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Numbers along profiles A and B are well numbers 

FIGURE 32.-Profiles of piezometric surfaces. A, Central Florida. B, North-central Florida. (Stringfield, 1936.) 

The piezometric surface shows not only the effects 

of withdrawal of wate:~.· from wells but also natural 

discharge areas, recharge areas, and the direction of 

the lateral movement of the water, which is from 

areas of recharge to areas of discharge. The high 

areas of the piezometric surface in general indicate 

recharge, and the low areas indicate discharge. However, recharge may occur in some of the areas of 

relatively low pressure, as the saddle in the Marion 

County area in the Florida peninsula. 

The movement of water in the principal artesian aquifer is much more widespread than the 

movement in the overlying formations. Water that 

enters the aquifer at some places may travel more 

than 50 miles before it leaves the aquifer through a 

well or spring or by upward leakage into an overlying formation. The long distance through which 

artesian water may travel is generally recognized 

and may be responsible for the erroneous opinion 

(Mummey, 1943, p. 46) that water in the principal 

FIGURE 33.-Profile of piezometric surface in the southern 

part of Marion County, Fla. (Stringfield, 1936.) 

artesian aquifer in Florida and Georgia comes from 

remote places such as the Appalachian Mountains, 

the Great Lakes, or the Rocky Mountains. Actually, 

all the fresh water in the principal artesian aquifer 

is from recharge within the area of this report. A 

small amount of the water may reach recharge areas 

from surface streams that rise outside the region. 

For convenience, the piezometric surface is discussed by areas beginning with Georgia and South 

Carolina·. Florida is divided into 12 parts, as shown 

in the index map in figure 29. 

GEORGIA AND SOUTH CAROLINA 

In Georgia and South Carolina the piezometric 

surface slopes east and south from the recharge 

areas, where the aquifer is at or near the land surface. It extends in a broad belt from southwestern 

Georgia northeastward into South Carolina. The 

highest part of the piezometric surface is about 250 

feet above sea level in a recharge area in Worth, 

Turner, and Wilcox Counties, Ga. As described by 

Warren (1944, p. 19) east of the 83d meridian, the 

artesian water appears to be moving chiefly toward 

the southeast, except in parts of Clinch and Echols 

Counties where some of the water may be moving 

southwestward to discharge areas in the Suwannee 

River, Ga. In the coastal counties north of Glynn 

County, however, the water moves east and northeast toward Savannah. This northeastward movement of water toward natural discharge areas northeast of Savannah may also be seen in the original 

piezometric surface (fig. 30). The movement of the 

water in adjacent parts of South Carolina is toward 

the southeast. 

In Glynn and Camden Counties in southeastern 

Georgia, where the general movement of the water 

is toward the east, the original piezometric surface 

·and subsurface information show no indica~ion of 

submarine discharge areas near the coast. Therefore, the water moving to the east in these areas 

either discharges many miles offshore or moves 

northward to submarine discharge areas east of Savannah or southward to the submarine discharge 

area east of the Volusia County area in Florida. 

Part of the water may leave the aquifer by leakage 

into the overlying formations. A large submarine 

spring in this area, 21;2 miles east of Crescent Beach, 

is one of the well-known points of submarine discharge of water from the artesian aquifer. If the 

relatively impervious beds of the Hawthorn Formation, which prevent or retard upward movement of 
PRINCIPAL ARTESIAN AQUIFER 123 

the artesian water, are continuous between the coast 

of southeastern Georgia and the edge of the Continental Shelf (about 75 miles from the coast) and if 

salt water head were sufficient to prevent discharge 

of artesian water, there would be a flat isopiestic 

area of the piezometric surface between the areas 

of discharge to the north and to the south. 

As stated by Warren (1944, p. 18), in some of the 

recharge areas where the aquifer is exposed in river 

valleys, such as the Savannah, Ogeechee, Ocmulgee, · 

and Flint Rivers, part of the water that enters the 

aquifer in its area of recharge is discharged into 

these rivers and through springs. The piezometric 

surface in Screven County, Ga., indicates the discharge of water from the principal Tertiary artesian aquifer into the Savannah River. 

Farther upstream in the valley of the Savannah 

River near the Fall Line, Siple (1960b, p. 163-166) 

has shown that the Cretaceous aquifer, which is recharged locally, discharges into the Savannah River 

in the area where clay beds have been removed. 

Siple showed this discharge by a map of the piezometric surface of the artesian water in the Tuscaloosa Formation of Cretaceous age. The lowest part 

of the piezometric surface in the area of discharge 

in the Savannah River valley has an oval shape, indicating upward leakage from the aquifer, as in the 

St. Johns River valley in the Vol usia County area in 

Florida. In contrast, the contours of the piezometric 

surface in areas of discharge, as in the Savannah 

River valley in Screven County, Ga., have a V-shape 

where they cross the river. The contours point upstream, a fact indicating the aquifer is exposed, and 

part of the water moves laterally from the aquifer to 

the stream. Under these conditions, as on the Flint 

and Suwannee Rivers, the rivers reduce discharge of 

the aquifer during flood stages and receive water 

from the aquifer during low stages. 

Blue Springs, 3.3 miles northwest of the ScrevenEffingham County line at the west edge of the Savannah River valley in Screven County, Ga., is one 

of the places of discharge (Warren, 1944, p. 18, 19) 

which have a noticeable effect on the piezometric 

surface. The discharge through large limestone 

springs on both sides of the Ocmulgee River in Wilcox County and the northern part of Ben Hill 

County, Ga., and through large springs near the 

banks of the Flint River in Dougherty, Baker, and 

Decatur Counties is indicated locally by the relatively low areas of the piezometric surface. As 

stated by Warren south of Dougherty County in 

areas 10 to 15 miles wide bordering the Flint River, 

water levels in wells ending in the aquifer fluctuate 

through a range of 10 to 20 feet and are only 

slightly above river level during low stages of the 

river. This fluctuation indicates there is exchange 

of water between the aquifer and the river, as has 

. been observed on the Suwannee River in Florida, 

where the direction of movement of the water in the 

aquifer depends on the stage of the river. At high 

stages, some water moves from the river to the 

aquifer, but at normal and low stages the movement 

is reversed. 

A map of the piezometric surface of Dougherty 

County, Ga., by Wait (1963, p. 59 and pl. 2) shows 

two valleys in the pressure surface south of Albany 

and east of the Flint River. As suggested by Wait, 

these appear to represent cavernous zones in the 

limestone. The valleys appear to join a zone of underflow in the Flint River valley. Changes in stage 

in the Flint River are reflected by changes in 

ground-water levels as much as 3 miles from the 

river in Dougherty County (Wait, 1963, p. 62). The 

flow of Radium Springs about 4 miles south of Albany and a short distance east of Flint River is relatively small because the elevation of the outlet is 

only a few feet below the piezometric surface. 

In southwestern Georgia, a map of the piezometric 

surface in Seminole, Decatur, and Grady Counties 

by C. W. Sever (1965, pl. 1) shows discharge from 

the aquifer to the Flint and Chattahoochee Rivers 

and Spring Creek. The map also shows recharge in 

interstream areas. The piezometric surface was 

more than 100 feet above sea level in the Valdosta 

area in Lowndes and Brooks Counties where there is 

local recharge through sinkholes and drainage wells, 

when mapped by Warren in 1942. Vorhis (1961, p. 

123-129) reported that local withdrawal of water 

has lowered water levels in part of the area but that 

a large part of the artesian water moves southwestward into Florida. West of this area, the movement 

is southward to Florida. 

The gradient of the piezometric surface southeastward between the 230-foot and 80-foot contours 

in Georgia is relatively steep and as much as 15 

feet per mile, in comparison with relatively low gradients of less than a foot per mile between this area 

and the coast. The steepest gradient borders large 

recharge areas. H. E. LeGrand (written commun., 

1963) suggested this steep gradient" appears to be 

due in part to upward leakage into the beds overlying the principal aquifer .. Some of this water is 

discharged into surface streams. The gradient decreases as the water moves under confining beds in 

the Hawthorn Formation. As stated by Warren 

( 1944, p. 19), these low gradients probably indi-
124 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

cate an increase in the permeability and thickness 

of the limestone. 

Coastal Counties 

The original piezometric surface in the coastal 

area of Georgia, southeastern South Carolina, and 

·northeastern Florida, figure 30 (Warren, 1944, 

fig. 6) ranged from about 70 feet in the western 

part of the area to less than 30 feet in the Savannah 

area. In Georgia, north of Glynn County, the general direction of the movement of the water is 

northeastward toward a submarine discharge area 

east and northeast of Savannah. In southeastern 

South Carolina, the movement is toward the southeast to the discharge area. In St. Johns County in 

northeastern Florida, the movement is southeastward to a submarine discharge area. 

A map of the coastal area in 1940 by Warren 

(1944, fig. 2) and Stringfield, Warren, and Cooper 

(1941, p. 704) figure 31, shows the piezometric surface was at least 70 feet above sea level in the western part of the coastal area and about 30 to 55 feet 

along the coast, except at Savannah and Fernandina. 

At Savannah, where the withdrawal of water was 

about 35 mgd, the piezometric surface was more than 

30 feet below sea level and more than 70 feet below 

its original level; an~ at Fernandina, where the withdrawal was about 33 mgd, the piezometric surface 

was at or near sea level and as much as 60 feet 

below the original level. In con~rast, at Brunswick, 

although the withdrawal of water was ·about 32 

mgd, the piezometric surface was about 45 feet above 

sea level and only about 20 feet below its original 

level ; and at Jacksonville, where the withdrawal of 

water was about 35 mgd, the piezometric surface 

was about 30 feet above sea level and only about 30 

feet below the original artesian surface. 

These differences in the effect of withdrawal on the 

piezometric surface show significant differences in 

the thickness or permeability of the aquifer, or 

both. Differences in permeability appear evident 

in comparing the Brunswick area with the Fernandina area where the thickness of the aquifer is 

approximately the same, as suggested in the discussion of the aquifer under Duval and Nassau 

Counties, Fla. 

These differences in the water-bearing properties 

of the aquifer. may also be noted in figure 29 by 

comparing the differences in the piezometric surface 

in these areas of large withdrawal in 1957 and 1958 

when the withdrawal of water was 60 mgd in the 

Savannah area, 90 mgd in the Brunswick area, 52 

mgd in the Fernandina area, and 26.6 mgd in the St. 

Marys area in southeastern Camden County in 

Georgia as reported by Stewart and Croft (1960, 

p. 84). 

FLORIDA 

For convenience in describing the piezometric surface in Florida, the State is divided into areas, each 

of which includes one or more major features. In 

the Florida peninsula, the areas are the same as 

those used by Stringfield (1936, pl. 12). The remainder of the State west of the Suwanee River is 

described as three areas. The general location of 

these areas is shown on the inset map (fig. 29) . 

Western Florida 

In Florida, west of the Suwanee River, the piezometric surface slopes in general from Georgia and 

Alabama to the Gulf of Mexico. The contours of 

the piezometric surface are approximately parallel 

to the coast in a large part of the area. Along the 

Alabama State line, the piezometric surface is more 

than 120 feet above sea level in a recharge area in 

Jackson and Holmes Counties, Fla. It is as much 

as 130 feet above sea level in Santa Rosa County 

at the Alabama line, owing in part to recharge in 

Alabama. Along the coast west of Wakulla County, 

the piezometric surface rises above sea level to 

more than 60 feet in Santa Rosa County. 

For convenience in describing the piezometric surface, the area west of the Suwannee River is divided into the Madison County area, the Wakulla 

County area, and the Jackson County area. 

MADISON COUNTY AREA 

In Madison, Taylor, and Lafayette Counties, the 

piezometric surface has the shape of a flat-topped 

ridge between the Suwannee River and Aucilla River. 

The piezometric surface ranges from about 80 feet 

above sea level at the Georgia State line to sea level 

along the Gulf of Mexico. The highest and widest 

part is adjacent to a high area of the piezometric 

surface in the Valdosta area, Georgia. 

The aquifer is at or near the surface in most of the 

:Madison County area. Recharge may occur throughout most of the area. Some recharge is through 

sinkholes. At the Georgia State line, movement of 

the water is southward into Florida. In Florida, 

the movement is from the crest of the ridge of the 

piezometric surface eastward into the Suwannee 

River and westward and southward to the Aucilla 

River and the Gulf of Mexico. 

WAKULLA COUNTY AREA 

In Wakulla and Leon and adjacent counties between the Aucilla and the Apalachicola Rivers, the 
PRINCIPAL ARTESIAN AQUIFER 125 

piezometric surface generally ranges from 60 feet 

above sea level at the Georgia State line to sea level 

along the coast. The piezometric contours, on an unpublished map by James W. Yon, Jr., in Jefferson 

County and by Charles W. Hendry, Jr., in Leon 

County in 1961 on investigations of the Florida 

Geological Survey, show that the piezometric surface was a few feet· higher in the northern parts of 

Jefferson and Leon Counties than when. mapped by 

Stringfield in 1936. This change is probably due to 

seasonal fluctuations of water levels in the limestone. Hendry mapped a local area where the piezometric surface is as much as 100 feet above sea 

level in southwestern Leon County. There probably 

is recharge through sinkholes which are filled and 

covered with permeable sand. That feature was not 

discovered in the mapping in 1936 and also is not 

shown in a later map by Healy (1962a). 

The aquifer is at or near the surface in the southern part of the Wakulla County area, but it is overlain by the Hawthorn Formation in the northern 

part where underground solution in the aquifer and 

collapse of the overlying Hawthorn Formation has 

formed lake basins east of the Ochlockonee River. 

As described by Sellards (1917, p. 118; 1910, p. 

53-63), some of these basins, at times, drain into 

the aquifer through sinkholes when they are not 

clogged with silt and debris. In the area between the 

Ochlockonee and Apalachicola Rivers, the aquifer is 

overlain by the Hawthorn and younger formations 

of sufficient thickness to prevent sinkholes and lake 

basins. 

A large part of the drainage in the southern part 

of the Wakulla County area is underground. Although there is local recharge, the discharge through 

the solution channels in the limestone is large. Part 

of the water discharges through Wakulla Spring 

into Wakulla River to the gulf. The discharge in the 

area causes a valley in the piezometric surface extending from the coast into Leon County. The 

cavern through which the water moves into the 

spring has been described by Olsen ( 1958, p. 

396-403). 

JACKSON COUNTY AREA 

This area includes all Florida west of the Apalachicola River. The piezometric surface is more than 

120 feet above sea level near the Georgia and Alabama State line in a recharge area in Jackson and 

Holmes Counties where the aquifer is at or near the 

land surface. The piezometric surface slopes, in 

general, toward the south. Along the coast it ranges 

from a few feet above sea level in Gulf County to. at. 

least ,60 feet above sea level in Santa Rosa County, 

except in two areas of pumping where it is below 

sea level. The gradient of the piezometric surface 

is more uniform and steeper in the western part of 

the area, where some of the water-bearing formations of the aquifer grade from limestone and marl 

into sands and other clastic material. In the western part of the ar.ea, all the recharge appears to be 

in Alabama. In the eastern part of the area in 

Jackson and Holmes Counties, the piezometric surface shows the effects of springs and other discharge of the aquifer in the headwaters of the 

Chipola and Choctawhatchee Rivers where the 

aquifer is at or near the surface. There is recharge 

through sinkholes in Holmes, Washington, and 

northern Bay Counties. However, the discharge 

into Pinelog Creek, Holmes Creek, and other streams 

where the aquifer is near the surface forms. a v~lley 

in the piezometric surface. Some of the discharge is 

from sinkhole lakes. The contours of the piezometric surface in Bay County suggest upward leakage of the aquifer along Bear Creek and the upper 

part of North Bay, even though the top of the 

aquifer (fig. 23) is at least 100 feet below sea 

level. Also, the· shape of the contours in the vicinity 

of Choctawhatchee Bay in Walton County suggests 

upward leakage. It is entirely possible that a stream 

tributary to North Bay and Choctawhatchee Bay 

cut a channel in the material overlying the aquifer 

during a low stand of the sea in Pleistocene time. 

Pumping from wells has caused two cones of depression in the piezometric surface, one in the 

Panama City area and the other in the Fort Walton 

area. 

Florida Peninsula 

For convenience in describing the piezometric 

surface, the peninsula is divided into nine areas 

which are the same as those used in 1933 (Stringfield, 1936, p. 147-154) as shown on inset map (fig. 

29). Although there may be recharge and discharge 

in all of the areas, those characterized chiefly by 

recharge are discussed first, followed by areas of 

large discharge. 

In recharge areas in the central and northern 

parts of the peninsula, the piezometric surface is at 

least 80 feet above sea· level in the northern part 

and more than 120 feet in the central area; but in 

the intervening saddle, it is only 40 to 50 feet above 

sea level, where there is discharge as well as recharge. The piezometric surface in the saddle area 

slopes to sea level on the gulf coast and to only a 

few feet above sea level in the St. Johns River 
126 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

valley. The high area of the piezometric surface in 

the central part slopes to a relatively flat area in 

southern Florida, south of Lake Okeechobee. 

POLK COUNTY AREA 

One of the most conspicuous features of the piezometric surface is in the central part of the peninsula, 

in Polk County and adjacent counties, where the 

surface has an elongated dome, a large part of 

which is 90 to 130 feet above sea level. This dome 

extends northward into Marion County at an altitude of about 50 feet; it extends southward into the 

southern part of the peninsula, where it merges 

about 50 feet above sea level into a relatively flat 

part of the piezometric surface. The total northsouth extent is about 150 miles. The dome extends 

to the Atlantic coast ·on the east, where it has an 

altitude of 10 to 20 feet. On the west the dome 

merges into a relatively small saddle and domeshaped feature in Pasco County and a valley in the 

Hillsborough County area. The dome extends to the 

Gulf of Mexico on the southwest. The total east-west 

extent is about 120 miles. Maps showing local 

details of the piezometric surface in this area are 

included in county reports cited on Brevard, Highlands, Hillsborough, Indian River, Manatee, Orange, 

Sarasota, and Seminole Counties .. 

The piezometric surface in the lake region of the 

upland indicates local recharge of the aquifer, 

largely in Polk, Highlands, and Lake Counties. Most 

of the recharge occurs in the lake region in Polk 

County, in the northwestern part of Highlands 

County, in the south-central part of Lake County, 

and in the lake region of Orange County. Part of 

the recharge at Orlando and in adjacent parts of 

Orange County is through drainage wells. In Highlands County, Kohout and Meyer (1959, p. 66) estimated that downward leakage from Lake Placid to 

the principal artesian aquifer averaged 2 to 3 inGhes 

per month during the first half of 1956. Pride and 

others (1961, p. 86, 87) reported evidence of recharge sinkholes in the Green Swamp area in Polk 

and Lake Counties. 

The principal artesian aquifer is overlain by relatively impervious beds of the Hawthorn Formation 

in part of the Polk County recharge area. However, 

well records show that in parts of the area the Hawthorn is relatively thin or absent. Within the area 

are numerous lakes that occupy sinkholes now 

filled with sand that permit downward movement 

of the water. The log of a well at Davenport, Polk 

County (Stringfield, 1936, p. 148), at the edge of 

the depression of a filled sinkhole, indicates the presence of unconsolidated quartz sand to a depth of 110 

feet. Phosphatic marl, probably representing the 

Hawthorn Formation, occurs in the interval between 110 and 120 feet, below which is soft limestone (Ocala) of the artesian aquifer. Under these 

conditions, local recharge of the Ocala Limestone 

may readily occur. 

Artesian water moves laterally in all directions 

from the Polk County recharge area. It is the source 

of recharge to the artesian aquifer in the southern 

part of the peninsula and to other adjacent areas. 

As the water moves laterally toward the coast, 

some of it may leak upward into the overlying Hawthorn in the areas of artesian flow. In northeastern 

Brevard County, there is discharge of water to the 

Indian River and also to the St. Johns River north 

of Lake Poinsett as described by Brown, Kenner, 

Crooks, and Foster (1962, p. 74). 

In western Manatee County, Peek (1958a, p. 45) 

described a low pressure area of the piezometric 

surface in the vicinity of Palma Sola and Palmetto· 

that indicates upward leakage through irrigation 

wells and through unconsoHdated material which 

filled valleys cut into the Hawthorn during a low 

stand of the Pleistocene sea. 

PASCO COUNTY AREA 

West of the Polk County area, in east-central 

Pasco County, the piezometric surface generally is 

at least 80 feet above sea level. The high area extends into Hernando County and slopes northward 

to a lower area in Citrus County. Westward on the 

Gulf of Mexico and southward on Tampa Bay, the 

piezometric surface slopes to an altitude of about 10 

feet. On the east, it is bordered by a small saddle 

about 60 to 70 feet above sea level where it merges 

with the Polk County area, much higher than the 

saddle. A detailed map of the piezometric surface 

in .Pasco and Hernando Counties by Wetterhall 

(1964) showed that the piezometric surface had 

an altitude of as much as 95 feet in east-central 

Pasco County and 100 feet at the Hernando County 

line in October 1960. 

In most of the area, the top of the aquifer is at 

or near the ground surface and permits groundwater recharge. The Hawthorn Formation with 

relatively impervious material overlies the aquifer in 

east-central Pasco County and adjacent parts of 

Hernando County where the piezometric surface is 

at least 80 feet above sea level. However, within 

that area there are sinkholes and lakes occupying 

sinkholes through which recharge may take place, 

accounting in part for the high water levels in wells 

in the principal aquifer. The geology, topography, 

and ground-water conditions in some respects are 
PRINCIPAL ARTESIAN AQUIFER 127 

comparable to those of Polk County area. Artesian 

water in the principal aquifer moves laterally in all 

directions from the central part of the recharge 

area. This recharge is the source of artesian water 

for the aquifer in most of Pasco County, parts of 

Hernando and Pinellas Counties, and the northwestern part of Hillsborough County. 

Along the coast and in the Gulf of Mexico where 

the aquifer is at or near the floor of the gulf, the 

piezometric surface is less than 10 feet above sea 

level because of the large discharge of water into 

the gulf. W. S. Wetterhall (written commun., May 

1961) has observed and photographed many springs 

in the Gulf of Mexico west of Pasco County, some of 

which are as much as 60 miles offshore. Photographs 

of these springs show that the water rises to the 

floor of the gulf through circular depressions, which 

may be submerged natural wells or sinkholes or other 

solution features. 

A detailed map of the piezometric surface in 

Pinellas County (Heath and Smith, 1954, fig. 13) 

shows local recharge of the aquifer in Pinellas 

County, except in the northern part of the County 

where part of the recharge is from Hillsborough 

County. Heath and Smith reported that the rate of 

recharge is probably greatest in the area centered 

about a mile south of Coachman, where the piezometric surface has the shape of an elongated dome 

as much as 16 feet above sea level. Lakes in the 

area appear to occupy sinkholes and solutiQn depressions. Tarpon Lake (formerly Lake Butler) 

occupies a large solution depression and at times 

discharges through an underground solution channel 

to Tarpon Springs and the Gulf of Mexico. Sinkholes filled with sand and other unconsolidated material may be covered by surficial sand in the Coachman area. Heath and Smith reported recharge 

through sinkholes in the eastern part of Dunedin. 

PU'l'NAM COUNTY AREA 

In the northwestern part of. Putnam County and 

parts of Alachua, Clay, Columbia, Bradford, Baker, 

and Union Counties, the piezometric surface is about 

50 to more than 90 feet above sea level. North of 

Putnam County, it forms a ridge 60 to 80 feet above 

sea level extending into Georgia. On the east, it 

slopes to the Atlantic Ocean to an altitude of about 

20 to 40 feet. On the south, it merges with a broad 

saddle about 50 feet above sea level in Marion 

County. On the west it forms a broad area in Alachua County about 40 to 60 feet above sea level. 

Farther west it extends to the Suwannee River valley, where it ranges from a few feet to about 50 feet 

above sea level. 

Clark, Musgrove, Menke, and Cagle (1962, p. 

78-82) included a map and description of the 

piezometric surface in Alachua, Bradford, Clay, and 

Union Counties showing the recharge to the piezometric surface in part of the Putnam County area. 

Meyer (1962) included a map and description of the 

piezometric surface in Columbia County. 

The principal artesian aquifer is not exposed 

where high areas of piezometric surface show local 

recharge, but typica·l sinkhole topography affords 

·conditions favorable for recharge. Clark, Musgrove, Menke, and Cagle (1963) showed the conditions of recharge to the aquifer through sinkholes 

and the relation of the piezometric surface and 

water table to the lake levels in the southwestern 

part of Clay County. In the southern and western 

parts of the area, recharge is through sinkholes or 

directly to the aquifer where it is at or near the surface. In the eastern part of Baker County in the 

northern part of the area, although the piezometric 

surface of water in the principal artesian aquifer 

is at least 70 feet above sea level, little or no recharge takes place locally because the aquifer is 

overlain by relatively impervious beds of the Hawthorn Formation. However, water is supplied 

through a recharge area in parts of Columbia 

County, as well as in Baker County and in Georgia. 

In the eastern part of Baker County, static water 

levels in wells in the middle and upper part of the 

Hawthorn Formation will rise higher than the level 

in the aquifer. However, in Duval and Nassau 

Counties, the pressure of the artesian water of the 

Hawthorn is less than that in the principal artesian 

aquifer except in areas, such as Fernandina, where 

withdrawal of water has caused the artesian levels 

to decline below that of the Hawthorn. Cones of 

depression in the piezometric surface in the Jacksonville area in Duval County and Fernandina areain Nassau County, as shown by Leve (1961a, p. 14) 

and in figure 31, are caused by withdrawal of water 

from wells. 

A small local depression in the piezometric surface about 30 to 40 feet above sea level is present at 

Green Cove Springs and vicinity in Clay County. 

The withdrawal of water from wells appears to be 

insufficient to cause the depression. However, withdrawal of water and subsurface leakage from wells 

together may be sufficient to account for it. The 

flow of Green Cove Springs doubtless affects the 

head of water in the Hawthorn in the vicinity of 

the springs. Stringfield (1936, p. 150) was of the 

opinion that the spring did not directly affect the 

head in the principal aquifer. However, the chemi-
128 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

cal quality of the water (Ferguson and others, 1947·, 

p. 60) is similar to that from the aquife·r (Black 

and Brown, 1951, p. 39). Foster (1962, p. 7-8) 

showed large subsurface leakage from the principal aquifer to the Hawthorn and younger forma,. 

tions through wells. Therefore, it seems likely that 

some of the water of the spring is from that aquifer. 

In the southern part of the Putnam County area, 

the water in the principal artesian aquifer moves 

laterally from the recharge area into Putnam, 

Alachua, Marion, Clay, and Bradford Counties. In 

the northern part of the area some of the water 

moves to the east into Nassau and Duval Counties 

and some of it moves to the west toward the 

Suwannee River. The hydraulic gradient in the eastern part of Nassau and Duval Counties is relatively 

low except in areas where the piezometric surface 

has been depress.ed by heavy withdrawal of water 

from wells. 

MARION COUNTY AREA 

In Marion County the piezometric surface forms 

a broad saddle about 40 to 50 feet above sea level 

between the Putnam County area on the north and 

the Polk County area on the south. In this area the 

top of the aquifer (the Ocala Limestone) is at or 

near the surface, and sinkholes afford favorable 

conditions for recharge. The recharge doubtless is 

large, and also large quantities of water move into 

the area from the Polk County area and the Putnam 

County area. There are no surface streams in part 

of the area where all of the drainage is underground. 

As the limestone is permeable and cavernous, water 

moves through it freely. During and after periods 

of large rainfall, part of the saddle area of the piezometric surface is as much as 10 feet higher than at 

normal times. Under such conditions, the 50-foot 

contour lines, instead of closing on the north and 

south of the saddle as mapped in figure 29, will 

extend along the eastern and western parts of the 

saddle and connect the Polk County area with the 

Putnam County area. 

Marion County is also an area of very large discharge. It furnishes water for Silver Springs and 

Rainbow Springs (formerly Blue Springs), two of 

the largest springs in the State. The discharge of 

these springs having a combined maximum flow of 

about 2,097 cubic feet per second (1,255 mgd) 

and a minimum of 1,136 cfs (734 mgd) in part 

causes the saddle in the piezometric surface. Part 

of the water in the aquifer flows eastward and is 

discharged in the St. Johns River valley in the Volusia County area, and a large part flows westward 

from the saddle area to the Gulf of Mexico. 

VOLUSIA COUNTY AREA 

Volusia, Flagler, and parts of adjacent counties 

form an area of recharge and discharge of the 

principal artesian aquifer, although the aquifer is 

not exposed at the surface. Recharge through sinkholes and the lakes occupying old sinkholes was 

recognized and mapped in 1933 (Stringfield, 1936, 

p. 152). The data obtained at that time revealed a 

recharge area where the piezometric surface was 20 

to 30 feet above sea level in a narrow district, 

extending from the southeastern part of Putnam 

County into the northwestern part of Volusia 

County, between St. Johns River valley and Crescent· Lake. A similar area, including De Land, 

Orange City, and Lake Helen in Volusia County, 

east of the St. Johns River valley was recognized, 

but records were not available to map the piezometric surface. A map in 1955 (Wyrick, 1960, p. 

26) showed that there are high areas of the piezometric surface, as much as 35 feet above sea level, 

in northwestern Volusia County. This map also 

shows that the piezometric surface has the shape of 

a broad ridge extending from Flagler County on the 

north through the central part of Volusia County 

to Seminole County. The highest part of the ridge 

in the piezometric surface is about 40 feet above 

sea level. It slopes to about 10 feet above sea level 

on the Atlantic coast where there is submarine discharge from the aquifer. It slopes to the south and 

west to about 15 feet above sea level in the St. 

Johns River valley, where there is upward leakage. 

In the southeastern part of Putnam County, the 

piezometric surface has the shape of a north-south 

ridge between Crescent Lake and the St. Johns 

River. A detailed map of the county by Leve (1958, 

p. 16) showed that the ridge is as much as 60 feet 

above sea level northeast of Pomona Park. To the 

east, the piezometric surface slopes to about 30 feet 

above sea level. On the west, it slopes to less than 

10 feet above sea level in the St. Johns River valley, 

where there is upward leakage. These features also 

are shown .on a map of the piezometric surface 

(Bermes and others, 1963) in Flagler, Putnam, and 

St. Johns Counties. 

As described by Wyrick, the high areas of the 

piezometric surface are in areas where there are 

sinkholes and sinkhole lakes through which recharge 

occurs. Sinkhole topography extends several miles 

north and south of De Land on the Penholoway terrace and also along the terrace near Pierson and 

Seville. Wyrick (1960, p. 9-10) showed these terraces on a map and a profile from the St. Johns 

River to the Atlantic Ocean, across Volusia County. 
PRINCIPAL ARTESIAN AQUIFER 129 

Wyrick reported that, in sinkholes, surface deposits 

in some places in De Land have slumped as much as 

40 feet below the level of the Penholoway terrace, 

which is about 70 feet above sea level. It is entirely 

possible that east of Penholoway terrace sinkholes 

may have formed but were filled by sand and other 

material at the time the sea covered that area. 

As stated by Wyrick (1960, p. 27) most, if not 

all, of the fresh artesian water in Volusia County is 

from recharge areas within the county. Areas of 

low pressure surround the recharge areas. This low 

pressure is caused in part by discharge of ground 

water through springs in the St. Johns River valley 

and submarine discharge through springs and sinkholes in the Atlantic Ocean. · 

A map of Flagler County by Bermes (1958a, p. 17) 

in 1956 showed the piezometric surface to be relatively flat, ranging from about 5 feet to more than 15 

feet above sea ievel. The lowest point is in an area 

about midway between Bunnell and Crescent Lake, 

where relatively large quantities of water were 

being withdrawn for irrigation of truck crops. The 

contour interval of the piezometric map is too large 

to show it, but Bermes reported some local recharge 

in areas around Espanola, northwest of Bunnell, 

and around Favorita, southeast of Bunnell. Although he believed the recharge is due to downward 

leakage from the nonartesian aquifer, it seems more 

likely that recharge is through sinkholes which were 

filled and covered with unconsolidated deposits during Pleistocene time. The relatively low chloride 

content of the artesian water (25 ppm or less), which 

is surrounded by artesian water with a higher 

chloride content in the Espanola area, indicates that 

local recharge has flushed the high-chloride water 

from the aquifer in this area. 

The piezometric surface is relatively low in an 

area southwest of Bunnell surrounding Haw Creek 

and its tributaries, indicating upward leakage into 

these streams. Bermes (1958a, p. 17) reported that 

several small springs in Haw Creek and Sweetwater 

Branch yield highly mineralized water from the 

aquifer. The part of this area in which the piezometric surface is lowest is generally the same as 

that in which the chloride content is 750 to more 

than 2,000 ppm in the upper part of the aquifer, the 

top of which is about 100 feet below the land surface. This fact suggests that in addition to upward 

leakage decreasing the head, the difference in· the 

specific gravity between the high-chloride water and 

the fresh water in the aquifer may cause the water 

levels to stand lower tha~ in adjacent areas. 

The piezometric surface in Seminole County on 

the northeast side of the Polk County area merges 

with the Vol usia County area in the St. Johns River 

valley. Local recharge occurs in the areas of sinkhole lakes as described by Heath and Barraclough 

( 1954, p. 22). However, part of the artesian water 

of the Polk County area moves northeastward from 

Orange County into Seminole County. Although 

part of the artesian water of the principal aquifer 

discharges in the St. Johns River valley, there has 

not been sufficient discharge and time for all of the 

salt water in the aquifer to be flushed out. The relation of fresh artesian water to the salt water in 

some parts of Seminole County is similar to that in 

Volusia County where local recharge through sinkhole lakes has flushed out the salt water, resulting 

in a fresh-water area surrounded by salt water. 

The piezometric surface slopes from about 60 feet 

above sea level in the southwest corner of Seminole 

County northeastward to about 15 to 20 feet above 

sea level in the St. Johns River valley. The details 

are shown on maps by Heath and Barraclough 

(1954) and Barraclough (1962). 

HILLSBOROUGH COUNTY AREA 

The piezometric surface in _Hillsborough County 

ranges from less than 10 feet on Tampa Bay to 

more than 60 feet where it merges with the Pasco 

County· area and more than 70 feet in the Polk 

County area. At Port Tampa, it is about 3 feet 

above sea level (Stringfield, 1936, p. 152). From 

Tampa and vicinity northeastward to Pasco County 

the piezometric surface has the shape of a valley 

that heads in a saddle in PasGo County, between the 

Pasco County and Polk County areas. This valley is 

caused in part by leakage of artesian water through 

springs in the outcrops of the Tampa Limestone, 

which is the top of the aquifer along the valley of 

the Hillsborough River. The largest of these springs 

is Sulphur Springs near Tampa. One of the best 

known of the smaller ones is Crystal Springs near 

the town of Crystal Springs. Also, the piezometric 

surface shows leakage of artesian water into the 

Alafia River and Tampa Bay. 

Wetterhall (in Menke and others, 1961, p. 83-86) 

showed that the piezometric surface in 1958 ranged 

from about 100 feet above sea level in the northeastern part of Hillsborough County to a few feet above 

sea level on Tampa Bay. As stated by Wetterhall, 

the piezometric surface slopes toward Tampa Bay 

from the high recharge areas of the piezometric 

surface in Polk and Pasco Counties. In his discussion 

of the northwestern part of Hillsborough County, 

Wetter hall suggested that a major fault shown by 
130 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Vernon (1951, fig. 11) may affect the shape of the 

piezometric surface. However, the writer can find 

no evidence that the movement of the water or 

shape of the piezometric surface is affected by a 

fault. 

A map of the piezometric surface by Peek (1959b, 

p. 52) for the Ruskin area in southwestern Hillsborough County showed that the piezometric surface ranges from sea level on Tampa Bay to more 

than 40 feet above sea level eastward. Along the 

coast from Alafia River southward to Manatee 

County the piezometric surface increases in altitude from sea level to about 16 feet above sea level 

at the Manatee County line. 

CITRUS COUNTY AREA 

In Citrus County and adjacent parts of Hernando, 

Sumter, Marion, and Levy Counties, the piezometric 

surface slopes from an altitude of about 40 feet in 

the eastern part of the area to less than 5 feet in the 

western part, on the gulf coast. The Ocala Limestone or Suwannee Limestone of the principal artesian aquifer is at or near the surface, and sinkholes 

are well formed, especially in Citrus County, facilitating local recharge. The aquifer is permeable and 

cavernous and thus permits fairly free movement of 

the water. The general direction of movement is 

toward the Gulf of Mexico, and most of the water 

discharges as springs along the coast or on the floor 

of the gulf. Some water from the Marion County, 

Polk County, and Pasco County areas moves into the 

Citrus County area. The alinement of some of the 

sinkholes in an east-west direction indicates the 

course of some of the underground streams. Such an 

alinement might be expected because the contours 

representing the piezometric surface show .that the 

movement of the water is toward the west. In the 

northern part of Citrus County along the Withlacoochee River, the ground-water level during normal stages is about the same as the water level in the 

river. During flood stages, the river may lose water 

to the aquifer. 

SUWANNEE RIVER AREA 

This area is one of large discharge of artesian water into the Suwannee and Santa Fe Rivers. The 

piezometric surface has the shape of a· valley along 

the Suwannee River. The ground-water level along 

the stream is generally about the same as the water 

level in the river. The piezometric surface generally 

slopes from 50 to 60 feet above sea level near the 

State line on the north to 10 feet above sea level on 

the Gulf of Mexico. On both sides of the valley, it 

rises to at least 50 feet above sea level. The gradient· 

on the east side, however, is lower than that on the 

west, indicating that the aquifer is more permeable and more cavernous on the east side than on the 

west. Nevin Hoy (written commun., 1962) believed that the steep gradient on the west side is due 

to a larger volume of water moving through that 

section than on the east side of the river. Oligocene 

and Eocene limestones of the principal artesian aquifer are present at or near the surface in this area 

and thus receive recharge. During low stages of the 

Suwannee River, its flow is largely derived from 

ground water, but during flood stages it loses some 

water to the aquifer. These relations between surface water and ground water also exist along the 

lower course of the Santa Fe River, a tributary of 

the Suwannee. 

In Suwannee County about 0.2 mile west of Falmouth and 3.5 miles southeast of the Suwannee 

River at Ellaville, a small section of the roof of an 

underground stream has collapsed, and the stream 

is exposed. This exposure is known as Falmouth 

Spring. During normal stages of the Suwannee 

River, the water level of Falmouth Spring is higher 

than the river, and water from the spring flows 

westward to the river. However, during flood stages 

the river is somewhat higher than the spring and 

contributes water to the underground stream, and 

the flow of Falmouth Spring is reversed. When visited by the writer in 1930, 1961, and 1963, the water 

appeared to be under sufficient artesian pressure so 

that the water level in the spring stood above the 

underground channel which feeds it. 

SOUTHERN FLORIDA 

The piezometric surface in southern Florida 

ranges from a few feet to about 50 feet above sea 

level. In the southern part of the area only a few 

wells penetrate the lower part of the Hawthorn 

Formation and the underlying rocks, and, therefore, 

only a few control points are available to represent 

the piezometric surface. When the piezometric surface was mapped in 1934 (Stringfield, 1936, p. 154), 

the available records indicated that the altitude of 

the piezometric surface was approximately sea level 

on the Florida Keys and about 40 feet or more at 

Miami and that it was about 50 feet at the south 

end of Lake Okeechobee. 

Later investigations (Lichtler, 1960, p. 40) 

showed the 50-foot contour line farther south of 

Lake Okeechobee than on the map prepared in 1934. 

McCoy (1962) included a map and discussion of the 

piezometric surface in Collier County. The 50-foot 
PRINCIPAL ARTESIAN AQUIFER 131 

contour line shown by Healy (1962a) suggests upward leakage from the aquifer or differences in 

transmissibility of the aquifer in Okeechobee, Highlands, and Glades Counties. This feature may actually be due to subsurface leakage through one or 

more of the observation wells. The water level or 

shut-in pressure on such wells is less than the pressure in a well with adequate casing which would 

prevent subsurface leakage. 

The principal artesian aquifer is deeply buried in 

southern Florida, and no recharge occurs locally. 

Part of the water enters the aquifer through sinkholes and lakes occupying sinkholes in the Polk 

County area, moves southward, and spreads out toward the coast. With this increase in cross section 

of the aquifer through which the water moves, the 

gradient decreases from about 3 feet per mile to less 

than about 0.5 foot per mile. The gradient increases 

in the coastal counties. That increase may be attributed to a decrease in the thickness and permeability of the aquifer and submarine discharge of the 

artesian water. There seems to be submarine discharge through some outcrops of the Atlantic coast. 

The aquifer is not known to crop out in the Gulf of 

Mexico west of southern Florida, but there probably 

is upward leakage of artesian water. 

REI.ATION OF STRUCTURE TO SOLUTION CAVITIES 

AND MOVEMENT OF WATER IN Lll\:IESTONE 

Where a water-bearing formation is overlain and 

underlain by relatively impervious beds, water tends 

to move laterally through the formation from areas 

of recharge to areas of discharge. If the formation 

is folded into anticlines or other structures, water 

may move approximately parallel to the dip of the 

overlying and underlying confining beds. Under 

these conditions the water may move dowridip from 

recharge on the crest of an anticline and (or) updip 

in the flank of an adjacent syncline to a discharge 

area, if conditions of recharge and discharge are 

favorable as described by Reeves (1932) and Cady 

(1936) in the Shenandoah Valley of Virginia. In 

any case, the general direction would be parallel to 

the dip. Breathing Cave, described by Deike (1960), 

apparently was formed downdip; however, in his 

report on caverns of Virginia, McGill (1933, p. 14) 

found the main passages of caverns chiefly along the 

strike of the water-bearing limestone. 

In limestone or other soluble rocks, solution cavities form in zones more or less parallel to the direction of movement of the water. Under some of the 

conditions given in the preceding paragraph, the 

zones would be approximately parallel to the dip of 

the water-bearing formations. In many parts of the 

Coastal Plain the artesian aquifer is exposed at the 

surface, and it dips toward the coast beneath relatively impervious beds that prevent upward movement of water. In these areas, the water moves 

downgradient which is also downdip. However, 

where there is no discharge area downdip, the water 

will move in the direction of a discharge area, 

even in a direction other than that of the dip. 

Regional structures, such as the Ocala uplift in 

Florida, have been a factor in bringing the limestone nearer the land surface. In the areas where 

the Hawthorn Formation is thin or absent, solution 

has been most active in forming many sinkholes and 

natural wells. The sinkhole topography caused the 

early investigators to suspect a major uplift in 

north-central Florida. Although the major structures which extend to the surface, such as the Ocala 

uplift, have influenced the formation of sinkholes 

and solution channels in limest<;me of the principal 

artesian aquifers, the direction of movement of the 

artesian water is independent of the structure. For 

example, in the Polk County recharge area in central Florida on the south flank of the Ocala uplift, 

lateral movement of the water takes place in all directions from the central part of the recharge area ; 

the geologic structure in this case has ·little or no 

effect on the movement. 

Joints or fractures and bedding planes may have 

a pronounced effect on the solution patterns and the 

movement of water in limestone and other carbonate rocks. In the Tertiary limestone of the southeastern States, the joints are generally vertical, and 

the bedding planes are approximately horizontal or 

. have low dips. Some of the limestone, such as the 

upper part of the Ocala Limestone, is chalky without 

bedding planes but has joints and fractures. 

Most of the vertical pipes or natural wells-which 

are also known as vertical shafts, dome pits, and 

chimneys-in caves apparently form at the intersection of two sets of joints. Long narrow vertical 

openings may form along joint planes. Vernon 

(1951, p. 48) showed a fundamental regional pattern made by the regular formation of two systems 

of fractures trending northeast-southwest and 

northwest-southeast in the northern part of the 

Florida peninsula. These or similar joint patterns 

are present in the limestone in other parts of this 

region. Although the extent of formation of these 

joints with depth is not known, they probably extend through the aquifer. 

Faults may affect the lateral movement of the 

water and the solution of the limestone, especially if 

water-bearing beds are fa1,1lted against relatively 
132 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

impervious beds that block the lateral movement. 

Some fault zon~s may serve as avenues through 

which water may move. Sayre and Bennett (1942, 

p. 19-27) concluded that the Balcones fault zone in 

the Coastal Plain in Texas affects the movement of 

the water in the Edwards Limestone. Welder and 

Reeves (1962, p. 41) recognized the movement of 

water in solution channels along faults in the Balcones fault zone in Uvalde County, Tex. DeCook 

(1963, p. 48, 52) reported that, in the region of the 

Balcones fault zone in Hays County, Tex., faults 

form conduits for ground-water movement at some 

places and in other places form barriers. He also reported some sinkholes along faults. Lobeck (1939, 

p. 132) showed how solution resulting in sinks may 

occur along a fault. If faulting occurs after solution 

channels have been formed, the channels may be 

offset vertically to an extent that affects the movement of the water. However, Theis (1936, p. 34) 

found that in limestone in south-central Tennessee, 

the influence of faults on movement of ground water 

appeared to be negligible. In a study of the origin 

of caves in folded limestone of the Appalachian region, Davies (1960) concluded that the passages 

are joint controlled and that faults exert very little 

influence. Passages rarely follow faults for any 

great distance. 

The writer believes that faults in the thick sequences of limestone of Tertiary age in the southeastern United States generally have little or no 

effect on the quality and movement of the artesian 

water in the area of this report, although some of 

the investigators report areas in which they believe 

faults affect the quality and movement of the water. 

C. W. Sever, Jr. (written commun., 1961) and 

Callahan (1964, p. 33) believed that the steep gradient of the piezometric surface in Georgia (fig. 28), 

extending from Berrien and Coffee Counties northeastward to Toombs County, is influenced by one or 

more faults. However, the writer believes that the 

change in gradient is caused by recharge and discharge relationships and by changes in permeability 

and thickness of the limestone. 

D. W. Brown, W. E. Kenner, and Eugene Brown 

(1957, p. 29) showed the Hawthorn Formation in 

Brevard County, Fla., faulted against the waterbearing limestone of the principal artesian aquifer. 

They concluded that the fault affects the movement 

and quality of the water. 

Lichtler (1960, p. 16-17, 35) reported that the 

principal artesian aquifer is displaced as much as 

300 to 400 feet by one or more faults parallel to and 

about 5 miles west of the Atlantic coast in Martin 

County, Fla. The depth to the aquifer is greater on 

the down thrown block (east side of the zone of displacement) than on the upthrown (west side), but 

displacement does not seem to affect the piezometric 

surface. 

Bermes (1958b, p. 10-11) showed that the artesian aquifer below the Hawthorn Formation is displaced by faulting in Indian River County. However, the writer finds no conclusive evidence that the 

movement of the artesian water is affected by 

faults. 

A north-south fault reported by Bermes, Leve, 

and Tarver (1963, p. 34, 42) in the St. Johns River 

valley in southeastern Putnam County seems to have 

no effect on the lateral movement and quality of the 

water. Solution of the limestone may have been 

more rapid along the fault, but the available information does not seem to confirm this. 

Barraclough (1962, p. 18) and Wyrick (1960, p. 

11) reported faults in Seminole and Volusia Counties, Fla., respectively, that seem to be part of major 

fault systems described by Vernon (1951, p. 53-

61, pl. 3) in north-central Florida on the Ocala uplift. 

However, the salt water and direction of movement 

of the water may result from factors other than 

faults. 

Under some conditions, the lateral movement of 

the water may be influenced by bedding planes. 

Barr (1961, p. 12-13) reported that caves in Tennessee have at least two major patterns depending 

upon the inclination of the beds in which the caves 

are formed. In strata of low dip, the floors and ceilings of such caves are essentially horizontal. In 

strata that are steeply dipping or moderately inclined, the caves have floors and ceilings which are 

inclined with the dip and in which the major passages tend to follow the strike. In these areas, different levels of caves and channels are not superimposed as a rule but are downdip from, and usually 

parallel to, other levels. Barr found only one example of a cave in steeply dipping limestone along a 

fault zone-New River Cave in Giles County, Va. 

Five caves have been formed along the axes of small 

anticlines. 

Carson (1964) reported that in Tolleys Cave, Va., 

on the northwest limb of a jointed and faulted syncline, the cavern passages, in general, parallel the 

dominant trend of the joints. A photograph of the 

lower entrance shows a passage approximately parallel to the strike of the beds. 

In a study of caves in West Virginia, Davies 

( 1949, p. 17) stated that in both horizontal and 

folded limestone, caves that have . more than one 
PRINCIPAL ARTESIAN AQUIFER 133 

level of passages commonly occur. Where vertical 

control is along a set of vertical joints, different levels may coincide in pattern. In thick limestones that 

cap the surface of the upland and have little or no 

dip, caves have simple patterns consisting of single 

or, in some cases, several parallel passages with few 

side passages. The vertical shafts and dome pits are 

abundant in the areas especially where the limestones flank higher ridges. Davies concluded that 

caves show no consistent relation to the dip of formations. Steeles Cave in West Virginia exhibits a 

trend along the dip slope, but two of its branches 

cross distinct anticlines and synclines. He found 

that the connections between levels in caves were 

generally by vertical shafts and crevices. Some 

broad passages are connected by cliffs. The steep 

vertical slopes of the cliffs are often modified by 

slabs and rocks which fall from the roof of the cave. 

Also, clay deposits may modify the steep slopes. 

Davies found that the pattern of caves is primarily controlled by joints, the individual pattern of 

each cave depending on its relation to local rock 

structure. Also several caves along St. Clair fault in 

West Virginia indicate that the fault is secondary to 

joints in controlling the pattern. Passages follow 

faults for short distances, reverting to joints for the 

greater part of the caves. 

Lobeck (1939, p. 140) showed five levels of passageways and some of the principal vertical shafts 

in Mammoth Cave, Ky., where the limestone dips 

gently westward toward Green River. The lowest 

level is Echo River, an underground tributary of the 

Green River west of the cave. Lobeck suggested that 

the different levels of the cave correspond approximately with the more soluble bedding planes of the 

limestone. Perhaps a more important factor is the 

difference in levels corresponding with different levels of the top of the zone of saturation. These levels 

changed as the elevation of points of discharge 

changed in Green River. The limestone on the west 

side of Green River does not have a cave system like 

Mammoth Cave on the east side because the only 

discharge area for water entering the limestone on 

the west side is into the river. Therefore, water 

does not move downdip into the limestone west of 

the river. 

Although differences in the solubility of the limestone as suggested by Lobeck may affect the level at 

which lateral channels form, changes in the eleva- . 

tion of the discharge points are believed to be one of 

the principal controlling factors. For example, W. 

D. Johnston, Jr. (1933, p. 67-69, 365) showed a solution channel in Alabama Caverns in Alabama which 

has a channel above and below a bed of siliceous 

dolomite that forms a bridge at one place in the 

channel. Its resistance to solution is evident in 

some parts of the cave where most of the bed has 

been removed, but the resistant remnants project 

from the· walls of the cave. Under these conditions 

its resistance to solution and erosion was not sufficient to control the altitude at which the channel 

formed. 

However, where a limestone aquifer is underlain 

by a sufficient thickness of relatively impervious 

beds, the structure of the aquifer and underlying 

beds may affect the movement of the water. For 

example, in the Huntsville area in northern Alabama where cavernous limestone of Paleozoic age 

overlies the Chattanooga Shale, LaMoreaux, Swindle, and Lanphere (1950, p. 23) concluded that the 

most important structural features governing the 

movement of ground water in the area are extensive 

joints and bedding planes. Later, LaMoreaux and 

Powell (1960, p. 370) found that not only joints and 

bedding planes but also local folds and regional dips 

influence the direction of movement of the water 

under the control of gravity and in the direction of 

the regional dip of beds in the area where the Chattanooga Shale serves as a relatively impervious 

floor above which the general movement of the water is to the south and southeast. Under these conditions, the solution of the limestone was most rapid 

in the trough of a syncline which is parallel to 

the regional structure. This solution of limestone 

and collapse of overlying surficial material may explain the unique combination of a valley forming on 

a syncline. 

In illustrating solution in folded and faulted limestone, Lobeck (1939, p. 132) showed surface streams 

parallel to and in the trough of synclines in limestone, but he showed that most of the solution openings are outside the valleys. Generally, valleys parallel to folds are expected on anticlines (as the 

Sequatchie anticline in eastern Tennessee and northern Alabama) where the less resistant and soluble 

rocks are nearer the surface than in synclines. 

Another example of solution occurring in the limestone where it is at or near the surface on a geologic 

structure may be seen on the Ocala uplift in northcentral Florida where solution cavities and sinkholes 

are numerous. 

Most of the caves and solution channels in the 

area of the present report are below the zone of saturation and therefore are not as accessible as those 

above the water table. Available records of wells 

and other subsurface information are not yet suffi-
134 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

cient to give many of the details of the relation of 

structure to movement of water, solution channels, 

and cave patterns in limestone. However, the information on the geology and hydrology and caves of 

the area leads to the conclusion that joints in the 

limestone and the position of recharge and discharge 

areas with reference to each other and to sea level 

have been major factors in controlling the direction 

of movement of the water (both artesian and nonartesian) in the limestone and in controlling the dif.:. 

ferent levels at which solution channels have formed. 

In a few places, movement of water and solution 

of the limestone may have occurred locally along 

faults. 

As more detailed subsurface information is obtained, a better understanding of the solution patterns, both vertical and lateral, will become available. Apparently, the general direction of many of 

the solution channels is parallel to the movement of 

the water as shown by maps of the piezometric surface. Locally, the lateral channels may follow joints, 

but the general direction is downgradient at right 

angles to the contour lines. 

Where streams such as the Suwannee and Flint 

Rivers have cut channels in the limestone, the direction of movement of the water is to or from the 

river in solution channels; some of the solution channels are approximately perpendicular to the river, as 

shown by a channel exposed at Falmouth Spring, 

Fla. The underground channels, approximately parallel to the direction of flow, probably are connected 

with a network of cross channels or by permeable 

limestone because most if not all wells in the limestone yield water and also because static water levels, in wells not affected by pumping, are approximately the same in a given area. The alinement of 

sinkholes in an east-west direction in Citrus County, 

Fla., indicates that the course of the underground 

channels is in the same general direction as movement of the water, that is, to the west. Some sinkhole basins occupied by lakes, as in the Orlando area, 

Florida, have shapes suggesting they formed in a 

.meander of an underground stream. 

CHEMICAL QUAT.ITY OF ARTESIAN WATER 

In Florida, reports by Collins and Howard (1928) 

and Black and Brown (1951) contain analyses 

of ground- and surface-water samples collected 

throughout the State. A report by Parker, Ferguson, and Love ( 1955) contains many analyses of 

ground and surface water in southeastern Florida. 

A report by Ferguson, Lingham, Love, and Vern on 

( 194 7) contains chemical analyses of water from 

many springs in Florida. Ground-water reports by 

counties, as cited, include many analyses. All these 

reports contain analyses of water from the principal 

artesian aquifer as well as the overlying aquifers. 

In Georgia reports by Wait (1960a) and Warren 

(1944) and local reports by counties and areas contain analyses of water from the principal artesian 

aquifer. Cooke ( 1936) reported analyses of ground 

water in southeastern South Carolina. Hastings 

(in Carter and others, 1949, p. 244-263) included 

analyses of ground water in southeastern Alabama. 

In that report LaMoreaux discussed the quality of 

water in the water-bearing formations. Cagle and 

Floyd (1957) included analyses of samples of ground 

water from Escambia County, Ala. 

Water falling in the form of rain or snow generally contains little or no dissolved mineral matter. 

Its content is usually chiefly gases of the atmosphere-especially oxygen and carbon dioxide. However, there are exceptions such as those in coastal 

areas where the chloride content of rainwater from 

storms is reported to be as much as several hundred parts per million. 

Water has a solvent action on the water-bearing 

formations when it comes in contact with, and 

moves into, these formations. This solvent action is 

greatly increased by carbon dioxide, absorbed from 

the atmosphere and from the soil where it is formed 

by organic processes. The amount and character 

of the dissolved mineral matter depend upon the 

chemical and physical composition of the material 

through which the water passes, the temperature, 

pressure, and duration of contact, as well as the 

presence of sea water or other salt water in the 

formations. 

The mineral constituents shown in the analyses 

are reported as parts per million, which can be converted to grains per U.S. gallon by dividing by 

17.12. One part per million is equivalent to one milligram of a given constituent in one liter of water 

or 8.34 pounds of the constituent per million gallons 

of water. Many of the analyses include the following: total dissolved solids, silica; iron, calcium and 

magnesium, strontium, sodium and potassium, bicarbonate, sulfate, chloride, nitrate, pH, hydrogen 

sulfide, color, and total hardness~ Three natural radioactive elements-tritium, radium, and uraniumas well as gross radioactivity are included in a few 

analyses. 

In general ground water in the report area may be 

placed in the following types : 

1, Calcium bicarbonate water whose hardness generally ranges from 50 ppm to several hundred 

parts per million. Most of the artesian water 
PRINCIPAL ARTESIAN AQUIFER 135 

is of this type except in southern Florida and 

some of the coastal areas where the fresh artesian water is mixed with remnants of sea water that has not been flushed from the aquifer. 

The hardness of the salt water is much higher 

than that of other artesian water. 

2. Calcium sulfate water whose hardness is as much 

as 900 ppm, as reported by Black and Brown 

(1951, p. 77) for Manatee County, Fla. In 

southwestern and southern Florida the artesian water has relatively large amounts of calcium sulfate which apparently is from gypsum 

or anhydrite in the aquifer. 

3. Sodium bicarbonate water whose hardness is 

less than 50 ppm. The artesian water of the 

principal aquifer in Okaloosa, Santa Rosa, and 

Escambia Counties, Fla., and adjacent parts 

of Alabama is of this type. 

4. Sodium chloride water in which the fresh artesian water .is mixed with salt water. 

5. Water in surficial sand formations having total 

dissolved solids less than 50 ppm. 

All with the exception of type 3 are represented 

in a general way by the analyses of samples of water 

from springs, as given and discussed in that part of 

this report. 

TOTAL DISSOLVED SOLIDS 

The total dissolved solids indicates approximately 

the amount of dissolved mineral matter in the water. 

As stated by Black and Brown (1951, p. 10) the total obtained by evaporating a known quantity of 

water to dryness and weighing the residue after it 

has been dried at a definite temperature includes 

any organic material present as well as some water 

of crystallization. In the case of high bicarbonate 

water, common in the area of this report, the total 

reported will be considerably less than the sum of 

the constituents because during the process of evaporation the bicarbonate ion is broken down with loss 

of water and carbon dioxide. This difference will be 

directly proportional to the total alkalinity of the 

water. 

Water having less than 500 ppm of total dissolved 

solids is generally satisfactory for domestic and 

most industrial uses except for difficulties which 

may result from the hardness. Water having more 

than 1,000 ppm of dissolved solids is likely to contain enough of certain constituents to produce a 

noticeable taste or to make the water unsuitable in 

some other respects. Some water with more than 

1,000 ppm of dissolved solids may be satisfactory. 

The total dissolved solids in fresh ground water in 

1 the Southeastern United States ranges from a few 

parts per million in the surficial sands to more than 

1,000 ppm in parts of the limestone. The total dissolved solids is much higher in the water mixed with 

sea water or other salt water. 

The dissolved solids in water having a low chloride content in the principal artesian aquifer ranges 

from about 100 ppm in recharge areas to about 500 

ppm at a considerable distance from recharge areas. 

The maximum reported (1,600 ppm) in water having low chloride (50 ppm) was in calcium sulfate 

water at Palmetto in Manatee County, Fla. (Black 

and Brown, 1951, p. 63, 77). Among the lowest of 

these were analyses of water from a group of six 

wells 540 to 1,055 feet deep at the U.S. bombing 

range near Avon Park, Highlands County, where 

the dissolved solids ranged from 89 to 98 ppm. Also, 

analyses of water from two ~ells 1,400 feet deep at 

Sebring in that county had a total dissolved-solids 

content of 80 ppm. 

Pride, Meyer, and Cherry (1961, p. 87) reported 

water having low mineral content in the artesian 

aquifer in the Green Swamp area in Polk and Lake 

Counties. A sample from a well 200 feet deep had a 

mineral content of only 15 ppm. 

Another recharge area in which the water from· 

the principal aquifer contains less than 100 ppm of 

total dissolved solids is indicated by the analyses of 

a sample from a well 450 feet deep at Keystone 

Heights in Clay County and from a well 210 feet 

deep at Putnam Hall in Putnam County, Fla. (Black 

and Brown, 1951, p. 39, 96). 

The wells in Highlands County are in the Polk 

County recharge area, and the wells in Putnam 

County are in the Putnam County recharge area. In 

these areas, relatively impervious beds of the Hawthorn Formation overlie the aquifer, but recharge 

· occurs through sinkholes filled with permeable 

sands. The low mineral content of the water also 

suggests that the water-bearing cavities in the limestone are filled with sand. In recharge areas where 

the aquifer is at or near the surface, the water has 

more contact with the limestone, and therefore the 

mineral content is higher in these recharge areas 

than in the lake regions, such as the Polk County 

area and the Putnam County area. 

Downgradient the mineral content of the water 

increases in general with the distance from the recharge areas. For example, in moving from the Polk 

County recharge area to Manatee and Sarasota 

Counties, a distance of 50 miles or more, the total 

dissolved solids of the water increases several hundred parts per million. Many of the samples in the 
136 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

recharge area had total solids of less than 200 ppm, 

and some had less than 100 ppm. In Sarasota and 

Manatee Counties, the total solids ranges from about 

500 to about 1,000 ppm. The total solids is more 

than 1,000 ppm where the artesian water is mixed 

with remnants of connate water or other salt water 

which has not been flushed from the aquifer in 

coastal areas. Artesian water with similar quality 

is present in southern Florida and much of the area 

where the chloride content of the water is at least 

100 ppm. Another example of an increase in total 

dissolved solids as the artesian water moves downgradient a distance of at least 50 miles from the recharge area is the change b~twe;n the Putnam 

County recharge area and Duval and Nassau Counties in northeastern Florida. 

The total dissolved solids is less than 100 ppm in 

some of the water in that recharge area of the 

principal artesian aquifer in Clay and Putnam 

Counties. Downgradient at least 50 miles from the 

recharge area, the total dissolved solids ranged from 

about 350 to 500 ppm. A few samples were more 

than 500 ppm, but :hone was as high as those in 

Sarasota and Manatee Counties, partly. because the 

aquifer has more anhydrite . (calcium sulfate) in 

Sarasota and Manatee Counties than it does in 

northeastern Florida. Also, the aquifer in south-

. western and southern Florida contains remnants 

of sea water which has not been completely flushed 

from the water-bearing formations. In Duval and 

Nassau Counties in northeastern Florida, the low 

chloride content of artesian water shows that no 

remnants of sea water remain in the aquifer. 

In most of the area of this report, the principal 

artesian aquifer has calcium bicarbonate water, 

which is typical of water in limestone. However, in 

western Florida, southeastern Alabama, and southwestern Georgia where the water-bearing formations of the aquifer grade from limestone into sands 

and clays, the aquifer has sodium bicarbonate water, 

which is common in the artesian water in sandy 

water-bearing formations of Tertiary and Cretaceous age in the Atlantic and Gulf Coastal Plain. 

The total dissolved-solids content of samples of soft 

sodium bicarbonate water from a well 600 feet deep 

at Shalimar and from two wells 834 and 880 feet 

deep at the Eglin Air Force Base near Crestwood 

in Okaloosa County, Fla., ranged from 315 to 385 

ppm. 

An artesian well, 1011 feet deep, at Vichy Springs, 

Escambia County, Fla., yielded sodium bicarbonate 

water having total dissolved solids of 3,697 ppm 

(Black and Brown, 1951, p. 52). However, a relatively high chloride content of 1691 ppm indicates 

that the artesian water is mixed with sea water 

that has not been completely flushed from the 

aquifer. 

The shallow· sand aquifers from the land surface 

to depths of more than 200 feet yield water with 

a low mineral content. For example, the total dissolved solids of water samples from four municipal 

wells at Pensacola 200 to 240 feet deep ranged from 

27 to 43 ppm. The total dissolved solids of water 

samples not contaminated with sea water from 

many wells in the very productive, shallow limestone 

aquifer in southeastern Florida ranged from about 

250 to about 350 ppm (Parker and others, 1955). 

SILICA 

Silica (Si02) is dissolved from nearly all rock. 

The quantity present in the ground water in the 

area of this report ranges from about 2 to 63 

ppm. It is relatively unimportant except where this 

amount may contribute to scale formation in boilers used for the· production of steam. In general, the 

silica content of much of the water in the surficial 

aquifers and some recharge areas of the artesian 

aquifer is less than 10 ppm. Water with the highest 

silica content is deep in the artesian aquifer or is 

some distance from recharge areas.· An exception to 

this may be noted in Highlands County, Fla., where 

the silica content of wat~r from a well 1,055 feet 

deep is only 6.4 ppm (Black and Brown, 1951, p. 

63, 78). However, there is local recharge in this area 

through sinkholes filled with permeable sand. In 

Marion County, water from a well 1,220 feet deep 

at Ocala had a silica content of 63 ppm. The silica 

content of water from two wells, one 455 feet and 

the other 350 feet deep, at Ocala ranged from· 7 to 

27 ppm. In southeastern Georgia, silica in analyses 

of samples from the principal aquifer reported by 

Warren (1944, p. 139, 140) ranged from 33 to 56 

ppm. Apparently the silica content, in general, is 

highest in the water which has been in contact 

with the aquifer for the longest period of time. 

Differences in the silica content in the waterbearing formations probably affect the silica content in the water, but wells in the limestone generally are not cased except in the material overlying 

the aquifer. Therefore, most of the samples are 

composites from several formations. The samples 

show a range in silica content which apparently 

correlates with alkalinity and pH of the water 

and length of time in the formations. The silica 

content generally is highest in the water having 

high alkalinity and pH. 
PRINCIPAL ARTESIAN AQUIFER 137 

IRON 

Iron (Fe), generally in the form of ferrous bicarbonate, is objectionable in water in amounts of 

more than 0.3 ppm because it gives the water a 

disagreeable irony taste and stains bathroom fixtures. Iron in excess of 0.1 ppm may separate out 

and settle as a reddish sediment. It remains in 

solution as a ferrous bicarbonate, Fe (HC03 ) 2, 

and the water is clear until it is exposed to the air 

which oxidizes the iron to the ferric state and precipitates it as the hydroxide, Fe ( OH) 3, or oxide, 

Fe20a. Iron as bicarbonate in water may be removed simply by aeration. However, where iron is 

combined with organic matter, additional treatment 

is required. 

Iron in small amounts, generally not exceeding a 

few parts per million, is present in some places in 

water in the shallow surficial sands in the Southeastern States. However, iron is absent, or present 

in only trace amounts, in water in the principal 

artesian aquifer and other limestone overlying the 

aquifer. Some of the iron reported in analyses may 

be from rusty well casings or pipes through which 

the water flowed. The iron content of samples of 

the large springs in Florida, such as Silver Springs 

arid Rainbow Springs in Marion County and Wakulla Spring in Wakulla County which receive water 

from the principal artesian aquifer, ranged from 0.04 

to 0.15 ppm (Ferguson and others, 1947). 

Bishop (1956, p. 53, 58) reported that most of 

the samples from the principal artesian aquifer in 

Highlands County, Fla., contained no iron. One 

sample had 0.62 ppm of iron. The others ranged 

from 0.1 to 0.6 ppm iron. One sample from a well 

30 feet deep in the Hawthorn Formation or younger 

deposits had an iron content of 3.2 ppm. The other 

samples from shallow wells were less than 1.0 ppm, 

except four samples that ranged from 1.1 to 1.9 

ppm. Lichtler (1960, p. 52) showed that some samples from the principal artesian aquifer in Martin 

County, Fla., contained no iron. The highest reported was 0.43 ppm. Wyrick (1960, p. 37-39) 

reported on the iron content of 24 samples from the 

principal artesian aquifer in Volusia County, Fla.; 

13 samples had less than 1 ppm of iron, the remainder ranging from 1.0 to 3.2 ppm, except two 

samples which had 3.9 ppm and 6.1 ppm of iron. 

Apparently, some of this iron was from the well 

casings. Analyses reported by Black and Brown 

(1951) show that many of the samples from the 

principal artesian aquifer in Florida had no iron. 

vVhere present, the iron content in many of the samples was less than 0.5 ppm. 

In southwestern Georgia, Wait (1960a) reported 

that some samples from the principal artesian aquifer contained no iron. The iron content in the 

other samples ranged from 0.01 to 0.37 ppm. Warren 

(1944, p. 139, 140) showed that the iron content of 

water in southeastern Georgia ranged from 0.01 to 

0.87 ppm. 

CALCIUM AND MAGNESIUM 

Calcium (Ca) is dissolved in large quantities from 

limestone, which is essentially calcium carbonate. 

Some of the calcium in ground water in the Southeastern States is from anhydrite, which is anhydrous 

calcium sulfate (CaS04 ), or gypsum, which is hydrous calcium sulfate (CaS04·2Hz0). Because dolomite and dolomitic limestone contain the double carbonate of calcium and magnesium, this limestone is 

the chief source of magnesium (Mg) in the fresh 

water. 

Except in the areas where sea water has not been 

completely flushed from the water-bearing formations or where sea water has entered the aquifer in 

Recent time, calcium is highest where the aquifer 

contains calcium carbonate or calcium sulfate, and 

the magnesium is highest where the aquifer contains dolomite or dolomitic limestone. In some areas 

as in Sarasota County and in northeastern Florida 

and southeastern Georgia, the calcium content of 

much of the water in the principal artesian aquifer 

and the overlying Hawthorn Formation is about 

twice the magnesium content. 

However, in some other areas, the calcium content 

is much more than twice the magnesium content in 

the principal aquifer. Also, limestones overlying the 

principal aquifer, as in the shallow productive aquifer ranging in age from late Miocene to Recent 

(Parker and others, 1955) in southeastern Florida, 

may contain very little magnesium. The concentration of magnesium is as little as one-tenth to onetwentieth that of calcium (Black and Brown, .1951, 

p. 11) in the water which is not mixed with sea 

water. 

Because magnesium is one of the abundant constituents of sea water, it is present in relatively 

large quantities in the ground water mixed with sea 

water that has not been flushed from the aquifer or 

that has moved into the aquifer in Recent time. 

Where mixed with sea water, ground water may 

contain more magnesium than calcium. 

The calcium content of the water having low chloride content in the principal artesian aquifer ranged 

from 16 ppm in a sample from an area of recharge 

through sinkholes filled with sand and other mate-
138 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

rial in Highlands County to 304 ppm in Sarasota 

County, some distance from recharge areas. The 

magnesium content in these two samples was 6.6 

ppm in Highlands County and 132 ppm in Sarasota 

County. In much of the area of this report, water 

having a low chloride content in the principal artesian aquifer had a calcium content of less than 50 

ppm and a magnesium content of less than 25 ppm. 

In the soft sodium bicarbonate water in western 

Florida, the calcium content was as low as 4.4 ppm, 

and the magnesium content, 3.5 ppm (Black and 

Brown, 1951, p. 83 ). 

The content of calcium is high in comparison with 

that of magnesium in areas where the aquifer consists chiefly of pure limestone, as at Cross City in 

Dixie County, Fla. Where the calcium ranged from 

81 to 120 ppm, the magnesium ranged from 4.5 to 

6.8 ppm, and the sulfate ranged from 1.6 to 4.5 ppm 

(Black and Brown, 1951, p. 47). 

For Highlands County, Fla., Bishop (1956, p. 53) 

gave analyses in which the calcium content from the 

principal artesian aquifer ranged from 16 to 40 ppm. 

The lowest magnesium content was 1.5 ppm in a 

sample from the A von Park limestone of the aquifer. 

The highest magnesium content was 21 ppm in the 

sample which also had the maximum ( 40 ppm) of 

calcium. In addition to these analyses, one sample 

from the Ocala Limestone of the aquifer in the 

southeastern part of the· county had 61 ppm of calcium and 46 ppm of magnesium. However, the sample had 110 ppm chloride, indicating that the arte-

. sian water is mixed with the remnants of sea water 

that has not been flushed from that part of the 

aquifer, as was sugge~ted by Bishop (1956, p. 64). 

In Manatee County, the maximum calcium content 

is in calcium sulfate water. One sample reported by 

Black and Brown (1951, p. 77) from the principal 

aquifer at Palmetto in Manatee County had a calcium content of 352 ppm. The magnesium content 

in that sample was only 8.5 ppm, but the sulfate 

content was 650 ppm. The chloride content in the 

sample was 50 ppm, and the bicarbonate content 

was 154 ppm. Total dissolved solids was 1,600 ppm, 

and total hardness was 916 ppm as CaC03 • 

Peek (1958a, p. 56, 59) reported that the calcium 

in composite samples from the Suwannee and Tampa 

Limestones of the principal artesian aquifer in Manatee County, Fla., ranged from 50 to 320 ppm. Samples 

from the Hawthorn and younger formations had a 

calcium content that ranged from 36 to 204 ppm. 

The magnesium content of water from the Suwannee 

and older formations ranged from 28 to 167 ppm. 

Water from the overlying Tampa Limestone contained 13 to 113 ppm of magnesium, and water from 

the Hawthorn and younger formations contained 5.8 

to 99 ppm but generally less than 50 ppm. 

In Martin County, Fla., where the artesian water 

is mixed with remnants of sea water in the aquifer, 

the magnesium content is about as high as that of 

the calcium. In one of the samples reported by 

Lichtler (1960, p. 52, 58) the content of magnesium 

was higher than that of calcium. Because the aquifer in that area consists chiefly of limestone with 

little dolomite, the relatively high magnesium content apparently results from sea water in the 

formation. 

In southeastern Georgia, the calcium content of 

samples of water from the principal artesian aquifer 

ranged from 19 ppm in Liberty County to 75 ppm in 

Charlton County. The magnesium content ranged 

from 3.8 ppm in Candler County to 39 ppm in Camden County. The calcium content in analyses of 

samples of water in the principal artesian aquifer of 

Tertiary age in southwestern Georgia ranges from 

about 16 ppm in the Ocala Limestone in Lee County 

to 102 ppm in Colquitt County (Wait, 1960a). The 

magnesium content ranged from a trace in several 

samples in different counties to 4 7 ppm in Colqui~t 

County. A sample from a well in the Ocala in Mitchell County had no magnesium. 

STRONTIUM 

As stated by Odum (1951b, p. 20) strontium (Sr) 

is associated with calcium in nature, but there is 

only about 1 atom of strontium for every 1,000 

atoms of calcium. It is chemically similar to calcium, and natural strontium is no more toxic than 

calcium and never approaches harmful concentrations. Skougstadt and Horr (1960, 1963) studied 

the strontium content of surface streams to obtain 

information which could be used in a study of the 

extent to which strontium-90, a long-lived radioactive isotope of nuclear fission, might be diluted by 

stable strontium in streams. 

Celestite, strontium sulfate, is a common mineral 

in carbonate rocks. It is associated with limestone 

and calcite; without optical tests, it may be mistaken for calcite. Unpublished analyses in 1961 

by the U.S. Geological Survey for 12 samples of 

water from the aquifer in Martin County, Fla., had 

a strontium content ranging from 10 to 49 ppm. 

Feulner and Hubble (1960, p. 180) reported that 

strontium in ground water in carbonate rocks in 

western Ohio in concentrations of as much as 30 

ppm is principally from solution of strontium-bearing minerals such as celestite. Although such min-
PRINCIPAL ARTESIAN AQUIFER 139 

erals have not been detected in the aquifers in the 

area of this report, they probably are the source of 

the small quantities of strontium reported by Odum 

(1951b, p. 20-21) and by Skougstadt and Horr 

(1960, p. 314) in water in Florida. 

Horr (1959, p. 2-3) reported that in the deposition of carbonate rocks the strontium content and 

the relative solubilities of calcium and strontium in 

sea water cause limestone and dolomite to be deposited before celestite. When the concentration is 

sufficient to cause gypsum to be deposited, celestite 

also is deposited. Therefore, celestite deposition 

would be expected in the upper zone of carbonate 

rocks in contact with gypsum. Celestite may also 

be present in fossils. 

F. H. Stewart (1963, p. Y40) stated that most of 

the strontium of marine evaporites replaces calcium in the sulfate and carbonates. He reported 

0.17 to 0.69 percent SrO in anhydrite and 0.003 to 

0.13 percent in SrO in gypsum. Gypsum which 

has replaced earlier anhydrite by hydration at 

ordinary temperatures cannot always retain all the 

strontium of anhydrite, and consequently celestite 

is formed. 

Rankama and Sahama (1950, p. 295) reported 

the average strontium content of sea water as 13 

ppm. However, in a statisticar study of his own data 

and those of several others, Odum (1951a, p. 

211-213) gave an average figure of 8.1 ppm, which 

Horr (1959, p. 3) believed was more nearly correct. 

Odum (1951b, p. 20-21) reported the strontium content of water from some of the springs and streams. 

All the samples had less than 1 ppm of strontium, 

except Salt Springs in Marion County, which had 

about 6 ppm. 

Skougstadt and Horr (1963, p. 77, 80) reported 

that strontium content of samples of water from 

several streams in Florida ranged from 0.8 to 1.1 

ppm. The sample having the highest strontium 

content was from the St. Johns River, which receives artesian water from carbonate rocks of the 

principal aquifer in its upper course from Putnam 

County to Brevard County. Ground-water circulation in the part of the aquifer that contributes water 

to the other streams sampled has been sufficient to 

remove water or most minerals which might be a 

source of strontium. Therefore, the low strontium 

content of the water from these streams might be 

expected. However, the aquifer in the St. Johns 

River valley south of Putnam County has not been 

completely flushed of sea water which entered the 

formation when the sea stood higher during Pleistocene time than at the present time. The remnants of 

sea water may contribute to the relatively high strontium content in the samples from the St. Johns 

River near Cocoa and in a sample having 6 ppm of 

strontium from Salt Springs, which is part of the 

St. Johns River system. 

If sea water has a strontium content of about 8 

ppm, several parts of the strontium content of 6 

ppm from Salt Springs, which has total dissolved 

solids and chloride about one-sixth that of sea water, comes from the aquifer. A comparison of the 

quality of water from Salt Springs with that of 

Silver Springs, 22 miles southwest of Salt Springs, 

indicates that the aquifer has considerably more 

calcium sulfate (anhydrite or gypsum) at Salt 

Springs than at Silver Springs. The water having 

relatively high chloride has more calcium sulfate 

and strontium than can be explained by the presence of sea water. This condition suggests that 

strontium-bearing minerals such as . celestite and 

possibly some salt might be present in the aquifer as 

part of an evaporite series. Such thin deposits 

would not be easily detected in test wells but could 

contribute to the salinity of water in the aquifer 

and in the salt springs such as those in the St. 

Johns River valley and in Marion and Sarasota 

Counties, Fla. 

Also, Braidech and Emery (1935, p. 557) reported 

a strontium content of 10 ppm for the municipal 

supply of Jacksonville, Fla., which is from the principal artesian aquifer. Although the calcium sulfate 

content of the water is relatively high, all sea water 

has been flushed from the aquifer in that area, as 

indicated by the low chloride content of the water. 

Additional investigations of occurrence and distribution of natural strontium might seem of little 

practical value, However, information on the strontium content of the ground water throughout the 

aquifer would be helpful in understanding the geochemistry of the ground water and the source of 

the water, which may be remnants of Pleistocene 

sea water or other sea water that has not been 

flushed from the aquifer. 

SODIUM AND POTASSIUM 

Sodium (Na) and potassium (K) are present in 

all natural water, but they are present in only 

small quantities in the ground water in the southeast, except in some coastal areas and in southern 

Florida where the water-bearing formations contain 

remnants of sea water or sea water has entered the 

formation along the coast. Because sea water is essentially a solution of sodium chloride (common 

table salt), relatively large quantities of sodium are 

present in the ground water mixed with sea water or 
140 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

in contact with salt in the water-bearing formations. Ordinarily, where the ground water is not 

mixed with sea water, the sodium and potassium 

combined ranges from a few parts per million to 

about 40 ppm. Many of the samples have less than 

10 ppm. However, where mixed with sea water or 

salts in the formations, the sodium and potassium 

may be as much as that of sea water which has an 

average of 10,710 ppm of sodium and 390 ppm of 

potassium. 

Moderate amounts of sodium and potassium have 

no effect on the suitability of water for all domestic 

and most industrial purposes. Excessive amounts of 

sodium obtained from food and water may adversely 

affect some persons. More than 100 ppm of sodium 

may cause foaming in steam boilers unless special 

precautions are taken to prevent it. 

However, ground water having a sodium content 

of more than 100 ppm occurs only in the area where. 

it is mixed with sea water and in a few areas in 

Okaloosa, Santa Rosa, and Escambia Counties · in 

western Florida where the water in the principal 

aquifer has a relatively high sodium content because 

of natural softening of the water in which calcium 

and magnesium were exchanged for sodium. In water having only a few parts per million of sodium, 

the amount of potassium is somewhat less than that 

of the sodjum. Generally, where the concentration 

of sodium and potassium increases, the concentration of sodium is much larger than that. of potassium, as in some parts of coastal areas and southern 

Florida where the water is mixed with sea water or 

salts in the formation. The sodium content may be 

a problem in irrigation water as discussed in the 

section of this report on the quality of irrigation 

water. 

BICARBONATE 

Bicarbonate (HC03 ) in natural water results from 

the action of carbon dioxide, dissolved in the water, 

on carbonate rocks. The total alkalinity of water is 

the sum of its hydroxide (OH), carbonate (C03 ), 

and bicarbonate alkalinities, all expressed in terms 

of equivalent quantities of CaC03• Of the three, the 

bicarbonate is the one more commonly present in 

ground water in the Southeastern States. Some 

ground water that has not been in contact with 

carbonate rocks may have less than 10 ppm of bicarbonate. For example, the bicarbonate in samples of 

ground water for the public supply at Pensacola, 

Fla., as reported by Black and Brown (1951, p. 51), 

ranged from 2.9 to 7.3 ppm. Bicarbonate in samples 

of water from the principal artesian aquifer ranged 

from about 50 to about 350 ppm. Most of the sampies had less than 300 ppm, and many had less than 

200 ppm. The bicarbonate content in the shallow 

ground water in the Everglades of southeastern 

Florida is much higher than that in the principal 

artesian aquifer. As stated by Love (Parker and 

others, 1955, p. 733), ground-water samples from 

some parts of the Everglades had concentrations of 

500 to 1,000 ppm of bicarbonate. 

In Manatee County, Fla., Peek (1958a, p. 59) reported that water samples from the Suwannee and 

older formations of the principal artesian aquifer 

had a bicarbonate content of 102 to 264 ppm. Water 

samples from the Tampa Limestone of the principal 

aquifer had a bicarbonate content of 162 to 270 

.PPm. Samples from the. overlying Hawthorn Formation had from 48 to 557 ppm of bicarbonate, but the 

bicarbonate generally was higher in the Hawthorn 

than in the principal artesian aquifer. 

SULFATE 

Sulfate ( S04 ) is dissolved in large quantities 

from gypsum or anhydrite (calcium sulfate) in 

some of the water-bearing formations. It is also 

formed by the oxidation of sulfides of iron, such as 

pyrite, which is present in some of the limestones. 

Some of the sulfate in part of the ground water in 

the Coastal Plain of Southeastern United States is 

from sea water or salts in the formations. The sulfate content of ground water in this area ranges 

from zero to as much as 1,000 ppm. Sulfate in much 

of the water from the principal artesian aquifer in 

recharge areas is generally less than 10 ppm. 

The sulfate content is highest in the deeper water 

and is relatively high in the Atlantic coastal area, 

southern Florida, and the gulf coastal areas from 

the Florida Keys to Tampa Bay. In most of that 

area, part of the sulfate apparently is from gypsum 

or anhydrite in the aquifer. Vernon (1951, fig. 17) 

showed many thin beds of anhydrite and gypsum 

in the principal artesian aquifer below a depth of 

about 250 feet below sea level in Citrus and Levy 

Counties, Fla. Some gypsum occurs above that 

depth in some of the coastal areas and in ·southern 

Florida, where the chloride content of the water is 

more than 100 ppm. Some of the sulfate is from sea 

water which has not been completely flushed from 

the aquifer. The highest sulfate content of the samples low in chloride was 1,132 ppm from a well in 

the principal artesian aquifer in Sarasota County 

(Black and Brown, 1951, p. 102). 

Sulfates of calcium and magnesium cause noncarbonate hardness, which is more difficult to remove 

from the water than carbonate hardness. The sulfate in sufficient quantities may give the water a 
PRINCIPAL ARTESIAN AQUIFER 141 

bitter taste, and magnesium sulfate has a laxative 

effect on persons who drink sufficient quantities of 

the water. Sulfate in hard water makes the scale, 

which forms in steam boilers, more difficult to remove. 

CHLORIDE 

The chloride ( Cl) content of ground water in the 

Southeastern States may be used as an index of the 

extent to which the water is mixed with present or 

former sea water or salt in the water-bearing formations. Chloride is dissolved in small quantities 

from most geologic formations. It is present in 

large quantities in ground water mixed with sea 

water or with salts (sodium chloride) in the waterbearing formations. The average chloride content 

of sea water is about 19,350 ppm. A small quantity 

of chloride in some ground water is from finely divided salt spray carried with dust particles by wind 

and precipitated with the rain. Collins and Howard 

(1928, p. 183) reported that maps of "normal chlorine" for some regions indicate that the quantity 

of chloride from rain ranges from less than 1 ppm 

far inland from the coast to 5 or 6 ppm near the 

coast. However, along the Atlantic coast rain from 

storms has been reported that had a chloride content 

of as much as several hundred parts -per million. 

Sewage or industrial wastes may increase the chloride content of water with which it is mixed. 

Except in coastal areas and southern Florida 

shown in figure 36, where the ground water has a 

chloride content of more than 100 ppm, the chloride 

in the principal artesian aquifer is generally less 

than 50 ppm. In some recharge areas the chloride 

content is less than 10 ppm. Generally, below depths 

of about 2,000 feet, salt water may be expected. 

The occurrence and distribution of ground water 

with a relatively high chloride content is discussed 

in the part of this report on areas of salt water. 

Chloride, like sodium with which it forms sodium 

chloride (common table salt) , has little effect on 

water for ordinary use unless there is enough to 

give a salty taste. However, even in small amounts, 

salt makes the water more corrosive. Water having 

less than 250 ppm of chloride is acceptable for public supply if otherwise satisfactory, according to 

standards of the U. S. Public Health Service. Water 

with a chloride content of 500 ppm or more will 

ordinarily taste salty and is undesirable for public 

supply. Water having a chloride content of 2,000 

ppm is not suitable for many uses, including irrigation of certain crops (Westgate, 1950, p. 116-123). 

FLUORIDE 

Fluoride (F) is present in small quantities in 

some of the ground water in the Southeastern States. 

Water with fluoride concentrations in excess of 1.5 

ppm may cause mottling of the enamel of the teeth 

of children if they drink the water during the calcification, or formation, of their teeth (Cox and 

Ast, 1951, p. 641-648). Teeth with mottled enamel 

develop a dull chalky white color which in many 

cases changes to a dark-brown stain. However, normally formed teeth of adults have not been known 

to become mottled later regardless of the fluoride 

content of the water. Also, it is now generally recognized that water having a fluoride content of 0. 7 to 

1.5 ppm in public supplies results in a 50 to 63 percent 

reduction in dental caries or tooth decay among children using the water (Black and Brown, 1951, p. 15). 

In their study of occurrence of fluoride, Black and 

Brown (1951, p. 15) indicated that 375 samples of 

water in Florida had small quantities of fluoride. 

Surface-water samples analyzed contained none or 

only traces. Water from the Hawthorn Formation 

of Miocene age almost invariably contained small 

amounts of fluoride, generally more than 1.0 ppm 

and in a few samples as much as 2.5 ppm. Black, 

Slearns, H. H. McClane, and T. K. McClane (1935, 

p. 21,22) reported that the largest areas in which 

untreated well water contained relatively high concentrations of fluorides is in a tier of nine counties 

(Manatee, Hardee, Sarasota, De Soto, Charlotte, 

Glades, Lee, Hendry, and Collier) in southwestern 

Florida. In other areas such as the section surrounding Jacksonville in northeastern Florida, water from 

wells in the Hawthorn contains significant amounts 

of the element. Because the Hawthorn Formation· 

is present in all of these areas, the writer believes 

that most, if not all, of the water having a fluoride 

content of more than about 1.0 ppm is from the 

Hawthorn Formation or other formations of Miocene age or younger containing phosphatic deposits. 

Love (Parker and others, 1955, p. 734) reported 

that the maximum fluoride content of samples of 

surface water in southeastern Florida was 0.6 ppm, 

and most of the samples had less than 0.3 ppm. 

Fluoride content in public supplies ranged from 0.0 

to 0.3 ppm, except a sample having 2.4 ppm from a 

well 600 feet deep at La Belle in Hendry County. 

The fluoride content of water from this well probably is from the lower part of the Hawthorn Formation. Apparently, the well at LaBelle is the source 

of maximum fluoride of 2.4 ppm reported by Klein, 
142 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Schroeder, and Lichtler (1964, p. 74) for Glades and 

Hendry Counties. 

Water in the principal artesian aquifer has little 

or no fluoride except in areas where the lower part 

of the Hawthorn forms the upper part of the aquifer 

and in western Florida, southeastern Alabama, and 

southwestern Georgia where the principal artesian 

aquifer grades laterally into sands and clays, which 

yield soft sodium bicarbonate water having a fluoride content of as much as 6.5 ppm (Barraclough 

and Marsh, 1962, p. 24) . 

According to analyses of 36 samples of ground 

water from Highlands County, Fla., as given by 

Bishop (1956, p. 55), 17 contained no fluoride, and 

19 contained 0.1 to 0.8 ppm. Although Bishop reported that a few of the samples containing fluoride 

were from Eocene limestone of the principal artesian 

aquifer, it seems possible that all of the fluoride is 

from the Hawthorn. 

Lichtler (1960, p. 60) reported that in Martin 

County, Fla., the fluoride ranged from 0.0 to 0.4 

ppm in the shallow aquifer and from 0.1 to 1.6 ppm 

in the artesian aquifer. The shallow aquifer extends 

from the surface to a depth of 150 feet and includes 

at its base the Tamiami Formation, which cannot be 

distinguished from the Hawthorn Formation except 

by fossils, according to Lichtler. The fluoride water 

in the shallow aquifer is probably from the Tamiami 

which was formerly considered part of the Hawthorn. The fluoride in the artesian water is probably 

from the Hawthorn Formation. 

Wait (1960a, p. 35) stated that only small quantities of fluoride, generally less than 1 ppm, are present in ground water in the Coastal Plain in Georgia. 

Hastings (Carter and others, 1949, p. 242) stated 

that the water in southeastern Alabama seldom contains more than 0.5 ppm of fluoride. A few wells in 

the Eutaw Formation of Late Cretaceow;; age yield 

water containing more than 1 ppm. 

The fluoride content of water from the large 

springs fed by artesian water from the principal artesian aquifer, where the Hawthorn Formation is 

absent, ranges from 0.0 to 0.1 ppm. The highest 

fluoride content of spring water reported by Ferguson, Lingham, Love, and Vernon (1947, p. 145-146) 

is 1.6 ppm for Little Salt Spring near Murdock in 

Sarasota County. This fluoride content indicates 

that the water is from the Hawthorn Formation. 

As stated by LaMoreaux (1948, p. 30-37), there 

are several sources of fluoride in ground water. In 

some areas fluoride may be traced directly to magmatic sources or to vapors in the atmosphere from a 

volcanic source. In the Cretaceous and Tertiary formations in the Atlantic and Gulf Coastal Plain, it 

appears to be from fluoride-bearing minerals such as 

apatite, tourmaline, topaz, vesuvianite, lepidolite, 

phlogopite, glauconite, and others in the water-bearing formations. 

Fluoride has been correlated with the presence of 

volcanic ash and bentonitic material in the Catahoula 

Sandstone .of Miocene age in the Gulf Coastal Plain 

in Louisiana by Maher (1939). Black and Brown 

(1951, p. 15) reported that water from the Hawthorn Formation, which contains phosphatic material, almost invariably contains fluoride in excess of 

1.0 ppm, a few samples having as much as 2.5 ppm. 

Except for the hard water in the Hawthorn Formation, the ground water having a fluoride content 

of more than about 1.0 ppm is a soft sodium bicarbonate water, which is common in some of the Tertiary and Cretaceous formations of the Atlantic and 

Gulf Coastal Plain. As suggested by Carlston (1942, 

p. 17-20), glauconite and other materials cause exchange of calcium and magnesium ions for sodium 

ions, and these minerals may be contributing fluoride to the ground water as it moves downgradient. 

The increase in fluoride downgradient may merely 

be the accretion over a long period of time as the 

water moves downgradient through materials which 

have only small quantities of fluoride-bearing minerals. 

Carlston (1942, p. 19) reported that phosphate 

occurs in the upper part of the Eutaw Formation of 

Cretaceous age, which contains water having a relatively high fluoride content. According to Mansfield 

( 1940, p. 863-879), phosphates and fluoride have an 

affinity for each other, and deposition of fluoride 

could occur in localized areas where conditions favor 

the accumulation of phosphates. Also, conditions 

are favorable for the formation of relatively stable 

deposits of phosphates or fluorapatite only during 

times of volcanic activity when large amounts of 

fluoride are available. He found that all major phosphatic deposits in the United States may be correlated with periods of volcanic activity. 

In a study of the fluoride.in water in the Hawthorn 

Formation, Black, Stearns, H. H. McClane, and T. K. 

McClane (1935, p. 22-23) indicated that the fluor.ide 

is from the phosphatic material. The phosphatic rock 

as mined contains approximately 4 percent fluorine. 

Samples of tap water stirred for varying periods of 

time with commercial phosphatic rock dissolved an 

average of 1.7 ppm of fluoride, the exact amount depending on the conditions employed. The low solubility of the phosphate as determined in that study 

probably accounts for the relatively small fluoride 
PRINCIPAL ARTESIAN AQUIFER 143 

content, a maximum of only about 2.5 ppm in the 

Hawthorn Formation. 

Gwynne (1934, p. 139-140) suggested that the 

breaking down by weathering processes of the less 

soluble fluoride minerals might be accomplished by 

action of sulfuric acid formed by decomposition of 

pyrite. As stated by LaMoreaux (1948, p. 31), pyrite 

occurs in many of the aquifers in Tertiary and Cretaceous formations in the Southeastern States. The 

presence of fluoride-bearing minerals and abundance 

of pyrite in some of the water-bearing formations 

seem to support Van Burkalow's theory (1946, p. 187-

188) that fluoride in soluble form might be expected 

where there is an abundance of fluoride minerals and 

an abundance of pyrite in association with concentrated organic material, which would facilitate decomposition of the minerals and release of the 

fluoride. 

In a table listing the principal water-bearing 

sands and the presence of volcanic or phosphatic material, pyrite, lignite, and glauconite, LaMoreaux 

(1948, p. 33) showed that water having a relatively 

high fluoride content correlates with these materials. 

The table also shows that the presence of glauconite 

alone is not responsible for the presence of fluoride. 

For example, the sands of the Nanafalia and Lisbon 

Formations of Eocene age are very glauconitic, but 

the fluoride in the ground water from these sands is 

generally low. LaMoreaux (1948, p. 35) observed 

that the fluoride content increases downgradient, indicating that the distance the water has moved and 

length of time in contact with the fluoride minerals 

are factors in the content. He suggested also that 

greater pressure and temperature at greater depths 

may catalyze the reaction. 

Siple (1957a, p. 297-298) reported that water 

with relatively high fluoride content in the Cretaceous formations of South Carolina occurs under conditions similar to those described by Carlston in Alabama. Also, Siple concluded that the presence of 

glauconitic or phosphatic minerals alone is not responsible for the fluoride because some deposits of 

Tertiary age in South Carolina contain large quantities of the minerals but do not contain fluoride water. 

NITRATE 

Nitrate (NOa) is produced by oxidation of nitrogenous material. The presence of nitrate in excess of 

50 ppm may be a contributing factor in the development of cyanosis, or methemoglobinemia, in infants 

(Black and Brown, 1951, p. 12). However, only a 

few samples of water high in nitrate have been reported in the Southeastern States. Most ground water in the Southeastern States has less than 1 ppm. 

This small amount has no effect on the value of water 

for ordinary use. 

HARDNESS 

Hardness of water may be recognized by the lack 

of suds when washing with soap. It is the CaCOa 

equivalent of calcium, magnesium, and other cations 

having similar soap-consuming properties. Hardness 

may be of two kinds, carbonate and noncarbonate. 

Calcium and magnesium bicarbonate cause the carbonate hardness, which is referred to as temporary 

hardness. A large part of the carbonate hardness 

may be removed by boiling or treatment with lime. 

Sulfates, chlorides, and nitrates of calcium and magnesium cause noncarbonate hardness, often called 

permanent hardness, which is more difficult and 

costly to remove than the temporary hardness. Both 

forms of hardness may be entirely removed by passing the water through a zeolite-type softener, but 

water softened by this method still contains approximately the original quantities of dissolved mineral 

matter. The total hardness expressed as calcium carbonate is the sum of the parts per million of calcium 

multiplied by 2.50 and the parts per million of magnesium multiplied by 4.11. Water having a hardness 

of less than 60 ppm (equivalent CaC03 ) is generally 

regarded as soft, and treatment to soften such water 

seldom is justified for public supply. Hardness between 60 and 120 ppm is generally regarded as moderate and does not seriously interfere with the use of 

water for most purposes ; it does, however, increase 

soap consumption slightly, making the removal of 

hardness by softening process profitable for laundries or other industries that use large quantities of 

soap. Hardness between 120 and 200 ppm is regarded 

as troublesome for many industrial and domestic uses. 

Such water requires treatment to prevent scale when 

used in steam boilers. Hardness of more than 200 

ppm is regarded as very hard. However, water with 

hardness of 200 to 400 ppm is used by many people 

who obtain water supplies from privately owned 

wells. Although very hard water is furnished by 

some public supplies, there is an increasing tendency 

for cities to soften their supplies if the untreated 

water has hardness of more than 150 ppm. 

The hardness of ground water in the report area, 

including that of the principal artesian aquifer, 

ranges from about 5 to about 1,000 ppm. A table of 

hardness of water for the larger public water supplies 

in Florida by Black and Brown (1951, p. 13, 15) 

shows that the hardness of the untreated water 

ranged from 4.0 to about 1,000 ppm. The hardness 

of water (chiefly ground water) as, distributed by 

96 larger public supplies ranged from 0 to 50 ppm 
144 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

for 3 percent of the cities, 51 to 150 ppm for 68 percent, 151 to 250 ppm for 2 percent, and more than 

250 ppm for 9 percent. In general, the softest water 

in the principal artesian aquifer is in recharge areas, 

and the hardest is some distance from recharge 

areas. An exception to this is in Okaloosa, Santa 

Rosa, and Escambia Counties, Fla., where natural 

softening has removed the hardness as the water 

moved through the aquifer. 

A comparison of hardness ranging from about 60 

to about 100 ppm in a recharge area in Clay County 

with that ranging from about 200 to about 3oo ppm 

in Duval County in northeastern Florida shows the 

increase in hardness with distance from recharge 

areas. In southwestern Florida, a comparison of the 

hardness of less than 70 ppm in the principal artesian aquifer in a recharge area in Highlands County 

with that of as much as 1,000 ppm in Sarasota 

County shows the increase in hardness with distance 

from recharge areas. In areas where sea water is 

mixed with the fresh artesian water, the hardness 

may be much more than 1,000 ppm. In recharge 

areas the hardness generally increases with depth of 

well. Water-bearing sands which are recharged locally, as at Pensacola, Fla., yield water having a low 

mineral content and a hardness of less than 10 ppm. 

The hardness of fresh ground water in the shallow 

aquifers in southeastern Florida ranges from about 

150 to 300 ppm, as reported by Love (in Parker and 

others, 1955,p.784). 

The hardness of samples of water reported by Warren (1944, p. 138) from the principal artesian aquifer in southeastern Georgia ranged from 86 to 348 

ppm. The highest hardness was in the southeastern 

part of the area. In southwestern Georgia, the hardness of samples of ground water reported by Wait 

(1960a, p. 42-72) ranged from 70 to 448 ppm in the 

principal artesian aquifer of Tertiary age. The underlying Cretaceous aquifers generally have soft sodium bicarbonate water. Also, some sandy formations of Tertiary age in southwestern Georgia, southeastern Alabama, and western Florida contain soft 

sodium bicarbonate water. 

HYDROGEN SULFIDE 

Hydrogen sulfide (H2S) is a gas which gives the 

characteristic odor of rotten eggs to sulfur water. 

Black and Brown (1951, p. 15) suggested two possible sources of the gas in natural water-the reduction of sulfate to sulfides by organic material under 

anaerobic conditions in aquifers, resulting in decomposition of the metallic sulfide by free carbon dioxide and, in some cases, the anaerobic reduction of 

organic matter with which the water comes in contact. 

In the principal artesian aquifer, the hydrogen 

sulfide ranges from 0 to more than 4 ppm (Black 

and Brown, p. 15). Wetterhall (1965, p. 14) reported that water from depths of 125 to 130 feet in 

an open sinkhole (Blue Sink) in Pinellas County, 

Fla., contained more than 37 ppm of hydrogen sulfide. Although the sink is in the principal artesian 

aquifer, the relatively high sulfide may represent 

local conditions in the sink. As little as 1 ppm gives 

the water a noticeable sulfur odor. Because of aeration, part of the gas is eliminated, and the remainder 

is rapidly oxidized by dissolved oxygen absorbed 

upon aeration. Special sampling and analytical 

methods must be used to determine the amount of 

the gas in the water. For this reason, relatively few 

values for hydrogen sulfide are reported. However, 

water discharging from many artesian wells has a 

noticeable odor of hydrogen sulfide. 

HYDROGEN-ION CONCENTRATION 

The hydrogen-ion concentration (pH) of water is 

the number of moles of ionized hydrogen per liter. 

Pure water contains 10-7 gram of hydrogen ions per 

liter. In order to avoid the use of exponential numbers·, a system· involving the sb-called pH values has 

been developed with pH value of 7 for pure water. 

'\Vater with pH of less than 7.0 is corrosive and acidic, 

the acidity increasing as the pH value decreases. 

Water with pH of more than 7 is alkaline. The alkalinity increases as the pH value increases. The pH 

of most natural water depends on the amount of free 

carbon dioxide and the amount and character of the· 

types of alkalinity present. Free carbon dioxide 

readily escapes from water samples; therefore, the 

determination of pH should be made in the field at 

the time the sample is collected. Samples high in alkalinity will usually undergo only slight changes in 

alkalinity, but soft water high in free carbon dioxide 

will usually be higher in pH after the sample has 

been collected for some time (Black and Brown, 

1951, p. 12). 

Black and Brown (1951) gave the pH values of 

many samples of water throughout Florida. Parker, 

Ferguson, Love, and others (1955) gave pH values 

for the public water supplies in southeastern Florida. 

The pH of water from the principal artesian aquifer 

ranged from 7 to 8.75. Samples of soft water of low 

mineral content had a pH that ranged from 5.4 to 

7.0. Most of these samples were from wells ranging 

from a few feet to about 250 feet deep. The deepest 

wells are at Pensacola, Fla. 
PRINCIPAL ARTESIAN AQUIFER 145 

COLOR 

Color of water as shown in analyses refers to the 

appearance of water that is free of suspended material. Natural color in water is almost entirely from 

organic matter, extracted from leaves, grass, and 

other dead vegetation. A color of less than 20 based 

on a graduated standard of colored glass disks usually passes unnoticed. Some swamp water has a natural color of 200 or more. As stated by Love (Ferguson and others, 1947, p. 19) exceptionally clear water seems blue when seen through a depth of several 

feet. This natural blue color of clear water is caused 

largely by scattering of sunlight by water molecules. 

As most of the scattering occurs in the short wave 

lengths of light which are near the blue end of the 

visible spectrum, the water appears to be blue. Scattering of sunlight increases with depth of penetration, causing deep water to appear bluer than shallow water, as may be noticed in the artesian springs 

in Florida and Georgia. 

Shallow aquifers recharged by surface water containing organic color yield colored water, as in the 

Everglades of Florida or along streams as the Suwannee River during high stages when colored water in the stream enters the cavernous limestone. 

Colored water may also enter the limestone aquifer 

through open sinkholes. However, in areas where 

the limestone is not near the surface, as in Highlands 

County, Fla., the sinkholes are filled with permeable 

sand. Water moving through that material probably 

loses most, if not all, of its color. Bishop (1956, p. 

56) reported that of 36 samples analyzed, 12 were 

colorless, 16 had color of less than 10, and 8 had color 

ranging from 12 to 104. All the colorless samples 

were from the principal artesian aquifer. Two samples from the aquifer had a color of 7, which probably is from lignitic material in the aquifer. 

Most of the large springs in Florida are clear. 

Two of the largest, Silver Springs and Rainbow 

Springs, in Marion County, are always clear. Wakulla Spring, which receives colored water through 

open sinkholes, has noticeable color during and after 

rains when colored surface water enters the aquifer. 

During dry times, the color is zero, as indicated in 

an analysis given by Ferguson, Lingham, Love, and 

Vernon (1947, p. 174). One analysis each shows that 

Silver Springs had a color of 4 and Rainbow Springs 

a color of 2 when sampled. Although both of these 

springs are in the Marion County recharge area, 

where the aquifer is recharged through sinkholes, 

the sinks are filled with permeable sands. Therefore, 

the water is never turbid. Also, some water in that 

area is from the Putnam County recharge area to the 

north and the Polk County recharge area to the 

south. As water from only a few artesian wells has 

noticeable color, very few color determinations have 

been made for this water. Although no water with 

noticeable color has been reported from artesian 

wells in the Southeastern States, water from the 

part of the aquifer containing large quantities of 

lignitic material may have noticeable amounts of 

organic color. 

ELECTRICAL CONDUCTIVITY 

The electrical conductivity of water, also known 

as specific conductance, is a measure of its capacity 

to conduct current. It is the reciprocal of specific resistance in ohms and is expressed in reciprocal ohms 

at 25°C (77°F). In order to avoid the use of small 

figures, the measured values of conductance are multiplied by 106 and expressed as micromhos. Some of 

the· first measurements made in Florida were mul~iplied by 105 (Parker and others, 1955, p. 730) instead of 106• However, the measurements in later 

reports are given in micromhos. The specific conductance of water is a function of the amount and 

kind of the dissolved mineral matter. It varies with 

the concentration and also with the degree of ionization of the minerals in solution. It is an indication 

of the total dissolved solids, which generally is approximately equal to the conductance multiplied by 

a factor of 0.6 to 0.8. Specific conductance is used by 

the U.S. Salinity Laboratory Staff (1954, p. 60-82) 

in classifying the suitability of water for irrigation. 

QUALITY OF WATER FOR IRRIGATION 

The characteristics of water that appear to be 

most important in determining its quality for irrigation in the Western States are: ( 1) total concentration of soluble salts, (2) relative proportion of 

sodium to other cations, (3) concentration of boron or 

other elements that may be toxic, ( 4) and under 

some conditions the bicarbonate concentration as related to the concentration of calcium plus magnesium (U.S. Salinity Lab. Staff, 1954, p. 69-72). In 

the humid climate in the Southeastern States, where 

annual rainfall is as much as 60 inches, the standards set for arid and semiarid areas of the Western 

States are not entirely applicable but may be used in 

a general way. · 

In the Southeastern States the first two characteristics-total concentration of soluble salts and the 

relative amount of sodium to other cations-probably are most important in determining the quality 

of irrigation water. The total concentration of soluble salts (salinity hazard) may be indicated approximately as the electrical conductivity of the water. 
146 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

The relative proportion of sodium to calcium and 

magnesium (sodium or alkali hazard) may be 

expressed as the sodium-adsorption-ratio (SAR) 

which is defined by the equation: 

SAR == N a+ IV ( Ca + + + Mg++) /2 

where N a, Ca, and Mg are expressed in equivalents 

per million. If the proportion of sodium is high, the 

alkali hazard is high; conversely, if calcium and 

magnesium predominate, the hazard is low. 

Classification of irrigation water according to the 

salinity hazard and sodium hazard as given by the 

U.S. Salinity Laboratory Staff (1954, p. 79-81) for 

the Western States is as follows : 

Salinity haz~rd class 

C1 (low)----------------------------··----------------··-----

C2 (medium) ------------------------------------------- C3 (high) --------------------------------------------------- C4 (very high) ·----------------------------------·------

Conductivity 

(micromhos per em at 25°C) 

100- 250 

250- 750 

750-2,250 

2,250-5,000 

Sodium-adsorption-ratio 

Sodium (alkali) hazard class (SAR) 

S1 (low)------------------------·---------------------------- 0-10 

S2 (medium)--------------------------------------------- 10-18 

S3 (high)--------------------------------··--·--------------- 18-26 

S4 (very high)--------------------------·--------------- 26-30 

Low-salinity water ( C1) can be used for irrigation of most crops on most soils without developing 

soil alkalinity. Some leaching of soil is required but 

this occurs under normal irrigation except in soils of 

extremely low permeability: Mediltm-salinity water · 

( C2) can be used if a moderate amount of leaching 

occurs. Plants having moderate salt tolerance can 

be grown in most cases without special salinity control. High-salinity water ( C3) will be harmful if 

used on· soil where drainage is restricted. Special 

management for salinity control may be required ; 

plants having good tolerance for salt should be selected even though the drainage is adequate. Very 

high salinity water ( C4) is not suitable for irrigation under ordinary conditions but may be used 

occasionally under special circumstances for crops 

that tolerate salt. The soils must be permeable, drainage must be good, and excess water is required to 

provide considerable leaching. 

Low-sodium water (S1) can be used on almost all 

soils without danger of development of harmful 

levels of exchangeable sodium. However, sodium~ 

sensitive crops, such as stone-fruit trees and avocados, may accumulate injurious concentrations of 

sodium. Medium-sodium water (S2) presents an 

appreciable sodium hazard in fine-textured soils of 

high-cation-exchange capacity, especially under lowleaching conditions, unless gypsum is present in the 

soil. This water may be used on coarse-textured or 

organic soils of high permeability. High-sodium water ( S3) may produce harmful levels of exchangeable sodium in most soils and will require special 

soil management where there is good drainage, high 

leaching, and the addition of organic material. Soils 

containing gypsum may not develop harmful levels 

of exchangeable sodium, except that addition of 

amendments to the soil may not be feasible· with 

water of high salinity. Very high sodium water 

( S4) is generally unsatisfactory for irrigation purposes except at" low and perhaps medium salinity, 

where the solution of calcium from the soil or addition of gypsum or of other amendments makes the 

use of this water feasible. 

In a humid area such as the Southeastern States, 

where leaching action from rain is greater than in 

arid and semiarid areas in the Western States, the 

above classification probably should be modified to 

some extent. However, Wait (1960c, p. 25-27) used 

the sodium-adsorption-ratio, the specific conductance classification, and salinity for samples of water from 30 wells in the Tertiary and Cretaceous 

formations in southwestern Georgia and found that 

only three samples were unsuitable for irrigation. 

Two samples from the Tertiary formation at Cairo 

and Moultrie, having calcium and sulfate as the 

principal constituents, had a low sodium hazard but 

a high salinity hazard. The other sample from the 

Eutaw Formation of Cretaceous age at Georgetown, 

having sodium and bicarbonate as the principal constituents, represents water of medium salinity hazard and a very high sodium hazard. Water represented by a sample from the Cretaceous at Fort 

Gai:rl.es, Ga., having sodium and bicarbonate as the 

principal constituents, has a medium sodium and 

medium salinity hazard. Of four wells in the principal artesian aquifer studied for irrigation classification in Columbia County, Fla., one of the deepest 

( 996 feet) showed a salinity large enough to restrict its use as an irrigation supply (Meyer, 1962, 

p. 52). The chemical constituents of the sample consisted chiefly of calcium sulfate; the chloride content 

was only 12 ppm. 

Although water samples from other parts of the 

area covered by the present report have not been 

classified as to suitability for irrigation, it seems 

that the sodium-adsorption-ratios might present a 

problem only in part of western Florida and southeastern Alabama where ground water may have relatively large amounts of sodium and bicarbonate 

and small amounts of calcium and magnesium. 

The salinity hazard, however, is present in some 

of the coastal areas and in southern Florida where 

the concentration of soluble salts is relatively high 

in the ground water mixed with sea water. The 
PRINCIPAL ARTESIAN AQUIFER 147 

conductivity of the water in the shallow aquifer 

(Hawthorn Formation) in Manatee County ranged 

from 418 to 2,530 micromhos, except one sample 

having 53,600 micromhos (Peek 1958b, p. 80). This 

water is more concentrated than sea water. The 

conductivity of samples from the principal artesian 

aquifer ranged from 556 to 5,260 micromhos. In a 

few areas, the mineralization is due chiefly to calcium sulfate from gypsum and anhydrite in the 

aquifer. Where some of the water is high in calcium sulfate but low in sodium chloride, as in part 

of Manatee County, it may have total dissolved 

solids of as much as 1,250 ppm and specific conductance of 1,500 micromhos. Although this kind of 

water would be in the high salinity class for Western 

States, it seems to be satisfactory for irrigation in 

Florida. In some of the coastal areas and in southern Florida, where the chloride content is more than 

100 ppm, as shown in figure 36, the conductivity 

may be more than 2,250 micromhos. 

Lichtler (1960, p. 52) reported that the conductivity of water samples from the principal artesian 

aquifer in Martin County, Fla., ranged from 1,310 

micrc;>mhos to 11,300 micromhos. Lichtler noted that 

the total dissolved solids in Martin County can be 

estimated by multiplying the conductance by a factor of 0.6. 

Klein, Schroeder, and Lichtler (1964, p. 70-71) 

showed by a graph (after Wilcox, 1948, p. 25, 26) 

the suitability of ground water for irrigation in 

Glades and Hendry Counties, Fla., where specific 

conductance of samples of water ranged from less 

than 500 to more than 3,500. The graph showed 

that most of the water samples from the shallow 

aquifers were in the range fr01n excellent to permissible but many of the samples from the principal 

artesian aquifer were in the doubtful or unsuitable 

range. 

CHANGES IN QUALITY OF WATER IN AQUIFERS 

Under natural conditions, the quality of ground 

water is generally constant. However, in some locations, especially in recharge areas, contaminated water at the land surface may move into an aquifer 

under natural conditions, or through wells used to 

dispose of surface water or to recharge the aquifer. 

Under some conditions, withdrawal of water from 

the aquifer may cause water of poor chemical quality, such as salt water, to be drawn into the aquifer. 

Chemical changes may occur as the water moves 

through the aquifer. Some of these, such as natural 

softening, may improve the quality of the water. In 

general, however, the mineral content of the water 

increases as it moves through the aquifers. Water 

moving into and through aquifers may lose undesirable properties, such as color, turbidity, and contaminants, some of which may cause the water to be 

harmful or hazardous for human consumption if 

used without adequate treatment. The distance of 

travel in which these changes take place may be a 

few feet or many miles. 

One of the factors which control these natural 

changes is the kind of material through which the 

water passes. Clean sand and gravel will serve as a 

filter for water moving through these materials. 

Water passing through permeable formations containing clay minerals or other material with ionexchange capacity may lose some contaminants. As 

stated by Hem ( 1961, p. 21), although the waterbearing material of productive aquifers generally 

contains relatively little clay, there may be enough 

as a thin coating over sand grains and large rock 

particles to give considerable adsorptive capacity. 

Some of the geologic factors relating to groundwater contamination are described by De Buchananne and LaMoreaux (1961, p. 3-7). Some hydrologic 

factors pertinent to ground-water contamination are 

given by R. H. Brown (1961, p. 7-16). 

Contamination of Ground Water 

Contaminants of. water may be grouped as ( 1) 

biological, including bacteria and viruses, (2) chemical, which may be organic or inorganic, and (3) 

radioactive. 

In areas of cavernous limestone where the water 

may move rapidly through the limestone without 

natural filtering or ion exchange, contaminated water may become a serious problem. The problem of 

biological contamination of water has been recognized for many years. Radioactive, organic, and 

inorganic chemical contamination will become a 

problem if materials are released to the environment 

without adequate control. Fortunately, in the area 

covered by this report, problems of contamination in 

the limestone aquifers are confined to recharge areas 

in which water may enter the limestone at the 

surface or through open sinkholes or drainage wells. 

Only a few cases of such pollution are known in the 

region. One example of pollution through a sinkhole 

is reported by Meyer (1962, p. 51). Where there is 

recharge through sinkholes filled with permeable 

sand, as in some recharge areas in the lake region, 

biological contamination of the water in the limestone is unlikely because the water passes through 

the sandy fillings in the sinkholes. Some underground cavities are also filled with sand and clay. 
148 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Most, if not all, of the solution cavities, both horizontal and vertical, in the shallow limestone aquifer 

in southeastern Florida are filled with sand and clay. 

Although the surface water of relatively high organic color from the Everglades does not lose all its 

color in passing into the aquifer, there is no known 

biological pollution of wells from surface water entering the aquifers naturally. The capacity of the 

sand in the cavities in the limestone and permeable 

parts of the limestone to remove organic color and 

turbidity in the principal artesian aquifer is shown 

by the lack of color and turbidity in most of the 

large limestone springs. 

Water from shallow wells in cavernous limestone 

along streams which cut the aquifer, as along the 

Suwannee River in Florida and the Flint River in 

Georgia, may yield water which enters the aquifer 

from the river. Because of these conditions, at 

Albany, Ga., deep wells were drilled through the 

cavernous limestone into the underlying aquifer to 

prevent possible pollution from the river. 

Baker (1961, p. 142) observed that water of varying degrees of pollution has been discharged through 

drainage wells and sinkholes into the limestone in 

several areas in Florida. Treated municipal sewage 

and organic industrial wastes are being disposed of 

in this manner. The Florida State Board of Health 

has adopted a program to prevent any increase in 

the amount of polluted waste being discharged into 

the ground. Disposal of heated water into wells is 

permitted if the water is passed through closed 

cooling systems without contact with the atmosphere. Also the board issues a permit for the construction of a drainage well only if the required 

specifications are met. Outside the areas of recharge where relatively impervious beds overlie th~ 

limestone, there is little or no chance of the water . 

in the limestone being contaminated by surface water, except through drainage wells or wells with 

defective casings. 

The limestone in some of the coastal areas where 

the aquifer contains or is exposed to salt water at 

the submarine outcrop may become contaminated 

with salt water as discussed in the section on salt 

water. Contamination of the fresh-water aquifer 

may also occur where salt water from the formations underlying the fresh-water aquifer moves upward. 

Ion Exchange and Natural Softening of Ground Water 

·Investigators of soil chemistry have shown that 

soil colloids, usually the aluminum silicate clay components, have the property of adsorbing one or more 

cations-as calcium, magnesium, and sodium-from 

solution and of releasing them again in exchange 

for other cations under suitable conditions. Changes 

in the chemical composition of ground water as it 

moves through water-bearing materials have been 

described by Renick ( 1925, p. 53-72) . He found 

evidence of cation exchange in ground water at 

depths of less than 600 feet in two geologic formations in Rosebud County, Mont. Samples of water 

from wells less than 125 feet deep in the Lance 

Formation contained 43 to 162 ppm of calcium and 

magnesium, and those from wells more than 125 feet 

deep contained 5.2 to 18.1 ppm. Samples from wells 

less than 80 feet deep in the overlying Fort Union 

Formation contained from 99 to 212 ppm. These 

results show that the samples from shallow wells 

were relatively high in calcium and magnesium but 

low in sodium and those from deep wells contained 

little calcium and magnesium but were relatively 

high in sodium. Renick gave evidence that this natural softening of the water by the exchange of calcium and magnesium for sodium is due to clay 

minerals of the leverrierite group. However, he recognized that other hydrated aluminum silicates, 

such as kaolin, feldspars, and mica, are also capable 

of exchanging all or part of their sodium and potassium for other cations. As the exchange was accomplished within depths of 125 feet or less in the 

aquifer, Renick concluded that although the water 

may move many feet and even miles downgradient, 

its calcium and magnesium content was essentially 

removed by percolating through relatively few feet 

of the aquifer. 

Howard (Stephenson and others, 1928, p. 42, 43) 

apparently reached the same conclusion in his discussion of natural softening of water in the Ripley 

Formation of Cretaceous age, which consists chiefly 

of sands and clays and some glauconite, in northern 

Mississippi where analyses show a change similar to 

that reported by Renick. Calcium and magnesium 

were exchanged for sodium, but the total dissolved 

solids apparently remained about the same. Howard 

included analyses of two samples from depths of 461 

and 155 feet, respectively, in the same township in 

Tippah County, Miss. The sample from a depth of 

461 feet was low in calcium and magnesium but relatively high in sodium and potassium. The sample 

from 155 feet was relatively high in calcium and 

magnesium but low in sodium. This difference at 

different depths in the same township was biterpreted by Howard as natural softening with downward movement of the water. Although such 

changes similar to that of zeolite softening of water 
PRINCIPAL ARTESIAN AQUIFER 149 

in water treatment may occur after a few feet of 

downward movement of water in recharge areas, 

probably most of the changes in water in the artesian aquifers in the Atlantic and Gulf Coastal 

Plain occur as the water moves downgradient and 

downdip in the water-bearing sand, sandstone, silt, 

and clay. Soft sodium bicarbonate water commonly 

occurs in the aquifer many miles from its recharge 

areas. Also, in some areas, sodium bicarbonate and 

other constituents, as fluoride, increase with distance from recharge areas. These aquifers contain glauconite, volcanic ash, bentonite, and other 

materials which may act as zeolites in natural softening of the water. 

This kind of soft sodium bicarbonate water is 

present in the principal artesian aquifer of Tertiary 

age where the aquifer grades from limestone and 

marls to sands in Okaloosa, Santa Rosa, and Escambia Counties in western Florida and parts of southeastern Alabama and southwestern Georgia (Barraclough and Marsh, 1962). The soft sodium bicarbonate water in the aquifer along the coast in 

western Florida probably entered the aquifer where 

it is at or near the surface in Alabama. In parts of 

that area the aquifer consists chiefly of limestone 

containing relatively hard calcium bicarbonate water. In Georgia, Wait (1960a, p. 12) reported sodium calcium bicarbonate water in feldspathic sand 

in the lower part of the Clayton Formation. The increase in sodium is attributed to sodium feldspar 

in the basal sand. 

As stated by Foster (1937, p. 407), the depth at 

which softening begins varies with the relative proportion of calcium and magnesium carbonates to the 

base-exchange materials through which the water 

passes. If the carbonates are present in amounts 

more than equivalent to the exchange mineral, or if 

the capacity of the base-exchange minerals has been 

exhausted in the shallower material, ground water 

must travel farther before being softened. 

Some sodium bicarbonate water has the same bicarbonate content as the shallower calcium bicarbonate water in the same formation. However, some 

soft sodium bicarbonate water contains several hundred parts per million more of the bicarbonate than 

the calcium bicarbonate water. According to Foster 

( 1950, p. 33-48), the water contains much more 

sodium bicarbonate than can be attributed to solution of calcium carbonate through the action of 

carbon dioxide derived from air and soil. After a 

study of the field data and laboratory experiments, 

Foster show.ed ( 1950, · p. 33) that the presence of 

carbonaceous material, as a source of carbon dioxide, with calcium carbonate and ion-exchange minerals in a formation is sufficient to account for the 

high sodium bicarbonate content of the water. Foster ( 1950, p. 48) suggested that carbon dioxide 

evolved from the carbonaceous material probably 

would permeate the aquifer and under these conditions the water would receive the carbon dioxide 

without coming in contact with the carbonaceous 

material. Disseminated organic debris in quantities 

not readily detected by means of chemical and microscopic aid could also contribute carbon dioxide to 

the water. 

In a study of the quality of ground water in the 

Everglades and the very productive shallow aquifer 

in southeastern Florida, Love (in Parker and others, 

1955, p. 578, 821-822) found evidence of cation exchanges as indicated by general increases in·· C"'.alcium concentrations which were compensated by 

losses in magnesium and sodium. Because the waterbearing limestone in the shallow aquifer· in the Everglades contains little or no aluminum silicate clays, 

except such material as that filling many cavities in 

the limestone, Love suggested that the cation exchange takes place largely through the medium of 

organic matter which colors practically all the shallow ground water in the area. He postulated that 

some of the mineral content of ground water in the 

Everglades is from remnants of Pleistocene sea 

water that has not been completely flushed out of 

the area and some of it is from cation exchange 

processes. He suggested that organic colloids saturated with sodium and magnesium from the sea water came in contact with fresh calcium bicarbonate 

water in the limestone, with the result that sodium 

and magnesium were exchanged for calcium. Calcium bicarbonate is readily brought into solution by 

carbon dioxide furnished in large part by decomposing organic material. When in contact with the 

material which contains the sodium and magnesium, 

the calcium is exchanged for the sodium and magnesium. The water then comes in contact with more 

limestone which dissolves to form more calcium bicarbonate. Repetition of the process increases the 

bicarbonate content in excess of 500 ppm and as 

much as 1,000 ppm. 

RADIOCHEMICAL ELEMENTS 

The development of nuclear energy has increased 

the interest in radioisotopes and radioactivity of 

water. Radioisotopes in water are being studied to 

determine the natural radioactivity and its relation 

to the geology and hydrology. Radioisotopes in water also are being studied to detect changes resulting 
150 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

from radioactivity from nuclear reactors, nuclear 

weapons tests, and other activities of man. Some 

radioisotopes are being used to good advantage in 

studying the movement of water on the surface and 

underground. A few of these are helpful in determining the movement and the relative age of water. 

In connection with the present investigations, a 

few water samples were tested for tritium to aid in 

studies of recharge areas of the principal artesian 

aquifer. During 1960 and 1961 in another investigation of the U.S. Geological Survey to determine the 

natural background radioactivity of water, a few 

samples of water from the principal artesian aquifer 

were tested for uranium, radium, and gross gammabeta radioactivity. Tests of carbon-14 in peat have 

been made for a few samples to determine the age of 

these deposits in the Florida Everglades south of 

Lake Okeechobee (Parker and others, 1955, p. 109). 

Carbon-14 content of water was recently used by 

Hanshaw, Back, and Rubin (1963, p. 74) to determine the age of water in the Southeastern States. 

Tritium is being used to determine the age of water 

not more than 50 years old. The use of carbon-14 

content gives information on the relative age of ar· 

tesian water which is too old to be tested by tritium. 

Tritium 

Tritium, or hydrogen-3, is the only known radioactive is<?tope of hydrogen found in nature. Hydrogen-4 is known only in the laboratory and has a 

very short half life . (L. L. Thatcher, written 

commun., June 1962). The other isotopes of hydrogen are hydrogen-1, or protium, and hydrogen-2, 

or deuterium, which forms heavy water. Tritium is 

present in detectable quantities in nature as the 

product of the collision of cosmic rays with the 

atmosphere. It had been sought in natural- water 

prior to discovery of its natural radioactivity (Libby, 

1955, p. 301). It has a half life of 12.5 years and 

disintegrates to form the stable isotope of helium-3. 

The tritium content of water may be expressed as 

tritium units (TU) in which 1 TU represents 1 

tritium atom for 1018 atoms of ordinary hydrogen 

atoms. The radioactivity of 3.3 TU is 10-8fLC per cc 

(microcurie per cubic centimeter), according to Kaufman (1960, p. 49). The quantity of tritium occurring 

naturally is so small that its presence has no effect 

on the use of water. 

In addition to natural tritium produced by cosmic 

rays, tritium from nuclear weapons tests and as a 

fission product of nuclear reactors has been added 

to the environment. The nuclear weapons tests 

raised the tritium level in precipitation to many 

times the normal level. After the tests, the triti urn 

level declined but never returned to the normal 

level, which L. L. Thatcher estimated was about 

6 TU along the Atlantic coast. On this basis, Thatcher 

estimated that water with tritium content of 1.5 TU 

because of disintegration rate alone would be about 25 

years old. 

The tritium content of 11 samples of water from 

the principal artesian aquifer in South Carolina, 

Georgia, and Florida, tested in the Geological Survey tritium laboratory in Washington, D.C., ranged 

from less than 0.5 to 4.2 TU, as follows: 

Location 

Hilton Head, S.C ---------------------------------------- Beaufort, S.C .. --------------------------------------------- Beaufort, S.C .. --------------------------------------------- Savannah, Ga ______________________________________________ _ 

Keystone Heights, Clay County, Fla ____________________________________ _ 

Northwest of Lake Okeechobee, Fla., (sec. 28, T. 38 S., R. 34 E.) ________________ _ 

Polk City, Fla ---------------------------------------------- Marietta, Duval County, Fla ___________________ _ 

Silver Springs, near Ocala, 

Marion County, Fla-------------------------------- Salt Springs, 28 miles northeast of Ocala, Marion County, Fla __________________ _ 

Radium Springs, 4 miles 

south of Albany, Ga--------------------------------

Depth of 

well 

(feet) 

543 

95 

102 

557 

492 

1,300 

425 

612 

Date collected 

11-3-60 

2-24-61 

2-24-61 

11-14-60 

1-9-61 

12-8-60 

1-13-61 

12-22-60 

1-5-61 

1-6-61 

1-11-61 

Tritium 

units 

<0.5 

< .5 

1.6 

1.5 

.9 

1.0 

3.8 

1.2 

4.2 

1.7 

1.0 

The sample containing 4.2 TU was collected 

from a depth of 60 feet in Silver Springs, Fla. 

Although there probably is local recharge of the 

principal aquifer within a few miles of Silver 

Springs, part of the water in this area is from the 

Putnam County area to the north and the Polk 

County area to the south, as indicated by the piezometric surface of the artesian water (fig. 29). The 

low organic color and the absence of turbidity also 

indicate that the water may move a considerable 

distance through the aquifer. The content of 3.8 

TU in the sample from a well in Polk County supports other information which indicates local recharge to the principal artesian aquifer. The tritium content of the water that recharged the aquifer 

locally is not known. However, judging from a 

sample of shallow ground water collected from 

Nags Head, N.C., Apr. 5, 1961, containing 47 TU, 

the tritium content of the shallow ground water 

recharged to the aquifer locally was much higher 

than 3.8 TU. Since the time of travel from the surface to the aquifer through sinkholes filled with 

permeable sands should be only a few days or weeks, 

the low tritium value suggests that tritium in the 

water in the aquifer decreases with depth and the 

sample tested was a composite which included some 

old water in the lower part of the aquifer which did 

not contain tritium. The sample from Keystone 

Heights in Clay County had a tritium content of 

only 0.9 TU even though it is in a recharge area. 
PRINCIPAL ARTESIAN AQUIFER 151 

Also, a sample from a recharge area in Beaufort, 

S.C., had a value of only 1.6 TU. These values appear 

to indicate that the samples represented young 

water mixed with old water with little or no tritium 

in the aquifer. The artesian well sampled at Okeechobee in southern Florida is in an area of artesian 

flow about 25 miles east of the nearest known recharge area in Polk County. The sample from 

Marietta is from a well at the west edge of the area 

of artesian flow where there may be little or no local 

recharge, about 30 miles northeast of the nearest 

known recharge area in Baker and Union Counties. 

The sample containing 1.6 TU from Beaufort, S.C., 

is in an area where the piezometric surface is relatively high and where the land surface has shallow 

depressions which may represent sinkholes extending 

to the aquifer but which were almost concealed by 

terrace sediments deposited when the Pleistocene 

sea covered this area. 

In the Savannah area where the sample of water 

from the principal artesian aquifer had 1.5 TU, the 

piezometric surface was formerly as much as 40 

feet above sea level, as shown in figure 30, and wells 

overflowed at the land surface. Large withdrawal of 

water from wells has lowered the piezometric surface as much as 100 feet below sea level in the center 

of the cone of depression. The nearest known recharge area is about 35 miles west of Savannah. If 

the water with 1.5 TU is about 25 years old and 

is from that recharge area, the rate of lateral movement would be more than a mile .a year. However, 

as estimated by Warren (1944, p. 126) for the 

Savannah area and discussed in the section on the 

principal aquifer in the present report, the maximum rate would be 1,150 feet a year for each foot 

of hydraulic gradient. The average gradient between the known recharge area and Savannah is 

almost 3 feet per mile. Assuming a rate of movement of 1,150 feet per year for each foot of gradient, 

the rate would be less than a mile, only 3,450 feet 

per year with a gradient of 3 feet per mile. It is 

entirely possible that local recharge occurs through 

concealed sinks between the known recharge areas 

and the coast. If such sinks are present under tidewater in the Savannah area, they probably are 

filled with relatively impervious material which prevents salt water from moving downward into the 

aquifer. 

The TU values of 1.0 at Okeechobee and 1.2 at 

Marietta appear to indicate some downward movement of water through the Hawthorn Formation 

between the area of artesian flow and the known 

recharge areas. Judging from the available information on the geology and hydrology of the aquifer, 

it probably would require more than 100 years· for 

the artesian water to move 25 miles in these areas 

where the gradient of the piezometric is less than 

2 feet per mile, as discussed in the part of this report 

on the rate of movement of water in the principal 

artesian aquifer. Vertical movement through the 

Hawthorn Formation, which is as much as 500 feet 

thick with relatively impervious beds, would also 

be very slow and under some conditions might require 25 years or more to move downward to the 

artesian aquifer. The result would be water with a 

tritium content of about 1.5 TU mixing with older 

water with little or no tritium in the aquifer. With 

this dilution, detectable amounts of tritium would 

not be expected. This suggests that if the laboratory tests on the tritium are correct, there are unmapped recharge areas where there is insufficient 

recharge to be noticeable on a generalized map of 

the piezometric surface but sufficient to add to the 

aquifer enough young water so that the mixed water 

has 1.5 TU. Possibly, local recharge occurs through 

sinkholes which were filled with unconsolidated sediments and concealed below the Pleistocene terraces. 

Uranium and Radium 

Untnium-238 and radium-226, radioactive isotopes of the uranium-radium series, were determined for a few samples of water from the principal artesian aquifer as part of another investigation 

(Scott and Barker, 1958, p. 153-157, and 1962, p. 

34) . This is a natural radioactive series which 

starts with uranium-238 and ends with the stable 

isotope lead. Uranium is present in small quantities 

in some of the phosphatic material in Miocene and 

younger deposits in Florida. 

The Bone Valley Formation has been leached 

by acid ground water, forming a zone characterized 

by aluminum phosphate minerals. This zone generally averages 0.010 to 0.02 percent uranium (Altschuler and others, 1956, p. 503). The matrix, or 

calcium phosphate zone, constituting the lower 

phosphorite part of the Bone Valley Formation and 

the upper residual part of the Hawthorn, consists 

chiefly of equal parts of quartz sand, phosphate particles, and slime. Uranium content of the coarse 

material averages between 0.010 and 0.020 percent 

as reported by Cathcart (1956, p. 489), who believes the uranium was absorbed by phosphate particles as they formed on the sea floor. In his study 

of the abnormal radioactivity south of Ocala, Fla., 

Espenshade (1958, p. 218) concluded that much of 
152 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

the radioactivity probably is from leached phosphorite that is similar to rock of the leached zone of the 

Bone Valley Formation. Also, abnormal radioactivity at some places in the Ocala area is caused by 

leached, uraniferous pellet phosphorite. 

In their study of the radium and uranium in 

ground water in the United States, Scott and 

Barker (1958, p. 153~154) gave the range of radium 

and uranium concentrations expressed as micromicrocuries per liter (p,p,c per 1) and micrograms per 

liter (p,g per 1), respectively, in 89 samples from the 

Atlantic and Gulf Coastal Plain. The method of 

analysis used did not differentiate between radium226 of the uranium series and radium-224 of the 

thori urn series. The range in urani urn was less than 

0.1-15 p,g U per l and in radium was less than 

0.1-8.6 p,p,c Ra per I. The maximum uranium reported by Scott and Barker (1962, p. 12-13) was in a 

sample from Miocene sand and clay containing 

volcanic ash in Texas. They suggested the uranium 

may be from the volcanic ash. 

A water sample reported by Lichtler (1960, p. 52) 

from the principal artesian aquifer in Martin 

County, Fla., had 1.2 p,g U per I and 11 p,p,c Ra per I. 

The gross beta-gamma radioactivity was 200 p,p,c 

per I. Also, a sample from Salt Spring in Marion 

County, Fla., which seems to be from the principal 

artesian aquifer, had 0.5 p,g U per I and 4.7 JLJLC 

Ra per I (Robert Scott, written commun., 1959). 

Natural uranium in water is not known to have a 

harmful effect. However, radium which results from 

the radioactive disintegration of uranium and 

thorium may occur in harmful amounts. The maximum permissible concentration of radium in water 

for general use apparently has been set by the U.S. 

Public Health Service as 3.3 JLf.LC per I. Except in a 

few places, natural potable ground water ·has less 

than 3.3 p,p.c Ra per I. The occurrence of 11 f.LJLC Ra 

per l in the principal artesian aquifer in Martin 

County may be from small quantities of uranium in 

phosphatic material in the Miocene rocks in the upper part of the aquifer. Other samples from the 

aquifer including one from Wakulla Spring near Tallahassee, Fla., and Silver Springs near Ocala, Fla., 

show low uranium and radium content as might be 

expected in the principal artesian aquifer where little or no phosphatic material is present. 

TEMPERATURE OF ARTESIAN WATER 

The temperature of shallow ground water, as indicated by Collins (1925, p. 97-104), is in general 

about the same as the mean annual temperature of 

the air. Near the ground surface the temperature 

of the water follows the changes in air temperature. 

At greater depths, the water has a higher temperature, corresponding to the increase of the earth's 

temperature. C. E. Van Orstrand (Collins, 1925, 

p. 98) computed that under normal conditions the 

temperature of ground water at a depth of 30 to 60 

feet will generally exceed by 2 o to 3 oF the mean 

annual air temperature. At a depth of about 20 feet, 

the temperature of the ground water may range 

from 10°F above to 10°F below the mean annual 

temperature of the air. 

A generalized map by Collins of the approximate 

temperature of water from nonthermal wells in the 

United States at depths of 30 to 60 feet shows a 

temperature range from 67 oF in the southern part 

of the Coastal Plain in South Carolina to 77 oF 

in southern Florida. In Martin County, Fla., where 

the mean annual temperature of the air is 75.2°F, 

Lichtler (1960, p. 61) reported that temperatures of 

120 samples from shallow wells 10 to 100 feet deep 

ranged from 70° to 82°F. The average was 75.5°F, 

which is about the same as the air temperature. 

However, many samples were 2° to 3°F above the 

mean annual temperatures, as suggested by the 

study by Van Orstrand. Lichtler also observed that 

the temperature of the shallow ground water varied 

according to the sea~on. The greatest variation was 

in the water nearest the land surface. 

The temperature of artesian water in the principal artesian aquifer as measured at the mouths of 

wells ranged from about 62°F in South Carolina to 

91 °F in Martin County in southern Florida. The 

highest temperature recorded for the artesian water 

in the Cretaceous aquifers underlying the principal 

artesian aquifer of Tertiary age was 103°F from 

depths of 2,610 to 3,450 feet in a well at Parris 

Island, S.C. 

The temperature of water in springs from the 

principal artesian aquifer ranged from 67°F in 

northern Florida to 86°F in Warm Salt Spring in 

Sarasota County in southern Florida. The highest 

temperature recorded by Stringfield (1933c) for 

artesian wells in Sarasota County was 82°F, with 

the exception of an oil test well 1,332 feet deep 

whose temperature was 87°F. It appears that a 

temperature of 86°F for Warm Salt Spring was 

affected by the air temperature. Most measurements 

of the temperature of spring water ranged from 

about 69°F in northern Florida and southern Georgia to about 70° to 74°F in central Florida. The 

measurements showed some variation in the temperature of the springs at different times, but this 

variation probably reflected in part the changes in 
PRINCIPAL ARTESIAN AQUIFER 153 

the air temperature. Some measurements showed 

little or no change in the temperature, as for example, 8 of 11 measurements for Weekiwachee Spring 

at different times were 70°F. The other measurements were 72°, 75°, and 77°F. This wide range of 

three measurements may be due in part to the use of 

the thermometers which had not been calibrated, or 

perhaps to measurements in different places on the 

surface of the spring. 

Measurements of the temperature of water at the 

mouths of representative wells in the principal artesian aquifer by Warren (1944, p. 138-140) in 

southeastern Georgia ranged from 69°F in Effingham County to 78°F in Mcintosh County. In Escambia County in southeastern Alabama, Cagle and 

Floyd (1957, p. 24-29) reported that the temperature of water from wells ranged from 68° to 76°F. 

The temperature of the water from the principal 

artesian aquifer in Martin County, as measured by 

Lichtler at the mouths of wells about 500 to 1,380 

feet deep, ranged from 75° to 91 °F. However, 

only one well had a temperature of more than 85°F. 

The well having the highest recorded temperature, 

91 °F, is 843 feet deep. Water from another well 

about the same depth and only 3 miles away had a 

temperature of 81 °F. The records of the two wells 

indicate that the increase in the temperature with 

depth is 1 °F for each 55 feet in one well and 1 °F 

for each 140 feet in the other well. This difference 

may be due in part to the fact that the wells are 

not cased in the aquifer, which is as much as 500 

feet thick. In one well the water may be from the 

upper part of the aquifer, and in the other it may be 

from the lower part even though the wells are about 

the same depth. However, in view of the fact that 

all but one deep well had temperatures of 85°F or 

less, the temperature of 91 °F appears anomalous. 

Lichtler (1960, p. 52, 63) suggested that radioactivity may cause the higher temperature, but this 

explanation seems unlikely to the writer. It appears 

more likely to be related to some other features. 

F. C. Westendick (in Stringfield, 1936, p. 169) recorded a temperature of 88°F in artesian water 

from a well reported to be 620 feet deep in Lee 

County, Fla., indicating a thermal gradient of about 

1 °F for each 56 feet of depth. This suggests that 

the differences in temperature may merely be due 

to differences in depths at which the water enters 

the well. 

The lowest temperature of the artesian water in 

Martin County is in the eastern part. Lichtler (1960, 

p. 63) suggested that the relatively low temperature may be due to the cooling effect of the ocean 

water on the submarine outcrop of the aquifer which 

is near the shore. Nevin Hoy (written commun., 

1960) observed lower temperatures of artesian water 

near the coast of Dade County, Fla. Hoy suggested 

that the lower temperature may be due to the cooling 

effect of the Gulf Stream. Temperatures of about 

43° to 48°F on the submarine outcrop of the aquifer 

are only a few miles. offshore. 

Other reports which contain information on the 

temperature of artesian water from the principal 

aquifer in Florida include the following. Records of 

temperature measurements given by Stringfield 

(1936, p. 165-175) in the ·Florida peninsula ranged 

from 70° to 88°F. In Brevard County, D. W. 

Brown, W. E. Kenner, and Eugene Brown (1957, 

p. 85) reported temperatures ranging from 7 4 o to 

81 °F. Most of them were less than 80°F. Peek 

(1959a, p. 5-48) recorded temperatures that ranged 

from 75° to 82°F in the Ruskin area, Hillsborough 

County. Most of the measurements were less than 

80°F. Bermes (1958b, p. 67-68) recorded temperatures that ranged from 76° to 79°F in Indian 

River County. The measurements in Manatee 

County ranged from 77 o to 84 oF, but most of them 

were less than 80°F, as reported by Peek (1959a, 

p. 5-48). In Flagler, Putnam, and St. Johns Counties, Fla., Bermes and others (1963, p. 75) reported 

that the temperature of the artesian water ranges 

from 72° to 75°F, which is about 1° to 3°F higher 

than mean annual air temperature in that area. 

The higher temperatures appear to be from deeper 

wells away from recharge areas. Artesian water is 

used in parts of that area to moderate air temperature to prevent freezing of young tomato plants. 

Also, it is used in several homes for heating and 

cooling. 

Thermal Gradient 

The temperature of ground water increases with 

depth as the temperature of the formations in which 

it occurs increases. This increase of temperature, 

or the thermal gradient, may differ considerably 

from one area to another, depending on the geologic 

conditions. Collins (1925, p. 98) gave an approximate average of 1 °F for each 64 feet of depth 

reported by a committee of the British Association 

for Advancement of Science in 1882. 

The maximum thermal gradient for a water well 

in the Coastal Plain of the Southeastern States as 

observed by G. F. Brown (1947, p. 33) was 1 °F 

for each 53 feet of depth in an artesian well, 1, 7 46 to 

1, 786 feet deep, with a maximum recorded temperature of 98.7°F at Glen Allen, Washington County, 
154 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Miss. Paul Jones of the U.S. Geological Survey 

(written commun., 1950), recorded a temperature 

of 101 °F for ~rtesian water from a depth of 3,100 

feet and a temperature of 98° to 99°F for water 

from a depth of 2,850 feet in eastern Louisiana, indicating an increase in temperature of about 1 °F for 

each 100 feet of depth. The average of other measurements on artesian wells in that area is about 1 °F 

for each 97 feet of increase in depth. 

Incomplete data indicate that the thermal gradient may range from about 1 °F for each 55 feet of 

depth to about 1 °F for each 140 feet of depth in the 

area of this report. These data are based on measurement of the temperature of the water as it 

discharges from the wells, some of which are not 

completely cased. Temperature measurements at different depths in wells will be required to give a 

better understanding of the thermal gradient and 

the causes of the differences in these gradients. 

SALT WATER 

The potential fresh-water supply of aquifers in 

many areas is dependent on its relation to salt 

water that may be drawn into an aquifer and thus 

contaminate the fresh water. In the Southeastern 

States, this problem is most significant in the coastal 

areas. However, the problem is present in the upper 

part of the St. Johns River valley in Florida and in 

parts of the Florida Everglades, as on the south 

side of Lake Okeechobee. 

In areas where salt water has encroached or may 

encroach in an aquifer, the fresh-water supply may 

not be adequate for future increases in use. However, adequate information on the geology and 

hydrology (Parker and others, 1955) will make it 

possible to maintain a fresh-water supply indefinitely if the necessary precautions are taken, as in 

the Miami area, Florida, where part of the aquifer 

was contaminated by salt water before precautions 

were taken. If ignored, the problem may result in 

contamination of the aquifer by salt water and make 

it necessary to develop new well fields some distance 

from the contaminated areas. Once an area is 

contaminated by salt water, it may require many 

years under the most favorable ~onditions for the 

salt water to be flushed out. Therefore, in proper 

management and planning of ground-water resources it is essential that the problem of salt water 

in aquifers be understood. 

Salt water in fresh-water aquifers in the area of 

this report may come from one or more of the following sources : 

1. Water from the Atlantic Ocean and the Gulf of 

Mexico in the coastal areas where the freshwater head has been lowered to an extent that 

permits salt water to move into the aquifer. 

Salt-water spray along the coast contributes 

small amounts of salt to the ground water. 

Some shallow aquifers, as in the Florida Keys, 

are contaminated by salt water during storms. 

2. Connate water or sea water that remained in the 

formations after deposition. 

3. Sea water that entered the formations after they 

were deposited but before Recent time. In 

some areas sea water of Pleistocene age is present in the principal artesian aquifer and in the 

overlying aquifers. 

4. . Salt~ as thin beds, or disseminated in geologic 

formations. 

5. Sea water that became more concentrated by 

evaporation in tidal lagoons or other enclosed 

water bodies that received sea water during 

storms. 

Salt domes or plugs of salt that were pushed from 

salt beds upward into overlying formations are 

sources of salt in some water in the Gulf Coastal Plain 

west of Florida. Deep wells drilled for oil in southern Florida have penetrated salt beds in the Cretaceous strata, but available information shows no 

indication of salt domes or thick salt beds in the 

overlying Cenozoic formations in the area of this 

report. 

In shallow formations along the coast most, if not 

all, of the salt water is from sea water of Recent age. 

In the deeper formations, not exposed to sea water, 

near the coast the salt water is from connate water 

or sea water that entered the formation after it was 

deposited but before Recent time. Inland, the salt 

water is from connate water and sea water that entered the formation after it was deposited or from 

salt in the formations. 

Sanford (Matson and Sanford, 1913, p. 276) reported that a city well drilled to a depth of 780 feet 

at Titusville, Fla., penetrated a thin bed of salt at a 

depth of 50 feet. 

Salt water resembling sea water in composition 

but more than twice as concentrated as sea water 

was collected by Stringfield (1933c, p. 219) from an 

unfinished well 398 feet deep, owned by H. C. Ditmas, south of Anna Maria on Anna Maria Key, Manatee County, Fla., the only locality in the report area 

in which salt water more concentrated than sea water has been found at relatively shallow depths. 

However, Kimrey (1960, p. 14) reported ground water more concentrated than sea water, having a chlo-
PRINCIPAL ARTESIAN AQUIFER 155 

ride content of as much as 42,000 ppm, at depths of 

less than 110 feet at the Pea Island Campground on 

the northern tip of Hatteras Island, Cape Hatteras, 

N.C. This occurrence suggests concentration of sea 

water by evaporation in a tidal lagoon or other enclosed water body. 

CHEMICAL COMPOSITION OF SEA WATER 

The chemical composition of ocean water has been 

determined by analyses of samples collected from 

many places in the world. These analyses show that 

concentration of dissolved mineral matter differs 

considerably from place to place and varies from 

time to time. However, as stated by Love (Parker 

and others, 1955, p. 572) the ratio between the more 

abundant constituents is almost constant (Sverdrup 

and others, 1942, p. 165). 

The analyses commonly taken to represent the average composition of sea water are those made by 

Dittmar on 77 samples collected from many parts of 

the world by the Challenger Expedition in 1884. The 

average of these analyses is given in the following 

table, together with an analysis of water collected 

on May 23, 1941, from the Atlantic Ocean about 50 

feet offshore at 41st Street, Miami Beach, Fla. The 

concentrations of the different constituents in the 

samples collected off Miami Beach in 1941 are slightly 

greater than those reported by Dittmar, but their 

ratios to chloride are almost the same. 

Analyses of sea water 

[From U.S. Geol. Survey Water-Supply Paper 1255, p. 572] 

Average of 77 samples Miami Beach sample 

tion more thoroughly in a report published in 1901 

after he learned, by drilling wells on the Island of 

N orderny, "that the depth of salt water was a function 

of the height of the water table above mean sea level 

and of the density of the water of the North Sea. 

The results of these investigations were reviewed by 

Brown. 

Palmer (1957, p. 181-189) reviewed the history of 

the principle and proposed that it be called the Herzberg principle, without its various parallels, such as 

the Herzberg lens. According to Palmer (1957, p. 

188), Herzberg gave a far better presentation of the 

idea than Ghyben. Palmer included references to 

much of the literature on the subject. 

Application of the principle, as stated by J. S. 

Brown (1925, p. 16) and Black, Brown, and Pearce 

(1953), may be expressed as follows: 

Let 

H == total thickness of fresh water, 

h == depth of fresh water below sea level, and 

t == height of fresh water above mean sea level. 

Then 

H==h+t. 

However, the column of fresh water (H) must be 

balanced by a column of salt water (h) in order to 

maintain equilibrium. Therefore, if g is the specific 

gravity of sea water and the specific gravity of fresh 

water is assumed to be 1, then: 

H == h + t == hg, 

t == hg - h == h ( g -1), 

h == tj(g -1), 

Parts per Ratio to CJ Parts per Ratio to Cl in Which g - 1 is the difference in gravity between 

million (percentt> million (percentt) the salt water and the fresh water. (See fig. 34.) 

Calcium (Ca) ............................ . Magnesium (Mg) .................... .. Sodium (Na) ............................. . Potassium (K) .......................... . Bicarbonate (HCOn) ........ -.... .. Sulfate (SQ.,) ............................ . Chloride ( Cl) ............................. . B1·omide (Br) ........................ - .. Total dissolved solids .............. .. 419 

1,304 

10,710 

390 

146 

2,690 

19,350 

70 

35,000 

2.17 

6.73 

55.35 

2.02 

.75 

13.90 

.36 

423 2.14 

1,324 6.70 

10,970 55.49 

429 2.17 

147 .74 

2,750 13.91 

19,770 .................... .. 49 .21 

35,800 .................... .. 

10 ~.Contents of indicated ion divided by chloride content and multipled by 

RELATION OF SALT WATER TO FRESH GROUND WATER 

Certain general relations between salt water and 

fresh ground water in coastal areas have been summarized by J. S. Brown (1925, p. 16). The principle 

of equilibrium between salt and fresh water, as applied to the hydrology of a seacoast, is sometimes referred to as the theory of Ghyben and Herzberg because they were among the first investigators to 

recognize the principle. Badon Ghyben announced 

the theory in 1889 after an examination of water in 

sand dunes in Holland. Herzberg described the relaThe specific gravity of sea water differs somewhat 

from one locality to another and may also be different 

at different depths. For example, in July and August 

1913, Bigelow (1915, figs. 55, 61) found that the 

specific gravity of surface water in the Atlantic 

Ocean ranged from 1.019 near the mouth of the 

Chesapeake Bay to 1.025 in the Gulf of Maine. Also, 

at certain points opposite Chesapeake Bay, the specific gravity ranged from 1.019 at the surface to 

more than 1.028 below a depth of 110 fathoms (660 

feet). A map by Lindenkohl (1896, p. 358) showed 

that the specific gravity of surface water was 1.024 

near the coast, about 1.026 about 10 miles offshore, 

and 1.028 at a distance of nearly 100 miles. The density of water below the surface may be greater, although Lindenkohl suggests that it may actually decrease to a depth between 700 and 800 fathoms and 

increase below that depth. The average specific grav-
156 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

A B 

FIGURE 34.-Relation of salt water to fresh water in 

aquifers. (from Warren, 1944). 

ity reported by Parker, Ferguson, Love, and others 

(1955, p. 573) from samples of water from the Atlantic Ocean at Miami, Fla., is 1.02680. 

Where an aquifer is exposed in the ocean, sea water may enter it under some conditions. Under nonartesian conditions, sea water will be at such a depth 

that the overlying column of fresh water will balance 

a column of heavier sea water, according to the Ghyben-Herzberg principle. Thus, under static conditions, if the fresh ground water has a specific gravity 

of 1 and the sea water has a specific gravity of 1.025, 

the contact between the sea water and the overlying 

fresh water at any place is depressed 40 feet below 

sea 'level for every foot that the water table stands 

above sea level. Under these conditions, if the height 

of the water table above sea level is known, it is possible to determine with a reasonable degree of accuracy the depth to which fresh water is present. If 

sea level remained at a constant level and recharge 

from rainfall were at a uniform rate, the salt waterfresh water interface would remain in the same position, and salt water would remain motionless while 

the fresh water would move toward the sea in the 

same way as if the interface were an impermeable 

surface. However, the ocean tides, as well as variations in recharge and discharge, continually disturb 

the balance between salt water and fresh water and 

cause the interface to fluctuate. By this natural fluctuation as well as by diffusion of the salt water, the 

sharp interface is destroyed, and a considerable transition zone of brackish water may be created. 

If a well is pumped and a cone of depression in the 

water table is developed under such conditions, salt 

water will rise below the well and will form an upright cone, theoretically having a height about 40 

times the depth of the cone of depression in the water 

table. If pumping is continued at a constant rate 

without change in the cone of depression, the contact theoretically remains stationary and salt water 

remains motionless while fresh water moves .from all 

directions toward the well. If, however, the rate of 

pumping is increased or because of depletion of the 

supply the water table is further depressed, the apex 

of the salt-water cone may reach the bottom of the 

well, salt water may be drawn into the well, and 

movement in the salt-water zone may begin. 

Under artesian conditions, the same general principle may hold, but under modified conditions, as 

shown in figure 34 where artesian conditions exist, 

sea water has access to the aquifer at its outcrop beneath the sea where it is not covered by confining 

beds or at points where a fissure or other opening occurs in the confining bed. The relation between salt 

and fresh water under these conditions may be compared to those conditions in a U-shaped tube, one 

side of which is filled with salt water and the other 

with fresh water. One leg of the tube is comparable 

to the sea and the other to the aquifer, and the walls 

of the tube represent the confining beds. 

If the confining bed is completely impervious and 

the head of water in the aquifer is not large enough 

to push the salt water back to the submarine outcrop 

of the aquifer, the condition is one of equilibrium 

between two bodies of water of different densities. 

On the other hand, if the' head of water is sufficiently 

great, a hydraulic gradient will be established in the 

aquifer, the salt water will be pushed back to the 

submarine outcrop, and fresh water will escape into 

the sea. Under the first condition, there is no discharge of fresh water into the sea. Hence, there is 

no hydraulic gradient, the head of the water in the 

aquifer is the same at all points, and the piezometric 

surface becomes an even surface at some height 

above sea level. An area in which the head is the 

same at all points has been called an isopiestic area 

by Palmer (1927, p. 39-40). Under the first condition, the water is under artesian pressure that is due 

in part to the back pressure of the salt water. 

Whether the active or static conditions exist depends on such factors as the artesian head and the 
PRINCIPAL ARTESIAN AQUIFER 157 

depth of the submarine outcrop or the depth at which 

the sea water enters the aquifer. If the head is relatively high or the submarine outcrop is relatively 

near sea level, active conditions may prevail. Under 

these conditions, there is a hydraulic gradient; water is moving through the aquifer, and the soluble 

salts have generally been removed if there has been 

sufficient time and if the artesian water is relatively 

free of mineral matter. Conversely, if the head is 

low or the submarine outcrop is at great depth, static 

conditions may prevail. The aquifer is plugged by 

pressure of salt water, and there is no leaking out of 

the soluble salts, except as artesian water may escape 

through the overlying confining beds or through 

nearby submarine outcrops where the aquifer is near 

enough to sea level so that the fresh-water head in 

the aquifer at the outcrop exceeds the back pressure 

from the salt-water column in the ocean. 

In the area of this report water-table aquifers are 

exposed to sea water along the coast, and in some 

places artesian aquifers are exposed to sea water. In 

these areas the problem of salt-water encroachment 

is present where withdrawal of water through wells 

or drainage of the coastal area, as in south~astern 

Florida (Parker and others, 1955, p. 165-166, 580-

584) , has lowered the water table or artesian head 

enough to cause the sea water to move into the 

aquifers. 

In nearly all the coastal areas where the aquifers 

are exposed to sea water, the Ghyben-Herzberg principle can be used to estimate the position of the interface between the salt water and fresh water. 

However, the interface is deeper and nearer the 

coast than that indicated by the Ghyben-Herzberg 

principle where there are dynamic conditions in a 

very permeable formation and large quantities of 

fresh water move along the zone of diffusion at this 

interface and discharge over the salt water. Several 

investigators, including Muskat (1937, p. 289), Hubbert (1940, p. 924), Glover (1959, p. 457-459), and 

Henry (1959, p. 1911-1919), reported that under dynamic conditions where the fresh water flows seaward, especially with a steep water table, the position of the interface of the salt water in relation to 

the fresh water is governed by a dynamic equilibrium between flowing fresh water and almost static 

salt water. 

Cooper (1959, p. 461-467) and Kohout (1960, p. 

2133-2141) and others observed that during periods 

of heavy recharge in the shallow aquifer, the fresh 

water, the salt water, and the zone of diffusion move 

seaward in the Miami area, Florida. The shallow 

aquifer consists of the Tamiami Formation of Miocene age and overlying younger formations which 

are exposed at the surface and are exposed to salt 

water in Biscayne Bay. Although the gradient of the 

water table is very low, the aquifer is very permeable, and the flow of water through it is therefore 

large. Under these conditions, the diluted salt water 

in the zone of diffusion continues to flow seaward 

while the fresh water head is low, and the salt water 

in the lower part of the aquifer flows inland. 

Kohout (1960, p. 2141) indicated that under some 

conditions about 20 percent of the total salt water 

flowing inland below the fresh water discharges seaward in the diffusion zone between the salt water 

and fresh water. A ground-water velocity test, using 

fluorescein dye as a tracer, showed that water in that 

zone containing 1,500 to 2,000 ppm chloride was flowing seaward at a rate greater than 70 feet per day. 

This cyclic flow acts as a deterrent to the encroachment of sea water, and therefore the contact between 

the fresh water and salt water is .deeper and not as 

far inland as that computed by the Ghyben-Herzberg 

principle which holds for static conditions. 

Dynamic conditions similar to those in the shallow aquifer at Miami seem to be present on the gulf 

coast in Citrus and Levy Counties, Fla., where Eocene limestones of the principal artesian aquifer crop 

out in the gulf. Large quantities of fresh water discharge through the cavernous limestone aquifer into 

the Gulf of Mexico. Information on the depth to salt 

water in north-central Florida, including Levy 

County, obtained in a surface electrical-resistivity 

survey in 1937, is given in an unpublished report ("A 

Geophysical Survey in North-Central Florida" by 

J. H. Swartz, G. R. MacCarthy, and A. C. Byers, U.S. 

Geol. Survey, 1937) which describes a surface resistivity survey at three selected areas along a line from 

Yankeetown on the gulf coast in Levy County through 

Dunnellon, Ocala, and Silver Springs to Welaka and 

Pomona east of the St. Johns River. The line from 

Yankeetown to Silver Springs in Marion County is 

approximately along the proposed route 13-B (U.S. 

Army, Corps of Engineers, 1933; U.S. Congress, 

Senate, 1936) for a ship canal across Florida. The 

first of these areas is along the road from Yankeetown to Dunnellon ; the second is south of Ocala; and 

the third is east of the St. Johns River between Welaka and Pomona in the southern part of Putnam 

County. 

Of twelve surface resistivity stations along the 

Yankeetown-Dunnellon highway, the first five beginning at Yankeetown recorded measurements to a 

depth of 1,000 feet, and the remainder, to a depth of 

2,000 feet. The first station at the edge of a saltwater marsh indicated salt water to a depth of 40 

feet, but there was no indication of salt water in the 
158 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

interval between 40 and 1,000 feet. Also, except for 

a shallow zone less than 100 feet deep, there was no 

indication of salt water at the seven stations, which 

were measured to a depth of 2,000 feet farther inland. This observation suggests dynamic conditions 

that modify the Ghyben-Herzberg principle. If 

there are large flows of fresh water in cavernous 

limestone, conditions are favorable for a thick diffusion zone and cyclic flow of salt water as in the shallow aquifer at Miami. 

In the second area, which is along the road from 

Pedro to Bellview, about 12 miles south of Ocala, 

measurements at three resistivity stations, two 

measurements to a depth of 2,000 feet and one to 

3,000 feet, showed no indication of a considerable 

thickness of salt water. Because the maximum freshwater head of about 50 feet above sea level in this 

area is not sufficient to depress salt water to a depth 

of more than about 2,000 feet, salt water would be 

expect~d below 2,000 feet if it is in balance with sea 

water according to the Ghyben-Herzberg principle. 

In the third area, Welaka to Pomona, which is 

known to be underlain by salt water at relatively 

shallow depths, the depth to salt water as determined by the resistivity measurements is approximately the same as that reported in records of wells. 

For example, at the intersection of Chestnut and 

Second Streets, Welaka, where the records of the 

Florida Geological Survey show that a sample of 

water from a well at a depth of about 330 feet had a 

chloride content of 8,880 ppm, the resistivity survey 

indicates salt water at a depth of about 300 feet. 

The unpublished report by Swartz, MacCarthy, and 

Byers shows that the depth to salt water increases as 

the head of fresh water increases. Also, the report 

indicates that the Ghyben-Herzberg principle seems 

to apply in a general way in that area. Judging from 

the geologic and hydrologic conditions, however, the 

present occurrence and distribution of salt water in 

this area depends chiefly on the extent to which the 

aquifer has been flushed of its salt water. 

A section across southern Florida (fig. 35) shows 

in a general way the relation of the fresh water to 

salt water in the aquifer. Where the flushing of the 

aquifer is incomplete, salt water is present, even 

though the application of the Ghyben-Herzberg ratio 

shows that the artesian head is sufficient to prevent 

salt-water encroachment in the aquifer. In Levy 

and Citrus Counties on the western coast of Florida, 

the large fresh-water flow through the aquifer seems 

to be similar to that in the shallow aquifer in the Miami area where the interface of the salt water with 

the fresh water is not as far inland and is deeper 

than that indicated by the Ghyben-Herzberg ratio. 

Under dynamic conditions, some of the salt water in 

the upper part of the zone of diffusion of the interface returns to the sea with the fresh water flowing 

to the submarine outcrop. 

RELATION OF SALT WATER TO ARTESIAN HEAD 

The principal artesian aquifer crops out in some 

places in the Atlantic Ocean and Gulf of Mexico. 

The areas of outcrop depend in part on the structure 

of the aquifer and the topography of the submarine 

floor. The depths to the sea bottom at numerous 

points in the Gulf of Mexico and Atlantic Ocean have 

been determined and charted by the U.S. Coast and 

Geodetic Survey and by the U.S. Hydrographic Office, as discussed by G. F. Jordan (1962). 

Gulf Coast 

From the western coast of the Florida peninsula, 

the sea bottom slopes gradually in a westerly direction to a depth of about 50 fathoms (300 feet) about 

125 miles offshore and thence more steeply. Thus, 

the depth increases to about 100 fathoms ( 600 feet) 

beyond 125 miles offshore and about 1,500 fathoms 

(9,000 feet) about 180 miles offshore. The structure 

of the aquifer beneath the Gulf of Mexico is not 

known. However, if it is that inferred by Cooke and 

Mossom (1929, pl. 2), as shown in figure 4, the aquifer crops out offshore at a depth of more than 800 

feet. The structure of the aquifer may not be as inferred, and it may actually crop out at less depth and 

nearer the shore. Moreover, it is possible that the 

salt water from the gulf may have access to the aquifer at lesser depths through permeable zones in the 

Hawthorn Formation or through openings in the 

confining beds in the Hawthorn. 

In the northern part of Sarasota County, Fla., . 

Stringfield (1933c, p. 174) found that the piezometric surface generally sloped to the west from an 

altitude of 40 feet above sea level along the east 

border of the county to 24 feet on Armand Island on 

tp.e gulf coast. The hydraulic gradient, about 1 foot 

per mile, indicates movement of the artesian water, 

presumably to the outcrop of the aquifer in the Gulf 

of Mexico. Under such conditions the piezometric 

surface would continue to slope from the coast to the 

submarine outcrop, and the head at the outcrop 

would be lower than at the coast by an amount necessary to produce the movement of the water. If the 

outcrop were at a depth of about 800 feet and the 

.specific gravity of the sea water were 1.025, the head 

created by the back pressure of the sea water would 

be sufficient to hold the fresh water in the aquifer at 
EXPLANATION 

Areas in which water 

having a relatively high 

chloride content is not 

completely flushed from 

aquifer 

-· Areas in which sea water 

in aquifer may be in con-

• Formations containing 

water having a relatively 

high chloride content 

FIGURE 35.-Section across southern Florida showing relation of salt water to fresh water in the principal artesian aquifer. 

'1:1 

~ 

z 

(") 

1-4 

'1:1 

> t"'4 

> 

~ 

~ 00 

1-4 

> 

z 

> .0 

d 

1-4 

"Zj 

tr1 

~ 

en """' 

CD 
160 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

a head of about 20 feet above sea level. The head at 

the coast would need to be greater by an amount 

needed to force the water to move to the submarine 

outcrop. The observed head of about 24 feet is apparently insufficient to provide for movement of the 

artesian water to a discharge point at a depth of 

800 feet and more than 125 miles offshore. Therefore, it appears that the submarine outlet is at a 

shallower depth or nearer the coast. If an isopiestic 

area is present in the piezometric surface west of 

Sarasota County, it is possible that the artesian water offshore moves northward parallel to the coast to 

an area where the aquifer is present at a shallow 

depth. There is also the possibility that the artesian 

water may discharge through upward leakage into 

the Gulf of Mexico. 

Along the gulf coast from Tampa Bay and Pinellas County to Franklin County in western Florida, 

the Eocene, Oligocene, and Miocene formations of 

the principal artesian aquifer are at or near the 

floor of the gulf. Closed depressions which appear 

to be sinkholes in a submarine valley, such as the 

DeSoto Canyon (Shepard, 1948, p. 125) in the Gulf 

of Mexico south of the Apalachicola River Delta, 

suggest that the limestone is near the ocean floor. 

Large quantities of artesian water flow directly into 

the gulf as indicated by the piezometric surface of 

artesian water and by many springs on the coast; 

among the largest of these springs on the coast are 

Homasassa and Chassahowitzka in Citrus County. 

A submarine spring has been recorded (Stringfield 

and Cooper, 1951c, p. 67) offshore from Crystal 

Beach in Pinellas County. W. S. Wetterhall (written commun., 1962) has observed many springs in 

the Gulf of Mexico west of Citrus County. Tarpon 

Springs in tidewater of the Anclote River near the 

coast of Pinellas County, as described. by Heath and 

Smith (1954, p. 38-42), is fed by water in solution channels in the artesian aquifer. At least one 

of these channels is connected to Lake Tarpon, formerly known as Lake Butler. 

South of Pinellas County, the principal artesian 

aquifer is at greater depth and does not crop out 

near the shore. The Hawthorn and younger formations which are confining beds for the artesian aquifer crop out, however, at or near the shore. Along 

the coast in western Florida, the artesian aquifer 

dips to the southwest to more than 1,000 feet below 

sea level at Pensacola. It is overlain by unconsolidated formations through which the artesian water 

probably leaks upward into the Gulf of Mexico. 

Atlantic Coast 

Available information indicates that the aquifer 

extends to the edge of the Continental Shelf in the 

Atlantic Ocean, at least offshore from Key West to 

West Palm Beach where the shelf is only a few 

miles from the coast. A map (fig. 23) of the top of 

the aquifer by Vernon (1955, fig. 2) and a structure 

contour map by Mossom ( 1926, pl. 1) show that 

the top of the aquifer ranges in depth from 600 to 

1,000 feet below sea level from Key West to Palm 

Beach. 

The top of the aquifer is 800 to 1,000 feet below 

sea level along the coast in Palm Beach and Broward Counties, 700 to 900 feet in Dade County, and 

600 to 800 feet along the Florida Keys in Monroe 

County. If the specific gravity of the ocean water is 

1.025, the head created by the pressure of the sea 

water would balance 15 feet of fresh-water head 

above sea level in the aquifer at a depth of 600 feet 

and 25 feet of head at a depth of 1,000 feet. The 

·artesian water is brackish, however, in this area, 

and the amount of artesian head required to balance 

the column of sea water would therefore be slightly 

less than that for fresh water. 

Along the coast from Miami to Palm Beach the 

artesian head is about 40 feet above sea level, which 

is sufficient to balance a column of salt water having 

a specific gravity of 1.025 to a depth of 1,600 feet. 

Above that depth, artesian water under that head in 

the aquifer would discharge into the ocean. Although the pressure will be somewhat less than 40 

feet at the submarine outcrop, it should be sufficient 

to cause artesian discharge into the ocean. From 

Miami to Key Largo, the altitude of the piezometric 

surface ranges from 40 to 20 feet, and the top· of the 

aquifer ranges from about 900 to 700 feet below sea 

level. South of Key Largo, it is about 600 feet below 

sea level, and the altitude of the piezometric surface 

ranges from 20 feet to less than 10 feet. South of 

Key Largo where the head is less than 15 feet above 

sea level and the top of the aquifer is more than 600 

feet below sea level, there is no artesian discharge, 

and salt water has moved into the aquifer. North of 

that area, artesian water is discharging into the 

ocean. 

North of Palm Beach the distance from the coast 

to the edge of the Continental Shelf increases. 

Lichtler (1960, p. 44) estimates that the aquifer 

crops out offshore about 25 miles east of Martin 

County and that the artesian head at the outcrop 

would be sufficient to cause artesian water to discharge into the ocean. However, he suggests that 

the outcrop is probably covered by relatively imper-
PRINCIPAL ARTESIAN AQUI~ER 161 

meable materials which could restrict discharge. 

This condition, however, appears unlikely on the 

steep slope at the edge of the Continental Shelf. 

East of the southern part of Brevard County, the 

edge of the shelf is about 35 miles from the coast in 

contrast to only a few miles at Palm Beach. At the 

Georgia-Florida line it is more than 75 miles east of 

the coast and at the Georgia-South Carolina line it is 

about 125 miles offshore. As shown on maps by 

Stringfield (1936, pl. 6) and by D. W. Brown, W. E. 

Kenner, and Eugene Brown (1957, fig. 28), the 

piezometric surface rises from 40 feet above sea 

level at Palm Beach to 50 feet in the southern part 

of Brevard County. This relatively high area of the 

piezometric surface suggests it might be due in part 

to the greater distance to the edge of the shelf and a 

point of discharge. Later maps (D. W. Brown and 

others, 1957, fig. 29, and Bermes, 1958b, fig. 7) 

show that the piezometric surface is less than 50 

feet above sea level in the southeastern part of 

Brevard County. Bermes shows that the piezometric 

surface slopes to the east from 40 to 30 feet in a 

narrow strip along the coast. These general features are shown in figure 29. 

In some parts of Brevard County the piezometric 

surface is relatively low because of withdrawal of 

water from wells. Bermes (1958b, p. 10, 24) believed, however, that the steep gradient along the 

east edge of the county probably is due to faulting 

along the coastal area. If the confining beds of the 

Hawthorn Formation were faulted, upward leakage 

might occur, but apparently the fault does not affect 

the overlying Hawthorn Formation that confines 

the artesian aquifer. Also, displacement of the formations which constitute the aquifer does not appear sufficient to affect the movement of water. 

Along the coast between southern Brevard County 

and St. Augustine, the piezometric surface decreases 

in altitude to about 10 feet above sea level in northern Brevard and Volusia Counties and increases to 

about 40 feet in St. Johns County north of St. 

Augustine (Tarver, 1958, fig. 7). 

The low piezometric surface in northern Brevard 

and Volusia Counties is due to discharge of artesian water through submarine springs and seeps. 

This area is on an arch on the east flank of the Ocala 

uplift where the top of the aquifer is not more than 

about 100 feet below sea level. One of the largest of 

these springs is about 21j2 miles east of Crescent 

Beach (Stringfield and Cooper, 1951c, p. 61) in St. 

Johns County. Matson and Sanford (1913, p. 236) 

described a spring offshore southeast of St. Augustine. A similar spring has been reported near Port 

Orange, south of Daytona. In that area the head is 

less than 10 feet above sea level, and because of this 

relatively low artesian pressure, discharge of springs 

may therefore not be notiCed. Two large submarine 

springs have been reported (D. W. Brown and 

others, 1962, p. 77) off the coast of Brevard County; 

one is about 20 miles east of Eau Gallie and the 

other is northeast of Cape Kennedy. The spring east 

of Crescent Beach and probably others in this area 

emerge through sinkholes, which become filled with 

sediments from the ocean floor if there is not sufficient artesian pressure to prevent such filling. 

Offshore northeast of the Savannah area, the original piezometric surface was less than 30 feet above 

sea level, indicating submarine discharge in an area 

where the top of the aquifer is not more than 150 

feet below sea level. Farther north along the coast 

at Parris Island, S. C., the Ocala Limestone, which 

represents the top of the limestone aquifer, is at or 

near the land surface. 

A map, figure 30, of the coastal area of northeastern Florida, Georgia, and southeastern South Carolina by Warren ( 1944, fig. 6) shows that prior to 

large withdrawal of artesian water, the piezometric 

surface along the coast was about 60 feet above sea 

level in northeastern Florida and southeastern Geor-

·gia. In Jacksonville (Matson and Sanford, 1913, 

p. 236), the original head was about 65 feet above 

sea level. Northward it decreased to about 30 feet 

above sea level in the Savannah area. 

In the Jacksonville area, the edge of the Continental Shelf is about 75 miles from the coast. If the 

structure is that inferred by Cooke and Mossom 

(1929, pl. 2) as shown in figure 4, the top of the 

aquifer crops out at the edge of the shelf at a depth 

of about 1,500 feet. Unpublished information (Ed 

Bradley, written commun., May 10, 1965) on a test 

well 62 miles offshore, however, indicated that the 

Ocala Limestone was reached at a ·depth of 504 feet 

below sea level. The back pressure of the salt water 

having a specific gravity of 1.025 at a depth of about 

500 feet is sufficient to balance fresh water in the 

aquifer, at a head of about 12.5 feet above sea level. 

Using a gradient (about 0.3 foot per mile) of the 

original piezometric surface of artesian water in 

northeastern Florida and southeastern Georgia, the 

loss of head in moving through 75 miles of the aquifer would be about 22 feet. That amount minus 60 

feet of head on the coast wouid leave 38 feet at the 

submarine outcrop. Under these conditions, the 

artesian water would have enough head to discharge 

at the submarine outcrop. If less favorable conditions exist and there is not sufficient fresh-water 
162 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

head to cause the artesian water to discharge at the 

outcrop, an isopiestic area would occur, and the 

fresh water would move upward through the overlying confining beds or to areas to the north and south 

where water discharges through submarine springs 

and other openings. 

At the present time, the withdrawal of artesian 

water in the coastal area of Georgia and northeastern Florida has lowered the head to an extent that 

there probably is not sufficient fresh-water head in 

the aquifer to discharge water at the edge of the 

Continental Shelf or northeast of Savannah where 

the aquifer is exposed to the sea. Warren stated that 

in the Savannah area (1944, p. 122-133) the cone of 

depression of the piezometric surface of artesian water extends to the former discharge area, which is 

now being recharged by ocean water. 

These geologic and hydrologic conditions along 

the Atlantic coast indicate that artesian water is 

moving eastward and discharging into the ocean except in some areas of large withdrawal of water 

where the cones of depression of the piezometric 

surface extend to the coast, such as at Savannah, 

Brunswick, and Fernandina. The water discharges 

through the submarine outcrop where the edge of 

the Continental Shelf is near the coast from the 

Florida Keys to Palm Beach. North of Palm Beach 

and Martin Counties, the distance from the coast to 

the edge of the shelf increases, and it appears that 

the artesian pressure of the fresh water is not sufficient to force water to the outcrop. Where the artesian pressure is low along the coast, such as from 

Cape Ker1nedy (formerly Canaveral) in Brevard 

County to St. Augustine and in an area northeast of 

Savannah, Ga., the area of discharge is within a few 

miles of the coast. Where the artesian pressure is 

relatively high as on the coast east of Jacksonville, 

Fla., the fresh artesian water moves eastward some 

·distance under the Atlantic Ocean and then moves 

upward through the overlying beds, or moves north or 

south approximately parallel to the coast to an area 

of discharge. 

SALTY GROUND-WATER AREAS RELATED TO THE 

PRINCIPAL ARTESIAN AQUIFER 

The relative amount of saltiness in water is commonly determined by the content of chloride ( C1), 

which is one of the two elements of sodium chloride, 

or common salt (N aCl), the principal constituent 

of sea water. 

Water having a chloride content of 500 ppm will 

ordinarily taste salty to many people. Water having a chloride content of 750 ppm or more has a 

marked salty taste. Water having a chloride content 

of 2,000 ppm is not suitable for many uses. The 

average chloride content of sea water is about 

19,350 ppm. 

CRETACEOUS FORMATIONS 

Cretaceous formations contain fresh water in a 

broad area between the Fall Line, where they are at 

or near the surface, and the coast. This area includes southeastern Alabama, Georgia, and South 

Carolina, except along the coast and in southeastern Georgia. The area of fresh water in the upper 

part of the Cretaceous may extend a short distance 

into western Florida from southeastern Alabama 

and Georgia. Fresh water extends to the coast of 

Parris Island, S.C.; the extent toward the coastal 

area of Georgia is unknown. However, the available 

records show no evidence of fresh ground water in 

the Cretaceous formations in southeastern Georgia. 

The chloride content of the salt water from some 

parts of the Cretaceous is much less than that of 

sea water, indicating that part of the connate water 

has been flushed from the aquifers. 

At Parris Island, S. C., records of two wells drilled 

by Layne Atlantic Co. at the U.S. Marine barracks 

11;2 miles west of Marine Corps headquarters reveal 

that fresh artesian water within the Tuscaloosa 

Formation of Late Cretaceous age is underlain and 

overlain by salt water. Well 1, which is 2,830 feet 

deep, was drilled in 1939, and well 2, which is 3,450 

feet deep, was drilled in 1940. Well 1 penetrated 

water of relatively high chloride to a depth of 2,500 

feet. However, sample 4, from a depth of 2,600 to 

2,811 feet, had a chloride content of only 82 ppm, 

as shown in the following table. 

Sample 

1 

2 

3 

4 

Analysis of water from wellt, Parris Island, S.C. 

Depth 

(feet) 

990-1149 

1850-1900 

1850-2500 

2600-2811 

[Constituents in parts per million] 

Car- Bicarbonate bonate Sulfate Chloride Fluoride 

(COs) (HCOa) (SO,) (Cl) (F) 

~------~---------- -------·---------- ---------------- 69 1,820 1 

8.500 

925 

485 

82 ------------------7 

Sample 1 was collected after the well was pumped 

several hours and all water-bearing formations were 

shut off above 990 feet. Static water level was 10 

feet below land surface. Sample 2 was collected after 

the well was pumped 24 hours and all water-bearing 

formations were cased off above 1,850 feet. Sample 

3 was collected after pumping 24 hours and waterbearing formations were cased off above 1,850 feet. 

Sample 4 was collected when strata were cased off 

above 2,600 feet. The artesian pressure was 49 

pounds at 11 feet above sea level. 

Well 2 was drilled 18 inches in diameter to a depth 
PRINCIPAL ARTESIAN AQUIFER 163 

of 2,450 feet. It was cored 95;11inches in diameter 

from 2,450 to 3,450 feet and underreamed 18 inches 

in diameter to 2,610 feet and 12 inches in diameter 

from 2,610 to 3,450 feet. The well was finished 

with 12-inch casing from the land surface to 2,610 

feet. The casing was grouted in with neat cement 

under pressure. Blank casing and screens 6 inches 

in diameter were set between 2,500 and 3,450 feet 

with No.4 and No.5 gravel used between the wall of 

the well and the screen. 

The following table gives a record of the depths 

below the land surface at which blank casing and 

screens are set in well 2. All measurements are in 

feet. No sand or gravel of any consequence was 

found between 3,430 and 3,450 feet. 

Depth 

Screen 

length 

Blankcasing 

length 

2,499.7.............. .................... 161.7 

~:~~t!:::::::::::::: ........ :~ ................ so ____ _ 2,751.4.............. 20 ---------- 2, 771.4 ...................... -......... 40 2,811.4.............. 20 .................. . 2,831.4.............. .................... 120 2,951.4.............. 20 .................. . 2,971.4.............. .................... 90 

3,061.4.............. 20 ................. .. 3,081.4.............. .................... 29 

Depth 

Screen 

length 

Blankcasing 

length 

3,110.4 .......... - 40 ··----- 3,156.4 ..... _______ ........ 111.3 

3,261. 7 .............. 20 ------- 3,281.7 .............. ------·-----·- 10 3,291.7.............. 10 ................... . 3,301.7.............. .................... 15 3,316.7.............. 20 ................... . 3,336.7.............. .................... 23.3 3,360.0.............. 70 .................. .. 3,430.0 .................................................... .. 

Tests "Yere made on well 2 to determine the flow of 

water and chloride content of samples at depths of 

2, 723 feet below the land surface, as shown in the 

following table. A packer connected by a 3-inch 

welded line to the end of the 41;2-inch drill pipe was 

inserted in the 6-inch blank casing of the well at 

depths shown. Water below the packer flowed to the 

land surface through the drill pipe; water above the 

packer flowed to the surface through the 12-inch 

casing of the well. Chloride analyses were by P. H. 

Shuey, Savannah, Ga. 

Chloride content Flow 

Depth to top (ppm) (gpm) 

of packer 

(feet) Above Below Above Below 

packer packer packer packer 

2,723 ................................ 88 1,328 112 174 

2,784 ........ -...................... 388 1,336 150 174 2,916 .... __________________ 92 1,368 160 174 

3,033 ................................ 304 1,420 160 160 

3,091._ ............... - .......... 664 1,416 230 140 

3,222.-............................ 1,144 1,024 480 26 

3,286 .... - ......................... 1,128 774 480 25 

3,309 ................................ 1,134 696 485 10 

3,346 ........ - ..................... 1,128 722 480 9 

Artesian water below the casing from depths of 

2,610 to 3,450 feet was reported to have a pressure 

of 60 to 65 psi and a temperature of 103° to 109°F. 

The well was pern1anently plugged from 2,950 feet 

to the bottom to stop the flow of the water of relatively high chloride content. The well was then reported to have a flow of 80 to 100 gpm ·with a 

chloride content of about 42 ppm. According to 

analyses of a sample collected in 1954 from each 

well reported by Siple (1957b, table 4), well 1 had 

a chloride content of 10 ppm, and well 2 had a 

chloride content of 58 ppm. 

Samples of cuttings from rotary drilling to a 

depth of 2,400 feet and of cores from 2,441 feet to 

the bottom in well 2 were studied by several geologists and paleontologists, including John B. Reeside Jr., J. A. Cushman, L. G. Henbest of the U.S. 

Geological Survey, R. S. Bassler of the National 

Museum, Miss Winnie McGlamery of the Alabama 

Geological Survey, and several micropaleontologists 

of oil companies. The log of the lower part of the 

well, by Miss McGlamery, is published in a paper 

by Munyan ( 1943, p. 596-607). 

Log of Well2, Parris Island, S.C. 

[Prepared by John B. Reeside, Jr.; no samples, 0-100 ftl 

Sample Depth Description 

(feet) 

Cuttings: 

1-3 

4-11 

12-16 

17-23 

24-26 

27-29 

30-43 

44-46 

47-50 

51-52 

53-57 

Jackson age (Ocala Limestone) 

100-140 

140-300 

300-410 

410-550 

550-610 

610-654 

Coquina of bryozoans and other organisms, light-gray to white. 

Limestone, light-gray, fine-grained; 

some of it finely granular. 

Limestone, light-gray, finely granular. 

Limestone, light- to brownish-gray, 

granular; contains some fine sand. 

Limestone, light- brownish- gray 

granular, glauconitic, sandy. 

Probably limestone, light-brownishgray, granular, glauconitic, sandy. 

Probably Claiborne and Wilcox age 

654-926 

926-970 

970-1030 

1030-1070 

1070-1165 

Sandstone, calcareous, light-yellowish-gray, glauconitic. 

Glauconite zone, in part light-gray 

sandy limestone; basal part, to 

judge by sample, a nearly ·pure 

glauconitic rock having grains up 

to 4 mm in diameter. 

Limestone, light-gray, calcareous, 

very sandy. 

Sandstone, light-gray; apparently 

loosely cemented; grains average 

0.2mm. 

Limestone, creamy-white, compact; a · 

little glauconite and coquina. 

Midway age 

58-67 1165-1325 Sandstone, light-gray, fine-grained, 

calcareous. 

Peedee-Black Creek age 

68-125 1325-2395 Silt, medium-gray, fine; some pyrite 

in small masses and a little ferruginous sandstone; some flaky 

medium-gray shale, and some clay. 

2395-2441 No samples. 
164 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Sample 

Cores: 

Depth 

(feet) 

Description 

Eutaw age 

1-8 2441-2579 Clay, olive-gray, with layers and 

filled borings of fine-grained soft 

micaceous light-colored sandstone; 

some layers of very hard, calcareous sandstone; some layers of fine 

silt; some layers glauconitic. 

9-15 2599-2666 Sandstone, light-gray, fine-grained, 

loosely cemented, micaceous; and 

some clay and silt of medium-gray 

color, in thin layers. 

Tuscaloosa age 

16-29 2672-2960 Clay, greenish-gray, waxy; contains 

small aggregations of pyrite and 

scattered quartz grains up to 2 

mm in diameter. Coarse-grained 

(grains up to 1,4 in.), subangular, 

largely of quartz, friable, lightgreenish-gray grit. Greenish-gray 

and maroon micaceous silt. Red 

and green sandy clay. All repeated 

many times. 

30 2966 Mudstone, medium-gray, rather hard, 

marine fossiliferous. 

30-37 2970-3108 Like interval 2672-2960, with some 

maroon and purple coloring. 

38-45 3123-3245 Clay, medium-gray, with small 

pockets of fine light-gray sand. 

Light-brownish-gray grit (grains 

up to 2 mm); coquina of molluscan 

fragments.. Silty, fine-grained 

light-gray sandstone; sandy brownish-gray glauconitic limestone. 

These make up a marine fossiliferous zone. 

46-55 3250-3454 Interval much like interval 2672-

2690 with more coarse materials. 

Pebbles up to 30 · mm in some 

samples. 

Records of the two deep wells show that the water 

sample having the highest chloride content, 8,500 

ppm, was collected in the interval between 990 and 

1149 feet deep from formations of middle and early 

Eocene age. The chloride content of water samples 

from formations of Cretaceous age in both wells. 

ranged from 82 to 1,420 ppm. Relatively impervious 

beds in the upper part of the Cretaceous retard 

the upward movement of artesian water and protect it from salt water in the underlying formations. 

The artesian pressure has been sufficient to flush 

connate water from the more permeable beds 

and to prevent sea water from moving into the beds 

of Cretaceous age at Parris Island. The pressure 

at the top of the Cretaceous is reported to be about 

40 psi at the land surface about 10 feet above sea 

level. This pressure is equivalent to 102.4 feet of 

water at sea level ( 40 X 2.31 + 10) and is sufficient 

to balance a column of sea water (specific gravity 

1.025) to a depth of about 4,010 feet below sea level 

(102.4 X 40). The pressure in the Tuscaloosa is 

reported to be 60 or 65 psi. 

The extent of the fresh water in the Cretaceous 

aquifers along the coast north and south of Parris 

Island is not known, but from available information 

it probably does not extend far in either direction. 

The records are not sufficient to show whether the 

fresh water in the Cretaceous aquifers in the interior extends as far south as northern Florida. 

The area of fresh water may extend from southwestern Georgia and southeastern Alabama into 

Florida where the Eocene formations are at or near 

the surface. 

The extent of the fresh water in the Cretaceous 

aquifers east of the South Carolina and Georgia 

coast is not known. Although some of the Eocene 

formations may crop out at the edge of the Continental Shelf, the slope beyond the edge of the shelf is 

interrupted by the Blake Plateau, an extensive terrace more than 150 miles wide at depths of 400-500 

fathoms (G. F. Jordan, 1962, p. 11). In the absence 

of structure which would decrease or reverse the 

dip, the Cretaceous formations would crop out at the 

east edge of tpe plateau. Under these conditions, 

the artesian head would not be sufficient to discharge 

water at the submarine outcrop. 

An oil test well, 7 miles west· of Savannah, at 

Cherokee Hill (Warren, 1944 p. 17, 127), 21.5 feet 

above sea level, was dr:illed to a depth of 2,130 feet 

in 1920 and penetrated chiefly limestone from 250 

to 870 feet, limestone and chert from 870 to 950 

feet, and marly limestone from 950 to 1,000 feet. 

Below 1,000 feet the material penetrated ·consists 

chiefly of marl and fine quartz sand from 1,980 

to 2,035 feet, which was the source of the salt water. 

The well was cased with 24-inch casing to 27 feet, 

18-inch casing to 107 feet, 15-inch casing to 250 

feet, 12-inch casing to 1,426 feet, 10-inch casing to 

1,630 feet, and 8-inch casing to 2,126 feet. At 2,000 

feet, it penetrated a sand containing salt water 

under sufficient pressure to overflow at the land surface. The well was flowing about 1 to 2 gpm from 

the spaee between the 10-inch and 8-inch casings 
PRINCIPAL ARTESIAN AQUIFER 165 

and returning to the well outside the 10-inch casing 

in 1939 when visited by M. A. Warren and the 

writer, but the casing of the well was in such poor 

condition that the shut-in pressure could not be 

determined. Later the casing at the surface was 

destroyed in the construction of an airport. The 

chloride content of the water was 2,4 75 ppm. The 

head of the principal artesian aquifer at the well 

was about 2 feet above sea level. The extent t.o 

which this salt water has contaminated the surficial 

aquifer and the principal artesian aquifer was not 

determined. Probably salt water underlies the Savannah area, but relatively impervious beds separate the salt water from the formations which form 

the principal artesian aquifer. 

The ages of the formations penetrated, as indicated by the record of the Georgia Geological 

Survey, are as follows: 

Depth 

Ago (feet) 

Miocene nnd younger---·------··········-----------------------:··------ 0- 250 

Oligocene and lute Eocene -------·······---------------------------· 250- 610 

Middle nnd early Eocene ---·------------------------------------------ 610-1400 

Paleocene ---------------------------·-----------···········-----------------·-·-- 1400-1680 

Cretaceous -----------------------------------------------------·-···········-·-· 1680-2130 

Herrick (1961, p. 101-103) reported a log of a well 

(GGS 506) 1,088 feet deep at an altitude of 43 feet 

above sea level at Cherokee Hill as follows: 

De1Jth 

Ago (feet) 

Pliocene to Recent ...... -----------------------············-···---------- 0- 47 

Miocene -----------·------------------------·-········---------------------------- 223- 270 

01 igocen e -------------------------···---------------------------------------·---- 2 70- 358 

Late Eocene (Ocala Limestone) -------------------------------- 358- 730 

Middle Eocene (Lisbon Formation) .. -------------------- 730-1000 

Middle Eocene (Tallahatta Formation) ------------------ 1,000-1088 

Wait (1960c, p. 28-29) reported that an oil test 

well, the J. W. West 1 in northwestern Calhoun 

County, reached salt water at a depth of 2,800 feet 

in the Upper Cretaceous rocks. On the basis of the 

electric log of the well, S. M. Herrick of the U.S. 

Geological Survey believed that salt water may 

have been reached at a depth of about 2,080 feet. 

The J. R. Sealy oil test well drilled just east of Calhoun County in southwestern Dougherty County, 

Ga., produced water at a depth of 1,200 feet that 

contained 435 ppm chloride, 586 ppm of sodium, 

and 820 ppm of bicarbonate. Records of a few test 

wells for oil in Florida give information on salt 

water in the Cretaceous formations. 

An analysis (Parker and others, 1955, p. 65) 

of a sample of water from a depth of 3,000 feet in 

a well (S-396, Cory 1) in Dade County, Fla., shows 

a chloride content of 14,200 ppm and total dissolved solids of 29,460 ppm, which is somewhat less 

than the average for sea water. According to a log 

of the well by Applin and Applin (1944, p. 1750), 

the sample is from the Oldsmar Limestone of early 

Eocene age. Four samples from depths of 9,500 to 

9,987 feet in Lower Cretaceous limestone under 

anhydrite had a chloride content which ranged 

from 11,200 ppm at 9,500 feet to 24,600 ppm at 

9,550 feet. The samples from depths of 9, 772 and 

9,987 feet had chloride contents of 15,000 ppm and 

17,100 ppm respectively. 

The record of a well (Cooke and Mossom, 1929, 

p. 44) 6,180 feet deep, penetrating basement rocks 

at about 4,000 feet, in sec. 10, T. 16 S., R. 20 E., 

in Marion County, Fla., in 1928 showed no record of 

salt water. A geophysical probe by J. H. Swartz 

and G. R. McCarthy (written commun., Nov. 1937) 

to a depth of 3,000 feet by a surface electricalresistivity method at the site of the well showed no 

evidence of salt water. However, Gunter (1949) 

reported that ·salt water was reached in 1947 at a 

depth of 4,637 feet in Candler well, sec. 16, T. l6 S., 

R. 23 E., Marion County. Salt water was reached 

at a depth of 2,470 feet in the Oldsmar Limestone 

of Eocene age in a well in Lake County. A sample 

from a depth of 3,419 feet in the Upper Cretaceous 

near the contact with the overlying Paleocene had a 

chloride content of 58,100 ppm. 

These records show that salt water is present in 

most, if not all, of the Cretaceous formations in 

Florida, except possibly in an area in western Florida where the top of the Cretaceous is less than 2,000 

feet below sea level, near the Alabama and Georgia 

State line, and possibly a small area in Marion 

County in central Florida, where the top of the 

Cretaceous is about 2,200 feet below sea level. 

TERTIARY AND QUATERNARY FORMATIONS 

The principal artesian aquifer, consisting chiefly 

of limestone ranging from middle Eocene to and 

including the lower part of the Hawthorn Formation 

of late Miocene age and aquifers within the Hawthorn Formation, contains water having a chloride 

content of 100 ppm or more in some areas (fig. 36). 

In Florida, the map of these areas is essentially the 

same as one prepared in 1934 by Stringfield (1936, 

pl. 16). A later map of Florida by Shampine (1964) 

gives more details. In the coastal areas and in 

southern Florida and the upper part of the St. 

Johns River valley south of Palatka, water having 

a relatively high chloride content is present in all 

the Tertiary formations. Hendry and Lavender 

(1957, p. 29-178; 1959, p. 28-29) included information on chloride in samples of water from many 

wells in the area of artesian flow in Florida. In 

the interior, salt water has been recorded in sev-
166 

28·r-----

27"r-----

26·r-----

ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

G {J .l 

p 

0 

/r> 

EXPLANATION 

D 

Area of water having low chloride content-water having chloride content 

of more than 100 ppm may be expected only locally in the lower part 

of the aquifer, generally in coastal areas 

Areas where water throughout the 

principal artesian aquifer may contain more than 100 ppm chloride 

Areas where water only in the upper 

part of aquifer contains less than 100 

ppm of chloride 

50 0 50 100 MILES 

., 

FIGURE 36.-Map sh?wing areas where water of the principal artesian aquifer has more than 100 ppm of chloride. 
PRINCIPAL ARTESIAN AQUIFER 167 

eral areas including the early Eocene and Paleocene 

formations in Lake County, Fla., and western Florida and in middle Eocene rocks near Thomasville, 

Georgia. 

Unpublished analyses of nine samples of water 

from depths of 1,408 to 3, 700 feet in the South Lake 

well, J. Ray Arnold 1, Florida Geological Survey 

W-275, sec. 17, T. 24 S., R. 25 E., 12 miles south of 

Groveland, Lake County, give the most complete 

information available on the salinity of the water 

from the lower part of the Tertiary and upper part 

of the Cretaceous formations in central Florida. 

The well was started in February 1935 and completed in May 1937 by the Oil Development Co. of 

Florida. It was drilled to a depth of 6,129 feet from 

the surface, which was 113.66 feet above sea level. 

The chloride results given in the following table 

are in the open files of the U.S. Geological Survey in 

Washington, D.C., and Tallahassee, Fla., and the 

Florida Geological Survey in Tallahassee, Fla. The 

geologic correlations used in the following table are 

from a log of the well by Applin and Applin (1944, 

p.1748): 

Chloride content of water samples from South Lake well, 

Lake County, Fla. 

[Chemical analyses by M.D. Foster, U.S. Geol. Survey] 

Depth Chloride 

Snmple (feet) (ppm) Remarks 

1 1,408-1,416 20 Water from artesian flow, Lake City Limestone 2 2,258 781 Sample collected after 48 hours of bailing, Oldsmar Limestone 

3 2,300 6,020 Oldsmar Limestone 4 2,352 6,290 Oldsmar Limestone 

5 2,470 23,020 Oldsmar Limestone near contact with 

Cedat• Keys 6 2,590 310 Cedar Keys Limestone 7 2,593 12,000 Cedar Keys Limestone 

8 3,419 58,100 Upper Cretaceous, Lawson Limestone 

9 3,700 13,650 Upper Cretaceous, Lawson Limestone 

NoTg.-Samplcs 3 to 9 inclusive were collected by drill-stem tester with 

bottom of tester set at depth shown, except for sample 4, which came from 

depth of nbout 2,352 feet when tester was set at 2,312. 

J. L. McCord of the Oil Development Co. of Florida indicated that sample 8 was collected from 

oolitic limestone under anhydrite. The log by Applin and Applin ( 1944, p. 17 48) shows oolitic limestone in the .lower part of the Cedar Keys Limestone in contact with the underlying Upper Cretaceous at a depth of about 3,365 feet. This indicates 

that the brine represented by sample 8 is at or near 

the contact of the Tertiary (Paleocene) with the 

Cretaceous. It seems possible that the relatively 

low chloride content of water sample 9 from the 

Cretaceous and sample 6 from the Tertiary limestone in the South Lake well in Florida may have 

been due to inadvertent mixing with fresh water 

when the sample was collected. If the samples are 

representative of the aquifers from which they were 

collected, the relatively low chloride contents of 

the samples 6 and 9 suggest that the aquifers from 

which they were collected are more permeable than 

the underlying and overlying formations that yield 

water having a higher mineral content. 

The fresh-water head in the artesian aquifer in 

the area is about 90 feet above sea level. This head 

is sufficient to hold the fresh-water contact with 

the salt water at a depth of 3,600 feet, if the fresh 

water were in equilibrium with the water in the 

Gulf of Mexico or the Atlantic Ocean. The chloride 

content of the water shows that the water in the 

principal artesian aquifer is separated from the underlying salt water by relatively impervious beds 

and that the Florida peninsula is not a fresh-water 

lens floating on salt water, as has been supposed 

by some investigators. 

In the coastal area of South Carolina, Siple 

(1957b, p. 18-22) has described salt-water encroachment in Parris Island, S.C., where some of the 

water in the Tertiary aquifer in the area has a 

chloride content of more than 100 ppm. 

Savannah Area, Georgia and South Carolina 

Counts and Donsky (1959, p. 101) reported that 

the chloride content of samples ·of water from test 

wells on Hilton Head Island and Daufuskie Island, 

S.C., and on Cockspur Island, Ga., increased with 

depth and with time. The highest chloride sampled 

on September 30, 1957, from the Cockspur test was 

40 ppm in a sample from a depth of 695 feet. A 

sample from that depth had 675 ppm chloride on 

January 6, 1959. At Hilton Island, the highest 

samples in June 1957 were 290 ppm at a depth of 

609 feet and 1,950 ppm at 693 feet. On January 

6, 1959, the water was 535 ppm at 609 feet and 2,020 

ppm at 693 feet. Counts and Donsky (1959, p. 101; 

1963, p. 75) concluded that the relatively high 

chloride content is from Pleistocene sea water or 

older sea water that has not been flushed out of the 

aquifer. Judging from the available information, 

this conclusion is reasonable. 

At Savannah, the cone of depression in the piezometric surface of artesian water extends to the 

coast and has reversed the movement of the water 

in the aquifer. Under these conditions, salt water 

in the aquifer and sea water which enters the aquifer will move westward into the Savannah cone. As 

stated by Warren (1944, p. 122-133), any lateral 

movement of the salt water would be only a few 
168 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

feet a year and there. would be time to reduce withdrawal of water and stop the encroachment before 

it moves far inland. Adequate observations to detect encroachment therefore should be continued 

in the area. 

Along the coast from the Savannah area to St. 

Johns County, Fla., north of St. Augustine, Fla., 

water in the principal artesian aquifer has a chloride 

content of less than about 50 ppm. In much of the 

area, it is less than 20 ppm (Collins and Howard, 

1928, p. 213, 222). Water having a relatively high 

chloride content, however, is present in the limestone under the aquifer. A few wells about 1,000 

feet deep have penetrated water in limestone having a chloride content higher than that in the 

overlying aquifer. Warren ( 1944, p. 134) reported 

that a test well drilled for oil to a depth of 4,829 

feet about 4 miles northwest of Hilliard in Nassau 

County, Fla., penetrated limestone between 412 and 

3,460 feet, with salt water at a depth of about 2,100 

feet in the Oldsmar Limestone of Eocene age (Applin and Applin, 1944, p. 145). 

Brunswick, Ga. 

At Brunswick, Ga., about 40 miles northeast of 

the well at Hilliard, J. W. Stewart (1960, p. 19) 

reported that water from an artesian well, drilled 

to a depth of 1,063 feet in 1939, had a chloride 

content of 69 ppm. A sample from a water well 

completed at a depth of 1,057 feet in 1942 had a 

chloride content of 146 ppm. After the well was 

plugged at a depth of 1,000 feet additional samples 

were collected at the overflow of a small-diameter 

pipe lowered to different depths in the well. At 

depths ranging from 7 43 to 943 feet, the samples 

showed an increase in chloride from 465 to 545 

ppm. A sample from 960 feet had a chloride content of 112 ppm. Other wells 900 to 1,026 feet deep 

have not shown marked changes in the chloride 

content of the water for the period of record, 1943 

to 1958. Water having a chloride content ranging 

from 138 to 430 ppm between beds of hard dense 

cherty dolomitic limestone was penetrated by a 

group of wells at depths between 1,014 and 1,062 

feet at Brunswick (Wait, 1962a, p. 42). Another 

well did not, however, penetrate water having a 

relatively high chioride content before it reached a 

depth of 1,743 feet. Thus the zone at depths of 

1,014 to 1,062 feet is probably limited in lateral 

extent. 

Exploration of an oil test well drilled to a depth 

of 4,615 feet (Wait and McCollum, 1963) revealed 

that water having a relatively high chloride content 

is flowing upward from aquifers below about 

2,000 feet into the principal aquifer between 610 and 

920 feet. This probably is the source of the relatively 

high chloride content in some of the wells in the 

area. Water overflowing from the oil test well at 

the land surface contains as much as 7, 780 ppm 

chloride. 

Because the fresh-water head of the artesian water between Brunswick and the coast is sufficient 

to prevent lateral encroachment of sea water, it is 

concluded that the high chloride content of the 

water entering the wells is from remnants of connate water in the underlying formations. The concentration and distribution of this water is controlled in part by the extent to which the formation 

has been flushed of its salt water. The flushing depends ·in part on the permeability, recharge, and 

discharge of the water-bearing formation, and the 

artesian head. In general, the deeper formations 

have a higher artesian head than the overlying 

aquifers, from which salt water (connate water) 

has been completely flushed. The opportunity for discharge was, however, better in the overlying aquifers. The exception to this generalization is at 

Parris Island, S.C., where deep Cretaceous sands 

have been completely flushed of salt water but the 

overlying sands contain ·salt water. Investigations 

(J. W. Stewart, 19·60, p. 40; Wait, 1962a, p. 44) 

are continuing in the Brunswick area to obtain 

more information on the occurrence, distribution, 

and concentration of the salt water underlying 

the fresh-water aquifer. 

If there are only small areas of water of relatively high chloride content under low pressure, it 

may not be difficult to control the problem. If there 

are large quantities of such water under high pressure throughout the area, however, it may seriously 

affect the future potential of the fresh-water aquifer of the area, even though it is expected that the 

maximum concentration of the salt water will be 

less than sea water. In order to protect the aquifer, 

it would be necessary to limit the depths of wells 

and reduce the draft wells in which the chloride 

content of the water shows an increase above the 

normal for the aquifer. Special care will have to 

be taken because the wells generally are not cased 

below the top of the aquifer and one well pumping 

salt water may contaminate a large part of the 

aquifer. Wells that reach salt water will contaminate the overlying fresh water if the salty part is 

not properly plugged. 
PRINCIPAL ARTESIAN AQUIFER 169 

East Coast of Florida 

The artesian water along the coast in Florida 

from northern St. Johns County to and including 

the Florida Keys and in the upper part of the St. 

Johns River valley has a chloride content of more 

than 100 ppm. Within these areas of water of 

relatively high chloride content, there are areas of 

low chloride content, as in Putnam and Volusia 

Counties, where the piezometric surface is relatively high and where local recharge has flushed out 

the salt water from the aquifer. Salt Springs in 

Marion County, one of the large springs in the 

peninsula, yields salty water. There are many small 

salt springs along the valley of the St. Johns River 

from Putnam County to Brevard County. 

The area of water of relatively high chloride content extends from the east coast through the southern part of Florida and occupies a narrow belt on 

the west coast. There are salt springs in Sarasota 

County and along the coast in Citrus and Levy Counties. An area in Anna Maria Key in Manatee 

County is the only one in which the salt water in 

the Tertiary aquifer is more concentrated than sea 

water. This condition appears to be due to concentrations of salt by evaporation of sea water at the 

time the formation was deposited. 

NASSAU COUNTY 

At Fernandina in Nassau County, salt water 

underlying the aquifer has been reached by a few 

deep wells, indicating that the Oldsmar Limestone 

and possibly the lower part of the Lake City Limestone have not been completely flushed of the salt 

water which entered the formation prior to Recent 

time. Leve (1961b, p. 15) reported that the chloride 

content of water samples from wells less than 1,400 

feet deep ranged from 26 to 41 ppm and samples from 

wells 1,400 to 1,826 feet deep ranged from 50 to 1,060 

ppm. However, the chloride content of samples from 

one well, 1700 feet deep, ranged only from 38 to 52 

ppm. 

The chloride content of water samples from a 

well 2,100 feet deep (Leve, 1961b, fig. 7), collected 

during construction at 10-foot intervals between 

1,230 feet and 1,450 feet, ranged from less than 100 

ppm to more than 500 ppm, indicating a local zone 

of water of high chloride content in the lower part 

of the aquifer. As the wells are not cased in the 

aquifer, the water having a relatively high chloride 

content may have moved upward through a well. 

The bottom of the well is in the Lake City Limestone 

which contains salt water at a depth of 2,100 feet 

at Hilliard, Fla., as reported by Applin and Applin 

(1944, p. 1745). 

ST. JOHNS COUNTY 

A map of the distribution of the chloride water in 

St. Johns County (Tarver, 1958, fig. 11) shows the 

north limit of artesian water having a relatively 

high chloride content in Florida. The chloride contents of samples from most of the water wells range 

from about 10 ppm in the northwestern part of St. 

Johns County to about 3,000 ppm in the southern 

part of the county in the area of Crescent Beach. 

The minimum and maximum samples were less than 

3 ppm near Switzerland and in the northwestern 

part of the county and 7,200 ppm 2 miles west of 

Crescent Beach in the southeastern part of the 

county. The salinity increases with depth. The 

wells in the principal aquifer range in depth 

from about 150 to 900 feet, but most of them are 

less than 350 feet. Water from wells less than 350 

feet has a maximum chloride content of 500 ppm. 

Tarver recognizes a general correlation between 

the piezometric surface and the chloride content of 

the water. The areas of relatively high chloride 

content correlate with those of relatively low pressure, and areas of low chloride content correlate 

with those of high pressure. As he suggests, the 

correlation may indicate one or more of the following: ( 1) The aquifer has been flushed less in lowpressure areas, (2) higher artesian pressure in the 

deep zones causes salt water to move upward, and 

(3) Pleistocene seas encroached farther into the 

aquifer where the piezometric surface is low and the 

flushing is less advanced downgradient. There is 

also the possibility that wells in low pressure areas 

were drilled deeper than in high pressure areas. In 

the Hastings area where artesian water is used for 

irrigation, the increase in the salinity of the water 

indicates that water having a chloride content of 

as much as 2,500 ppm is being drawn up from deeper 

zones in areas of greatest water use. The salinity is 

highest during the irrigation season when the wells 

are pumped. 

As chloride and sulfate ions are present in the 

artesian water throughout St. Johns County but in 

different proportions in the north and south sections, Tarver (1958, p. 29) used the ratio of these 

ions to indicate the possible source of the chloride 

water. He found that the ratio of chloride to sulfate 

in the high chloride water in the southern part of 

the county was 7 to 1, which is approximately the 

same as sea water. In the northern part of the 

county, the ratio of chloride to sulfate is reversed, 
170 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

indicating the presence of anhydrite or gypsum in 

the limestone-aquifer. 

One area where the artesian pressure is lowest 

in the area of highest chloride content is where 

submarine discharge occurs through springs, such 

as the large spring 21;2 miles east of Crescent Beach 

(Stringfield and Cooper, 1951c). Since the freshwater head of 15 feet is sufficient to prevent lateral 

encroachment of sea water to a depth of about 600 

feet and water of high chloride content is present 

at shallower depths in the aquifer, it is concluded 

that the salt water entered the aquifer during a 

high stand of the sea in Pleistocene time when the 

sea covered the area. At that time, the aquifer was 

exposed to the sea in a channel in the valley of the 

St. Johns River which was cut below present sea 

level when the Pleistocene sea stood as much as 300 

feet below present sea level. The channel probably 

cut into the aquifer in its course from St. Johns 

County to Brevard County where the top of the 

aquifer is now less than 200 feet below sea level. 

There were also sinkholes and other solution depressions through which salt water could enter in that 

area extending east of the present coastline. Submarine springs discharge through some of these 

sinkholes at the present time. North of St. Johns 

County the aquifer was overlain by a thickness of 

· as much as 500 feet of the Hawthorn Formation 

and, therefore, was not exposed to sea water during 

Pleistocene time. The low chloride content of water 

in the aquifer in some parts of north-central Florida 

and in some other areas where it was exposed to 

Pleistocene sea water shows that the connate water 

as well as the Pleistocene water has been flushed 

from some parts of the aquifer. 

In the area of water of relatively high chloride 

content in southern Florida, the aquifer is overlain 

by about 500 feet of the Hawthorn Formation 

which protected it from contamination from Pleisto~ cene sea water when the Pleistocene seas covered 

that part of the State. The chloride probably is 

from salt water that entered the formation before 

Pleistocene time. 

. PUTNAM COUNTY 

In Putnam County, as stated by Leve (1958, 

p. 24), the saline water in the aquifer appears to be 

due principally to sea water which entered the aquifer during Pleistocene time when the sea stood above 

its present level and much of the present land was 

inundated (Cooke, 1939, figs. 12-16). After the 

Pleistocene seas receded, fresh water circulated 

through the aquifer and flushed it of salt water, 

· except in local areas. Leve reported that the chloride 

content of samples from more than 160 wells in the 

principal artesian aquifer ranged from less than 2 

to 1,080 ppm. Although the wells range in depth 

from 130 to 460 feet, most of them are 180 to 300 

feet deep. Leve's map (1958, fig. 10) shows that 

the chloride content of water in the artesian aquifer 

is 50 ppm or less in the northwest half of the 

county and in an irregular area surrounded by water of relatively high chloride content in the southeastern part of the county and northwestern part of 

Volusia County. A comparison of this map with the 

map of the piezometric surface shows that the water 

having a small chloride content is in and near recharge areas, thus indicating flushing has been more 

thorough in the recharge areas. The highest chloride ( 500 ppm or more) is in an area in the vicinity 

of Welaka, where natural discharge from springs 

in the St. Johns River maintains a depression in 

the piezometric surface. Also, the chloride is relatively high (250 to 500 ppm) in a vegetable farm 

area, east of Palatka, where discharge from many 

irrigation wells during irrigation season lowers the 

piezometric surface, which in turn results in sale 

water moving upward into the fresh-water zone. 

This correlation of the low chloride areas with recharge areas of Putnam, Seminole, and Volusia 

Counties was recognized in 1934 by Stringfield 

(1936, p. 162) when he mapped the piezometric 

surface of the artesian water and the area of water 

of relatively high chloride content in the Florida 

peninsula. 

Leve (1958, p. 27) found that water from shallow 

wells in Miocene or Pliocene beds of mud and shells 

overlying the principal aquifer has a chloride content of less than 30 ppm, but a sample from one of 

the wells had a chloride content of 3,840 ppm. 

These beds probably have not been flushed as much 

as the more permeable limestone aquifer. 

FLAGLER COUNTY 

Bermes ( 1958a, p. 24) reported that the chloride 

content of the artesian water in the principal aquifer in Flagler County ranges from 15 ppm in recharge areas, as near Espanola, to more than 4,400 

ppm southwest of Bunnell, where water levels are 

lowered by irrigation. The wells range from 55 to 

555 feet in depth. His map of the chloride content 

of water from artesian wells shows that the chloride 

is lowest, 25 ppm or less, in a recharge area in the 

north-central part of the county between 1 and 2 

miles wide and about 4 miles long, extending from 

the Espanola area. Around that area, the chloride is 

25 to 100 ppm. That zone extends southeastward 
PRINCIPAL ARTESIAN AQUIFER 171 

and includes all the southern part of Flagler County. 

The chloride water in the northeastern part of the 

county ranges from 100 to 750 ppm. The chloride 

water extends as a narrow belt to the central part of 

the county near Bunnell ; from Bunnell it extends 

to the southwestern part of the county. Water in an 

area southwest of Bunnell has a chloride content of 

2,000 or more ppm. That area is surrounded by a 

zone in which the chloride content of artesian water 

ranges from 750 to 2,000 ppm. 

Bermes ( 1958a, p. 29) found that west of Bunnell 

the highest chloride content was in water from the 

deeper wells, but southwest of Bunnell, the highest 

chloride content comes from some of the shallower 

wells. West of Bunnell, and near Codys Corner, the 

chloride content is highest when the withdrawal of 

ground water is greatest and water levels are lowest. The chloride increased from 300 to 2,100 ppm 

when the water level declined 10 feet. The chloride 

content decreased to about 550 ppm when the water 

level recovered about 10 feet. 

VOLUSIA COUNTY 

Volusia County is one of the areas in which the 

correlation of the differences in salinity of the water 

with the piezometric surface was made in 1934 

(Stringfield, 1936, p. 162). Wyrick and Leutze 

(1956) and Wyrick (1960) made detailed studies of 

the area and confirmed the conclusions reached in 

1934. The wells range in depth from less than 100 

to 480 feet. 

A map of the county by Wyrick (1960, fig. 21) 

showed that in recharge areas where the piezometric 

surface is highest the chloride content is less than 

25 ppm. In most of the county, the chloride content 

ranges from 25 to 250 ppm. In a narrow belt 

along the St. Johns River and in a few places along 

the coast, as at New Smyrna Beach and the southeastern part of the county, the chloride content 

ranges from 250 ppm to more than 1,000 ppm. A 

section from the St. Johns River valley across the 

county to the Atlantic Ocean shows the chloride 

content of the water to a depth of 800 feet (Wyrick, 

1960, fig. 22). In the area where the piezometric 

surface is 60 feet above sea level, the water having a 

chloride content of less than 25 ppm extends to a 

depth of about 500 feet. The chloride ranges from 

25 to about 1,000 ppm between about 500 and 700 

feet. Below 700 feet, the chloride is 1,000 ppm or 

more. In the. St. Johns River valley and on the east 

coast where the piezometric surface is only a few 

feet above sea level, artesian water having a chloride 

content of 1,000 ppm or more is present throughout 

the aquifer. In the eastern part of this section 

where there is no local recharge, test wells show 

that water having a chloride content of less than 70 

ppm is present to a depth of about 500 feet about 7 

miles west of the coast, but the level of the water 

having a higher chloride content rises to the top of 

the aquifer near sea level where the artesian water 

discharges into the ocean. 

Wyrick (1960, p. 44) stated that the salt water in 

the St. Johns River valley moves upward along a 

fault. As shown by the piezometric surface of the 

artesian water, the upward leakage of salty artesian water in the St. Johns River, however, occurs 

for many miles where the top of the aquifer is near 

sea level and the confining beds were removed by 

erosion and solution. Under these conditions, there 

is no need to postulate a fault to explain the upward 

leakage of the artesian water. 

SEMINOLE COUNTY 

Heath and Barraclough (1954, p. 33) found that 

the chloride content of samples from 637 wells in 

Seminole County generally ranged from 5 to 5,000 

ppm. Artesian wells in the county range in depth 

·from 50 to 1,222 feet. More than 95 percent of the 

wells, however, are between 75 and 250 feet in 

depth. The l.owest chloride content, 4 ppm, was for 

samples from wells near Paola, near the southwest 

shore of Lake Jessup and southeast of Lake Mary. 

In all hilly upland areas, where there is recharge 

through sinkhole lakes, the artesian water has a 

chloride content of less than 25 ppm. In the lowland 

in the valleys of the St. Johns River, Wekiva River, 

Little Wekiva River, and Econlockhatchee Creek 

and bordering Lake Harvey, Lake Jessup, and Lake 

Monroe, the artesian water has a chloride content 

of more than 25 ppm. Within this area of water of 

relatively high chloride content, there are two areas 

(the upland area of sinkhole lakes around Geneva 

and a small area northwest of Lake Geneva) where 

there is local recharge through the bottoms of the 

lakes and sinks which has flushed the salt water 

from the aquifer. Salt water entered the aquifer 

during Pleistocene time when the sea covered the 

valley of the St. Johns River. The aquifer was exposed to the salt water through the channel of the 

St. Johns River, sinkholes, and solution basins which 

were open prior to being filled with Pleistocene 

and Recent sediments. 

Barraclough (1962, p. 71-80) recognized that the 

low chloride in the areas of upland lakes may be due 

to recharge causing more complete flushing of the 

aquifer than in the St. Johns River valley where 

there is no local recharge. Also, as suggested by 

Barraclough, the artesian water having a chloride 
172 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

content of more than about 250 ppm is in areas 

where the land surface is less than about 30 feet 

above sea level. The aquifer was exposed to the sea 

in those areas, while adjacent areas above sea level 

were being flushed of salt water to some extent. If 

the Pleistocene history, as discussed in this report, is 

correct, salt. water was probably flushed from the 

aquifer during the time the sea stood 300 feet or 

more below its present level. Later, the sea rose 

above its present level and entered sinkholes and 

river valleys and other places where the aquifer was · 

exposed. During the remainder of Pleistocene time, 

as the sea retreated, some flushing of the aquifer 

continued to take place. 

During later advances, however, the sea stood 

about 25 feet and then 8 feet above the present level. 

The parts of the aquifer exposed to those invasions 

of the sea have had the least time to be flushed of 

salt water; therefore, water having the highest chloride content may be expected in the parts of the 

aquifers exposed. As the A von Park Limestone of 

the principal artesian aquifer was exposed to the 

sea in the St. Johns River valley, it now contains 

some of the most highly mineralized water in Seminole County. This local occurrence of salt water in 

the A von Park caused Stubbs ( 1938, p. 27) to conclude that the Coskinolina zone, which is part of the 

A von Park, is the source of the highly mineralized 

water in Seminole County. Actually, in that part 

of St. Johns River valley, the highly mineralized 

water may be present in any water-bearing formation which was exposed to the sea when it stood at a 

higher level than at present. The difference in the 

mineral content of the water in these formations 

today is due in part to factors such as permeability 

and recharge which control the movement of the 

artesian water through the aquifers. 

Heath and Barraclough (1954, p. 40) reported 

that a comparison of chloride analyses of artesian 

water made in 1937 with those made in 1954 showed 

that in general there was no change. An exception 

was in a small area southwest of Sanford where 

the chloride content seems to have increased as much 

as 100 ppm. The seasonal fluctuation in chloride is 

from 50 to 150 ppm in farming areas where water is 

used for irrigation. In the farming areas near 

Oviedo, the seasonal change is generally less than 50 

ppm. During the period 1937 to 1954, the artesian 

pressure declined slightly in areas where withdrawals increased. In Seminole County, most of the 

water for irrigation is obtained from natural flow; 

therefore, the loss of head is no greater than about 

20 feet, the maximum height above the land surface 

to which water would rise in a tightly cased well. 

As artesian water can be obtained at relatively 

shallow depths, the general practice has been to 

drill several shallow wells having small flows in 

different parts of the area to be irrigated instead of 

one deep well with a larger flow. This results in a 

much lower chloride content than would be likely 

from deeper wells. 

BREVARD COUNTY 

In Brevard County D. W. Brown and others 

(1957, p. 89) reported that the chloride content of 

samples of artesian water ranged from 32. to 14,500 

ppm. Both the highest and lowest samples were 

from the Titusville area. Samples reported by Collins and Howard (1928, p. 209) include one with a 

chloride content of 14,276 ppm from a well 400 feet 

deep at Titusville and one from a lake 8 miles west of 

Titusville having a chloride content of 3, 700 ppm. 

The chloride contents in most of the samples of 

artesian water tested, however, were not more than 

several thousand parts per million. Eight of the 

wells sampled had a chloride content of less than 

250 ppm. These wells are in two areas north of 

Titusville where there may be local recharge and 

one area in the southeastern part of the county. The 

top of the aquifer is about 300 feet below sea level. 

The aquifer at this depth probably was not exposed · 

directly to Pleistocene sea water. In the Titusville 

area and in the northwestern part of the county 

where the top of the aquifer is only 75 to 100 feet 

below sea level, Pleistocene sea water probably entered the aquifer directly in the St. Johns River valley and through sinkholes. The shape of the piezometric surface in the northeastern part of the 

county indicates a submarine discharge area near 

the shore. Such a discharge is probably through 

sinkholes, similar to the large submarine spring 21;2 

miles east of Crescent Beach. 

INDIAN RIVER COUNTY 

The wells of the principal aquifer reported by 

Bermes ( 1958b, p. 67-72) in Indian River County 

range in depth from about 500 to 1,000 feet. Wells 

penetrating more than about 275 to 300 feet into the 

aquifer probably yield water having a chloride content of more than 100 ppm. Generally, the chloride 

gradually increases with depth in most wells. The 

highest chloride samples of about 1,000 ppm were 

not, however, from the deepest wells. Some of 

the analyses show increases in chloride which may 

be the result of increased withdrawal of water from 

the aquifer in the eastern part of the county in recent years. This increase in chloride may be due to 

upward movement of salt water through uncased 
PRINCIPAL ARTESIAN AQUIFER 173 

wells or through the formation. The distribution of 

the chloride water, as suggested by Bermes (1958b, 

p. 30), indicates that the salt is from connate water 

or sea water that entered the aquifer prior to Recent time. 

Artesian water in the Hawthorn Formation above 

the principal aquifer and some of the nonartesian 

water in the Hawthorn and overlying surface formations have a chloride content of more than 100 

ppm. The source of the chloride water in the Hawthorn probably is from Pleistocene sea water, except 

in areas where the water-bearing material is exposed 

to ocean water at the present time. 

Southern Florida 

The belt of water of relatively high chloride content along the east coast extends through St. Lucie 

County into an area which covers the south end of 

the Florida peninsula as shown in figure 36. Reports 

by Lichtler (1960, p. 63-79) on Martin County, 

Schroeder, Milliken, and Love (1954, p. 25) on 

Palm Beach County, Parker, Ferguson, Love, and 

others (1955, p. 580-682) on Dade County, and 

Klein (1954, p. 55-60) on Collier County give details 

on the occurrence and the range of the chloride content of the water. Analyses of water from two wells 

in the Kissimmee Valley in southeastern Highlands 

County (Bishop, 1956, p. 53) show that the area in 

which water having a chloride content of more than 

100 ppm in the principal aquifer and the overlying 

aquifers extends north of Lake Okeechobee into the 

Kissimmee Valley. Reports by Black and. Brown 

(1951) and Collins and Howard (1928) which contain analyses of water throughout the State include 

many analyses of samples from southern Florida. 

Throughout southern Florida, the principal aquifer generally has a chloride content ranging from a 

few hundred to several thousand parts per million. 

The Hawthorn Formation and the younger formations in the Florida Everglades yield water having a 

chloride content of more than 100 ppm. Most of this 

chloride water in the Hawthorn and younger formations probably is from sea water which covered the 

area in Pleistocene time. Some of the water in the 

lower part of the Hawthorn· Formation may be connate or caused by upward leakage from the underlying artesian aquifer. In parts of the areas, such as 

in Dade County (Schroeder and others, 1958) and 

in Collier County (Klein, 1954), some parts of the 

Hawthorn Formation and the overlying formations 

have been flushed of salt water. In Dade County, the 

very productive shallow aquifer has relatively high 

chloride content only along the coast and the coastal 

canals where sea water enters the formations. The 

underlying Hawthorn Formation has not, however, 

been completely flushed of salt water. In the Naples 

area in Collier County and elsewhere along the west 

coast, flushing has been complete in some parts of 

the Hawthorn Formation. 

Gulf Coast of Florida 

Northward on the gulf coast, the large area of 

water of relatively high chloride content in southern 

Florida becomes narrow in Sarasota County and extends as a narrow strip into Pasco County. In Citrus, Levy, Dixie, and Wakulla Counties, the large 

ground-water flow through the principal aquifer, 

which is cavernous limestone in these counties, has 

flushed out all the connate· and Pleistocene sea water and has prevented salt-water encroachment into 

the aquifer. In some areas on the Florida coast west 

of Wakulla County, the water has a chloride content 

of more than 100 ppm. 

SARASOTA AND MANATEE COUNTIES 

Reports by Stringfield (1933c, p. 175-177, 218-

220) on Sarasota County and Peek (1958a, p. 71-

73) on Manatee County give information on the 

occurrence of salty ground water in these counties. 

In the southern part of Sarasota County, the chloride content of the artesian water ranges from a few 

hundred parts per million to several thousand parts 

per million. A sample from Warm Mineral Springs in 

sec. 25, T. 39 S., R. 20 E., about 15 miles southeast of 

Venice had a chloride content of 9,550 ppm. The 

area of water of relatively high chloride content extends eastward in De Soto County where Black and 

Brown (1951, p. 46) reported that a sample from a 

well at Carlstrom field had a chloride content of 121 

ppm. North of Venice, the water having a chloride 

content of more than 100 ppm is confined to a narrow belt along the coast. Sarasota is on the east 

edge of the belt. 

Maps of Manatee County by Peek (1958a, fig. 

32-40) show that the coastal belt within which the 

chloride content of the artesian water is more 

than 100 ppm extends iniand several miles north 

and south of the Manatee River. In the lower part 

of the principal artesian aquifer, the highest chloride content recorded was 2,400 ppm. 

The maps showing the water of highest chloride 

content adjacent to Palma Sola and Terra Ceia Bays 

suggest that the aquifer was exposed to sea water in 

Pleistocene time in valleys which were cut into the 

aquifer during low stands of the sea. These valleys 

have been filled with Recent sediments sufficiently 

impervious to confine the water. The head is sufficient to prevent salt-water encroachment from the 
174 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

gulf. The aquifer is not, however, completely flushed 

of sea water. 

A sample of water from a depth of 398 feet collected by Stringfield (1933c, p. 219) just south of 

Anna Maria on Anna Maria Key resembled sea water although it was more than twice as concentrated . 

as sea water. Peek (1958a, p. 62) sampled the water 

and reported a chloride content of 44,000 ppm. He 

reported that the sample is from the Hawthorn 

Formation and attributed the high salinity to solution of mineral salts in the formation. He showed 

the bottom of the Hawthorn and the top of the underlying Tampa at a depth of less than 350 feet 

below sea level. This occurrence suggests the salt 

water might be in the upper part of the Tampa 

Limestone or at the contact between the Tampa and 

the Hawthorn where a brine could have formed on 

the eroded surface of the Tampa by evaporation, as 

suggested in the part of the present report on the 

source of salt water or salt deposits. Peek (written 

commun., 1960) explained that the sample containing 44,000 ppm was collected by R. B. Anders from 

well 31-43-2 (Peek, 1958b, p. 144) which was 

finished as a supply well in the Tampa Limestone. 

Field analyses of the chloride content of the water 

showed that well 29-42-1 penetrated the brine; the 

chloride content of the water in the Tampa Limestone 

was about 150 ppm below a depth of 350 feet. 

Peek concurs with the writer that the brines or 

salt may have formed as a result of evaporation of 

sea water in a lagoon or an arm of the sea. As he 

suggests, the present occurrence of the brine may 

reflect the pattern of circulation of the artesian water. Leakage of water from the underlying Tampa 

Limestone, where the artesian pressure is considerably higher than in the Hawthorn, may have diluted 

or essentially replaced brines that may have existed 

throughout much of the area. The present occurrence of brines may be restricted to the localities 

where such circulation has not been possible or has 

been extremely poor. There is no indication of verti· 

cal or lateral movement of the brines. Poor circulation of the ground water is also indicated by the fact 

that the brines were not flushed from the formation 

when the Pleistocene sea stood below the present sea 

level and valleys were cut into the area. These valleys are now drowned and form the bays along the 

coast. 

HILLSBOROUGH AND PINELLAS COUNTIES 

Reports by Peek (1959b, p. 59-72) on Hillsborough County and Heath and Smith (1954, p. 34-

45) and D. W. Brown (1958) on Pinellas County 

describe the chloride content of water in the principal aquifer in these counties. In a narrow belt 

along Tampa Bay and the gulf coast the ground 

water has a chloride content of more than 100 ppm. 

Some of the water of high chloride content in the 

lower part of the formation may be from Pleistocene sea water which has not been flushed out by the 

ground water. Part of the chloride water is, however, from encroachment of salt water from Tampa 

Bay and the gulf in areas along the coast. This is 

illustrated in the old well fields for the cities of 

Tampa and St. Petersburg, where the fresh water 

head was lowered by pumping to such an extent 

that salt water from Tampa Bay entered the aquifer. 

A new well field was developed for St. Petersburg 

in 1930 in the Cosme-Odessa area in the northwestern part of Hillsborough County, far enough inland 

to be safe from lateral encroachment of sea water. 

The chloride content in that area is low. M. L. 

Brashears, of Leggette, Brashears & Graham (written commun., 1961), reported that the chloride content of water samples from a test well recently 

drilled 1,200 feet deep in the Cosme-Odessa well 

field was less than 18 ppm. Also, Brashears reported 

that the chloride content of samples from wells 

ranging from 411 to 728 feet deep in a new field 

near Lutz was less than 14 ppm. These records 

show that the salt water has been completely flushed 

from the principal artesian aquifer to depths of at 

least 728 feet in the Lutz area and 1,200 feet in the 

Cosme-Odessa area. The chloride content of samples of water from three wells 300 feet deep, erroneously reported in the northwestern part of Hillsborough County (Black and Brown, 1951, p. 93), 

was 148, 150, and 309 ppm. These wells are actually in the old well field of the city of St. Petersburg 

in Pinellas County, near Tampa Bay. This old well 

field was abandoned at the time the Cosme-Odessa 

well field was put into service in 1930. 

Lake Tarpon, formerly known as Lake Butler, in 

the northern part of Pinellas County occasionally 

has a relatively high chloride content because it is 

connected by an underground channel to salt water 

in Spring Bayou, a tributary of Anclote River, a 

tidal stream at the town of Tarpon Springs. As 

stated by Matson (Matson and Sanford, 1913, p. 29), 

a spring in Tarpon Springs at the bottom of Spring 

Bayou, a few feet below mean tide level, is connected 

with Lake Tarpon by an underground channel. The 

flow of the spring is usually insignificant, but at 

times the discharge is large. Observations on the 

lake immediately before and after one of these outbursts of the spring show that the lake is lowered 

several inches while the spring flow is large. The 
PRINCIPAL ARTESIAN AQUIFER 175 

lake occupies a large solution basin in the Tampa 

Limestone. 

Studies by Heath and Smith (1954, p. 39-40) 

show that the lake discharges into a sinkhole as 

much as 115 feet deep just off the northwest shore of 

the lake. After entering the sinkhole, water moves 

through an underground channel or channels and 

emerges through an outlet in the bottom of Spring 

Bayou. Fluctuations of water levels in a well in the 

aquifer are almost identical with those in Lake Tarpon. The stage of the lake has ranged from 2.5 to 

5.5 feet above mean sea level at the start of the 

draining of the lake and 1.2 to 3.1 feet above mean 

sea level after cessation of the draining. The most 

plausible explanation of the phenomenon seems to be 

that suggested by Meinzer and Stringfield and described by H. H. Cooper, Jr. (Heath and Smith, 1954, 

p. 39) . The underground channel, with outlets in the 

lake and bayou, forms a crude U-tube, in which a 

column of the relatively dense sea water in Spring 

Bayou balances a higher column of fresh water in 

the lake. As long as the system is in balance, the contact between fresh water and sea water is in the lake 

outlet at a depth which depends on the lake stage, 

the height of the tide in the bayou, and the .relative 

densities of the two waters. This contact is depressed 

as the differential in head increases with a rising 

stage of the lake or a falling tide. When the differential in head is large enough to depress the contact to 

the bottom of the U-tube, any further increase 

throws the system out of balance. The sea water 

moves out of the channel, and the lake drains to a 

lower stage. The lake will cease to drain when a new 

static balance between salt water and the fresh water 

is established at a lower stage of the lake. Probably 

the cessation of flow occurs during a rising tide in 

the bayou, and subsequently, near high tide, sea water moves back through the channel to the outlet in 

the lake to complete the cycle. 

The cycles begin at different stages of the lake 

because of the variation of the density of the lake 

water and the height of the tide in the bayou. Occasionally the concentration of salts in the lake water, especially in the vicinity of the sink, may be so 

high as to allow the lake to drain under a considerably lower head differential than if the water were 

fresh. The highest stage, 5.5 feet above mean sea 

level, at which the lake started to drain suggests that 

with a ratio of 40 to 1 the depth of channel below sea 

level is ( 40 X 5.5) 220 feet below sea level. From the 

chloride content of the water in the lake at the sink, 

however, as reported by Heath and Smith, the ratio 

was less than 40 to 1, and the depth to the channel is 

therefore less than 220 feet. The maximum measured 

depth of the sinkhole through which the lake· drains 

is 115 feet (Heath and Smith, 1954, p. 40). Thus it 

seems that the depth of the channel is between 115 

and 220 feet. 

HERNANDO TO ESCAMBIA COUNTIES 

The known areas of water of relatively high chloride content are confined to the coast in this area, 

though a sample from a well 453 feet deep with 137 

feet of casing at Jim Woodruff Dam (Apalachicola 

River at Georgia State line) had a chloride content of 

5,330 ppm (Nevin Hoy, written commun., 1962). 

Matson and Sanford (1913, p. 226) reported saline 

water from limestones at a depth of less than 1,000 

feet at Chattahoochee in Gadsden County. 

From Hernando to Franklin Counties, the aquifer 

has been flushed of salt water. The water having 

high chloride content along the coast is from salt 

water from the Gulf of Mexico. In Citrus and Sumter Counties, however, salt water is present in the 

underlying limestone, according to records of two 

wells reported by Mossom (1926, p. 226, 230). In a 

well of Dundee Petroleum Co. (sec. 36, T. 20 S., R. 22 

E.) 3,090 feet deep about 4 miles northeast of Bushnell, Sumter County, salt water was reported at a 

depth of 2,405 feet. A well 1,900 feet deep near 

Crystal River in Citrus County reached salt water 

which flowed under artesian pressure. Water of relatively high chloride content is present in the aquifer 

along the coast from Franklin County, Fla., to the 

Alabama State line, as illustrated at Panama City 

and Fort Walton Beach. At Pensacola, in Escambia 

County, the aquifer is more than 1,000 feet below 

sea level and contains salt water (Matson and Sanford, 1913,p.303). 

In summ·ary, the Tertiary formations contain salt 

water along part of the coastal area, including southern Florida and the upper part of the St. Johns River 

valley. The lower Eocene and Paleocene formations 

contain salt water throughout most of Florida and 

southeastern Georgia. 

SPRINGS 

A classification of springs according to their average yield or discharge as proposed by Meinzer (1927, 

p. 3) consists of eight magnitudes. Springs of the 

first' magnitude have an average discharge of 100 

cfs (cubic feet per second) or more. One cubic foot 

per second equals 448.8 gpm or 646,317 gpd. Secondmagnitude springs yield 10 to 100 cfs; third-magnitude springs yield 1 to 10 cfs; and fourth-magnitude 

springs yield 100 gpm to 1 cfs. Springs of fifth to 
176 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

eighth magnitudes range from 100 gpm to less than 

a pint a minute. All the springs of first-order magnitude and many of the smaller springs in Florida are 

described by Ferguson, Lingham, Love, and Vernon 

(1947). 

The first-magnitude springs and many smaller 

springs shown on figure 37 are from the principal artesian aquifer. In the area where the aquifer is far 

below the land surface (fig. 23), as in the western, 

southern, and northeastern parts of Florida and the 

coastal area of Georgia, all the springs are small and 

are from the Hawthorn and younger formations 

overlying the principal artesian aquifer. There are 

17 springs of first magnitude in Florida (Ferguson 

and others, 1947, p. 37). Measurements of the largest spring in Georgia, Radium Springs (formerly 

Blue Spring), 4 miles south of Albany, range from 

26.4 to 135 cfs (Stephenson and Veatch, 1915, p. 

240). However, the minimum recorded in 1954 was 

less than 18 cfs (R. L. Wait, written commun., 1962; 

Callahan, 1964, p. 30) . Many springs are along 

streams, as the Suwannee River and its tributaries 

in Florida and the Flint River in Georgia, where the 

rivers are flowing on Oligocene and Eocene limestones of the principal aquifer. Also, there are submarine springs in coastal areas where the aquifer is 

at or near the ocean floor. Many springs along the 

rivers discharge at or below the water level in the 

rivers. · Falmouth Spring in Florida is a sinkhole 

formed by collapse of part of the roof of a solution 

channel which connects with the Suwannee River. A 

submarine spring east of Crescent Beach, Fla., appears to be of nrst magnitude at the ocean surface, 

·but Brooks (1961) estimated a flow of 40 cfs. 

Vernon (in Ferguson and others, 1947, fig. 6) 

showed the locations of the springs on the Suwannee 

River, the bed of which is marked by an almost continuous line of springs. Large quantities of water 

flow into the bed of the river from the aquifer, in addition to the springs and streams tributary to the 

Suwannee. As reported by Vernon (p. 18), the 

minimum flow of the Suwannee River above White 

Springs is 4.8 cfs, whereas at Ellaville the minimum 

discharge is 1,000 cfs. The total discharge from tributary springs and streams is less than 400 cfs, which 

leaves more than 600 cfs that must be discharged directly into the river. Although the water from many 

of the springs on or near rivers is probably from the 

upper part of the aquifer, some of them receive a 

large part of the water from greater depths, such as 

Radium Springs on the Flint River near Albany, Ga. 

Most, if not all, of the springs of first magnitude 

(100 cfs or more) and some of the smaller springs 

from the principal aquifer are artesian and rise from 

considerable depths through vertical solution channels which appear to be sinkholes or natural wells. 

Some of the springs, such as Silver Springs, emerge 

below the water surface from a series of outlets 

which may be along a large solution channel. W akulla Spring south of Tallahassee is one of a series of 

outlets for a large underground stream system, as 

described by Sellards (1917, p.136). At the present 

time, Wakulla Spring forms the head of Wakulla 

River. 

The Hawthorn Formation is the source of a few of 

the second-magnitude springs, such as Rock Springs 

in Orange County and numerous smaller springs. 

Rock Springs is one of the few large springs, in the 

area of this report, that has an outlet of the underground stream in part above the water level. 

The remarkable depth of some of the springs is illustrated by Bugg Spring, about half· a mile northwest of Okahumpka in Lake County, Fla., which is 

176 feet deep. As shown on a contour map ( Ferguson and others, 1947, p. 97), the spring is less than 50 

feet in diameter at the bottom and about 400 feet at 

the surface-the typical shape of sinkholes in this 

part of Florida, where the Hawthorn Formation is 

overlain by unconsolidated material which tends to 

slump into the sinks. Except on the northwest side, 

the walls of Bugg Spring are essentially vertical below a depth of about 60 feet. The head of the spring 

is an elliptical cavity approximately 200 by 100 feet 

submerged in a nearly circular pool about 400 feet in 

diameter. The outline of the bottom of the spring 

suggests that it was formed by one sinkhole around 

which one or more small sinks or vertical shafts 

formed and later coalesced with the central sink. 

One of the deepest pools of the first-magnitude 

springs is that of W eekiwachee Spring near Brooksville in Hernando County which, according to measurements made by sounding line by D. G. Thompson 

and the writer (Stringfield, 1936, p. 157), has a depth 

of about 145 feet. 

Warm Mineral Springs and Little Salt Spring near 

Murdock in Sarasota County appear to be circular 

sinkholes about 250 feet in diameter. The depth of 

Warm Mineral Springs, as reported by Lingham (in 

Ferguson and others, 1947, p. 145-148) is 167 feet. 

William M. Stephens in an article, "Early Cave Man 

in Florida Springs," in "All Florida Magazine," (Dec. 

27, 1959), and Lowell Brandle in an article, "Exciting Fossil Find Made in 210-foot Deep Florida 

Spring," in the Tallahassee Democrat (May 14, 

1959) reported that divers penetrated to a depth of 

210 feet in Little Salt Spring. 
PRINCIPAL ARTESIAN AQUIFER 177 

86" as· 84" 

~ 

t'"' 

·-r=~9t===-+---l-+--1--\-t:==:.::~=!:+--H--_:.~-p=:!=+,;.---=~--!·->·-----t----"i 

z 

~ 

0 30• '-------i----==:j~:::.....4~-~=--.:~.;£:.~4~~~-l-~~-\,aL-&--f~t+-_j."'_+--+-- Cl . 

c u .l 

p 

0 ~ 

29" 

28" 

0 

27"· -----r-----+--~---1-------1-------+-

26" ------1 

50 

EXPLANATION 

f2 

Major spring 

Average flow of 100 cfs or nwre 

(1 cfs = 646,317 gallons a day) 

rl 

Large spring 

Average flow less than 100 cfs. (Numbers 

refer to those in table of springs) 

0 50 100 MILES 

., 

~ 

';l> 

''Z 

FIGURE 37.-Location of large springs. Florida springs from Ferguson, Lingham, Love, and Vernon (1947); Georgia 

springs from Callahan (1964). 
178 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

S. J. Olsen ( 1958, p. 401) reported that Wakulla 

Spring extends to a depth of 100 feet where the bottom slopes sharply downward to 180 feet before it 

levels off and the sand floor gives way to limestone 

rubble. Three hundred feet farther along on the 

floor the depth reaches 225 feet where one side of the 

wall of the cave opens into a depression, the bottom 

of which is 240 feet below the surface and about 230 

feet below sea level. This depression seems to be a 

sinkhole in the cave floor. Layers of clay exposed at 

the edge of the sink indicate that the sink was originally filled with clay. At a distance of 1,100 feet 

from the spring and at the depth of 250 feet, the 

floor of the cavern slopes down out of sight. 

The depth of the submarine spring east of Crescent Beach, Fla., is only about 75 feet below the ocean 

floor. Zans (1951, p. 267-279) reported a circular 

submarine basin in the Bay of Bueno, Jamaica, having a depth of 840 feet, where fresh water issues in 

such a quantity that the sea water on the surface is 

nearly fresh. 

The flow of the springs varies with the artesian 

head in the principal artesian aquifer, as is shown 

by the comparison of the discharge of Silver Springs 

in Marion County with the head of an artesian well 

about 4 miles southeast of the spring. A rating curve 

based on the artesian head in the well and the discharge of the spring showed that with a range of 

artesian pressure from about 3 feet to 11 feet (with 

reference to the measuring point at the well) the discharge ranged from about 600 to 1,150 cfs (Stringfield, 1938, p. 52-54). 

A comparison of discharge of Silver Springs to the 

artesian pressure at Sharpes Ferry shows a good correlation between the two, except following rains 

when surface-water runoff increases the discharge 

of Silver Springs more than does the artesian pressure. 

The flow of the artesian springs also varies with 

the relation of artesian head to the altitude of the 

outlet of the spring. For example, Bugg Spring 

yields water from the principal artesian aquifer, but 

the yield was only about 17 cfs when measured in 

1943 and 1946 (Ferguson and others, 1947, p. 98). 

Although the artesian head is much higher at Bugg 

Spring in Lake County than at Silver Springs, as 

shown on the map of the piezometric surface, figure 

29, the outlet for Bugg Spring is approximately as 

high as the artesian head in the area. If the head 

were lowered or the outlet raised sufficiently there 

would be no flow. Although the measurement made 

in 1943 was reported to be at the lowest stage remembered by old residents (Ferguson and others, p. 

96), the writer visited the spring in 1932 when the 

artesian head at Sharpes Ferry and the discharge of 

Silver Springs were lowest during the 1931-46 period. Apparently there was little or no discharge 

from Bugg Spring, and according to reports at that 

time, the flow of the spring would reverse at different times. The water level in the spring is probably 

affected in the same way as that of an artesian well 

in which the water level declines with an increase of 

barometric pressure and rises with a decrease in barometric pressure. Under these conditions, with a 

low flow, the barometric pressure may depress the 

water level in the spring to such an extent that the 

flow of the spring would stop and the water in the 

discharge stream would flow into the spring. 

The discharge of the springs from the principal 

artesian aquifer ranges from a few gallons a minute 

to more than 1,000 cfs. Two of the largest springs 

are Silver Springs near Ocala and Rainbow Springs 

near Dunnellon in Marion County, Fla., with a combined maximum flow of 2,310 cfs. As reported by 

Ferguson, Lingham, Love, and Vernon (1947, p. 

117), the maximum discharge measured for Rainbow Springs (formerly Blue Springs) before 1947 

was 927 cfs (599 mgd), November 9, 1935, and the 

minimum was 487 cfs (315 mgd), October 3, 1932. 

However, the discharge on September 28, 1950, was 

1,060 cfs. The maximum discharge measured for 

Silver Springs before 1947 was 1,170 cfs (756 mgd) 

on August 4, 1930, and the minimum was 649 cfs 

( 419 mgd) on June 22, 1945. Later measurements 

showed a maximum of 1,290 cfs on September 28, 

1960, and a minimum of 539 cfs on May 3, 1957. 

Ichatucknee Springs in Columbia County ranks third 

in average flow. The combined average discharge of 

the springs has been estimated to be 3,700 mgd (U.S. 

Congress, Senate Select Committee on National W ater Resources, 1960, p. 40-45). The estimated total 

use of water, both surface and ground water, in 1956 

in Florida was 3, 799 mgd. 

The following list of springs by counties gives 

maximum and minimum discharge measurements 

where more than two measurements are available. 

The records for Florida are from Ferguson, Lingham, Love, and Vernon (1947) who included detailed 

descriptions of the springs and their location with 

discharge records and other records, as temperature 

measurements and chemical analyses of the water. 

In that report Vernon gave a table of Tertiary and 

Quaternary formations in Florida indicating the 

aquifers of selected springs. Reports by McCallie 

(1908) and Stephenson and Veatch (1915) contain 

descriptions and records of springs in Georgia. Calla-
PRINCIPAL ARTESIAN AQUIFER 179 

38.-Silver Springs, Marion County, 

toward head of springs. 

han (1964) lists 55 springs flowing from the principal artesian aquifer in Florida and Georgia. Of 

these, 22 are in Georgia. However, except for Radium Springs, the maximum flow recorded in Georgia 

is less than 50 cfs. The largest of the Georgia springs 

are on the Flint River in Dougherty County, the 

Withlacoochee River in Brooks County, and the 

Ocmulgee in Wilcox County, where the aquifer is 

near the surface. 

Twenty-seven of the largest springs in the Florida 

peninsula, listed by Stringfield (1936, p. 155-156) 

approximately in order of discharge, include all but 

four of the springs of first magnitude in the following list. Three springs-Silver Springs, Rainbow 

Springs, and Weekiwachee Spring-are shown in 

figures 38, 39, and 40. 

View 

FIGURE 40.-Weekiwachee Spring, Hernando County, Fla. 

View looking downstream from head of spring. 

Springs shown on map (fig. 87) 

Discharge and temperature: Records for Florida (Ferguson and others, 1947; U.S. Geological Survey, 1960b); records for Georgia (Callahan, 

1964; Wait, 1963). 

Discharge: Maximum (max) and minimum (min) given where there are 

several discharge records. 

Spring 

No., Location and name Cfs 

Temperature measurements: By many persons in different places in the springs with different thermometers, some of which were not calibrated. 

Aquifer: 1, principal artesian aquifer; 2, Hawthorn and younger Miocene 

formations; 3, post-Miocene formations; C, indicates chemical analyses 

published in reference. 

Discharge Aquifer Temperature 

I Date OF I Date 

Florida 

1 

2 

3 

1 

1 

Alachua County: 

Glen Springs near Gainesville __________ -------·-

Magnesia Spring near Hawthorn _____________ _ 

Poe Springs near High Springs _____ . 

Bay County: 

Blue Springs near Bennett: 

Spring !_ ____________________ ----·---·------- ---·--------· 

2-----------·----------------------·------------· - 3--------------·-------------------------------------

Bradford County: 

Heilbronn Spring near Starke ________________ _ 

See footnotes at end of table. 

0.32 

.33 

1.8 

31.2 (min) 

86.5 (max) 

4.7 

44.5 

.56 (max) 

.08 (min) 

Dec. 10,1941 

Apr. 16,1946 

Dec. 10, 1941 

Mar. 14, 1932 

Feb. 19,1917 

May 22,1942 

-----------------------------

Nov. 14,1941 

1913 

May 8,1946 

3,C 

2,C 

1,C 

1 

1 

2,C 

72 

75 

73 

71 

70 

Apr. 16, 1946 

Apr. 16, 1946 

July 22, 1946 

May 22, 1942 

May 8,1946 
180 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Springs shown on map (fig. 37 )-Continued 

Spring Discharge Aquifer Temperature 

No.I Location and name 

I 

Cfs 

I 

Date OF I Date 

Florida-Continued 

Citrus County: 

1 Chassahowitzka Springs near Homosassa Springs __________________________________________________________ 101 (max) Oct. 9,1930 1,C 74 Feb. 14,1933 

54.6 (min) Nov. 81935 75 July 25, 1946 

2 Homosassa Springs at Homosassa Springs ____________________________________________________________ 141 (min) Feb. 14,1933 1,C 75 Apr. 3, 1946 

222 (max) Mar. 7,1936 

Clay County: 

1 Green Cove Spring at Green Cove Spring __ 5.4 (max) Feb. 12,1929 2,C 70 Feb. 16, 1924 

4.4 (min) Apr. 18, 1946 77 Apr. 18, 1946 

2 Wadesboro Spring at Orange Park_ ______________ 1.4 Apr. 18, 1946 2,3,C 

Columbia County: 

1 Ichatucknee Springs near Hildreth _______________ 578 (max) Apr. 29, 1948 1,C 71-72 May 17,1946 

241 (min) Jan .. 28, 1956 

Gadsden County: 

1 Glen Julia Springs at Mount Pleasant _________ .78 May 16,1946 3,C 69 May 16,1946 

Gilchrist County: 

1 Hart Spring near Wilcox. ______________________________ 63.1 May 12,1932 1,C 73 July 24, 1946 

58.6 July 24, 1946 

2 Rock Bluff Sp·rings near BelL ____________________ 42.1 Dec. 8,1942 1 

Hamilton County: 

1 White Springs at White Springs---------------·-· 72 (max) Feb. 13,1907 . 1,C 72 Sept. 3,1923 

36.2 (min) Nov. 4,1931 70 May 6,1946 

Hernando County: 

1 W eekiwachee Spring near Brookville ___________ 231 (max) May 6,1931 1 1 74 Sept. 9,1944 

106 (min) Feb. 14,1933 

Hillsborough County: 

1 Buckhorn Spring near Riverview _______________ ... 11 May 1,1946 2 76 May 1,1946 

2 Eureka Springs near Tampa _________________________ 3.9 May 1,1946 2 74 May 1,1946 

3 Lithia Springs near Lithia _____________________________ 39.2 (min) Apr. 13, 1943 1,C 70 July 19,1923 64~2 (max) Apr. 30, 1946 76 Apr. 30, 1946 

4 Purity Spring at Tampa ________________________________ 1+ ----------------------------- 2,C 70 July 20,1923 

4 Sulphur Springs at Sulphur Springs ____________ 12.9 (min) Feb. 12,1934 2,C 70 July 1923 

163 (max) Aug. 3,1945 

Holmes County: 

78 Apr. 6,1931 

1 Ponce de Leon Springs at Ponce de Leon ____ 20.7 May 20,1942 1,C 68 May 20, 1942 

18.1 Dec. 9,1946 

Jackson County: 

1 Blue Springs near Marianna __________________________ 86.4 (min) Oct. 14, 1941 1,C 70 May 20, 1942 

277 (max) 

Jefferson County: Apr. 11, 1946 

1 Wacissa Springs at Wacissa __________________________ 120+ July 16, 1942 1,C 

Lafayette County: 

1 Troy Spring near Branford 2 _________________________ 55.2 May 15,1927 1 

14S 

Lake County: July 17,1942 

1 Alexander Springs near Astor _______________________ 117 (avg) 1931-46 1,C 74 Apr. 2,1946 

2 Bugg Spring near Okahumpka ______________________ 17.3 Mar. 16, 1943 1,C 74 Apr. 19, 1946 

17.6 Apr. 19, 1946 

3 Messant Spring near Sorrento _______________________ 18.4 May 10,1946 1,2 79 May 10, 1946 

4 Seminole Springs near Sorrento ___________________ 27.1 Feb. 5,1931 1,2 80 Feb. 5,1931 

10.2 (min) Mar. 8,1932 76 -------------------------------· 35.8 max) Feb. 10,1933 74 Feb. 10, 1933 

5 Spring at Echo Glen at Yalaha ______________________ 4.6 Apr. 19, 1946 2 

Leon County: 

1 Natural Bridge Spring at Natural 

Bridge south of Tallahassee ______________________ 115 May 19,1942 1,C 68 May 19, 1942 

132 May 14,1946 69 May 14, 1946 

2 Rhodes Spring south of Tallahassee __________ 70+ May 19,1942 1 69 May 19,1942 

Levy County: 

1 Fanning Spring near Wilcox _________________________ 79 (min) Mar. 14, 1932 1,C 72 Mar. 14, 1942 

137 (max) Dec. 17,1942 See footnotes at end of table. 
PRINCIPAL ARTESIAN AQUIFER 181 

Sp'rings shown on map (fig. 37}-Continued 

Spring Discharge Aquifer Temperature 

No.I Location and name Cfs 

I 

Date OF 

I 

Date 

Florida-Continued 

Levy County-Continued 

2 Manatee Spring near Chiefland .......... 14~ (max) Mar. 14, 1932 1,C 72 Mar. 14, 1932 

137 (min) July 24, 1946 73 July 24, 1946 

3 Wekiva Springs near Gulf Hammock .... 100 (max) Feb. 1,1929 1 78 Feb. 9,1931 

55 (min) Mar. 16, 1932 74 July 25, 1946 

Madison County: 

1 Blue Spring near Madison ..... ---- ---- . - ~. 145 July 23,1946 1,C 70 Mar. 16, 1932 

71 July 23, 1946 

2 Pettis Spring near Greenville ................. .16 May 16,1946 1,C 68 May 16,1946 

Marion County: 

1 Juniper Springs near Ocala .................... 12.8 Feb. 11,1929- 1,C 72 Apr. 4,1946 

(avg of 11) Apr. 4,1946 

2 Rainbow Springs near Dunnellon ................. 487 (min) Oct. 3,1932 1,C 72 Feb. 9,1931 

1020 (max) Sept. 28, 19·50 76 June 18, 1946 

3 Salt Springs at Lake Kerr .............................. 105 (max) May 5, 1931 1,C 75 Apr. 4, 1946 

54 (min) Oct. 15,1935 4 Silver Glen Springs near Astor .................... 89.9 (min) Feb. 7,1933 1,C 73 Apr. 1,1946 

129 (max) Apr. 12, 1935 

5 Silver Springs near Ocala ............... ______________ 526 (min) June 6, 1932 1,C 74 Mar. 2,1945 1240 (max) Sept. 9, 1933 72 Aug. 31, 1946 

Orange County: 

1 Rock Springs near Apopka 51.9 (min) May 20, 1933 ................... Mar. 8, 1932 2,C 74 

62.8 (max) Jan. 30,1935 75 May 9,1946 2 Wekiwa Springs near Apopka····--------------·--- 63.9 (min) Mar. 8,1932 2 75 May 9,1946 72.5 (max) Nov. 7, 1935 

Pasco County: 1 Crystal Springs near Zephyrhills ............... 147 (max) July 19,1941 1 74 Feb. 17,1933 20.3 (min) July 1,1946 75 Dec. 27,1946 Polk County: 

1 Kissengen Springs near Bartow .................. 43.6 (max) Oct. 11, 1933 1,C 72 Aug. 24, 1923 

0 (min) Feb. 1950 77 Mar. 10, 1932 Sarasota County: 1 Little Salt Spring near Murdock ................ 1.49 (max) Apr. 29, 1946 2,C 77 Apr. 29, 1946 

.17 (min) Jan. 1943 82 May 29,1946 2 Pinehurst Spring near Sarasota ........ ___________ .11 (max) 

.006 (min) Apr. 1946 2,C 73 Apr. 30, 1946 3 Warm Salt Spring near Murdock----------------- 11.0 (max) Oct. 1,1942 2,C 86 Apr. 29, 1946 

10.8 (min) Apr. 29, 1942 

Seminole County: 1 Palm Springs near Longwood -------·--------· 9.7 Nov. 12, 1941 2,C 2 San lando Springs near Longwood·---------- ..... 22.4 Nov. 12, 1941 2,C 74 Apr. 23, 1946 

21.7 Apr. 23, 1946 3 Sheppard Spring near Longwood------------------ 16.7 July 25, 1944 2,C 74 July 25, 1944 

Sumter County: 1 Fenney Springs near Coleman ____ .. 21.6 July 26,1946 1 76 July 26, 1946 2 Panasoffkee River (formerly Branch 

Min Springs) group. Includes Fenney 

and other springs ---------------·------------------------- 8.6 (min) Feb. 17,1933 1 74 Feb. 17, 1933 

Suwannee County: 

40.2 (max) July 26, 1946 76 July 26, 1946 

1 Charles Springs near Luraville ___________________ 9.4 (min) Dec. 12,1941 1 69 May 29,1942 

2 Falmouth Spring at Falmouth. The 

36.8 (max) May 29,1942 

flow on Feb. 10, 1933, was from the 

Suwannee River ------------------------------------------ 365 Feb. 10,1933 1,C 71 July 22, 1946 

59.6 Dec. 9,1942 157.0 July 22,1946 3 Suwannee Springs near Live Oak. ________________ 44 May 17,1906 1,C 70 Mar. 16, 1932 

6.1 Mar. 16, 1932 Dec. 27, 1945 

37.9 May 16,1946 May 16,1946 Taylor County: 1 Hampton Springs near Perry ...... ------~- ---·---- .15 (min) June 25, 1959 1,C 70 Nov. 21, 1923 

2 Waldo Springs near Perry ______________________________ .58 (max) May 21,1923 73 July 23, 1946 

26.5 (max) 1913 

Vol usia County: 

3.3 (min) July 24, 1946 1 71 July 24, 1946 

1 Blue Spring near Orange City ______________ ------- 188 (max) Dec. 5,1932 1,C 73 Mar. 7,1932 

2 Ponce de Leon Springs near De Land __ ... __ ... ___ 62.7 (min) Nov. 6,1935 74 Jan. 3, 1947 20.4 (min) Mar. 7, 1932 1,C 79 Oct. 26, 1923 41.8 (max) Apr. 23, 1946 73 Nov. 27, 1946 
182 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Springs shown on map (fig. 37)-Continued 

Spring Discharge Aquifer Temperature 

No. J Location and name Cfs I Date OF l Date 

Florida - Continued 

Wakulla County: 

1 River Sink in River Sink Precinct 

south of Tallahassee·----- __ -·-·- -- 178 May 19, 1942 1 72 Oct. 14, 1941 

2 Wakulla Spring near Crawfordville ______ ·-- 283 (avg) 1941-47 1,C 77 Apr. 22, 1931 

1 

1 

2 

3 

1 

1 

2 

Walton County: 

Morrison Spring near Ponce de Leon ·- -- 121 

89 

Washington County: Beckton Springs near Vernon ____________________ 49.0 

Blue Springs near Redhead ... ______________________ 31.6 

52.5 

Cypress Spring near Vern on ________________________ 84.9 

St. Johns County: 

Submarine Spring 2% miles east of 

Crescent Beach. Temperature taken 

at a depth of 121ft by U.S. Coast and 

·Geodetic Survey------------------------------------------

Georgia 

Brooks County: Blue or Wade Spring_______________________________________ 18.9 

23.21 

M cln tyre Spring---------------------------------------------- 46.42 

Dougherty County: 

1 Radium Springs, formerly Blue Spring, 

May 27,1942 

Dec. 9,1946 

May 26,1942 

May 26,1942 

Dec. 10,1946 

May 26, 19-42 

Apr. 22, 1937 

1 

1 

1 

1 

1 

1 

1 

74 Sept. 15,1931 

73 June 18, 1946 

69 May 23, 1942 

67 Dec. 9,1946 

67-73 -····---------------------------

71 May 22,1942 

7114 1925 

near Albany----------------------------------------------- __ 135 (max) Apr. 19, 1904 1 69 Not recorded 

18 (min) Feb. 7,1954 3 4.09 

Pulaski County: 

Oct. 19,1954 

1 Mock Spring ____________________________________________________ _ 6.47 Oct. 20,1943 1 68 Sept. 17,1954 

9.28 -----------------------------

5.57 Sept. 17, 1959 

4.64 ----------------------------- 1 67 Oct. 23, 1962 2 Blue Spring ____________________________________________________ _ 

1.66 Oct. 23,1962 

Wilcox County: 1 Poor Robin Spring _________________________________________ .. 2.75 Sept. 16,1954 1 68 Sept. 16,1954 

.62 ------------------------------

4.52 Oct. 25, 1962 __ ..,. ____________ ·-------------------------------

18.57 ------------------------------ 1 67 Oct. 24, 1962 2 Osewichee Spring ___________________________________________ _ 

1% to 2 Oct. 24.1962 

1 Eight of eleven measurements at different dates are 74°F, the others are 72°, 75°, and 77°F. 2 According to reports, no flow visible during extremely low stage of Suwannee River. 3 Leakage through weir; not entire flow at spring outlet. 

Springs of first order of magnitude (an average 

discharge of 100 cfs or more) are indicated with 

open circles and those with smaller average discharge are shown with closed circles in figure 37. 

The submarine spring east of Crescent Beach, Fla., 

is discharging through a sinkhole similar to many of 

the large springs on land (Stringfield and Cooper, 

1951c, p. 67-72). This spring evidently is the same 

as that reported by Matson and Sanford (1913, p. 

207, 213, 397). 

As shown on U.S. Coast and Geodetic Survey 

Chart 3258 (Florida inside route, St. Augustine to 

Titusville, 1931), the ocean floor at the submarine 

spring about 21_h miles east of Crescent Beach is 

about 55 feet below sea level. The bottom of the 

spring, as described by A. M. Sobieralski (in Rude, 

1925, p. 85-91), is as much as 125 feet below sea 

level. The spring has sufficient pressure and discharge to be noticeable at the surface of the ocean 

as shown in figure 41 at the time it was visited by 

Florida State Geologist Herman Gunter, F. C. Westendick, and the writer in 1934. The water, like much 

of the artesian water in Florida, contains hydrogen 

sulfide, as could be detected by the odor at the surface of the spring. 

Underwater investigations of the geology and hydrology of the spring in 1959 and 1960 are described 

by H. K. Brooks (1961, p. 122-134). The maximum 
PRINCIPAL ARTESIAN AQUIFER 183 

FIGURE 41.-Submarine Spring, 2% miles east of coast at 

Crescent Beach, Fla. Spring forms smooth surface in background. 

depth recorded by him in diving is 132 feet. As described by Brooks, the floor of the spring, about 126 

feet below sea level, is pitted with conical depressions 

as much as 12 feet in diameter and 6 feet deep. W ater rises through loose, coarse, granular pebbly material irregularly distributed over the bottom. No 

outcrop of limestone was seen. Two samples of wat~r from spring discharge at the bottom had chloride 

contents of 7,680 and 8,720 ppm, which are comparable to the chloride contents of some of the artesian 

water from wells on that part of the coast. A sample 

of water at the bottom near the outer edge of a point 

of discharge had a chloride content of 16,560 ppm, as 

compared with 20,100 ppm for coastal water and 19-

800 ppm at the surface of the spring. ' 

Brooks estimated the discharge on the floor of the 

spring is 40 cfs. The boils of the spring about 75 feet 

in diameter at the surface of the ocean give the impression that the discharge is tremendous. However, 

he stated that the large boils on the surface of the 

ocean are not due to the swift current jetted upward but are due to the upward rising of large 

masses of relatively fresh artesian water of lower 

density than sea water. The temperature of the 

spring water also has an effect on the buoyancy because it is warmer than that of the sea water. Brooks 

suggests the temperature of the spring water may 

be as much as 80 °F but is more likely 74° to 76°F. 

The sea water was 71 °F November 3 and 72°F June 

16 at the time of the investigation. The measurement made by the Coast and Geodetic Survey at a 

depth of 121 feet in the spring was 7114 °F, as shown 

in the table of springs. 

The general direction of movement of water 

through the principal artesian aquifer from recharge 

areas to the springs is indicated by the piezometric 

surface of the artesian water as shown in figure 29. 

Aquifers which are the source of the springs are 

given in the list of springs. The course of the water 

from the Putnam County recharge area eastward to 

the submarine spring 2% miles east of Crescent 

Beach, St. Johns County, is described by Stringfield 

and Cooper (1951c, p. 61-72) and shown in figure 42. 

The movement of water in the principal artesian 

aquifer from a recharge area in Polk County to Kissengen Springs is indicated in figure 43, as shown in 

a section by Peek (1951, p. 78). These sections (figs. 

42 and 43) show deep circulation through sinkholes 

and solution channels. The low tritium content of 

water from Silver Springs near Ocala, Fla., and Radium Springs near Albany, Ga., also indicates deep 

circulation. 

As described by Wait (1963, p. 58), Radium 

Springs, about 4 miles south of Albany and 200 yards 

east of the Flint River, emerges from an opening 

about 3 feet in diameter in the bottom of a 15-foot 

depression in the Ocala Limestone. Below the opening is a cavern 300 feet wide, 150 feet long, and 80 

feet deep. Changes in the stage of the river affect the 

discharge of the spring. As the stage of the river 

rises, discharge from the limestone to the river decreases, and the water level rises. 

Although the discharge of the springs listed is 

many millions of gallons daily, that discharge represents only part of the water which moves through 

the principal artesian aquifer. For example, in addition to the visible springs on land and diffused discharge into streams, there is large discharge into 

the gulf through submarine outcrops along the western coast of Florida from Pinellas County to Franklin County. The range in the discharge varies with 

the season, depending on rainfall and recharge to 

the aquifer. 

Kissengen Springs with a maximum recorded flow 

of 43.6 cfs is the only known large spring of the principal artesian aquifer which has stopped flowing be500' 

1000' 

EOCENE AND OLDER STRATA 

Water having a chloride content 

of more than 100 parts per 

million 

Theoretical contact \ between salt water / \.. _...,/,.. 

and fresh water---) / 

l._.O_,_,_,_,~u._O __ _!IO __ _j20 MILES __..__...--.--

1500''_c_ ____________ ....<::.::: __.._.--____ __L 

FIGURE 42.-Section across Putnam and St. Johns Counties, 

Fla., showing submarine spring east of coast at Crescent 

Beach. 
184 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

w 

200' 

100' 

Sea level 

100' 

200' 

E 

0 5 MILES 

FIGURE 43.-Section through Kissengen Springs, Polk County, Fla. (From Peek, 1951, p. 78.) 

cause of withdrawal of water from wells. Peek 

(1951, p. 77, 81) pointed out that after 1936 the 

flow declined progressively until in February 1950 

it ceased to flow when the withdrawal of ground water from wells in southwestern Polk County reached 

approximately 110 mgd, of which about 75 mgd was 

used by phosphate companies. Peek estimated that 

about 20 mgd of the total was from the capture of 

the flow of Kissengen Springs and 90 mgd is partly 

from other natural discharge, partly from an increase in recharge, and partly from a slight reduction in storage in the aquifer where the piezometric 

surface is lowered. 

Notes by P.R. Speer dated February 5, 1929 (Peek, 

1951, p. 80; Ferguson and others, 1947, p. 141) show 

that Kissengen Springs stopped flowing once before, 

during the drilling of an oil test well a few hundred 

feet northwest of the spring in 1927. Speer stated 

that at a depth of 220 feet the well tapped the spring 

flow, practically draining it. The well was then 

cased and continued to 4, 700 feet, striking a strong 

sulfur flow the entire way. Speer reported also that 

the casing was set so that the flow from the well 

flowed back into the spring cavity and apparently 

increased the flow of the spring. A comparison of 

analyses of samples of water (Ferguson and others, 

1947, p. 143) collected from the spring in 1923 and 

1946 shows that the calcium sulfate content was 

higher in 1923 than in 1946, indicating some of the 

water was from the lower part of the aquifer. The 

low chloride content of 7.6 ppm in both samples suggests, however, that none of the water was from formations below the principal artesian aquifer. 

Chemical analyses of samples of water from several springs are given in the following list to indicate the composition of four of the five types of water as discussed in the section on quality of water. 

No spring yields soft sodium bicarbonate type water 

such as that from deep wells in the aquifer in western Florida. 
PRINCIPAL ARTESIAN AQUIFER 185 

Chemical analyses of water from seven springs 

[From Ferguson and others, 1947; results in parts per million except as indicated] 

0 

t; 0 ell 

~ <ll CIJ i '1:S -;;- ~ g 0 :g :rJ '1:S CIJ ·a 0 -;;- ~ 0 8 € ] = .. -~ C._.._ ::s 8 s e e "C:SO 0 

§_ -;- ·~ s aS ~ '1:S S"' ~~ ;a~ = ·~ .,...,. = CIJ CIJ CIJ CIJ E:!. s s 0 ~ '1:S '1:S ~ > ::o = .. N ell~ ::s CIJ .t:; ·;:: ·;:: ] oO 

~= Nnmc nnd location aS ·;::; = ::s ~ 

... aS 0 0 aS 

~"' ~._, .t:;O ~ = tlO :a aS ..... !: ... ...., Oj "' (,) -; :a ::s o"' '0'-' ::r: aS 0 0 0 aS Q Ci.i .!: 0 ~ .en ll< ~ en 0 ~ z i5 E-< 0 0 ~ 

Silver Springs, Marion County 68 9.6 4.0 1.1 201 34 7.8 0.1 1.3 237 209 5 4 7.8 ____________ Oct. 21 9.2 0.04 

Rainbow Springs, Marion County 4.0 2.9 .4 78 4.7 3.5 .0 .8 81 69 2 2 7.9 ___________ , June 18, 7.7 .08 21 

Salt Springs, Marion County ___________ . Apr. 4 11.0 .10 240 167 1540 38 87 613 2800 .0 ------- 5850 1290 ------- 0 7.1 

Little Salt Spring, Sarasota County _________ May 29 17 .05 194 136 758 24 171 534 1430 1.6 1.8 3480 1040 ------- 12 7.3 

Rock Springs, 

Orange County ............ May9 9.6 .07 29 8.4 

Hampton Springs, Taylor County ____________ , July 23 10.0 .13 189 85 

Glen Julia Springs, 

Gadsden County .......... May 16 4.6 .08 .5 .4 

The analyses of water from Silver Springs and 

Rainbow Springs represent the calcium bicarbonate 

type of water low in chloride and sulfate. This type 

of water is characteristic of most of the artesian water in the limestone and dolomite of the principal 

artesian aquifer, except in southern Florida and 

some of the coastal areas. The water from Rainbow 

Springs in central Florida is softer than that from 

Silver Springs. Its mineral content is less than that 

of Silver Springs, indicating that a large part of its 

flow is from local recharge. Judging from the chemical analyses of the water and discharge from Silver 

Springs, Ferguson, Lingham, Love, and Vernon 

(1947, p. 127) estimated that a ton of dissolved mineral .matter, consisting chiefly of calcium and bicarbonate and a moderate amount of sulfate, issues 

from the spring every 3 minutes. 

Little Salt Spring in Sarasota County and Salt 

Springs in Marion County represent calcium bicarbonate water mixed with remnants of sea water or 

salt in the aquifer. Only the springs in the St. Johns 

River valley and some flowing from the principal 

artesian aquifer in coastal areas have a relatively 

high chloride content. Little Salt Spring and Warm 

Mineral Springs in Sarasota County are in an area 

where the water in the Hawthorn Formation and the 

underlying principal artesian aquifer has a relatively 

high sulfate content from anhydrite in the waterbearing formations. 

Water from Hampton Springs has a higher content of calcium, magnesium, and sulfate than that of 

4.3 

7.0 

1.9 

.6 105 17 6.1 .1 .3 128 107 8 4 7.3 

2.0 288 557 8.8 .7 .0 1080 821 ------- 30 6.9 

.5 3.0 .2 3.1 .1 .7 15 2.9 14 10 5.7 

the other springs having a low chloride content but 

not as high as some of the water from wells in the 

principal artesian aquifer, as in Sarasota County, 

Fla. The sample from Rock Springs is typical of 

water from some parts of the Hawthorn which may 

be similar to that in the underlying artesian aquifer. 

The soft water having a low mineral content from 

Glen Julia Springs in Gadsden County is typical of 

the ground water in unconsolidated sands. 

The approximate temperature of the water ranges 

from about 67° to 86°F. Some of this difference 

may be due to approximate measuring with uncalibrated thermometers. Most of the measurements 

ranged from about 69°F in northern Florida and 

southern G~orgia to about 70° to 7 4 °F in central 

Florida. 

WELLS 

EARLY EXPLORATION 

A summary of the history of drilling of artesian 

wells and shafts by Tolman (1937, p. 316), based on 

a review of the history of development of artesian 

wells by Keilhack (1935), shows that 2,000 years 

before Christ, oases in Egypt were watered by numberless shafts as much as 300 feet deep. The word 

"artesian" originated from Artois, a province in 

) northern France, where wells that overflowed at the 

land surface under natural pressure were bored in 

the 12th century. The first of these wells was completed in 1126. 

The first artesian well in the United States 

(Carlston, 1943, p. 119-136) was constructed in 
186 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

1820 in Charleston, S. C., by sinking an iron pipe 

through clay; Auger boring for artesian water was 

used in Charleston in 1823; however, the first successful auger-bored well was not completed in the 

city until after 1825. The drilling methods and 

tools were copied from a description of a well bored 

in London, England. Auger boring of artesian wells 

in the Cretaceous chalk belt in the Coastal Plain in 

Alabama and Mississippi began about 1820 at Cahaba. At that time Cahaba was the capital of 

Alabama. 

After the construction of the early artesian wells 

in South Carolina, Alabama, and Mississippi in the 

first half of the 19th century, there was no discovery of artesian areas in other States until the latter 

part of the century when jetting and cable-tool 

methods were introduced in the Southeast. In 1854, 

before discovery wells were drilled in the other 

Southeastern States, Wailes ( 1854, p. 260, 265) estimated that there were about 100 flowing wells in 

Mississippi and more than 500 in Alabama. 

The standard cable-tool drilling rig in the United 

States was developed in drilling salt wells in West 

Virginia, Ohio, and Pennsylvania (Carlston, 1943, 

p. 119). The first successful well was drilled near 

Charleston, W. Va., in 1808. By using this method, 

it was possible to drill through hard rock; later the 

rotary method (Bowman, 1911, p. 70) was developed 

and used for drilling in both soft and hard rock. 

However, the cable-tool method was not used successfully for water-well drilling in the southeast until the first flowing well in Florida (Stringfield, 

1953) was drilled at St. Augustine between 1880 and 

1882 by a driller from the Pennsylvania oil fields. 

The discovery well for artesian water supply at 

Jacksonville, Fla., was completed about 1885. For 

many years, Jacksonville had the largest municipal 

supply derived entirely from natural flow of artesian 

wells. Although water for the public supply is now 

obtained by pumping artesian wells, the piezometric 

surface was 25 or more feet above sea level outside 

the deepest part of the cone of depression in 1962 

(Leve, 1965, fig. 12). 

Although at least six attempts had been made between 1840 and 1850 (Wait, 1957, p. 143), the first 

flowing well in Georgia (McCallie, 1898, p. 63-64) 

was completed in 1881 on a plantation 20 miles west 

of Albany. The second successful flowing well in 

Georgia was drilled in Savannah in 1885 (McCallie, 

1908, p. 72) . Artesian wells were drilled for the 

public supply of Savannah in 1887. In 1888 artesian 

wells completely replaced the city supply from the 

Savannah River. Wait reported that the failures 

prior to 1881 probably were due to improper construction. 

Much of the early drilling for artesian water, like 

the early drilling for oil, was without adequate geologic advice. A few notable exceptions in which 

geologic information was used, as at Jacksonville, 

Fla., have been recorded. For example, after the 

first flowing well was drilled at St. Augustine, R. N. 

Ellis, city engineer at Jacksonville, without an understanding of the geologic structure, assumed that 

artesian water could be reached at about the same 

depth at Jacksonville as at St. Augustine. The test 

well at Jacksonville was unsuccessful because it 

was not deep enough to tap the artesian aquifer, the 

top of which is about 500 feet below sea level at 

Jacksonville, although it is only about 200 feet below 

sea level at St. Augustine. The hope of obtaining 

flowing wells at Jacksonville was, therefore, abandoned until L. C. Johnson, a geologist of the U.S. 

Geological Survey, on a ground-water reconnaissance in Florida, was informed of the effort to obtain water. From his information on the geologic 

structure of Florida, Johnson estimated correctly 

that a flow of artesian water could be reached at a 

depth of about 500 feet. This discovery started the 

development of the large artesian system in the 

northeastern part of Florida. Thousands of artesian 

wells are now in use in the Coastal Plain of the 

Southeastern States. 

RECORDS AND YIELD OF WELLS 

Records of representative artesian wells in different parts of the Florida peninsula, on which the first 

map of the piezometric surface of water in the 

principal artesian aquifer was based, are included 

in a report by Stringfield (1936). The wells and 

measurements used for the first draft of the piezometric map for western Florida are recorded in an 

unpublished report by V. T. Stringfield and F. C. 

Westendick on artesian water west of the Suwannee 

River. A report by Warren (1944) gives records 

and measurements of wells used in mapping southern Georgia. Records of many additional wells and 

measurements have been published in later reports 

and have been URed in preparing more detailed piezometric maps. 

The areas in which the artesian wells will flow 

under natural pressure are shown in figure 28, and 

the height to which water would rise in tightly cased 

wells in 1961 is shown in figure 29. Artesian wells 

range from about 50 to 1,000 feet in depth, depending on the local conditions within the area in which 

they are constructed, and from about 2 to 12 inches 
PRINCIPAL ARTESIAN AQUIFER 187 

FIGURE 44.-Artesian well near Belle Glade, Palm Beach 

County, Fla. Well is finished with valve to control artesian 

flow. Casing at surface is enclosed in concrete. 

in diameter. Some of them are as much as 24 inches 

in diameter. Except in western Florida where part 

of the principal artesian aquifer consists of unconsolidated formations, few of the wells .are entirely 

cased. The casing generally ends in the top of the 

first limestone penetrated. Some wells, as much as 

1,000 feet deep, may have only about 100 feet of 

casing. 

Wells in areas of artesian flow are commonly finished with valves to shut off the flow when the water 

is not needed (fig. 44) . However, some wells flow 

continuously because the casings are corroded or the 

valves are broken or corroded (fig. 45). Hendry 

and Lavender (1957, p. 29-177) included records of 

967 wells which were flowing continuously in 22 

counties in Florida. They reported that the total 

flow from these wells was 37,762 gpm. 

Four methods used in casing wells, described by 

J. B. Foster (1962) for eastern Clay County, Fla., 

and illustrated in figure 46, are used in many parts 

of the region underlain by the principal artesian 

aquifer. The general direction of movement of water in the wells is shown by arrows. 

In well A, the casing is seated on a hard layer of 

rock, and the well is drilled to the top of the aquifer. 

A liner of smaller diameter is lowered into the well 

and seated near the top of the aquifer. The liner is 

sealed at the land surface to prevent flow of water 

through the opening between the casing and liner. 

Then an open hole is drilled into the aquifer to complete the well. This method is one used to prevent 

subsurface leakage from one permeable bed to another through wells. 

The construction of well B is similar to that of 

well A except that, instead of running the liner to 

the land surface and sealing it to the casing, the 

liner ends below the top of the casing and is not 

sealed to it. Under these conditions water may move 

from the aquifer to the top of the liner and then 

downward between the casing and the liner into 

permeable beds below the casing and above the aquifer. Subsurface leakage in wells of this type could 

be eliminated by sealing the liner to the casing with 

a packer. 

Well C illustrates the method commonly used. 

The well is cased to the first hard layer of rock. 

Well D is similar to well C, except that a short liner 

is set in the open hole to prevent sand and other 

unconsolidated material from caving into the well. 

Although the principal artesian aquifer is tapped 

by wells throughout its extent, wells are most numerous within areas in which the wells flow. The 

greatest concentrations are in irrigation districts 

as in Indian River, Seminole, Manatee, and Sarasota 

Counties, Fla. In Seminole County, several thousand 

wells have been drilled for irrigation of celery and 

other truck crops. Bermes (1958b, p. 40) reported 

that more than 2,000 wells yield water from the 

principal artesian aquifer in Indian River County. 

In parts of Seminole County, there is an average of 

orie or more wells for each acre of land irrigated. 

Some artesian wells are not more than about 50 feet 

deep in areas where the principal artesian aquifer is 

near the land surface. Artesian wells are also numerous in Jacksonville, Savannah, and in other large 

cities and industrial areas. 

FIGURE 45.-Artesian well in Flagler County, Fla., flowing 

about 750 gpm without valve to control flow. 
188 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Land 

surface 

50 

LLI (.) 100 

~ ·0::: 

::> 

(/) 

~ 150 

~ 

3: 

g 

~ 200 

~ LLI 

LL 

~ 250 

:C 

h: 

LLI 

0 

300 

400 

450 

EXPLANATION 

~ Sand 

m 

Clay 

~ Shells 

Limestone 

~ 

m 

Dolomite 

Crystalline 

~ 

dolomite 

D 

Phosphorite 

Direction of flow 

Static-pressure 

condition 

Indicates normal 

movement of water 

in the aquifer 

bD 

c:: 

'iii 

ro 

(.) 

Q) 

0 

.c 

c:: 

~ 0 

FIGURE 46.-Diagram of four methods used in casing wells. (From J. B. Foster, 1962.) 

Some nonflowing wells are used to drain surface 

water into the aquifer. The largest concentration-of 

these is in the Orlando area in Orange County, Fla., 

as described by Unklesbay (1944) and Unklesbay 

and Cooper (1946). A few wells used for drainage 

in the Miami area, Florida, are in the shallow aquifer' the chief source of ground water in southeastern 

Florida. Wells for drainage and many wells for water supply are finished in the shallqw aquifer without screens. The principal artesian aquifer is as 

much as 1,000 feet deep in southeastern Florida; 

the wells that tap it will flow. Therefore, wells are 

not used to drain water into the artesian aquifer in 

that area. However, farther north in the coastal 

area, the artesian flow from wells is used to drain 

lowlands by means of a venturi tube on the discharge pipe of the well. Bermes (1958b, p. 39) reported the use of this method to drain lowlands 

near the Sebastian River in Indian River County, 

Fla. Flowing wells used for drainage are called 

siphon wells. Westendick (Stringfield and Westendick, 1935, p. 15) reported the use of this method in 

Brevard County. As stated by Bermes, in some installations the venturi tube is submerged so that the 

surface water enters the tube directly. In others, 

the venturi tube is above the surface water, which is 

drawn into the tube by a pipe extended to the water. 

In a few areas as in Black Hammock, Seminole 

County, Fla., where the artesian aquifer is overlain 

by relatively thin confining beds, a shallow artesian 

well may be drilled to relieve the pressure and prevent sand boils during construction of drainage canals, as illustrated by Ferris, Knowles, Brown, and 

Stallman (1962, fig. 20, p. 81). 

The yield of the artesian wells depends on the 

hydrologic conditions. and the construction of the 
PRINCIPAL ARTESIAN AQUIFER 189 

wells. In general, the wens having the smallest capacities are in the southern part of Florida. The 

yield of flowing artesian wells under natural flow 

ranges from a few to several thousand gallons per 

minute. The largest yields by natural flow are in 

the coastal area and in southern Florida where the 

artesian pressure is relatively large and the surface 

of the ground is relatively low. One of the largest 

recorded yields by natural flow (Cooper, 1944, p. 

173) was 6,500 gpm from a well 12 inches in diameter near Yukon, Duval County, Fla., in November, 

1942, when the well was first completed. The initial 

flows of two other wells measured by Cooper were 

3,200 and 4,100 gpm. The yield of each of two wells 

drilled in 1964 near Palatka, Fla., exceeds those at 

Yukon (M. L. Brashears, written commun., 1964). 

Among the largest yields recorded from nonflowing we11s in the principal artesian aquifer is 7,500 

gpm from a we11 18 inches in diameter and 852 feet 

deep in Polk County, measured in 1926 by the 

American Agricultural Chemical Co. (Stringfield, 

1936, p. 159, 183). In southeastern Florida, nonflowing we11s in the shallow aquifer yield large quantities of water (Parker and others, 1955, p. 919, 940). 

Wells 12 to 14 inches in diameter have been reported 

to yield as much as 5,000 gpm with a drawdown of 

only about 5 feet. 

When wells are flowing under natural artesian 

pressure, the pressure at the mouth of the well is 

almost zero, so that the drawdown or loss in head 

resulting from discharge of water is almost equal to 

the head with reference to the outlet of the well. 

When nonflowing we11s are pumped, the drawdown 

is the difference between the static water level and 

the water level when the well is pumped. Where the 

we11 is pumped by suction lift, the drawdown may 

be determined by the vacuum created on the suction 

line of the pumped well. The maximum loss of head 

in a flowing well is limited to the shut-in head. 

This temporary loss in head for flowing wells in the 

principal artesian aquifer in different parts of the 

area of artesian flow ranges from a fraction of a 

foot to about 45 feet. The loss of head in a flowing 

well, or the drawdown; may be expressed in terms 

of specific capacity, which is the number of gallons 

discharged per unit loss of head.· 

The specific capacity is significant for comparison 

of yield of different wells and for determining the 

loss of head that will result if the yield of the well is 

increased by pumping. Data regarding the specific 

capacities of wells for which calculations could be 

made in Brevard, Clay, Flagler, Hendry, Polk, and 

Palm Beach Counties, Fla., in 1934, are included by 

Stringfield in a table ( 1936, p. 159). Data for wells, 

including specific capacities in southeastern Georgia, 

are given in a table by Warren (1944, p. 83-87). 

Many later reports on ground water include information on the specific capacity of wells. 

Some wells in the shallow aquifer in the Miami 

area, Florida, have larger specific capacities than 

those of the principal artesian aquifer. Some of 

them are as much as 2,600 gpm per foot of drawdown. Although Parker, Ferguson, Love, and others 

(1955, p. 197-290) do not give specific capacities 

of wells, they give detailed information on the 

water-bearing capacity of the shallow aquifer, which 

is very large. The highest specific capacity-833 

gpm for each foot of drawdown-in the principal 

artesian aquifer is reported for a well in Polk 

County, Fla., by Stringfield (1936, p. 159-160). The 

specific capacity of flowing wells recorded in Florida 

ranged from about 1 to 248 gpm. The maximum 

recorded by Warren ( 1944, p. 86) for flowing 

wells in Georgia was 206 gpm for a 16-inch well, 816 

feet deep, at Camp Stewart in Liberty County. 

SUBSURFACE LEAKAGE IN WELLS 

Few artesian wells in the principal artesian aquifer are completely cased and finished with screens, 

except in areas of western Florida where unconsolidated water-bearing materials will collapse into 

wells if they are not cased and finished with screens. 

\i\'here the aquifer consists chiefly of limestone, the 

casing may reach only to the first limestone, and the 

uncased part may extend through the aquifer, which 

in some places consists of several formations. Under these conditions, water entering the wells from 

formations of relatively high pressure may escape 

into formations of lower pressure instead of rising 

to the surface or remaining confined in the well. 

The artesian pressure of the water in the middle 

and upper parts of the Hawthorn Formation in different localities may be higher or lower than that 

in the underlying part of the Hawthorn and other 

formations of the principal artesian aquifer. In 

Baker County, Fla., and other areas west of the 

areas of artesian flow in northeastern Florida and 

southeastern Georgia, the artesian head of the middle and upper parts of the Hawthorn is higher than 

that in the lower part and in other parts of the 

principal artesian aquifer. A well drilled into the 

principal aquifer, therefore, will drain water from 

the Hawthorn to the principal aquifer if it is not 

cased to the top of the principal aquifer. Within 

the area of artesian flow in the coastal counties and 

in southern Florida, the pressure in the Hawthorn 
190 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

is less than that in the principal aquifer, and water 

will flow through the well from the aquifer into the 

Hawthorn if the casing does not extend from the 

surface through the Hawthorn to the top of the 

aquifer. 

Within the principal artesian aquifer, the water 

level or artesian pressures will be essentially the 

same at different depths except in recharge and discharge areas. The water levels or artesian pressures 

in general decrease with depth as the water moves 

downward into the aquifer. The water levels or 

artesian pressures increase with depth as the water 

moves upward to a discharge area. Also, the head 

in the upper part of the aquifer may become less 

than that in the lower part of the aquifer in areas 

in which water is withdrawn from the upper part of 

the aquifer through wells. Current-meter surveys 

in wells in two areas in Volusia County, Fla., as reported by Wyrick (1960, p. 14-15) showed that in an 

area of recharge the water moves downward from 

one part of the aquifer to a lower part through uncased wells. In a discharge area the direction of 

movement of the water in the well was upward 

into the aquifer. 

In Manatee County, Fla., Peek (1958a, p. 28-33) 

reported that current-meter surveys in wells show 

that the Suwannee Limestone, which is the deepest 

part of the principal aquifer penetrated by the 

wells, yields no water below a depth of 605 feet. 

All the artesian water that entered one well, 4 miles 

west of Bradenton, flowed into the upper part of 

the Hawthorn at depths of 60 to 70 feet where 

there was no casing. The well was cased above and 

below that interval. In Sarasota County, Fla., 

Stringfield (1933c, p. 199-216) found ·llO evidence of 

leakage into the Hawthorn. However, it is entirely 

possible that some leakage had taken place, but the 

pressure in the Hawthorn and the underlying principal artesian aquifer were in equilibrium at the time 

the tests were made. The current-meter survey in 

wells in Sarasota County showed that little or no 

water was coming from the lower part of the principal aquifer. 

On the coast of Manatee County, wells. that flow 

were reported to have been nonflowing during construction before their upper parts were cased. Near 

Sun City, in the southwestern part of Hillsborough 

County, Fla., a well 340 feet deep was reported 

(Stringfield, 1936, p. 161) to be nonflowing until a 

well at Sun City, 550 feet deep with only 42 feet of 

casing was constructed. This report thus indicates 

that part of the water from the formations penett·ated by the 550-foot Sun City well enters the formations penetrated by the 340-foot well. 

A well in the town of Green Cove Spring in eastern Clay County is reported to have had a pressure 

head of about 21 feet above the ground in 1927 

when it was constructed. In 1934 the well had a 

reported pressure head of 1.5 feet above the ground 

surface. The loss of head in that well may have 

been caused by leakage through defective casing. 

Although the loss of head may be attributed to 

other causes, the inference of underground leakage 

is substantiated to some extent by reports that the 

water level in this well is influenced by fluctuations 

in Green Cove Spring a few hundred yards to the 

east. The water from Green Cove Spring apparently 

comes from the Hawthorn Formation and should 

not influence the water level in a well cased to a 

depth of 400 feet unless there is some defect in the 

casing or the method used in casing the well does 

not prevent subsurface leakage. The piezometric 

surface of the artesian water in the principal artesian aquifer in that area indicates continuous 

discharge from the aquifer, and the quality of the 

spring water is similar to that in the principal 

aquifer. 

In eastern Clay County, J. B. Foster (1962) reported that 14 of 69 examined wells leaked underground. He estimated the loss of water from leaky 

wells to be about 1,000 gpm. Foster assumed that 

5 percent of the existing wells were inventoried, 

and it seems probable that the same percentage 

of leaky wells would be found among all the wells 

in the area. If these assumptions are correct, the 

total loss would be about 20,000 gpm or about 30 

mgd. 

J. B. Foster (1962) reported that a comparison 

of the piezometric surface of the principal artesian 

aquifer in 1934 with that in 1960 showed a decline 

of 5 to 10 feet in the vicinity of Green Cove Spring 

and 15 to 20 feet in the northeastern part of the 

county 'in the vicinity of Orange Park. Although 

part of this decline may be caused by withdrawal of 

water from wells in the vicinity of Jacksonville 

northeast of Clay County, part of the decline is the 

result of subsurface leakage. 

Even though the subsurface leakage recharges the 

permeable beds of the Hawthorn and other aquifers 

overlying the principal aquifer, the water is considered lost from the standpoint of recovery because water in the shallow aquifers is not used in that area. 

Subsurface leak~ge through wells may also be harmful if water of poor quality enters an aquifer that 

contains water of good quality. 
PRINCIPAL ARTESIAN AQUIFER 191 

SURFACE DRAINAGE INTO WELLS 

In some parts of the lake region and other localities in Florida and Georgia where the surface drainage is poorly developed and where ground water 

stands several feet below the surface in wells that 

penetrate permeable aquifers, surface water is 

drained into wells constructed for that purpose. 

These drainage wells are constructed ih sinkholes 

or other depressions along margins of lakes or in 

ditches (figs. 26 and 27). 

The greatest concentration of drainage wells is 

probably in and near Orlando, Orange County, Fla., 

where more than 180 wells penetrating the Ocala 

Limestone and older formations of the principal 

artesian aquifer are used for drainage. Lichtler, 

Anderson, and Joyner ( 1964, p. 39) reported more 

than 300 drainage wells in Orange County. The 

Orange Cop.nty Highway Department owns and operates 40 drainage· wells. The Orlando Air Force 

Base has 12 drainage wells, 40 are privately owned, 

and the city of Orlando owns 90. Nearly all the 

runoff from rainfall in the city is disposed of 

through drainage wells. Before a sewage disposal 

plant was built east of Orlando, the city sewage, as 

septic tank effluent, also was drained into wells 

which are called sanitary wells. Drainage wells 

described by Unklesbay (1944, p. 31) are as much 

as 1,000 feet deep, and some sanitary wells are 

more than 850 feet deep. The casings ranged from 

5 to 18 inches in diameter and 67 to 400 feet in 

depth. Current-meter explorations indicated that 

water from the wells entered the surrounding formations at depths ranging from 70 to 400 feet; in 

the deeper wells it may enter at greater depths. 

In different parts of Orange County, the static 

water levels representing the piezometric surface 

of water in the lower part of the Hawthorn Formation, the Ocala Limestone, and older formations 

of the principal aquifer, as measured in wells 

(Stringfield, 1936, p. 162), range from a few feet 

to as much as 60 feet below the surface of the 

ground. The estimated drainage capacities of the 

wells range from less than 100 gpm to several thousand gallons per minute. The maximum capacity 

reported was 9,500 gpm for well 50 (county well 

16), about 4 miles northeast of Orlovista. 

The effects of drainage wells on recharge of the 

principal aquifer in the Orlando area, Florida, and 

the Valdosta area, Georgia, has been discussed in 

regard to water-level fluctuations caused by surface 

drainage into wells. Where the water level in the 

drainage well is at or near the level of the surface 

water to be drained, the well is not effective for 

drainage. In some areas, as at Lake Greenwood 

and Lake Davis at Orlando, where the aquifer is 

under artesian pressure and the water levels in the 

drainage wells fluctuate several feet from season to 

season, drainage wells may overflow instead of receiving water after rains during wet seasons. 

In the Miami area, Florida, the shallow aquifer 

is very permeable, and drainage wells may be effective even though the water level in the wells stands 

near the land surface. In order not to contaminate 

the potable water supply in that aquifer, the drainage wells in the Miami area are constructed along 

the coast where the ground water is salty. 

USE OF "WATER AND ITS EFFECT ON THE 

PRINCIPAL ARTESIAN AQUIFER 

The principal artesian aquifer is the. chief source 

of water for municipal, industrial, and irrigation 

supplies in the area of this report. Although the 

aquifer yields water to the large limestone springs, 

nearly all the water consumed is from wells, both 

artesian and nonartesian, in the aquifer. A report 

by Ferguson, Lingham, Love, and Vernon (1947) 

discussed the utilization of springs in Florida. 

Many springs are used for recreation. A few small 

springs are used for water supply. A few mineral 

springs are used at health resorts, such as the 

Safety Harbor Spa near the head of Tampa Bay. 

One large spring, Weekiwachee Spring, in Hernando 

County, Fla., has been considered as a source of 

water for the city of St. Petersburg if additional 

water is needed to supplement the public supply 

from wells. 

The flow of the Withlacoochee River, fed chiefly 

by Rainbow Springs, 4 miles northeast of Dunnellon in Marion County, is used to operate a hydroelectric plant. Hillsborough River, which is sustained by springs during dry seasons, is the source 

of water for the public supply of the city of Tampa. 

A few of the artesian wells in areas of artesian 

flow have been used to generate electricity, and a 

few are used to lift surface water to drain low 

areas. In some areas where the water levels in the 

wells are below the adjacent land surface, water is 

drained into the aquifer through wells. 

A preliminary estimate by MacKichan and Kammerer (1961, 1962) of ground water used in southeastern river basins was 710 mgd in 1960. Although the region includes parts of the Piedmont 

province and the Cretaceous area, it does not include 

the Florida peninsula where large quantities of 

water from the principal artesian aquifer are used 

for irrigation, public, and private supplies. 
192 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Estimates of the average consumption of water in 

Florida alone in 1960 reported by M. I. Rorabaugh 

(written commun., 1961) are as follows: 

Gallons per day 

Public supplies ----------------------------------------------------------- 502,800,000 

Private supplies for industrial and commercial 

use ________ --------------------------------------------------------------------- 657,400,000 

Large quantities of ground water are used for 

irrigation of truck crops and citrus crops in the 

Florida peninsula. The average quantity used is 

difficult to estimate because of the difference in rainfall from one growing season to another. The 

largest quantities are used for truck crops such as 

celery in Seminole, Sarasota, and Manatee Counties 

and potatoes in Volusia County. During dry seasons 

many artesian wells are used to irrigate citrus 

crops. 

Most of the public water supplies, including those 

of Savannah, Jacksonville, St. Petersburg, and Tallahassee, are from the principal artesian aquifer. 

The public supply of Tampa, Fla., was from wells 

near Tampa Bay. After salt water from Tampa Bay 

contaminated these wells, a supply was obtained 

from the Hillsborough River, which is fed during 

dry times by springs and ground water from the 

aquifer. However, ground-vvater supplies can be 

obtained from wells drilled into the aquifer at a safe 

distance inland from coastal areas of salt-water 

encroachment. The supply for Miami is from a 

very productive shallow limestone aquifer. The supply for Pensacola is from a shallow, but very productive, aquifer consisting chiefly of sand. The principal artesian aquifer in both of these areas is deeply 

buried and contains water having a relatively high 

chloride content. 

In Georgia, Stewart and Croft (1960, fig. 3) 

estimated that the total annual withdrawal of artesian water in the 10 coastal counties was 279 

mgd. Of that amount 197 mgd was for industrial 

use (fig. 47), 31 mgd for public supplies, 21 mgd for 

domestic supplies, and 30 mgd flowed continuously 

from wells for domesti~ use, stock, and game preserves. A large part of that water was not used. 

This unused water amounts to about 11 percent 

of the average daily discharge or about the same 

as that used for municipal supplies in 1957. Callahan (1960, p. 22) estimated there were 377 uncontrolled flowing wells. In the Savannah area, the 

withdrawal of water has reduced the area of flow 

and thereby reduced the loss of water by uncontrolled flow of artesian water from wells. Large 

quantities flow to waste in the areas of artesian 

flow in Florida, where Hendry and Lavender (1957) 

reported a total flow of about 54 mgd from. 967 wells. 

82° 

31° 

30° 

BRUNSWICK AREA 

32 mgd (1940) 

90 mgd (1957) 

1957 

1~30 

ST. MARYS AREA 

5 nigd (1943) 

22.6 mgd (1957) 

1955 

1LIL FERNANDINA AREA 

33 mgd (1940) 

52 mg~ (1955) 

10 MILES 

L....L..J-'-'--'-----'' 

JACKSONVILLE 

1 AREA 

35 mgd (1940) 

120 m ;d (1959) 

FIGURE 47.-Map showing consumption of artesian water 

in the principal industrial areas in coastal counties of 

Georgia and northeastern Florida. 

The principal 1ocalities of large withdrawal in 

1957 were the Brunswick area with 90 mgd and Savannah area with 60 mgd. The total estimates of 

Stewart and Croft for 1957 are valid for 1962 

(H. B. Counts, written commun., 1962). The quantity of water used for irrigation in the coastal 

counties in Georgia is only a fraction of 1 percent 

of the total discharge. 

Although these large quantities of water withdrawn from the principal artesian aquifer are re-
PRINCIPAL ARTESIAN AQUIFER 193 

markable, they are only part of the many hundreds 

of millions of gallons of water discharged naturally 

each day. The discharges of the larger limestone 

springs, which rank among the largest in the world, 

show the large capacity of the principal artesian 

aquifer. Among the largest of these springs is the 

Silver Springs group having an average flow in 

excess of the consumption of ground water for public supplies in Florida. The combined flow of the 

springs has been estimated (U.S. Congress, Senate 

Select Committee on National Water Resources, 1960, 

p. 40) to be 3, 700 mgd and the total use of water 

from both ground and surface sources was 3,799 

mgd in 1956. Much of the large quantities of ground 

water discharging naturally can be salvaged and 

used when needed. 

Proposals for a ship canal that would cut into the 

principal artesian aquifer across the Florida peninsula have been considered in the past and may be 

reconsidered in the future. A barge canal, which 

will cut the aquifer is under construction (1965). 

Therefore, a brief discussion of possible effects of 

these projects on the artesian water follows. A 

sea-level ship canal, the proposed route 13-B (U.S. 

Army, Corps of Engineers, 1933; U.S. Congress, Senate, 1936) from the Gulf of Mexico across Marion 

County, Fla., a few miles south of Silver Springs 

and Rainbow Springs to the Oklawaha and St. Johns 

Rivers and to the Atlantic Ocean by the St. Johns 

River, at an estimated cost of about $240,000,000, 

would have cut the principal artesian aquifer in 

Marion County. Discharge of artesian water into 

the canal would have lowered water levels in the 

aquifer from their present levels 40 to 50 feet above 

sea level to approxin1ately sea level along the canal 

route in Marion County. Large discharge into the 

canal would have resulted. Lowered water levels 

would have caused salt-water encroachment in the 

aquifer. Discharge of Silver Springs and Rainbow 

Springs would have been captured by underground 

flow. Water levels in the pools of the springs would 

have been lowered to a point near sea level. 

These possible effects on water levels and quality 

of water have been discussed by Paige (1936, p. 

537-570); J. S. Brown (1937, p. 589-599); Thompson, Meinzer, and Stringfield (1938, p. 87-107) ; 

Hubbert (1940, p. 785-944). The extent to which 

this lowering of water levels would affect the 

water in the aquifer some distance from the canal 

would depend on the following : ( 1) The amount by 

which the area of cross section through which the 

water flows is reduced, (2) the quantity of water 

which is diverted and discharged into the canal, 

and (3) additional recharge resulting from the lowering of water levels in the limestone. 

If the cross section of limestone through which 

the water moves were to remain constant and if 

there were no diversion of water or additional recharge, the effects on the water levels in the limestone would extend to the highest parts of the 

piezometric surface south of the canal in Polk County 

and north of the canal in Putnam County. The new 

hydraulic gradient of the water would be parallel 

to the old gradient north and south of the canal and 

would be 40 to 50 feet below the old one. The highest 

part of the piezometric surface in Polk and Putnam 

Counties would be lowered by that amount. 

However, the new gradient would actually be 

steeper than the old one, and the lowering of water 

levels in the Polk County and Putnam County recharge areas would be less than that indicated by a 

new gradient parallel to the old one. The new gradient would be steeper than the old one because the 

area of cross section through which the water is 

moving would be reduced by 40 to 50 feet, the amount 

to which the water levels are lowered along the 

canal. If it is assumed that the thickness through 

which flow occurs in that area is about 500 feet, 

the cross section of flow would be reduced about 8 to 

10 percent and would increase the gradient by that 

amount. Lowering of the water levels along the canal would cause an increase in gradient of water 

moving to the canal from the north and south. Some 

of the water that normally flows in other directions 

would be diverted tpward the canal with the lowering of water levels in the limestone. Some of the 

sinkholes which are now partially filled with unconsolidated material would be opened, permitting additional recharge. Some of the lakes which occupy 

basins in filled sinks would drain into the aquifer, 

increasing the recharge. All these factors would make 

the new gradient steeper than the old gradient. However, the available information is not adequate to 

make detailed estimates of the amount of lowering 

of the water levels some distance from the canal. 

In any case, the proposed canal would have no effect 

on the shallow aquifers at considerable distances 

from the canal, such as in the Miami area in southern 

Florida where the principal artesian aquifer is 

deeply buried·. 

The barge canal being constructed along route 

13-B has locks to hold the water levels in the canal 

at approximately the same level as .the adjacent water level in the principal artesian aquifer in Marion 

County .(Vernon, 1961, p. 1-7). Water will be 

pumped from streams fed by Silver Springs and 
194 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Rainbow Springs into the summit level of the canal 

to replace water lost in operating the locks and leakage around locks. This use of water from the springs 

is to maintain the water level in the limestone at its 

natural level adjacent to the canal. As salt water is 

present in surface streams at each end of the section 

with locks, salt water eventually will be brought up 

to the summit level as water in the locks is raised to 

that level. If the natural fresh-water head in the 

aquifer is maintained, the salt-water and freshwater balance in the aquifer will not be disturbed. 

Except in a few areas of heavy withdrawal of 

water, the present use of water has had little or no 

effect on the aquifer. Outside these local areas many 

additional water supplies can be obtained in most 

of the region of this report without depleting the 

aquifer or creating problems of salt-water encroachment. The problem of salt-water encroachment is 

confined to a few places along the coastal areas and 

to a few places away from the coast where salt 

water is in the lower part of the principal artesian 

aquifer or in formations underlying the aquifer. 

Areas where water has more than 100 ppm chloride 

are shown in figure 36. As more information becomes available, a better understanding of the distribution of this water of poor quality and its relation to the overlying fresh water will be obtained. 

The large use of water from the principal artesian 

aquifer in the Southeastern States for industrial, 

municipal, domestic, and irrigation supplies emphasizes the fact that this water is one of the most 

valuable of the mineral resources of the region. 

SUMMARY AND CONCLUSIONS 

This report is based on many previous investigations and reports, including some by the writer. 

References to the literature are cited in the various 

chapters of the report. The area of this report includes Florida, most of the Coastal Plain in Georgia, 

and adjacent parts of Alabama and South Carolina. 

The surface, in general, is characterized by a 

plain that slopes to the sea and extends beneath the 

sea as the Continental Shelf. Pleistocene marine terraces record oscillations of sea level. Coastal terraces along the Atlantic Ocean and Gulf of Mexico 

ranging from sea level to as much as 270 feet above 

sea level cover much of the report area. The landward limit of each terrace is defined by the shoreline 

at which the sea stood when the terrace was under 

water. Some of the higher terraces are dissected 

forming hilly topography. Some uplands above the 

terraces also are hilly; others are relatively level 

plateaus. The region has been uplifted sufficiently 

to cause downcutting of major streams. Valleys are 

cut as much as 100 feet below some of the uplands. 

In some areas the lower terraces have been only 

slightly modified by erosion. In areas where limestone is at or near the surface, solution of the limestone has resulted in sinkhole or karst topography. 

Many lakes in the uplands and on some of the terraces 

occupy sinkholes formed by solution of the underlying limestone. Some of the sinkhole lakes are more 

than 100 feet deep. Lake Okeechobee, which covers 

about 730 square miles in Florida, is less than 20 

feet deep. The lake basin may have originated as a 

depression in the sea bottom. 

Some of the principal streams that drain the area, 

such as the Savannah River, rise in the Piedmont 

province and flow across the Coastal Plain to the sea. 

A few of the streams that rise in the Coastal Plain, 

such as the St. Johns River on the east coast of 

Florida, were formed as parts of coastal lagoons and 

are approximately parallel to the coast. 

On the Coastal Terraces there are many areas of 

poor drainage, especially in the swamps and low 

grassy plains. There are many swamps along the 

flood plains of streams. In southern Florida the 

Everglades cover an area about 40 miles wide, which 

slopes from 15 feet above sea level at the south side 

of Lake Okeechobee to sea level at the tip of the 

peninsula, a distance of more than 100 miles. The 

Okefenokee Swamp on one of the higher terraces in 

southern Georgia and northern Florida covers an 

area of about 660 square miles. The swamp slopes 

from about 120 feet above sea level to about 100 feet. 

Most of the water drains westward into the Gulf 

of Mexico; part of it drains southward to the 

Atlantic Ocean. 

The climate of the area ranges from temperate in 

the northern part of the report area to subtropical 

in southern Flor.ida. The annual rainfall ranges 

from about 50 to 60 inches in a large part of the region. However, rainfall decreases to a minimum of 

38 inches at Key West. The average annual temperature ranges from about 65 oF in the northern part of 

the area to about 76°F on the Florida Keys. Evaporation losses from water surfaces appear to average 

40 to 45 inches a year. Experiments indicate evaporation and transpiration losses combined may range 

from 50 to more than 100 inches a year in the Everglades. 

GEOLOGIC FORMATIONS 

The geologic formations that crop out in this area 

range from Late Cretaceous to Recent in age. Igneous and metamorphic rocks which underlie the Pied-
SUMMARY AND CONCLUSIONS 195 

mont province also underlie the sedimentary rocks 

in some places in the Coastal Plain. The Cretaceous 

formations consist chiefly of sand, gravel, and clay 

in the areas where they are at or near the surface. 

The overlying Tertiary formations consist chiefly of 

limestone, dolomite, and marl, with some anhydrite 

and gypsum. Some formations grade into sands and 

other clastic material in western Florida, southeastern Alabama, the northwestern part of the Coastal 

Plain in Georgia, and adjacent parts of South Carolina. 

Pleistocene and Recent deposits of sand, gravel, 

clay, and shells generally are less than 100 feet thick. 

In southeastern Florida, the Pleistocene formations 

include 100 feet or more of limestone, marl, sand, 

and shell beds. 

The Tertiary formations are at or near the surface 

in belts approximately parallel to the Cretaceous outcrops and the Fall Line in Georgia and adjacent 

parts of Alabama and South Carolina. The Tertiary 

formations also are at or near the surface on geologic 

structures, such as the Ocala uplift in north-central 

Florida and in the Jackson County area in western 

Florida and adjacent parts of Alabama and Georgia. 

Except where affected by local structure, the formations dip gently toward the coast at right angles to 

the belts of outcrops. The formations dip in all directions from the Ocala uplift. The thickness of the 

Tertiary formations ranges from less than 1,600 feet 

in Lafayette and Suwannee Counties on the northwest side of the Ocala uplift to about 4,500 feet in 

western Florida. South of the Ocala uplift in southern Florida, the thickness increases to 5,500 feet or 

more. North of the Ocala uplift in southern Georgia, 

the thickness increases to about 2,600 feet and then 

decreases to the northward to zero in the belt of the 

outcrops adjacent to the Fall Line. In South Carolina the maximum is about 2,400 feet thick at Parris 

Island. 

The Tertiary formations are the chief source of 

ground-water supplies, except in some outcrop areas 

in Alabama, Georgia, and South Carolina, where the 

underlying Cretaceous formations may be the chief 

source. Late Tertiary and Quaternary deposits are 

the chief source of ground water in a few places, such 

as the Miami area in southeastern Florida and the 

Pensacola area in western Florida, where the principal aquifer of Tertiary age contains water of poor 

quality. 

The Midway Group of Paleocene age is at or near 

the surface only in a belt of outcrops extending from 

southeastern Alabama into central Georgia. The 

water-bearing formations include limestone and 

sand, which are important sources of water in southeastern Alabama and southwestern Georgia. The 

Clayton, an argillaceous limestone containing solution cavities, is the chief water-bearing formation in 

some areas in Georgia and Alabama. The outcrops 

of the Clayton extend as far east as central Georgia, 

where they are overlapped by younger formations. 

In Florida, Paleocene deposits are not an important 

aquifer because of low permeability or because the 

water has a relatively high chloride content. The 

estimated thickness of the Clayton along the Chattahoochee River in southeastern Alabama is about 130 

feet.· The thickness reported at Savannah, Ga., is 

385 feet. In Florida, the Paleocene is represented by 

the Cedar Keys Limestone, which ranges in thickness from about 165 feet in northern Florida to about 

2,250 feet in southern Florida. The maximum thickness of the undifferentiated clastic equivalent in 

western Florida is about 1,000 feet. 

The Eocene series, overlying the Paleocene, includes formations of Wilcox age (early Eocene), Clai.:. 

borne age (middle Eocene) , and Jackson age (late 

Eocene) . Formations consisting of sand, sandstone, 

marl, and clay of early Eocene age crop out in a belt 

across Alabama to western Georgia where they are 

overlapped by middle Eocene formations. In southeastern Alabama and southwestern Georgia, sands 

of middle Eocene age are very permeable. The N anafalia forms an excellent aquifer as much as 100 feet 

thick in Alabama. The sands and other clastic formations in Florida and southeastern Georgia merge 

into dolomite and limestone. In South Carolina, the 

Black Mingo Formation, as much as 250 feet thick, 

represents the early Eocene. The formation consists 

of sand and clay, but the permeability is so small 

that it is of no significance as an aquifer. 

The Oldsmar Limestone represents the early Eocene in the Florida peninsula. It grades into a sandy 

facies in western Florida. It is less than 250 feet thick 

in the northern part of the peninsula over the Ocala 

uplift but increases in thickness to more than 1,000 

feet in the southern part of Florida. Little information is available on the water-bearing properties of 

the Oldsmar. Most, if not all, of the water in the 

Oldsmar is salty. However, a sample of water from 

a depth of 2,258 feet in the South Lake well in Lake 

County, Fla., had a chloride content of...pnly 781 ppm, 

indicating that some parts of the formation are 

almost completely flushed of salty water. 

Middle Eocene formations overlying the Oldsmar 

Limestone consist chiefly of limestone and dolomite 

in Florida and southeastern Georgia. They are represented by the Lake City Limestone and A von Park 
196 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Limestone in the peninsula and by undifferentiated 

clastics in the Florida panhandle. The Tallahassee 

Limestone forms part of the middle Eocene in the 

panhandle and part of the peninsula. 

The Lake City Limestone is the oldest and deepest 

of the water-bearing formations of the principal 

aquifer in Florida and southeastern Georgia. It overlies the Oldsmar unconformably and is overlain unconformably by the Tallahassee Limestone or the 

A von Park Limestone. In the Tallahassee area and in 

the northern part of the Florida peninsula, the Lake 

City Limestone is 400 to 500 feet thick. In the central part of the Florida peninsula in Lake County, 

it is about 990 feet thick, with the top about 1,010 

feet below sea level. It is 420 feet thick in Polk 

County with the top about 1,540 feet below sea level. 

The clastic facies in western Florida thickens from 

about 575 feet in Jackson County to 800 feet in Walton County, Fla. 

In central and north-central Florida, the Lake City 

is a productive water-bearing formation. The formation does not occur at or near the surface. It is 

recharged through sinkholes filled with permeable 

sands and through lakes which occupy sinkholes. 

Because wells as much as 1,550 feet deep yield relatively soft calcium bicarbonate water from the .Lake 

City Limestone in Highlands County, Fla., local recharge is indicated. The mineral content of water 

from the Lake City Limestone is relatively low and is 

less than that in the overlying Avon Park and Ocala 

Limestones in some areas such as Seminole County, 

Fla. The low mineral content may be du.e to local recharge and relative solubility of the different formations. Silicified limestone, chert, and some dolomite 

in the Lake City Limestone may be less soluble than 

the pure limestone in the overlying formations. 

The A von Park Limestone, consisting chiefly of 

chalky limestone and dolomite, unconformably overlies the Lake City Limestone at the type locality be- · 

tween depths of 600 and 930 feet in a well at A von 

Park in Polk County in central Florida. The Tallahassee Limestone,. where recognized as a formation, 

underlies the Avon Park Limestone. At the type locality, the Avon Park Limestone is overlain by the 

lower member of the Ocala Limestone. The A von 

Park Limestone is the oldest of the Eocene formations exposed in Florida. However, surface exposures 

have been found only on the Ocala uplift in Citrus 

and Levy Counties. The A von Park is very permeable and cavernous in some areas. It is one of the 

most productive water-bearing formations of the 

principal artesian aquifer in parts of Florida and 

southeastern Georgia. In the Fernandina area, Florida, it apparently is less productive than in some 

other parts of Florida. The thickness of the formation is 50 feet or less in the northern part of the peninsula, 150 to 300 feet in the central part, and 450 to 

650 feet thick in the southern part. A maximum of 

845 feet has been reported in Polk County. In westtern Florida and adjacent parts of Alabama and 

Georgia the beds of equivalent age include glauconitic, calcareous sands, cherty limestone, and fossiliferous bentonitic clay. These beds are correlated with 

the Gosport Sand and Lisbon Formation in part. 

In southeastern Alabama and adjacent parts of 

Georgia, the middle Eocene formations include the 

Tallahatta, Lisbon, and Gosport Formations. In 

South Carolina, the middle Eocene consists of the 

Congaree Formation at the bottom, overlain by the 

Warley Hill, Santee, and McBean Formations, with 

the Castle Hayne Limestone at the top. The formations consist chiefly of sands and other marine clastics that grade into limestone downdip in Florida. 

Upper Eocene formations are separated from the 

underlying middle Eocene series by an inconspicuous 

disconformity in some areas. In southeastern Alabama, the upper Eocene formations consist of the 

Moodys Branch Formation overlain by the Yazoo 

Clay and by the Ocala Limestone. In Escambia 

County, Ala., the Moodys Branch Formation, 55 feet 

thick, consists of glauconitic limestone and marl. It 

is relatively impermeable but may be the source of 

small quantities of water. The Yazoo Clay, 75 feet 

thick, consists of clay and glauconitic sand which is 

the source of small quantities of water. The Ocala 

Limestone, 60 feet thick, conta~ns solution cavities 

which yield moderate amounts of water to wells. In 

Florida and southeastern Georgia, the Ocala Limestone, with upper and lower members, represents the 

upper Eocene rocks. It rests unconformably on older 

Eocene formations. In the outcrop area in eastcentral Georgia the Ocala merges laterally with the 

Barnwell Formation, which is a marine pebbly sand 

and sandy limestone. 

The Florida Geological Survey regards the Ocala 

Limestone as a group consisting of, from bottom to 

top, the Inglis Formation, Williston Formation, and 

the Crystal River Formation. In the present report 

the upper member of the Ocala Limestone is considered the equivalent of the Crystal River, and the 

lower member, the equivalent of the Inglis and Williston Formations. 

The Ocala Limestone is about 100 to 300 feet thick 

in much of the panhandle of Florida, but it is much 

thicker in the Apalachicola embayment. It is thin in 

most of the central and northern part of the penin-
SUMMARY AND CONCLUSIONS 197 

sula but reaches a thickness of 400 feet in the northeastern part. In the southern part of the peninsula, 

it generally is 200 feet or less thick and probably is 

absent in the vicinity of Miami and Key West. 

In addition to a belt of outcrops extending from 

Alabama into Georgia, the Ocala Limestone crops 

out in two large areas in Florida. The largest area 

borders the gulf coast in the northwestern part of the 

Florida peninsula on the Ocala uplift. The other area 

is in western Florida in the north half of Washington 

and Jackson Counties and the eastern part of Holmes 

County. The outcrop area of the Ocala extends from 

western Florida into southeastern Alabama, then 

northeastward into east-central Georgia, where it 

merges with the Barnwell Formation. The Barnwell 

in the outcrop area and the Ocala downdip in Georgia extend into South Carolina. 

In the peninsula and northern Florida, the Ocala 

overlies the eroded surface of the Avon Park Limestone except at Live Oak, Suwannee County, and at 

Lake City, Columbia County, where the Avon Park 

is absent and the Ocala rests on the nonfossiliferous 

lower unit of the late middle Eocene. In Duval and 

Clay Counties, the Ocala rests on the basal part of 

the Avon Park. In western Florida where late middle Eocene formations are absent the Ocala apparently lies on deposits of early middle Eocene age. 

In the Florida peninsula it is usually possible to 

separate the Ocala into an upper and a lower member. The upper member is the typical limestone exposed at the surface on the Ocala uplift. It is a soft 

white chalky permeable limestone consisting chiefly 

of large foraminifers. The basal beds may contain a 

few beds of secondary dolomite as much as 12 feet 

thick. The youngest part of the upper member has 

been removed by erosion in the area of outcrop. The 

maximum thickness reported for the upper member 

is 380 feet. 

The lower member of the Ocala, the equivalent of 

the Inglis and "'illiston Formations of the Florida 

Geological Survey, is generally harder than the upper member and is commonly very calcitic. The In- · 

glis is 50 feet thick near Inglis in Levy County. The 

maximum thickness may be more than 100 feet. The 

base is generally marked by a barnacle bed and rubble of pebbles, concretions, and soil eroded from the 

underlying Avon Park Limestone. The Williston is 

about 30 feet thick and conformably overlies the 

Inglis. Silicified limestone is common in outcrops and 

generally is near the contact with the Inglis. 

In western Florida, these units of the Ocala apparently cannot be recognized. The upper and lower 

members are recognized in Georgia. 

The Ocala Limestone is one of the major waterbearing formations of the principal artesian aquifer. 

Some parts of the limestone are very permeable. 

Solution channels formerly occupied by water but 

now filled with sand and clay are exposed in some 

of the limestone quarries in Marion County, Fla. 

One exposed cavern has a vertical dimension of 30 

feet. 

The chert and silicified limestone are relatively 

impervious and do not yield water to wells, but water is commonly encountered beneath these rocks. 

The Flint River Formation appears to be the updip equivalent of the Suwannee and consists chiefly 

of siliceous limestone, residual chert, and sandy clay, 

representing the Oligocene in the Flint River valley 

in southwestern Georgia. The Cooper Marl in South 

Carolina and Georgia is of Oligocene age. 

In southeastern Alabama, the Oligocene includes 

( 1) the Marianna Limestone with the Red Bluff 

Clay at its base, (2) the Byram Formation, and (3) 

the Chickasawhay Limestone at the top. The Byram Formation includes the Bucatunna Clay at the 

top, a marl member in the middle, and the Glendon 

Limestone Member at the bottom. In the Florida 

panhandle, the Marianna Limestone is present with 

the Red Bluff Clay at the base. The equivalents of 

the Byram and Chickasawhay are not easily differentiated. However, the Bucatunna Clay has been 

recognized in Santa Rosa and Escambia Counties, 

where it separates the principal artesian aquifer 

into two parts. 

The Oligocene Series thickens downdip to a maximum of 800 feet in the Apalachicola areaJ Florida. 

The Suwannee Limestone, one of the most extensive of the Oligocene formations, crops out in the 

Suwannee River valley in Florida. It is at or near 

the surface in the west-central part of the peninsula. It is absent in southwestern Georgia and 

throughout the eastern and central parts of the 

peninsula, as far south as Palm Beach County on 

the Atlantic coast. In north-central Florida it is absent from coast to coast. 

The maximum thickness of the Suwannee in Georgia is about 200 feet in the south-central part near 

F1orida. It is 300 to 350 feet thick at Tallahassee 

and 450 feet thick in a well at Key West. 

Although the Suwannee is not as extensive as the 

underlying limestone of Eocene age, it is one of the 

major water-bearing formations of the principal 

artesian aquifer. The limestone contains many solution cavities which yield large quantities of water 

to wells. Parts of the limestone consisting chiefly of 

foraminifers are very permeable. The Cooper Marl 
198 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

in Georgia and South Carolina yields little or no 

water to wells. At Charleston, S.C., the permeability is so low that an unlined tunnel in the marl is 

used as a conduit for the public water supply. 

Miocene time may be divided into three parts in 

the area of this report. Each part was ushered in 

by an expansion of the sea upon land. In Florida 

and Georgia, the early Miocene is represented by the 

Tampa Limestone, which lies on the eroded surface 

of Eocene limestone or on the Suwannee Limestone 

and Flint River Formation of Oligocene age. 

In middle Miocene time, the sea may have spread 

out over all of Florida and covered part of Georgia, 

South Carolina, and Alabama. In western Florida, 

the Alum Bluff Group, consisting of the Chipola Formation and the overlying Shoal River Formation including the Oak Grove Sand Member, was deposited. 

The Hawthorn Formation was deposited in the remainder of the area covered by the middle Miocene 

sea. 

After the Hawthorn was deposited, the sea presumably withdrew beyond the present shoreline. 

In late Miocene time, the sea advanced and the 

Duplin Marl was deposited in some areas. 

The Tampa Limestone is at or near the surface 

in two general areas in Florida. One area, which 

includes the type locality near Tampa, is in Hillsborough, Pasco, and adjacent parts of Pinellas 

County. The other area is in the panhandle and extends westward from the Apalachicola River valley 

in western Gadsden and Liberty Counties to the 

west side of Holmes County. It extends from Florida 

into Georgia and South Carolina but is absent in 

eastern and northeastern Florida. 

The thickest natural exposure of the Tampa 

Limestone is 117 feet on the Apalachicola River at 

Chattahoochee, Fla. In southern Florida, it is as 

much as 250 feet thick. The Tampa unconformably 

overlies Oligocene and Eocene limestone formations. It is overlain by the Hawthorn Formation. 

In some places the Tampa appears to merge upward 

into the overlying Hawthorn; in other places the 

two formations appear to be separated by an unconformity. 

The Tampa generally consists of relatively impure limestone with considerable clay and sand in 

contrast to the Suwannee. However, in some places 

the Tampa also contains much pure limestone, ranging from 73 to 96 percent calcium carbonate. In 

some places, the limestone has been replaced by 

silica, which ranges from 20 to 70 percent. The 

Tampa is an important water-bearing formation 

of the principal artesian aquifer. 

The Hawthorn Formation consists essentially of 

as much as several hundred feet of interbedded 

clay, sand, limestone, and sandy phosphatic limestone and marl. Lenses of fuller's earth are widely 

distributed in the Hawthorn. Extensive deposits in 

the east half of Gadsden County in western Florida 

have been mined many years. 

The maximum thickness of the Hawthorn is 

about 550 feet in southeastern Florida. It is almost 

500 feet thick in northeastern Florida. It is thin or 

absent in north-central Florida, western Florida, 

and other places where older Miocene or Eocene 

formations are exposed. Except in southeastern 

Florida, the top of the formation is at or near the 

surface. In southeastern Florida, it is overlain by 

more than 100 feet of younger formations, which 

form the productive shallow aquifer in that area. 

The Hawthorn includes some permeable, waterbearing beds of sand, limestone, and marl, above and 

below which are less permeable beds. In some localities the water-bearing limestone contains solution 

channels that yield water to wells and springs. In 

general the lower part of the formation yields the 

most water, but usually wells supplied by water from 

the Hawthorn have only moderate yields. Where 

large supplies are required, the wells are drilled into 

the underlying limestone. With adequate development, however, relatively large supplies of water 

can be obtained from the formation. Much of the 

water is under artesian pressure, and the pressure in 

the lower part of the formation is comparable with 

that in the underlying limestone of the principal 

artesian aquifer. Under these conditions, the lower 

part of the Hawthorn constitutes the top of the 

principal artesian aquifer~ The relatively impervious clay and marl beds in the formation prevent or 

retard upward movement of artesian water. 

The Tamiami Formation, now assigned to late 

Miocene age and consisting of limestone, sand, and 

marl in the Miami area, Florida, was formerly regarded as Pliocene in age. It is as much as 150 feet 

thick in southern Florida. Permeable limestone in 

the upper part forms the lower part of the very 

productive shallow aquifer, which ranges in age from 

the late Miocene to Recent. 

The Duplin Marl of late Miocene age in South 

Carolina locally yields small supplies of hard water. 

The Alachua and Bone Valley Formations, considered Pliocene by the U.S. Geological Survey, in 

west-central Florida appear to range from Miocene 

to Pliocene. Both formations are at or near the surface and contain phosphate deposits. The Alachua 

contains the valuable hard rock phosphate deposits 
SUMMARY AND CONCLUSIONS 199 

of Florida. The Bone Valley Formation is the source 

of the pebble phosphate deposits of Florida. The 

Alachua is as much as 75 to 100 feet thick and overlies an irregular, eroded surface of the Ocala and 

older Eocene limestone, on which are residual pieces 

of Suwannee Limestone. This solution-pitted erosion surface was probably formed before the Hawthorn and Alachua Formations were deposited. The 

Bone Valley Formation, with a maximum thickness 

of about 50 feet, was apparently deposited in a 

broad delta of a stream that flowed southward into 

the ocean. Some parts of the formation may be 

from the Hawthorn, weathering in place. Although 

these formations contain permeable sands which 

probably would yield water to wells, they are not 

known to be important aquifers. 

In the present report, the Caloosahatchee Marl, 

Charlton Fo~mation, Waccamaw Formation, and 

Citronelle Formation· are included in the Pliocene. 

These formations, except the Citronelle, include 

shell marl and limestones and occur as surficial formations. The Citronelle consists chiefly of brown or 

orange sand, gravel, and clay on the uplands but extends under the highest and oldest Pleistocene terrace. The Caloosahatchee occurs in southeastern 

Florida where the maximum thickness is probably 

about 50 feet. The Charlton is in northeastern 

Florida and adjacent parts of Georgia. The Waccamaw Formation is in South Carolina, with a maximum thickness of 40 feet. 

All these formations will yield water to wells. The 

mineral content and hardness of the water from the 

Citronelle generally is low. Water from the formations which contain limestone and marl is hard. 

Pleistocene and Recent surficial sands cover most 

of the area. Shorelines of marine terraces up to 270 

feet above sea level have been recognized. Locally 

the sand is the source of shallow water supplies. 

Among the largest supplies from the shallow sands 

is the public supply for Pens2.cola, Fla. 

The Fort Thompson Formation, Miami Ooolite, 

Key Largo Limestone, Anastasia Formation, and 

Lake Flirt Marl consist chiefly of limestone, marl, 

and coquina. All are present only in southeastern 

Florida, except the Anastasia Formation, which extends along the east coast from Anastasia Island, St. 

Johns County, to the south boundary of Broward 

County, where it merges with the Miami Oolite. It 

extends westward into the Lake Okeechobee-Everglades area where it forms the marine members of 

the Fort Thompson Formation. The Anastasia Formation, which is chiefly coquina, and the Miami 

Oolite, which is oolitic limestone, form the Atlantic 

Coastal Ridge where both formations reach the 

maximum thickness. The maximum thickness of 

the Anastasia may exceed 100 feet. The thickness of 

the Miami Oolite may be as much as 40 feet. It is 

crossbedded to massive with many vertical and horizontal solution channels filled with permeable quartz 

sand. It' yields large quantities of water to wells and 

forms the upper part of the shallow aquifer which is 

the municipal source of water of the Miami area and 

other parts of southeastern Florida. The Fort 

Thompson Formation consists of only about 6 feet 

of alternating fresh-water, marine, and brackishwater marls, limestone and shell beds, and sand at 

Fort Thompson, its type locality, near La Belle, west 

of Lake Okeechobee. It underlies all of the Everglades and extends to the coast. In the Miami area, 

it has an average thickness of about 80 feet. It has 

vertical and horizontal solution channels like the 

overlying Miami Oolite. Most of the channels are 

filled with permeable sands. The Fort Thompson is 

one of the principal sources of fresh ground water 

in southeastern Florida. 

The Key Largo Limestone is chiefly a fossil coral 

reef which interfingers with the Miami Oolite and 

the Fort Thompson Formation in the Miami area. 

It underlies the Florida Keys. The Key Largo Limestone is very permeable but is exposed to sea water. 

Locally small supplies of fresh water floating on 

the salt water may be obtained from the formation. 

The Pleistocene terraces from sea level to 270 

feet above sea level consist chiefly of sands which 

are a good source of water for shallow wells in many 

areas. Seven marine shorelines from 25 to 270 feet 

above sea level are recognized. These are approximately parallel to the present coastline and extend 

up the valleys of some of the streams. A shoreline 

about 5 to 8 feet above sea level, formerly assigned 

to Recent time, is now assigned to the Pleistocene. 

The Pleistocene shorelines may be divided into 

four groups, three of which formed during three 

interglacial stages and the fourth in a recession in 

the Wisconsin Glaciation. The first group consists 

of the Hazlehurst, the highest and oldest of the 

Pleistocene shorelines, which was formed at an altitude of about 270 feet during the Aftonian Interglaciation following the Nebraskan Glaciation. The sea 

then declined to a level below its present level during 

the Kansan Glaciation. The second group consists of 

the Coharie at an altitude of about 215 feet, the 

Sunderland at about 170 feet, Okefenokee at 150 

feet, Wicomico at 100 feet, Penholoway at 70 feet, 

and Talbot at 42 feet. These formed after the Kansan Glaciation and during the Yarmouth Intergla-
200 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

ciation, when the sea rose to about 215 feet above 

the present level and then declined. The sea halted 

at the 170-foot level and lower levels as it declined. 

During Illinoian Glaciation, emergence continued 

with the accumulation of continental ice. 

At the close of the Illinoian Glaciation, the sea 

rose to 25 feet above its present level during the 

Sangamon Interglaciation when the Pamlico shoreline was formed. At the end of the Sangamon Interglaciation, the sea retreated below its present 

level and then rose about 6 feet above its present 

level in middle Wisconsin time at which time the 

Silver Bluff terrace was formed. 

·These advances and retreats of the sea had a significant effect on the solution of the limestone and 

the permeability of the Tertiary limestone. The salinity of the water also was affected in some coastal 

areas. 

GEOLOGIC STRUCTURE 

The formations dip in general toward the coasts 

except for broad gentle anticlines and basins including the (1) peninsular arch, (2) Ocala uplift, (3) 

Chattahoochee anticline, ( 4) Apalachicola embayment, ( 5) southwestern Georgia embayment, ( 6) 

southeastern Georgia embayment, and (7) the 

southern Florida embayment. 

The peninsular arch, a dominant structural feature, forms the axis of the Florida peninsula from 

southern Georgia to the vicinity of Lake Okeechobee. 

Its crest of Paleozoic sedimentary rocks is about 

60 miles west of Jacksonville. The crest was above 

sea level in Early Cretaceous and part of Late Cretaceous time, but sediments were deposited around 

it. During the remainder of Late Cretaceous and 

early Tertiary time, sedimentation was continuous 

with the exception of intervals of general emergence, as for example, at the end of the Cretaceous. 

The Ocala uplift was formed in Tertiary sediments as a gentle flexure approximately 230 miles 

long and 70 miles wide where exposed in the peninsula. During Miocene time, the northern part of 

the peninsula was affected by the Ocala uplift in 

Levy and Citrus Counties. The crest of the structure is as much as 150 feet above sea level southwest 

of the crest of the peninsular arch. The uplift resulted in the complete removal of Oligocene rock 

and the irregular ·erosion of the late Eocene rocks 

over a broad arch. On the east flank of the uplift, 

an arch extends to the coast at New Smyrna. 

Vernon (1951) showed that the north side of the 

uplift is composed of two shallow folds which converge southward in Levy and Citrus Counties, where 

they are separated by only a few miles and their 

crests are extensively fractured and faulted. On the 

southeast flank, one of the folds merges with a 

wedge-shaped block (Kissimmee faulted structure) 

approximately 90 miles long. It is 54 miles wide 

on the northwest border and 17 miles wide on the 

southeast margin. It is bounded by faults except on 

the northwest side. The fault on the southeast side 

forms the northwest boundary of a triangular block, 

the Osceola low in Osceola County. This faulted 

structure crosses the New Smyrna arch. East of the 

Kissimmee faulted flexure in Seminole and Volusia 

Counties, Vernon mapped a relatively high area of 

the arch as the Seminole high. 

A regional pattern of joints or fractures consists 

of two systems--one trending northwest-southeast, 

parallel to the axis of the Ocala uplift, and the 

other, northeast-southwest. The two systems form 

approximately a rectangular pattern as shown by 

Vernon. In addition to the regional pattern there are 

local joint patterns such as those in Union County, 

Fla., over the crest of the peninsular arch and the 

Osceola low. The pattern in Union County is radial, 

resembling the fracturing over structural domes. 

The pattern in Osceola County is similar to that on 

the Ocala uplift, but the northwest trend is more 

westerly than on the uplift. 

The jointing and fracturing on the Ocala uplift 

appear to reflect structural movement during late 

Tertiary. The patterns in Union and Osceola Counties may reflect adjustment of relatively unconsolidated sediments over stable pre-Mesozoic rock. 

SOLUTION IN LIMESTONE 

The water-bearing capacity of carbonate and associated rocks depends in part on the original permeability of the formation and on the secondary 

permeability which is formed by fracturing, solution, and other processes after the beds have been 

formed. The permeability due to solution of limestone, dolomite, anhydrite, and gypsum accounts 

for much of the large yield of the Tertiary and 

Quaternary limestone aquifers. 

Solution cavities are numerous in the aquifer and 

also are reported to occur in the older Eocene and 

Cretaceous formations. The record of a well in 

Monroe County, Fla., shows a cavity 18 feet high 

between 2,846 and 2,864 feet; one 4 feet high between 2,959 and 2,963 feet; and one 11 feet high 

between 2,986 and 2,997. Among the deeper cavities 

reported is one 40 feet high at a depth of 6,100 

feet in Collier County. Also, an oil-producing horizon at depths of 11,613 to 11,262 feet in the Sunni-
SUMMARY AND CONCLUSIONS 201 

land field in Collier County is cavernous limestone 

(Hughes, 1944, p. 75). These cavities at great depths 

were developed whEm the formations were nearer 

to the surface where water could enter the aquifer 

and discharge from it. The water in the deep cavities is essentially static without discharge. The discharge at submarine outcrops is controlled by the 

relation of the fresh-water head and the back pressure from the salt water. 

After deposition in the sea, most of the waterbearing formations of the principal artesian aquifer 

were exposed above sea level, and solution cavities 

formed in the limestone and other carbonate rocks 

before they were covered by the sea and by a younger 

formation. Many solution cavities were filled by 

the overlying formations. The cavities filled with 

Pleistocene and Recent deposits formed since the 

deposition of the Citronelle Formation, which is regarded as Pliocene in the present report. 

Although sinkholes are formed and solution cavities may be enlarged above the water table, a cavity 

in the zone of saturation near the water table is 

enlarged continuously by water, and the opportunity for solution in this zone is therefore greater 

than that in the zone of aeration. Solution channels 

in caves show that most of the solution has occurred 

in the zone of saturation. Solution which forms 

vertical pipes, natural wells, and similar features 

occurs chiefly in the zone of aeration. 

Most of the cavities penetrated by wells in the 

principal artesian aquifer at different depths seem 

to be in zones which correlate with levels at which 

the sea paused in its declines and rises in Pleistocene 

time. The principal artesian aquifer probably has 

caves and solution channels comparable in size 

and extent to those in Mammoth Cave, Ky. However, only the caves near the land surface, as in 

Marianna State Park in western Florida, are above 

the zone of saturation at the present time. In general, the solution cavities and channels are developed 

by vertical and lateral circulation of water. The 

vertical pipes and natural wells and similar features 

are formed by downward movement of water, chiefly 

in the zone of aeration. The horizontal cavities and 

channels are formed in the zone of saturation. 

Sinkholes generally are caused by solution and by 

collapse of the roofs of underground channels and 

caverns. Sinkhole topography, also known as karst 

topography, has formed chiefly in areas where the 

limestone is at or near the surface. As the Hawthorn 

Formation was removed by erosion in Florida and 

Georgia, more and more surface drainage went underground into solution channels. Sinkholes for:med 

in the Hawthorn and in the underlying limestone 

as the Hawthorn was eroded. The removal of .the 

Hawthorn progressed from parts of the coastline 

and from streams which cut into the underlying 

limestone. The escarpment formed by the more 

resistant beds of the Hawthorn retreated from the 

coast and from some of the streams. For example, 

in Leon, Wakulla, and Jefferson Counties, in Florida, an escarpment which is now at the edge of the 

Tallahassee Hills retreated northward from the 

coast to its present position, while surface erosion 

and underground solution removed the Hawthorn 

and part of the underlying limestone. In southwestern Georgia, the Flint River cut through the 

Hawthorn into the underlying Ocala Limestone. 

The escarpment formed by resistant beds of the 

Hawthorn retreated to the southeast to its present 

position. 

Where the Hawthorn was removed in Florida and 

Georgia, karst topography similar to that on the 

Pennyroyal Plateau of Kentucky developed. How-. 

ever the area was modified by invasions of the Pleistocene sea. The submarine conditions probably were 

similar to those at the present time in the submerged karst topography in the Gulf of Mexico 

west of the coast of Florida from Pinellas County 

to Wakulla County. 

Sinkholes are being formed at the present time 

in areas where (1) the limestone is near the surface, (2) the water level in the limestone is near 

the surface, and (3) the material overlying the 

limestone is too weak to prevent collapse into the 

underground streams. Sinks are not known to form 

in areas of artesian flow because the limestone is 

overlain by relatively impervious beds thick enough 

to prevent· collapse into underground cavities. The 

water in the cavities is under artesian pressure 

which gives some support to the roof of the cavity. 

Lake basins due to solution of limestone are 

chiefly in areas where the limestone is at or near the 

surface. However, in the upland ridge section of 

southern Florida, as in Polk and Highlands Counties, sinkholes which later became lake basins formed 

in areas where the limestone is as much ''as several 

hundred feet below the land surface. The basins 

range from a few feet to several miles in diameter. 

The depths range from a few feet to more than 200 

feet. The deepest lakes recorded have a diameter 

of 600 feet or less. 

Although the direction of artesian water may be 

controlled over considerable distances by geologic 

structure and although the movement may be parallel to the dip of the formations, the relative positions 
202 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

of the recharge and discharge areas are generally 

more important than the geologic structure in controlling the di_rection of movement of ~he water. In 

many parts of the Coastal Plain, the artesian aquifer is exposed . at the surface, and it dips toward 

the coast beneath relatively impervious beds which 

prevent upward movement of the water. In these 

areas, the gradient of the artesian water is generally 

parallel to the dip. However, where there is no discharge area downdip, the water will move in the 

direction of the nearest discharge area, which may 

not be in the same direction as the dip. A comparison of the direction of movement of the water in 

Polk County with the structure of the aquifer shows 

that the water moves laterally in all directions from 

the recharge area without being affected by the 

structure of the limestone. 

Joints or fractures and bedding planes may 

have a pronounced effect on the patterns of movement of water in limestone and other carbonate 

rocks. Most of the vertical pipes or natural wells, 

also known as vertical shafts, apparently form at 

the intersection of two sets of joints. Long narrow 

vertical openings develop along joint planes. Lateral 

movement of the water may be along bedding planes · 

locally but the movement does not appear to. be 

affected by the regional structure. 

Faults may affect both vertical and lateral movement of the water in some areas, such as the Balcones fault zone in the Coastal Plain in Texas. 

Major and minor faults are recognized in Florida, 

but the faulting occurred prior to the development, 

in Pleistocene time, of solution in the limestone. 

The faults therefore appear to have little or no effect on the movement of the water and the quality 

of the water. Some shallow local faulting occurs 

in areas where solution of the limestone has caused 

a collapse of the overlying material. However, these 

structures have little or no effect on the lateral 

movement of the water. 

ARTESIAN AQUIFERS 

Artesian aquifers in the Tertiary limestone of 

the Southeastern States consist of many local aquifers and one principal aquifer. The principal aquifer underlies Florida, southern Georgia, and adjacent 

parts of South Carolina and Alabama. Most of the 

local artesian aquifers consist of sand and limestone 

in the Hawthorn Formation. In some places sand 

and other permeable material overlying the Hawthorn contain water under artesian pressure. These 

shallow artesian aquifers generally do not yield large 

quantities of water. Where large supplies are required, wells are drilled into the underlying principal artesian aquifer, except in areas where the deep 

artesian water is too highly mineralized to be satisfactory for use. 

The most productive shallow aquifer in the area 

of this report is in southeastern Florida, where the 

aquifer extends from the surface to a depth of more 

than 100 feet in the Miami area. It consists chiefly 

of cavernous sandy limestone and calcareous sandstone, ranging in age from late Miocene to Recent. 

Most of the cavities are filled with permeable sand. 

The transmissibility of the shallow aquifer in the 

Miami area ranges from 4 to 15 mgd per ft. If 

there were a thickness of 100 feet, the average 

permeability would range from 40,000 to 150,000 

gpd per sq ft. Wells 18 inches in diameter yield as 

much as 5 mgd, with a drawdown of 2 to· 3 feet. 

The principal artesian aquifer, which is the source 

of practically all the artesian water in Florida and 

southeastern Georgia, consists chiefly of limestone 

ranging from middle Eocene to middle Miocene in 

age. It is as much as 1,500 feet thick. In Florida, 

the top of the aquifer ranges in altitude from more 

than 100 feet above sea level on the Ocala uplift and 

the Chattahoochee anticline to as much as 1,000 

feet below sea level in southeastern Florida. The 

maximum altitude of the aquifer is as much as 300 

feet above sea level in the belt where it crops out in 

Georgia, South Carolina, and Alabama. The aquifer 

includes the following formations or equivalents, 

from bottom to top: Lake City, Tallahassee, and 

A von Park Limestones of middle Eocene age, Ocala 

Limestone of late Eocene age, Marianna Limestone, 

Suwannee Limestone, and Flint River Formation of 

Oligocene age, and the Tampa Limestone and the 

lower part of the Hawthorn Formation of Miocene 

age. 

In southwestern Georgia and southeastern Alabama, where the Tertiary limestone formations 

merge into sandy formations, some act as separate 

aquifers. These have been designated in Georgia 

as Paleocene and Eocene limestone-sand aquifers. 

In Florida, the. principal artesian aquifer is also 

called the Floridan aquifer. In the present report 

it is designated as the principal artesian aquifer 

because it is the principal aquifer in a large part of 

Florida and southeastern Georgia. In South Carolina and parts of Georgia and Alabama, where the 

Tertiary formations are thin or absent, the principal aquifers may be sands of Cretaceous age. In 

southeastern and western Florida and other areas 

where water in the principal artesian aquifer is too 

hi gh1y mineralized to be satisfactory for most uses, 
SUMMARY AND CONCLUSIONS 203 

shallow aquifers are the principal source of ground 

water. 

As a hydrologic unit, the. principal artesian aquifer is unusual in its great thickness and areal extent. It is the source of the large limestone springs 

in Florida and Georgia. Silver Springs, in the northcentral part of Florida near Ocala, is one of the 

largest, if not the largest, limestone spring in .the 

world. The aquifer yields water to thousands of 

artesian wells, which are the source of some of the 

largest ground-water supplies in the country. 

Parts of the aquifer consist chiefly of soft masses 

of foraminifers or coquina that is very permeable. 

Part of the Ocala Limestone is chalky without 

bedding planes. Some of the formations are bedded. 

Many formations contain dolomite, dolomitic limestone, anhydrite, and gypsum. Apparently, all the 

formations have two intersecting joint systems. 

Solution of the limestone along these joints, fractures, and bedding planes forms channels and 

cavities which account for the very large waterbearing capacity of the aquifer. In general, the 

cavities are largest and most numerous where the 

aquifer is near the surface, as on the crest of the 

Ocala uplift in north-central Florida and in regions 

where sinkholes extend to the aquifer. 

The transmissibility of the aquifer differs considerably from place to place and at different depths. 

However, most if not all the wells yield water. In 

some places, as in southwestern Florida, the transmissibility decreases with depth. In others, as in 

Highlands County, Fla., the Lake City Limestone 

at the bottom of the aquifer is reported to be more 

productive than the overlying A von Park Limestone. 

The greatest transmissibility of the aquifer probably is in the cavernous limestone in the areas of 

the large limestone springs. 

The coefficient of transmissibility of the aquifer, 

as computed from a test on a well 26 inches in diameter and 1,200 feet deep in the vicinity of Lakeland 

in northwestern Polk County, Fla., is 1,000,000 gpd 

per ft. The average permeability estimated from 

that test is 1,100 gpd per sq ft, about 300 less than 

the highest average permeability re~orded at Jacksonville, even though the aquifer appears to be more 

cavernous in the Lakeland area than the Jacksonville area. This difference in permeability of the 

aquifer in the two areas may be due in part to the 

fact that many of the cavities in the Lakeland area 

may be filled with sand and clay that entered the 

cavities through sinkholes. The differences in transmissibility from one area to another in the coastal 

area of Georgia and northwestern Florida are 

large enough to be revealed by the shape of the 

piezometric surface in areas of large withdrawal 

of water. 

In the vicinity of Jacksonville, tests indicate that 

the transmissibility of the aquifer ranges from 50,-

000 to 1,000,000 gpd per ft. The smallest is from a 

well that penetrates only 250 feet of the aquifer, 

and the largest is from a well that penetrates 700 

feet. Much of· the water is from cavities in the 

limestone. The transmissibility from a well that 

penetrates 550 fe~t of the aquifer at Fernandina, 

Nassau County, Fla., is about 150,000. This gives 

a permeability of about 260 gpd per sq ft, which is 

only slightly more than the upper 250 feet of the 

aquifer at Jacksonville. 

Tests indicate that the coefficient of storage is 

about 0.00025 at Fernandina and 0.017 at Jacksonville. In Georgia, tests on wells give an average 

transmissibility of 250,000 gpd per ft and a coefficient of storage of 0.0003 for the aquifer in the immediate vicinity of Savannah. Southwest of Savannah at Camp Stewart, near Hinesville, Liberty 

County, the transmissibility is 780,000 gpd per ft. 

Farther south, in Glynn County, the results of the 

tests show a range of 75,000 to 1,000,000 gpd per 

ft. In the St. Marys area, in Camden County near 

the Florida State line and the Fernandina area in 

Florida, the transmissibility ranges from 104,000 

to 177,000 with an average of 140,000. 

The rate of movement of water in open channels 

in the aquifer may be comparable to turbulent flow 

in surface streams with a similar gradient. However, throughout most of the aquifer, the movement 

is laminar. The velocity is proportional to the hydraulic gradient, the permeability, and effective porosity of the aquifer. Viscosity of the water also 

affects the flow, but generally the differences in temperature in ground water are not large enough to 

have a sufficient effect on the viscosity. An exception 

to this is an aquifer recharged by cold water from 

a surface stream. 

Where there is a permeability of 500 gpd per 

sq ft and an effective porosity of 20 percent, the 

average velocity with which the water would move 

through the aquifer for each foot of hydraulic gradient would be 0.063 foot a day, or 23 feet a year. 

If there were a permeability of 1,500 and an effective porosity of 20 percent, the movement would be 

three times as fast, but only about 70 feet a year. 

If the effective porosity were 10 percent, the velocity 

would be twice as much, or 140 feet a year. If 

'i there were a hydraulic gradient of 5 feet per mile, 

the velocity would be five times as much, or 700 feet. 
204 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

However, the gradient is less than that except in a 

few areas of recharge and discharge. 

ARTESIAN HEAD AND WATER LEVELS 

Differences in head and artesian flow at different 

depths may be expected in different parts of the 

area of this report. The head in the lower part of 

the Hawthorn Formation generally is the same as 

that in the underlying limestone of the principal artesian aquifer, but it is different from that in the 

middle and upper parts of the Hawthorn and overlying formations, which may yield water locally under artesian pressure. In coastal counties and the 

southern part of Florida, where wells. in the principal artesian aquifer will overflow at the surface, 

the head is higher in the aquifer than in the middle 

and upper parts of the Hawthorn and younger formations. Although the principal artesian aquifer 

contains relatively impervious beds that retard vertical movement of the water locally, the head generally is the same throughout the aquifer except in recharge and discharge areas where the vertical and 

lateral movement of the water in the aquifer may 

not be in equilibrium. 

In general, in recharge areas such as the one in 

Highlands County, Fla., the head may decrease with 

depth of well. In areas of artesian flow, the head 

may increase with depth of well, especially if the 

artesian pressure has been lowered in the upper part 

of the aquifer by withdrawal of water from wells 

or by natural leakage upward, as described for wells 

at Jacksonville, St. Augustine, and Daytona Beach. 

The head in water-bearing formations below the 

principal artesian aquifer is generally higher than 

·that in the aquifer. For example, a test well for oil 

drilled to a depth of 2,130 feet at Cherokee Hill, 21.5 

feet above sea level, 7 miles northwest of Savannah, 

Ga., flowed salt water from a depth of 1,980 to 2,130 

feet. The piezometric surface of the artesian water 

in the overlying aquifer was about 2 feet above sea . 

level. 

Loss of 'head is a normal process that invariably 

accompanies withdrawal of large amounts of artesian water. In a few·areas, withdrawal of water has 

lowered artesian head to such an extent that pumps 

are installed on wells. The temporary loss due to 

pumping may be many tens of feet in a few hours. 

Uncontrolled flow and subsurface leakage in wells 

is stopped, thereby saving some of the water which 

forrnerly was lost when the wells flowed under artesian pressure. However, loss of head increases the 

cost of pumping and may permit mineralized water 

to enter the aquifer in areas where salt water is 

present. 

Artesian head and water levels in wells fluctuate 

continuously. These fluctuations range from a fraction of a foot to many feet. Among the causes of 

these fluctuations are the following: ( 1) Rainfall in 

recharge areas such as in Marion County; Fla., 

where water levels in wells may rise 10 feet or more 

after rains, (2) surface drainage into wells, as in 

Orange County, Fla., where water levels may rise as 

much as 10 feet after periods of heavy rains, (3) 

fluctuations in discharge or recharge from rivers, 

such as the Suwannee River, which has cut its channel in the principal artesian aquifer along its course 

in Florida, ( 4) changes in atmospheric pressure 

and wind, ( 5) ocean tides and earth tides, ( 6) compression of aquifers by temporary loads, such as 

railroads trains, (7) earthquakes, and (8) natural 

artesian flow or pumping from wells. Withdrawal 

of water from wells may cause fluctuations much 

larger than those from other causes. However, the 

smaller natural fluctuations give significant information on the properties of the aquifer. 

The areas in which artesian water is under sufficient pressure to rise in wells and to overflow on the 

ground surface include the Atlantic coastal area, 

southern Florida, and the gulf coast. The area of 

flow along the Atlantic coast extends from the Savannah area, Chatham County, Ga., to the Florida 

Keys. The area of flow originally covered most of 

Chatham County, the southern part of Effingham 

County, and adjacent parts of South Carolina. However, withdrawal of \\-J.ter from wells in the Savannah area has lowered the piezometric surface and 

reduced the area of flow. The withdrawal of water 

from wells at Fernandina, Fla., has lowered the 

pressure in the principal artesian aquifer and the 

overlying· Hawthorn Formation to the extent that 

wells no longer flow in that vicinity either. 

The area of flow extends far inland up some ·of 

the river valleys, beyond the area underlain by the 

principal artesian aquifer of Tertiary age, almost to 

the Fall Line. Artesian water between the Fall Line 

and the area of the Tertiary aquifer is from Cretaceous formations. The area of flow covers the 

southern part of Florida and extends along the Kissimmee River valley into northern Osceola County 

and along Peace Creek valley to the southern part of 

Polk County. In a few local areas, such as northern 

Collier County, wells do not flow. From southern 

Florida, the area of flow extends northward in a 

narrow belt along the Gulf of Mexico. Along the 

coast, where the aquifer is at or near the surface 
SUMMARY AND CONCLUSIONS 205 

from Pasco County to Wakulla County, flowing 

wells may be expected only where the land surface 

is near sea level. The area of flow extends westward 

from Wakulla County along the coast to Alabama. 

It extends inland up the valleys of rivers. Wells in 

shallow aquifers overlying the principal artesian 

aquifer will flow in the valleys of Escambia and 

Perdido Rivers. 

PIEZOMETRIC SURFACE OF WATER 

Movement of the water in the principal artesian 

aquifer is much more widespread than the movement in the overlying formations. Water that enters 

the aquifer in some places may travel more than 50 

miles before it leaves the aquifer through a well or 

spring or by upward leakage into an overlying 

formation. 

The piezometric surface in this report has been 

adjusted, insofar as practicable, to represent conditions in 1961. Where there is natural fluctuation of 

artesian pressure, the position of the piezometric 

surface is changing almost constantly, and the representation at one time shows only approximately 

the conditions at other times. However, the major 

features remain essentially the same. A comparison of the map compiled in 1961 with maps made 

25 years earlier shows no detectable net rise or decline of the piezometric surface except in areas of 

heavy withdrawal. Away from areas directly affected by changes in recharge and discharge, the 

fluctuations generally are less than a foot. In recharge areas the piezometric surface may fluctuate 

as much as 10 feet or more in accordance with seasonal changes in rainfall. In areas of heavy draft, 

the fluctuations may be tens of feet, many times 

larger than the largest natural fluctuation. 

The piezometric surface is above sea level, except 

in a few areas such as Savannah, Ga., and Fernandina and Panama City, Fla. The highest part of the 

piezometric surface is about 250 feet above sea level, 

in a recharge area in Worth, Turner, and Wilcox 

Counties, Ga. This high area extends northeastward across Georgia into South Carolina and southwestward into Alabama. The piezometric surface is 

as much as 100 feet above sea level in the Valdosta 

area and in Lowndes and Brooks Counties in Georgia where there is local recharge through sinkholes 

and drainage wells. In recent years, withdrawal of 

water from wells has lowered the water level in 

part of the area. The gradient between the 230- and 

80-foot contours in Georgia is relatively. steep, as 

much as 15 feet per mile in comparison with a low 

gradient of less than a foot per mile between this 

area and the coast. This change from the steep 

gradient to the low gradient indicates an increase in 

permeability or thickness of the aquifer, or both. 

North of Glynn County in Georgia, the water 

moves northeastward toward Savannah and to natural discharge areas in the ocean east and northeast 

of Savannah. In adjacent parts of South Carolina, 

it moves southeastward. At the present time, part 

of the water that normally would flow to the natural 

discharge area is withdrawn through wells in the 

Savannah area. This withdrawal has created a cone 

of depression in the piezometric surface and has reversed the direction of the movement of the water 

east of Savannah. Along the Atlantic coast, the 

piezometric surface is below sea level at present in 

the Savannah area of Georgia and South Carolina. 

It rises north and south of that area. The piezo~etric surface is as much as 40 feet above sea levei in 

southeastern Georgia, even though there are areas 

of heavy withdrawal of water. 

A comparison of the shape of the piezometric 

surface with the withdrawal of water in the coastal 

area of Georgia and northeastern Florida shows 

that the aquifer is more productive at Brunswick 

and Jacksonville than at St. Marys and Fernandina. 

As the thickness of the aquifer is approximately the 

same in these areas, the differences in productivity 

appear to be due to differences in the permeability 

of the aquifer. 

In Florida the piezometric surface shows several 

conspicuous recharge and discharge areas. The 

highest parts of the surface are in the recharge 

areas in Polk County, Pasco County, and Putnam 

County areas in the peninsula and in Jackson 

County area in western Florida. The highest of 

these is as much as 120 feet above sea level in Polk 

County and Jackson County area. Recharge is 

largely through sinkholes that pass from the surface 

to the underlying limestone of the principal artesian 

. aquifer. Many of these sinks are .filled with permeable sands. Many depressions formed by the sinks 

are occupied by lakes. In all recharge areas through 

sinks, water moves laterally in all directions without reference to the dip of the aquifer. 

Recharge occurs in the Madison County and 

J'ackson County areas, where the aquifer is at or near 

the surface. Recharge occurs through sinkholes in 

central Washington County, south of the area where 

the aquifer crops out. The aquifer also is recharged in a large area where the aquifer is at or 

near the surface on the Ocala uplift, in the Marion 

County and Citrus. County areas. Although recharge 

is large, there is also large discharge in these areas. 
206 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

In the Marion County area, large quantities of water 

are discharged through Silver Springs and Rainbow 

Springs. This large discharge through springs accounts in part for the saddlelike shape of the piezometric surface 40 to 55 feet above sea level. Along 

the coast the piezometric surface is approximately 

at sea level because of the large discharge into the 

Gulf of Mexico. 

Other places of discharge and recharge are in the 

Suwannee River area and Wakulla County area. 

Large quantities of water are discharged from the 

artesian aquifer to the Suwannee River during low 

stages of the river. The aquifer is recharged by the 

river during flood stages. The aquifer is recharged 

in a large part of the Wakulla County area, but 

there is large discharge at Wakulla Spring and 

along the coast. 

The piezometric surface is near sea level in the 

St. Johns River valley, east of the Marion County 

area, where the artesian water discharges into the 

river. Along the east coast of the St. Johns River, 

where the aquifer is 100 feet or less below sea 

level, there is discharge through submarine springs, 

such as the one about 21f2 miles east of Crescent 

Beach. Although the Hawthorn Formation is as 

much as 50 feet thick, the artesian water discharges 

through sinkholes in the Hawthorn. 

In southern Florida the piezometric surface south 

of th~ Polk County area is relatively flat, sloping 

from ·about 50 feet above sea level in the northern 

part to only a few feet below sea level on the Florida 

Keys. Some discharge occurs along the Atlantic 

coast where the aquifer crops out at the edge of the 

Continental Shelf. The amount of discharge depends in part on the relation of the artesian head to 

the back pressure from the salt water at the outcrop. 

CHEMICAL QUALITY 

The ground water in the area of this report may 

be divided in the following types: 

1. Calcium bicarbonate water whose hardness 

ranges from about 50 to several hundred parts 

per million. Most of the artesian water is of 

this type except in southern Florida and some 

of the coastal areas where the fresh artesian 

water is mixed with remnants of sea water 

that has not been flushed from the aquifer. 

The hardness of the salt water is much higher 

than that of the fresh artesian water. 

2. Calcium sulfate water whose hardness is as much 

as 900 ppm as reported in Manatee County. 

This type occurs only locally where the aquifer contains anhydrite or gypsum. 

3. Sodium bicarbonate water whose hardness is less 

than 50 ppm but whose total dissolved solids 

is relatively high. This type of water occurs in 

the principal artesian aquifer in western Florida and adjacent parts of Alabama and Geor-

·gia, where the limestone grades into sands, 

clay, and other clastics. The water is softened 

naturally as it moves through the aquifer, exchanging calcium for sodium. 

4. Sodium chloride water, which is a mixture of 

fresh ground water with salt water. This type 

of water occurs in some parts of the coastal 

areas and in the southern part of Florida. In a 

few places in the interior, salt water has been 

found in formations underlying the principal 

aquifer. 

5. Water in shallow surficial sands whose total dissolved solids is less than 50 ppm. The public 

supply of Pensacola and other supplies in 

Escambia County, Fla., are of this type. 

The amount of silica reported in the ground water 

of this region ranges from about 2 to 63 ppm. In 

general, it is. less than 10 ppm in water in surficial 

aquifers and some recharge areas. Some formations 

are more siliceous than others. However, the available information does not indicate whether the siliceous rocks yield water of a high silica content. 

The silica content of the water appears to correlate 

in a general way with the alkalinity and pH of the 

water and the length of time in the water-bearing 

formation. 

Iron, generally as ferrous bicarbonate, is objectionable in water in amounts of more than 0.3 ppm 

because it gives the water an unpleasant taste and 

stains plumbing fixtures. Iron as bicarbonate may 

be removed simply by aeration. Iron in small 

amounts, generally not exceeding a few parts per 

million, is present in some places in water in shallow surficial ·sands. However, iron is absent or 

present only in trace amounts in water of the principal artesian aquifer and the limestone overlying 

the aquifer. The iron content of samples from four 

of the largest springs that received water from the 

principal artesian aquifer ranged from 0.04 to 0.15 

ppm. 

In most of the area of this report, water having 

a low chloride content had a calcium content of less 

than 50 ppm and a magnesium content of less than 

25 ppm. In the soft sodium bicarbonate water in 

western Florida, the calcium content was as low as 

1

4.4 ppm and the magnesium, 3.5 ppm. Calcium is 

high in comparison with magnesium, where the 

aquifer consists chiefly of pure limestone, as at 
SUMMARY AND CONCLUSIONS 207 

Cross City in Dixie County, Fla., where the calcium 

ranged from 81 to 120 ppm and the magnesium 

ranged from 4.5 to 6.8 ppm. The sulfate ranged 

from 1.6 to 4.5 ppm. 

The maximum calcium content is in the calcium 

sulfate water. One sample from the aquifer from 

a well in Manatee County in southwestern Florida 

had a calcium content of 352 ppm. The magnesium 

content was 8.5 ppm, the sulfate was 650 ppm, and 

the chloride was 50 ppm. 

The concentration of magnesium is as little as 

one-tenth to one-twentieth of that of calcium in the 

artesian water that is not mixed with sea water. 

Where mixed with sea water, the ground water 

may contain more magnesium than calcium; however, in some areas the aquifer contains anhydrite 

or gypsum, :which gives water a relatively high 

calcium sulfate content, as in Sarasota County in 

southwestern Florida. In some areas such as Martin 

County, Fla., where the artesian water is mixed with 

remnants of sea water, the magnesium content is 

about as high as that of calcium. Generally, in 

areas where the ground water is not mixed with 

sea water, the total sodium and potassium ranges 

from a few parts per million to 40 ppm. Many 

samples are less than 10 ppm. .However, where 

mixed with sea water or other salt water in the 

water-bearing formations, the amounts of sodium 

and potassium may be as much as that of sea water. 

Bicarbonate in samples of water from the principal artesian aquifer ranged from 50 to about 350 

ppm. The bicarbonate in samples of ground water 

in the shallow aquifer in some parts of the Everglades is as much as 1,000 ppm. 

Sulfate is dissolved in large quantities from 

gypsum or anhydrite in some water-bearing formations. Some of it is from sea water or salt in the 

aquifer. Sulfate in the water in the principal artesian aquifer ranges from a trace to as much as 

1,000 ppm. However, in much of the area of this report the sulfate is less than 10 ppm. The sulfate generally is highest in the southeastern part of Georgia, 

the northeastern part of Florida, the Atlantic coastal 

area, southern Florida, and the gulf coastal areas 

from the Florida Keys to Tampa Bay. 

Chloride is present in large quantities in ground 

water mixed with sea water. Outside the coastal 

areas and the southern part of Florida, the chloride 

content is generally less than 50 ppm in the principal artesian aquifer, except in some deep wells that 

may reach water having a relatively high chloride 

content. In some recharge areas, the chloride content is less than 10 ppm. Generally, below depths of 

2,000 feet salt water may be expected. 

Fluoride is present in small quantities in some of 

the ground water in the Southeastern States. Water 

having fluoride in concentrations in excess of 1.5 

ppm may cause mottling of the enamel of children's 

teeth during calcification. However, a fluoride content of 0.7 to 1.5 ppm in public water supplies is 

reported to result in a 50 to 65 percent reduction in 

dental caries among children. 

Water samples from the Hawthorn Formation 

almost invariably contained small amounts of fluoride, generally more than 1 ppm. In a few samples, 

fluoride was as much as 2.5 ppm. Apparently, water 

in the principal artesian aquifer has little or no 

fluoride except in areas where (1) the lower part 

of the Hawthorn Formation has phosphatic material in the upper part of the aquifer and (2) in 

western Florida, southeastern Alabama, and southwestern Georgia where the aquifer grades laterally 

into sands and clays, which yield soft sodium bicarbonate water having a fluoride content of as much 

as 6.5 ppm. Fluoride in the Hawthorn is associated 

with the phosphatic material. Volcanic ash, bentonitic material, and glauconite appear to be the 

source of the fluoride in some water-bearing sands 

in the Coastal Plain. 

The hardness of ground water in the Coastal 

Plain in the Southeastern States, including that of 

the principal artesian aquifer, generally ranges 

from 5 to 1,000 ppm. Generally, the softest water 

in the principal artesian aquifer is in recharge 

areas, and the hardest water is some distance from 

recharge areas. An exception is in Okaloosa, Santa . 

Rosa, and Escambia Counties, Fla., where natural 

softening has removed the hardness by exchange of 

calcium for sodium as the water moves through the 

aquifer. In a recharge area such as Clay County, 

the hardness of samples of water from the principal 

aquifer ranged from 60 to 100 ppm. Northeast of 

that recharge area at Jacksonville in Duval County, 

Fla., the hardness ranged from 200 to 300 ppm. In 

a recharge area in Highlands County in central 

Florida, the hardness of the w·ater from the principal artesian aquifer was less than 70 ppm. In Sarasota County southwest of that recharge area, the 

hardness was as much as 1,000 ppm. However, 

part of the hardness is due to the presence of 

anhydrite and gypsum in the aquifer. 

In the principal artesian aquifer, the hydrogen 

sulfide ranged from 0 to more than 4.0 ppm. As 

little as 1 ppm of the gas will ,give the water· a 

noticeable sulfur odor. Part of the gas is elimi-
208 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

nated, and the remainder is rapidly oxidized by 

dissolved oxygen that is absorbed upon aeration. 

The pH of the water from the principal artesian 

aquifer ranges from 7 to 8".75. 

Organic color is present in much of the surface 

water in swamps, the Everglades, and some streams. 

Shallow aquifers in the Everglades contain colored 

water. There is little or no noticeable color in most 

of the water in the principal artesian aquifer although it receives surface-water recharge through 

sinkholes. Most of the large springs are clear 

where they flow from the principal artesian aquifer. 

Silver Springs and Rainbow Springs, two of the 

largest, are always clear. Water having noticeable 

color enters Wakulla Spring through sinks after 

rains. 

Water from the principal artesian aquifer and 

the overlying formations is satisfactory for irrigation, except where fresh artesian water is mixed 

with salt water. 

Three radioactive elements-tritium, uranium, 

and radium-were included in the analyses of a few 

samples of water. Tritium, or hydrogen-3, having 

a half-life of 121;2 years, is the only known radioactive isotope of hydrogen found in nature. It 

occurs naturally. in water and in fallout from nuclear tests and nuclear reactors. Analyses have 

been made on the tritium content of water in the 

principal artesian aquifer to determine the relative 

age and rate of movement of the water. The quantity of tritium occurring naturally is so small that 

its presence has no effect on the use of the water. 

A few analyses show that small quantities of 

uranium and radium are present in the principal 

artesian aquifer in some areas. As uranium is present in small quantities in some of the phosphatic 

material in the Hawthorn and some of the younger 

formations in Florida, it seems likely that phosphatic material may be the source of the uranium 

in the artesian water. Natural uranium in water is 

not known to have a harmful effect. However, 

radium that results from radioactive disintegration 

of radium and thorium may occur in harmful 

amounts. The ma:ximum permissible concentration 

of radium for general use has been set by the U.S. 

Public Health Service at 3.3 fLfLC per 1. One sample 

from Martin County, Fla., had 11 fLfLC Raper 1. Further studies are needed to determine the source 

and extent of the radium in artesian water in that 

part of Florida. 

TEMPERATURE OF ARTESIAN WATER 

The temperature of ground water at a depth of 

about 30 to 60 feet will generally exceed by 2° to 

3°F the mean annual air temperature. At a depth of 

20 feet, the temperature of ground water may range 

10°F above or below the mean annual temperature 

of the air. The temperature of ground water increases with depth. The rate of increase differs 

considerably from one area to another because of 

hydrologic conditions. The temperature of artesian 

water in the principal artesian aquifer, as measured 

at the mouths of wells, ranged from about 62°F in 

South Carolina to 91 °F in Martin County in southern Florida. The highest temperature recorded for 

the artesian water in the Cretaceous aquifers underlying the principal artesian aquifer of Tertiary age 

was 103° to 109°F at depths from 2,610 to 3,450 

feet in a well at Parris Island, S.C. Most of the 

measurements of the temperature of water from 

the large surface springs ranged from 69°F in northern Florida and southern Georgia to about 70° to 

7 4 oF in central Florida. Thermal gradient, as indicated by the temperature of water from wells of 

different depths in the principal artesian aquifer, 

ranged from a maximum of 1 oF for each 55 feet of 

depth to 1 °F for each 140 feet of depth. Both of 

these ranges are from wells in Martin County in 

southern Florida. Some of the differences may be 

due to the fact that wells were not cased below the 

top of the aquifer. Water may enter the wells at 

various depths. 

SALT WATER IN AQUIFERS 

Salt water in the fresh-water aquifers may be 

from ( 1) encroachment of sea water in coastal 

areas, (2) connate water and sea water which entered the aquifer during a high stand of the sea in 

Pleistocene time, (3) salt as thin beds or disseminated in the geologic formations, and ( 4) sea water 

which became more concentrated by evaporation in 

tidal lagoons or other enclosed areas which received 

sea water during storms. There is no evidence of 

shallow salt domes or upward movement of salty 

water from the deep formations underlying the 

principal artesian aquifer. 

In coastal areas where the aquifer is exposed to 

sea water, salt water will move into the aquifer if 

there is not a sufficient fresh-water head. Such encroachment has occurred in the principal aquifer 

in only a few of the coastal areas. Although the 

artesian aquifer is exposed to the sea in some places 

at the edge of the Continental Shelf in the Atlantic 

Ocean and the floor of the Gulf of Mexico, in a 
SUMMARY AND CONCLUSIONS 209 

large area along the coast from Pasco County to 

Wakulla County, the artesian head generally is 

sufficient to prevent salt-water encroachment into 

the aquifer. 

Water with a relatively high chloride content is 

present in the artesian aquifer in the coastal areas 

of Florida, south of St. Augustine and in southern 

Florida. It includes part of the St. Johns River 

valley. From southern Florida it extends along the 

west coast to Tampa Bay. Also, it is present along 

the coast in western Florida. This water having 

relatively high chloride content appears to be 

chiefly from sea water which has not been flushed 

from the aquifer. Some of it is connate water, and 

some of it entered the aquifer during Pleistocene 

time. 

SPRINGS 

The principal artesian aquifer is the source of 

many large springs, including 17 first-magnitude 

springs which have an average flow of 100 cfs or 

more. All these are in Florida. Silver Springs and 

Rainbow Springs in Marion County are the largest, 

having a combined maximum flow of more than 

2,310 cfs. Radium Springs, formerly known as Blue 

Springs, near Albany, with a yield ranging from 

less than 18 to 135 cfs, is the largest in Georgia. 

The largest known submarine spring from the aquifer is about 2lj2 miles east of Crescent Beach, Fla. 

Many springs are along the Suwannee River and its 

tributaries in Florida. All the large springs are 

artesian and are chiefly where the aquifer is at or 

near the surface. Many of them appear to rise 

through sinkholes. The low tritium content of water 

from Silver Springs and from Radium Springs indicates that the water travels long distances and is a 

mixture of young and old water. Chemical analyses 

of samples from several springs indicate that the 

springs represent three of the four types of water 

present in the artesian aquifer. No spring yields 

soft sodium bicarbonate water, such as that from 

deep wells in the aquifer in western Florida. Most 

of the springs have water of the calcium bicarbonate type, a few of the springs yield water with 

a high chloride content, and a few yield soft water 

with a low mineral content. 

Most of the measurements of the approximate 

temperature of the water from the springs range 

from 69°F in northern Florida and southern Georgia to 70° to 7 4 °F in central Florida. 

WELLS 

Thousands of wells, both flowing and nonflowing, 

have been drilled into the principal artesian aquifer. 

Most of the wells in limestone are cased to the first 

hard rock or to the top of the aquifer. Some wells, 

as much as 1,000 feet deep, may have only about 

100 feet of casing. Where the Hawthorn Formation 

is present, the casing generally is set in the lower 

part of that formation. Where there are differences 

in head at different depths in the aquifer, there may 

be leakage of water from one formation to another 

through wells. 

The artesian wells range from about 50 to more 

than 1,000 feet in depth and from 2 to more than 

24 inches in diameter. Many of the deeper wells 

may range from 6 to 12 inches in diameter. In some 

wells where the aquifer is near the surface, as in 

parts of Seminole County, flowing wells may be obtained from depths less than 100 feet. The diameter 

of many of these wells ranges from 2 to 6 inches. 

Several thousand have been drilled for irrigation of 

celery and other truck crops in the area of artesian 

flow of Seminole County, Fla. 

Wells in the principal artesian aquifer are finished 

without screens, except in western Florida, southeastern Alabama, and southwestern Georgia, where 

the water-bearing formations consist of sand and 

other unconsolidated material. 

The yield of wells having natural flow ranges 

from a few gallons to several thousand gallons a 

minute. The largest yields by natural flow are in the 

coastal areas and southern Florida, where the artesian pressure is relatively large and the surface 

of the ground is relatively low. One of the largest 

yields was 6,500 gpm from a 12-inch well in Duval 

County in northeastern Florida. The largest yield 

reported from nonflowing wells in the principal 

artesian aquifer is 7,500 gpm from a well 18 inches 

in diameter a-nd 852 feet deep in Polk County. One 

well is known to yield 833 gpm with each foot of 

drawdown of the water level, and the flowing wells 

range from a fraction of a gallon to 248 gpm for 

each foot of drawdown. 

As most of the wells in the principal aquifer are 

not cased, water may move from one formation to 

another through the wells. Such subsurface leakage 

through wells has been detected in a few areas where 

there is a difference of head in the water-bearing 

formation because of local recharge or discharge. 

In some areas, such as Orlando, where the water 

levels in wells in the principal artesian aquifer stand 

below the land surface, surface water is drained into 

the wells in cavernous limestone of the principal artesian aquifer. This drainage disposes of surface 

water and recharges the aquifer. 

The principal artesian aquifer is the chief source 
210 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

of ground water for municipal, industrial, and irrigation suppli~s in the area of this report. Although 

the aquifer yields water· through the large limestone 

springs, almost all the water. used for water supply 

from the aquifer is from wells. Many of the springs 

are used for recreation. A few small springs are 

used for water supply. A few mineral springs are 

used at health resorts. 

The estimated quantity of ground water used in 

1960 for public supplies in Florida, chiefly from the 

principal artesian aquifer, was 502 mgd; the quantity for private supplies for industrial and commercial use was 657 mgd. 

Large quantities are used for irrigation, especially for truck crops and citrus crops in the Flo:r:ida 

peninsula. The average consumption for irrigation 

is difficult to estimate because of the differences in 

rainfall from one growing season to another. During dry seasons, many artesian wells are used to 

irrigate citrus crops in the area of artesian flow. 

In Georgia, the largest quantities of artesian water are used in ten coastal counties, where the estimated annual discharge was 279 mgd. Of that 

amount 197 mgd was for industrial use, 31 mgd for 

public supply, and 21 mgd for domestic supply. 

About 30 mgd flowed continuously for domestic use, 

stock, and game preserves. A large part of that 

water was not used. 

FUTURE STUDIES 

Systematic and detailed studjes of the geology and 

hydrology should be continued to give more information on the water-bearing properties of all the geologic formations and the perennial yield of all aquifers. Studies of the geochemistry of the water and 

the relation of fresh ground water to salt water 

should be continued. Additional information is 

needed on all the subjects discussed in this .report. 

Geologic investigations should include all geologic 

formations which control the yield and quality of 

the water of the aquifers. More information is 

needed on conditions under which the formations 

were deposited and on the changes which have affected the permeability and other water-bearing 

properties of these formations. A better understanding of the relation. of the water-bearing formations of the principal artesian aquifer and the underlying and overlying formations is needed. 

Joint systems in limestone appear to have been 

significant in the solution of limestone in the zone 

of aeration. Bedding planes, unconformities, and 

faults may be significant, but more information is 

needed to understand the effects of these features. 

Tests on wells penetrating the aquifer and other 

geologic studies on both sides of faults would aid in 

determining the extent to which faults affect the 

movement and the chemical quality of the water. 

Additional studies are needed on the submarine 

hydrogeology. The geologic structure and places of 

outcrops of the geologic formations on the ocean 

floor and at the edge of the Continental Shelf should 

be understood to determine discharge areas and the 

relation of the fresh water to sea water in that part 

of the aquifer. 

The solution channels and cavities, sinkholes, and 

lake basins appear to have formed chiefly when the 

sea stood above and below its present level. Further ~t.udies are needed to determine the. lateral and 

vertical distribution of the existing solution cavities 

in the limestone and the extent to which they have 

been filled by unconsolidated material. Adequate 

information on the geologic history, from late Miocene time to the present, especially during· Pleistocene and Pliocene time, will give much additional 

information on the solution of the limestone, which 

accounts for a large part of the capacity of some of 

the limestone aquifers. 

The shallow aquifer overlying the principal artesian aquifer in the Miami area has been studied 

locally in considerable detail in southeastern Florida and also in the Pensacola and Cantonment areas 

in Escambia County, Fla. Shallow aquifers in other 

areas may also be important sources of water especially where the underlying principal artesian aquifer contains water of poor quality. 

The available information on the fluctuations of 

sea level in Pleistocene time suggests that many 

sinkholes and solution channels were formed during 

low stands of the sea. These cavities were filled 

with unconsolidated sediments when the sea rose 

high enough to cover the area. Channels of surface 

streams may also have been filled and concealed 

by terrace deposits. If such buried channels are present, they might contain permeable water-bearing 

material that would be a good source of water. Buried sinkholes might form concealed recharge areas 

of the principal aquifer. 

Studies of the shallow aquifers on the Wicomico 

terrace and lower terraces might reveal some of 

these concealed recharge areas. The recharge and 

discharge areas of the principal artesian aquifer are 

known only in a very general way. Piezometric 

maps of the artesian water show some of the recharge areas, but more information is needed on the 

quantity of recharge, especially in the lake regions 

where recharge occurs through sinkholes and lake 
SELECTED REFERENCES 211 

basins. The extent to which artificial recharge 

through wells or other methods is practical should be 

determined. 

The rate of lateral movement of the water in the 

principal artesian aquifer ranges from a fraction 

of a foot to many feet a day. More studies are 

needed to determine the rate of movement in different parts of the area. 

Considerable information has been obtained on 

the geochemistry of the water, but more is needed 

on the occurrence and source of trace elements, as 

fluoride, strontium, uranium, and radium. There is 

evidence of natural softening of the artesian water 

in the principal artesian aquifer in western Florida 

and adjacent parts of Alabama where the limestone 

aquifer grades into sand and clay. Adequate information on the geology and hydrology from the recharge area to wells downgradient should reveal 

the minerals which cause the natural softening and 

also the source of the fluoride in the water. Adequate information on the occurrence of tritium in 

the principal artesian aquifer will aid in determining recharge, discharge, and the rate of movement 

of water in that aquifer. 

The information on the temperature of artesian 

water gives a general idea of the thermal gradient 

of the water at different depths, ·but it is not sufficient to explain some results which appear to be 

anomalous. As the wells are not cased in the principal artesian aquifer, temperature measurements of 

the water should be made at different depths in the 

wells instead of measuring the temperature at the 

mouth of the well. Accurate information on the 

thermal gradient should show whether the differences in temperature are due to geologic structure or 

to some other factor. 

Salt water in some of the formations may be from 

several sources, such as connate water, Pleistocene 

sea water, salt in the water-bearing formations, and 

salt-water encroachment from the Atlantic Ocean 

and Gulf of Mexico in some coastal areas. The lateral and vertical extent of the water with a relatively high chloride content is known in a general 

way. It is known that the contact between the 

fresh water and salt water in the principal artesian 

aquifer is some distance offshore along the coast 

from northeastern Florida to South Carolina. Estimates of the position may be made by assuming certain conditions for structure, distance to outcrop 

salinity of water, and depth of salt water at th~ outcrop. However, the future potential of the fresh 

artesian water in these areas may depend on the 

exact position of the contact of the fresh water 

with salt water. Therefore, studies of the geology 

and hydrology offshore should include the relation 

of salt water to fresh artesian water in the aquifer. 

The formations underlying the principal artesian 

aquifer in some areas contain salt water. The relation of salt water to the overlying fresh water is 

being studied in a few areas, but that relation should 

be studied throughout the region to determine 

whether the salt water would move upward into the 

overlying aquifer when the artesian head in that 

aquifer is reduced by withdrawal of water. 

Although the total quantity of water withdrawn 

from the principal artesian aquifer is remarkable, 

it is only part of the billions of gallons a day discharged naturally. The discharge of the largest 

limestone springs indicates the large capacity of the 

principal artesian aquifer. The combined flow of the 

springs in Florida has been estimated at 3,700 mgd. 

The estimated consumption of ground water in-1960 

in Florida, exclusive of water used for irrigation, 

was about 1,160 mgd. This is less than half the 

amount which leaves the aquifer through springs. 

The large use of water from the principal artesian 

aqlJ:ifer emphasizes the fact that this water is one of 

th~. most valuable of the mineral resources of the 

region. The abundance of this resource, which is 

net' fully utilized in much of the region, shows the 

need for continued systematic local and regional investigations of the geology and hydrology to provide 

information required for wise and careful planning 

of its development and conservation. 

As stated by Leopold (1959, p. 827), wise development and management of a resource requires continuing appraisal. Adequate management requires 

intelligent application of data and knowledge in a 

framework that permits flexibility of action. 

SELECTED REFERENCES 

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aluminum phosphate zone of the Bone Valley formation, 

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U.S. Geol. Survey Prof. Paper 300, p. 495-504. 

Altschuler, Z. S., and Young, E. J., 1960, Residual origin of 

the "Pleistocene" sand mantle in central Florida uplands 

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-- 1952, Volume of Mesozoic sediments in Florida and 

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no. 12, p. 1673-1753. 
212 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Applin, P. L., and Applin, E. R., 1947, Regional subsurface 

stratigraphy. structure, and correlations of middle and 

early Upper Cretaceous rocks in Alabama, Georgia, and 

north Florida: U.S. Geol. Survey Oil and Gas Inv. Prelim. 

Chart 26. 

--- 1965, The Comanche Series and associated rocks in 

the subsurface in central and south Florida: U.S. Geol. 

Survey Prof. Paper 447, 84 p. 

Back, William, 1963, Preliminary results of a study of calcium carbonate saturation of ground water in central 

Florida: Internat. Assoc. Sci. Hydrology Bull., v. 8, no. 3, 

p. 43-51. 

Baker, R. H., Jr., 1961, Florida regulations pertaining to 

ground water contamination, in Ground-Water Contamination, Proceedings of 1961 Symposium: U.S. Public 

Health Service Tech. Rept. W 61-5, p. 141-149. 

Barksdale, H. C., Sundstrom, R. W., and Brunstein, M. S., 

1936, Supplementary report on t~e ground-water supplies 

of the Atlantic City region: New Jersey State Water 

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Barr, Thomas C., Jr., 1961, Caves of Tennessee: Tennessee 

Dept. Conserv. and Commerce, Div. Geology Bull. 64, 

567 p. 

Barraclough, J. T., 1962, Ground-water resources of Seminole 

County, Florida: Florida Geol. Survey Rept. Inv. 27, 

91 p. 

Barraclough, J. T., and Marsh, 0. T., 1962, Aquifers and 

quality of ground water along the Gulf Coast of western 

Florida: Florida Geol. Survey Rept. Inv. 29, 28 p. 

Bergendahl, H. H., 1956, Stratigraphy of parts of DeSoto and 

Hardee Counties, Florida: U.S. Geol. Survey Bull., 

1030-B, p. 65-98. 

Bermes, B. J., 1958a, Interim report on the ground-water 

resources of Flagler County, Florida: Florida Geol. 

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--- 1958b, Interim report on geology and ground-water 

resources of Indian River County, Florida: Florida Geol. 

Survey Inf. Circ. 18, 7 4 p. 

Bermes, B. J., Leve, G. W., and Tarver, G. R., 1963, Geology 

and ground-water resources of Flagler, Putnam, and St. 

Johns Counties, Florida: Florida Geol. Survey Rept. Inv. 

32, 97 p. 

Berry, E. W., 1916, The flora of the Citronelle formation: 

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Bigelow, H. B., 1915, Exploration of the coast water between 

Nova Scotia and Chesapeake Bay, July and August, 

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Bishop, E. W., 1956, Geology and ground-water resources of 

Highlands County, Florida: Florida Geol. Survey Rept. 

Inv. 15, 115 p. 

Black, A. P., and Brown, Eugene, 1951, Chemical character of 

Florida's waters-1951: Florida State Board Conserv., 

Div. Water Survey and Research Paper 6, 119 p. 

Black, A. P., Brown, Eugene, and Pearce, J. M., 1953, Geology 

and hydrology of Florida, cha.p 3 of Salt water intrusion 

in Florida-1953: Florida State Board Conserv., Div. 

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Black, A. P., Stearns, T. W., McClane, H. H., and McClane, 

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Survey ·Water-Supply Paper 257, 139 p. 

Braidech, M. M., and Emery, F. H., 1935. The spectrographic 

determination of minor chemical constituents in various 

water supplies in the United States: Am. Water Works 

Assoc. Jour., v. 27, no. 5, p. 557-580. 

Brandle, Lowell, 1959, Exciting fossil find made, 210-foot 

deep Florida spring: Tallahassee Democrat, May 14, 

1959. 

Bretz, J. Harlen, 1942, Vadose and phreatic features of limestone caverns: Jour. Geology, v. 50, no. 6, pt. 2, p. 

675-811. 

--- 1949, Carlsbad Caverns and other caves of the Guadalupe block, New Mexico: Jour. Geology, v. 57, no. 5, p. 

447-463. 

--- 1956, Caves of Missouri: Missouri Div .. Geol. Survey 

and Water Resources Rept., v. 39, 2d ser., 490 p. 

Brooks, C. E. P., 1949, Climate through the ages [2d ed.,]: 

New York, McGraw Hill Book Co., 395 p. 

Brooks, H. K., 1961, The submarine spring off Crescent Beach, 

Florida: Florida Acad. Sci. Quart. Jour., v. 24, no. 2, p. 

122-133. 

Brown, D. W., 1958, Changes in the chloride content of 

ground water in Pinellas County, Florida, between 1947 

and 1956: Florida Geol. Survey Inf. Circ. 16, 11 p. 

Brown, D. W., Kenner, W. E., and Brown, Eugene, 1957, 

Interim report on the water resources of Brevard County, 

Florida, with special reference to the central area: 

Florida Geol. Survey Inf. Circ. 11, 111 p. 

Brown, D. W., Kenner, W. E., Crooks, J. W., and Foster, 

J. B., 1962, Water resources of Brevard County, Florida: 

Florida Geol. Survey Rept. Inv. 28, 104 p. 

Brown, G. F., 1947, Geology and artesian water of the alluvial 

plain in northwestern Mississippi: Mississippi Geol. Survey Bull. 65, 424 ·P· 

Brown, J. S., 1925, A study of coastal ground water, with 

special reference to Connecticut: U.S. Geol. Survey 

Water-Supply Paper 537, 101 p. 

--- 1937, The Florida ship canal: Econ. Geology, v. 32, 

no. 5, p. 589-599. 

Brown, R. H., 1961, Hydrologic factors pertinent to groundwater contamination, in Ground-Water Contamination, 

Proceedings of 1961 Symposium: U.S. Public Health 

Service Tech. Rept. W 61-5, p. 7-16. 

Bryan, 0. C., 1962, Soils of Florida and their crop adaptation: 

Florida State Dept. of Agriculture Bull. 42, 48 p. 

Bue, C. D., 1963, Principal lakes of the United States: U.S. 

Geol. Survey Circ., 476, 22 p. 

Burdon, D. S., and Papakis, Nicholas, 1963, Handbook of 

karst hydrogeology, with special reference to the carbonate aquifers of the Mediterranean Region: Athens, 

Greece, United Nations, Institute for geology and subsurface research, 276 p. 

Cady, R. C., 1936, Ground-water resources of the Shenandoah 

Valley, Virginia, with analyses by E. ·w. Lohr: Virginia 

Geol. Survey Bull. 45, 137 p. 

Cagle, J. W., Jr., and Floyd, B. L., 1957, Interim report on 

ground water in Escambia County, Alabama, with special 

reference to the Brewton area: Alabama Geol. Survey 

Inf. Ser. 7, 30 p. 

Cagle, J. W., Jr., and Newton, J. G., 1963, Geology and groundwater resources of Escambia County, Alabama: Alabama 

Geol. Survey Bu11. 7 4, 205 p. 

Callahan, J. T., 1960, Wild-flowing wells wa.ste water: Georgia Mineral Newsletter, v. 13, no. 1, p. 21-23. 
SELECTED REFERENCES 213 

Callahan, J. T., 1964, The yield of sedimentary aquifers of the 

Coastal Plain, Southeast River Basins: U.S. Geol. Survey 

Water-Supply Paper 1669-W, 56 p. 

Carlston, C. W., 1942, Fluoride in the ground water of the 

Cretaceous area of Alabama: Alabama Geol. Survey 

Bull. 52, 67 p. 

--- 1943, Notes on the early history of water-well drilling 

in the United States: Econ. Geology, v. 38, no. 2, p. 

119-136. 

Carr, W. J., and Alverson, D. C., 1959, Stratigraphy of middle 

Tertiary rocks in part of west-central Florida: U.S. 

Geol. Survey Bull. 1092, 111 p. 

Carson, R. J., III, 1964, Tolley's Cave [Virginia] : Virginia 

Dept. Conserv. and Economic Devel., Div. Mineral Resources, Virginia Minerals, v. 10, no. 1, 7 p. 

Carter, R. W., Williams, M. R., LaMoreaux, P. E., and 

Hastings, W. W., 1949, Water resources and hydrology 

of southeastern Alabama: Alabama Geol. Survey Spec. 

Rept. 20, 265 p. 

Cathcart, J. B., 1956, Distribution and occurrence of uranium 

in the calcium phosphate zone of the land-pebble phosphate district of Florida in Page and others: U.S. Geol. 

Survey Prof. Paper 300, p. 489-494. 

--- 1963a, Economic geology of the Keysville quadrangle, 

Florida: U.S. Geol. Survey Bull. 1128, 82 p. 

--- 1963b, Economic geology of the Plant City quadrangle, Florida: U.S. Geol. Survey Bull. 1142-D., 56 p. 

Clark, W. E .. 1964, Possibility of salt-water leakage from 

proposed intracoastal waterway near Venice, Florida, 

well field: Florida Geol. Survey Rept. Inv. 38, 33 p. 

Clark, W. E., Musgrove, R. H., Menke, C. G., and Cagle, J. W., 

Jr., 1962, Interim report on the water resources of 

Alachua, Bradford, Clay, and Union Counties: Florida 

Geol. Survey Inf. Circ. 36, 92 p. 

--- 1963, Hydrology of Brooklyn Lake near Keystone 

Heights, Florida: Florida Geol. Survey Rept. Inv. 33, 

43 p. 

--- 1964, Water resources of Alachua, Bradford, Clay, 

and Union Counties: Florida Geol. Survey Rept. Inv. 35, 

170 p. 

Cole, W. S., 1941, Stratigraphic and paleontologic studies of 

wells in Florida-No. 1: Florida Geol. Survey Bull. 19, 

91 p. 

--- 1944, Stratigraphic and paleontologic studies of wells 

in Florida-No. 3: Florida Geol. Survey Bull. 26, 168 p. 

Cole, W. S., and Applin, E. R., 1964, Problems of the geogTaphic and stratigraphic distribution of American middle Eocene larger Foraminifera: Bulls. Am. Paleontology, 

v. 47, no. 212, 47 p. 

Collins, W. D., 1925, Temperature of water available for industrial use in the United States: U.S. Geol. Survey 

W dter-Supply Paper 520-F, p. 97-104. 

Collins, W. D., and Howard C. S., 1928, Chemical character 

of waters of Florida: U.S. Geol. Survey Water-Supply 

Paper 596-G, p. 177-233. 

Cooke, C. W., 1936, Geology of the Coastal Plain of South 

Carolina: U.S. Geol. Survey Bull. 867, 196 p. 

--- 1937, The Pleistocene Horry clay and Pamlico formation near Myrtle Beach, South Carolina: Washington 

Acad. Sci. Jour., v. 27, no. 1, p. 1-5. 

--- 1939, Scenery of Florida interpreted by a geologist: 

Florida Geol. Survey Bull. 17, 118 p. 

--- 1941, Two shore lines or seven?: Am. Jour. Sci., 

v. 239, no. 6, p. 457-458. 

Cooke, C .W., 1943, Geology of the Coastal Plain of Georgia: 

U.S. Geol. Survey Bull. 941, 121 p. 

--- 1945, Geology of Florida: Florida· Geol. Survey Bull. 

29, 339 p. 

--- 1954, Carolina bays and the shapes of eddies: U.S. 

Geol. Survey Prof. Paper 254-1, p. 195-207. 

--- 1959, Cenozoic echinoids of eastern United States: 

U.S. Geol. Survey Prof. Paper 321, 106 p. 

Cooke, C. W., and MacNeil, F. S., 1952, Tertiary stratigraphy 

of South Carolina: U.S. Geol. Survey Prof. Paper 243-B, 

p. 19-29. 

Cooke, C. W., and Mossom, Stuart, 1929, Geology of Florida: 

Florida Geol. Survey, 20th Ann. Rept. (1927-28), p. 

29-227. 

Cooper, H. H., Jr., 1944, Ground-water investigations in 

Florida (with special reference to Duval and Nassau 

Counties) : Am. Water Works Assoc. Jour., v. 36, no. 2, 

p. 169-185. 

--- 1959, A hypothesis concerning the dynamic balance 

of fresh water and salt water in a coastal aquifer: 

Jour. Geophys. Research, v. 64, no. 4, p. 461-467. 

Cooper, H. H., Jr., and .Kenner, W. E., 1953, Centr~.l and 

northern Florida, chap. 9 of U.S. Cong., House Comm. 

Interior and Insular Affairs, Subsurface facilities of 

water management and patterns of supply-type area 

studies: p. 147-161. 

Corbel, A., 1959, Erosion en terrain calcaire-vitesse d'erosion 

et morphologie: Annales de Geographie, no. 366, p. 

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Counts, H. B., and Donsky, Ellis, 1959, Salt-water encroachment, geolOJ!Y, and ground-water resources of Savannah 

area, Georgia and South Carolina-a summary: Georgia 

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--- 1963, Salt-water encroachment, geology, and groundwater resources of Savannah area, Georgia and South 

Carolina: U.S. Geol. Survey Water-Supply Paper 1611, 

100 p. 

Cox, C. R., and Ast, D. B., 1951, Water fluoridation-a sound 

public health practice: Am. Water Works Assoc. Jour., 

v. 43, no. 8, p. 641-648. 

Dall, W. H., and Harris, G. D., 1892, Correlation papersNeocene: U.S. Geol. Survey Bull. 84, 349 p. 

Darton, N. H., 1896, Artesian-well prospects· in the Atlantic 

Coastal Plain region: U.S. Geol. Survey Bull. 138, 232 p. 

Davies, W. E., 1949, Caverns of West Virginia: West Virginia Geol. Survey Rept., v. 19, 353 p. . 

-- 1960, Origin of caves in folded limestone [Appalachian 

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Davis, W. M., 1930, Origin of limestone caverns: Geol. Soc. 

America Bull., v. 41, no. 3, p. 475-628. 

DeBuchananne, G. D., and LaMoreaux, P. E., 1961, Geologic 

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p. 3-7. 

DeCook, K. J., 1963, Geology and ground-water resources of 

Hays County, Texas: U.S. Geol. Survey Water-Supply 

Paper 1612, 72 p. 

Deike, G. H., III, 1960, Origin and geologic relations of 

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Speleol. Soc. Bull. 22, pt. 1, p. 30-42. 
214 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Doering, J. A., 1960, Quaternary surface formations of 

southern part of Atlantic Coastal Plain: Jour. Geology, 

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Dole, R. B., 1914, Some chemical characteristics of sea water 

at Tortugas and around Biscayne Bay, Florida: Carnegie 

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Donn, W. L., Farrand, W. R., and Ewing, Maurice, 1962, 

Pleistocene ice volumes and sea level lowering: Jour. 

Geology, v. 70, no. 2, p. 206-214. 

DuBar, J. R., 1958, Neogene stratigraphy of southwestern 

Florida: Gulf Coast Assoc. Geol. Soc. Trans., v. 8, p. 

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--- 1959, The Waccamaw and Croatan deposits of the 

Carolinas: South Carolina State Devel. Board, Div. Geology, Geol. Notes, v. 3, no. 6, 9 p. 

--- 1962, New radiocarbon dates for the Pamlico Formation. of South Carolina and their stratigraphic significance: South Carolina Devel. Board, Div. Geology, 

Geol. Notes, v. 6, no. 2, p. 21-24. 

Engeln, 0. D.· von, 1942, Geomorphology; systematic and 

regional: New York, The Macmillan Co., 655 p. 

Engler, Kyle, Thompson, D. G., and Kazmann, R .G., 1945, 

Ground-water supplies for rice irrigation in the Grand 

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Espenshade, G. H., 1958, Geologic features of areas of abnormal radioactivity south of Ocala, Marion County, 

Florida: U.S. Geol. Survey Bull. 1046-J, p. 205-219. 

Espenshade, G. H., and Spencer, C. W., 1963, Geology of 

phosphate deposits of northern peninsular Florida: U.S. 

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Ewing, ·Maurice, Richards, Horace, Fray, Charles, anci Craig, 

James, 1962, Wisconsin sea level in southern hemisphere 

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Fairbridge, R. W., 1961, Eustatic changes in sea level, in 

Physics and chemistry of the earth, v. 4: New York, 

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Fenneman, N. M., 1938, Physiography of eastern United 

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Ferguson, G. E., Lingham, C. W., Love, S. K., and Vernon, 

R. 0., 1947, Springs of Florida: Florida Geol. Survey 

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Ferris, J. G., Knowles, D. B., Brown, R. H., and Stallman, 

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Feulner, A. J., and Hubble, J. H., 1960, Occurrence of strontium in the surface and ground waters of Champaign 

County, Ohio: Econ. Geology, v. 55, no. 1, p. 176-186. 

Fiedler, A. G., and Nye, S. S., 1933, Geology and ground-water 

resources of the Roswell artesian basin, New Mexico: 

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Flint, R. F., 1940, Pleistocene features of the Atlantic Coastal 

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Fortson, C. W., Jr., 1961, Peat deposits of Georgia: Georgia 

Mineral Newsletter, 1961, v. 14, no. 1, p. 1-21. 

Foster, J. B., 1962, Well design as a factor contributing to 

loss of water from the Floridan aquifer, eastern Clay 

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Foster, M. D., 1937, The chemical character of the ground 

waters of the south Atlantic Coastal Plain: Wash. Acad. 

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--- 1950, The origin of high sodium bicarbonate waters 

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Healy, H. G., 1962a, Piezometric surface and areas of artesian 

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Hughes, U. B., 1944, Developments in southeastern United 

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Jacob, C. E., 1939, Fluctuations in artesian pressure produced 

by passing railroad trains as shown in a well on Long 

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> 

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.... 
A Page 

A horizon. See Soils. 

Acknowledgments .......................................... 7 

Aeration zone ................................................. 84, 201 

Aftonian Interglaciation .............................. 8, 68 

Aiken Plateau, S.C.......................................... 12 

Alachua Formation ................................ 47, 66, 64 

Alachua Lake .................................................. 88 

Alachua sink .............................................. _. 88 

Alafla River .................................................... 14 

Alapaha River ............................ - ................. 18, 14 

Alkali hazard. See Sodium hazard. 

Alligator Lake ................. -----.................... 88 

Altamaha River ............... _ .......... -.............. 18 

Alum Bluff Group ............................................ 66, 68 

Alum Bluff stage.............................................. 55 

Anastasia Formation ...................... 18, 67, 71, 94 

Anastasia Island .......................... _ .......... __ 72 

Anclote River .................................................. 174 

Apalachicola basin ........ - ... -....................... 78 

Apalachicola embayment .............................. 200 

Apalachicola River .............. - ..... 9, 10, 18, 65, 56 

Apalachicola River valley .................. _. __ ,_ 56 

Apopka, Lake ....................................... ___ , 17,86 

Aquiclude .............................................. _,__ 90 

Aquifer recharge areas ......... - ......... --....... 204 

Aquifers, changes In quality of water...... 147 

discharge .................................................. 91 

recharge .................................................... 91 

Aquifuge ........ _ .................................... ___ 90 

Area zone ............................................ _.___ 68 

Artesian aquifer .................................... __ BOB 

discharge ...................................... _ 91, 98, 205 

elastic compression ................................ 92 

loss of flow ............ _............................... 111 

pressure changes ____ ,........................... 98 

principal ....................... - ..................... 96, 202 

areas of flow ............. __ , ___ ........ 117 

artesian head .................................. 109 

chemical quality of water.............. 184 

discharge .......................... _ .. _ 98, 126, 190 

extent _ ............................ _,____ 96 

piezometric surface of water........ 119 

rate of movement of water.......... 109 

recharge ..... ___________ , ___ 98, 126, 190 

recharge by drainage wells ----.......... 191 

relation of structure to solution 

cavities ....... _ ............. ______ 181 

salty ground-water areas ._........ 161 

springs .......... ___ ............ ------ 179 

thickness ....................... -·--·-·----· 96 

water-bearing properties ............ 100 

Florida ................. _................ 101 

Georgia ..................... -............ 108 

water use ....................... - ........ _.. 191 

recharge .................... _,_, ______ , __ 98, 205 

recharge areas ........................................ 111 

Tertiary limestone ................................ 94 

Artesian flow ............ _, ___ ............. _ .... 109, 204 

Artesian pressure head ................ 98, 178, 189, !04 

deflned ................ _................................... 109 

fluctuations of ....................... _ .. , ___ 111, 204 

loss of ..................................... _ ............ 110, 204 

INDEX 

[Italic page numbers indicate major references] 

Page 

Artesian water, defined ....................... -...... 91 

occurrence ........ -.................................... 89 

Artesian wells, water-level 

fluctuations in .................... 111, 204 

Atkinson Formation ...................................... 28 

Atlantic coast .................................................. 160 

artesian-flow areas ................................ 117 

Atlantic Coastal Ridge · .................................. 18, 72 

Atmospheric pressure, relation to water 

levels, artesian wells ........ 113, 204 

Aucilla River .................................................. 18 

Avon Park Limestone ............................ 37, 88,95 

Florida ...................................................... 41 

B 

B horizon. See Soils. 

Barge canal ................ -.................................. 193 

Barnwell Formation .................. 11, 12, 44, 45, 51 

Barometer, water ................................ -....... 118 

Barometric efficiency .................................... 115 

Bashi Marl Member ............... _______________ 86 

Bear Head - ................................. _................ 10 

Bedding planes .......................... 181, 132, 133, 202 

Bibliography ........................ -........................ B11 

Bicarbonate content .................................. 140, 207 

Big Cypress Swamp .................... 9, 17, 18, 72,87 

Biological contamination .............................. 147 

Biscayne aquifer ............................................ 94 

Biscayne Bay .................................................. 15 

Black Creek Formation ............... _.............. 63 

Black Mingo Formation -------------------------- 12, 36 

Bladen soils. See Soils. 

Blake Plateau .................................................. 164 

Blanton soils. See soils. 

Blue Springs. See Rainbow Springs. 

Bone Valley Formation ................. --........ 66,64 

Brandywine shoreline. See Hazlehurst 

shoreline. 

Breathing Cave ------------------------------------- 131 

Brevard County, Fla ................ 42, 47, 60, 101, 172 

Bronson graben ......................................... _ 75 

Brooklyn Lake ................................................ 88 

Brunswick, Ga ................................................ 168 

Bucatunna Clay Member .............................. 52, 58 

Buckingham Marl ........................ ___________ 64 

Bumpnose Member ........................................ 46 

Butler Lake. See Tarpon Lake. 

Byram Formation SB 

c 

C horizon. See Soils. 

Calcium bicarbonate type ................. -... 186, 209 

Calcium bicarbonate water ............ 184, 186, 206 

Calcium content --------------------------------- 187,206 

Calcium sulfate water ...................... 185, 138, 206 

Calhoun County, Ga........................................ 51 

Caloosahatchee Marl ........................ 63, 64, 66, 94 

Caloosahatchee River .............................. 14, 15, 18 

Canals ........................................ _________________ 193 

Cancellaria zone ............................................ 68 

Carolina Bays .................................................. 12, 86 

Patre 

Casing wells. See Wells. 

Catahoula Sandstone ...................................... 56 

Cave cycle ........................................................ 78, 82 

Caverns in limestone, origin of.................. 78 

Caves. See Solution cavities. 

Cedar Keys Limestone .................................. 86 

Central Highlands, Fla.................................. 9, 20 

Charlotte Harbor ............................................ 14 

Charlton Formation ............................ - ...... 64, 66 

Chattahoochee anticline .............. 73, 75, 200, 202 

Chattahoochee Formation .................... --- 56 

Chattahoochee Limestone ............................ 58 

Chattahoochee River .................. 12, 18, 23, 86, 87 

Chemical analysis, Glen Julia Sprinp, 

Gadsden County ...................... 185 

Hampton Springs, Taylor County...... 185 

Little Salt Springs, Sarasota County 185 

Miami Oolite ................ ------------------- 72 

Rainbow Springs, Marion County...... 185 

Rock Springs, Orange County ............ 185 

Salt Springs, Marion County ....... __ 185 

sea water .................................................. 155 

Silver Springs, Marion County .......... 185 

Tampa Limestone ....... ~.......................... 57 

well, South Lake _______ ......................... 167 

well 1, Parris Island, S.C...................... 162 

Chemical contamination .............................. 147 

Chemical quality ------------------------------------- !06 

Kissengen Springs ..................... _____ 184 

submarine spring discharge ......... -.... · 188 

water, Avon Park Limestone ........ 42, 48,44 

Caloosahatchee Marl ---------------- 66 

Citronelle Formation ------------ 67 

Hawthorn Formation ............ 60, 61, 62 

Lake City Limestone ............ 89, 40, 102 

marine terrace formations .......... 71 

Ocala Limestone --------------------- 50, 51 

Oldsmar Limestone ------------------ 102 

principal artesian aquifer ----- 114 

Tampa Limestone .......................... 57 

Chickasawhay Limestone ................... -.... 5! 

Chimneys ...................................... ____________ 181 

Chipola Formation .............................. ~- 55, 58 

Chipola River ............................ - ............ 10, 18, 76 

Chloride content ........................................ 141, 207 

Choctawhatchee Bay ............... __________ 9, 18 

Choctawhatehee Formation ---------------- 66 

Choctawhatehee Marl ............................ -..... II 

Choctawhatchee River -------------------- 18 

Choctawhatchee Stage .................................. 56 

Citronelle Formation ...................... - .... - 10, 64, 66 

Citrus County area, Florida --------------- 180 

Citrus County, Fla.......................................... 175 

Claiborne age ------------------------------------- 87 Clay County, Ga ........................... ___________ 11 

Clayton Formation ................................ -.... 24 

Climate ............................................................ 19 

Climatic optimum .................... -................... 69 

Coastal Lowlands, Fla ................................ _ 9 

Coastal Plain province .................................. 8 

Coastal Terraces, Ga ................................ ____ 11 

s.c ............................................. _.______ 12 

223 
224 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Page 

Cockfield Formation ------------------------------------- 37 

Coharie marine terrace -------------------------------- 10, 69 

Coharie shoreline ----------------------------------------- 8 

Collier County, Fla _______________________________________ 60, 102 

Color of water -------------------------------------------- 145, 208 

Columbia County, Fla ... --------------------------------- 102 

Comanche Series ------------------------------------------- 23 

Cone of depression -------·-------------------------------- 93 

Conecuh River ----------------------------------------------- 13 

Confined water -·-------------------------------------·-------- 90 

Congaree Formation -------·---------------------------- 37 

Congaree River --------------------------------------------- 12 

Congaree Sand Hills, S.C___________________________ 12 

Connate water ---------------------------- 154, 168, 170, 208 

Contamination, ground water ------------------- 1.1,1 

Cooper Marl --------------------------------------------- 44, 52, 59 

Corrasion in limestone ---------------------------------- 77 

Coskinolina zone ------------------------------------------ 172 

Cosme-Odessa well field ------------------------------ 97, 174 

Crescent Lake ----------------------------------------------- 17 

Cretaceous formations, salty groundwater areas ------------'----------------· 161J 

Crisp County, Ga·-------------------------------------------- 51 

Crystal River Formation __________ 45, 46, 47, 49, 50 

Crystal Springs ------------------------------------------- 129 

D 

Decatur arch --------------------------------------------------- 73 Decatur County, Ga________________________________________ 59 

Deep Head ------------------------------------------------------ 10 

Deep Lake ---------------------------------------------------- 87 

Deer Head ------------------------------------------------------ 10 

De Funiak Springs ---------------------------------------- 10 

Devils Garden ------------------------------------------------- 18 

Devils Mill Hopper --------------------------------------- 59 

Devils Pit ----------------------------------------------------- 85, 87 

Dexter, Lake ------------------------------------------------ 16 

Discharge, springs --------------------------------------- 179 

submarine springs ------------------------------ 183 

See also Aquifer and Artesian aquifer. 

Dismal Sink -------------------------------------------------- 87 

Dissolved solids, total · ---------------------------------- 135 

Dome pits --------------------------------------------------- 131, 183 

Dora, Lake --------------------------------------------------- 16 

Dougherty County, Ga .... ------------------------------ 51 

Dougherty Plain, Ga. _____________ 9, 10, 11, 12, 13, 21 

Drainage ------------------------------------------------------- 11!, 194 

Everglades ------------------------------------------- 11 

lakes ------------------------------------------------------- 16 

Oklawaha River -------------------------------------- 16 

relation to the principal artesian 

aquifer -------------------------------------- 11! 

St . .Johns River -------------------------------------- 15 

Santa Fe River -------------------------------------- 1.1, 

streams south of the Suwannee River 1.1, 

Suwannee River ----------------------------------- 1.1, 

swamps --------------------------------------------------- 17 

Withlacoochee River ---------------------------- 14 

Dry Creek ---------------------------------------------------- '76 

Duplin Marl --------------------------------------------------- 55, 69 

Duval County, Fla .......... -------------------------------- 102 

E 

Earthquake, Alaskan, 1964 116 

Earthquakes, relation to water levels, 

artesian wells ---------------------- 116, 204 

East coast, Florida ---------------------------------------- 169 

Ecphora zone ------------------------------------------------ 63 

Elasticity of the aquifer ------------------------------ 115 

Electrical conductivity -------------------------------- 145 

Emerald Sprin·g ---------------------------------------------- 87 

Eocene Series ------------------------------------------------ 96 Escambia County, Fla.___________________________________ 175 

Escambia River ---------------------------------------------- 10, 13 

Eustis, Lake ---------------------------------------------------- 16, 86 

Everglades ------------------- 9, 14, 15, 11, 18, 20, 72, 73 

Page 

F 

Fall Line Hills ------------------------------------ 9, 11, 12, 21 

Falling Water Sink -------------------------------------- 52, 83 

Falmouth Spring, Fla. _________________________ 53, 130, 134 

Faults -------------------- 76, 104, 105, 107, 131, 132, 202 

Fern Cave -----------·-------------------------------------------- 83 

Fish Pond Branch ------------------------------------------ 10 

Flagler County, Fla. ___________________________________ 108, 1 '70 

Flint River ·----------------------------------- 11, 12, 13, 88, 55 

Flint River Formation -------------- 52, 53, 54, 55, 95 

Flint River valley ---------------- 10, 11, 12, 18, 51, 53 

Florida basin, southern -------------------------------- 73, 75 

Florida Bay ------------------------------------------------ 9, 18, '72 

Florida Caverns State Park ------------------------ 81 

Florida embayment, southern ---------------------- 200 

Florida Keys --------------------------------------------------- 72, 75 

Florida panhandle ------------------------------------------ 9, 86 

Florida peninsula ----------------------------------------- 8, 125 

Florida, piezometric surface ---------------------- 114 

Florida Straits ---·------------------------------------------- 75, 76 

Floridan aquifer ------------------------------------------ 95, 202 

Floridian Plateau ---------------------- 23, 55, 68, 72, 75 

Fluoride content --------------------------------------- 141, 207 

Fluoride content, Hawthorn Formation 141, 207 

Folds --------------------------------------------------------------- 183 

Formation·s, geologic ---------------------------------- 1!1, 19.1, 

Fort Thompson Formation ------------------ 67, 71, 94 

Fort Valley Plateau, Ga ..... --------------------------- 11 

Fractures ---------------------------------------------- 76, 181, 202 

Franklin County, Fla ... ·--------------------------····· 175 

Fuller's earth, Decatur County, Ga............ 59 

Gadsden County, Fla.............................. 58 

Future studies ·---------------------------------------------- 210 

G 

Gadsden Limestone ··········-··-------------------------- 45 

George, Lake -----------·-···---------------------------------- 16, 1'7 

Georgia basin, southeastern ------------------------ '78 

southwestern -------------------------------------------- '73 

Georgia embayment, southeastern ------------ 200 

southwestern ----------------------------------------- 200 

Georgia, piezometric surface -------·------·-······ 122 

Ghyben-Herzberg principle ----·------- 155, 157, 158 

Glaciation, relation to changes in sea 

level -------------------------------------- 8, 18, 68 

Glen .Julia Springs -------------------------------------- 185 

Glendon Limestone Member ·····------------------ 52 

Gosport Sand ------··········----------------------------······ 87 

Graben --------------------------------------------------- 107 

Green Cove Springs ··-···-··-··············-------------- 127 

Green Swamp area ---------------------------------------- 126 

Greenville-Magnolia soils. See Soils. 

Griffin, Lake .......... :.-------------------------------------- 16 

Gulf coast -············-------------------------------------------

artesian-flow areas --------------------------------

Florida ----------·----··············--·-··-------------····· 

Gulf Series 

H 

158 

119 

173 

28 

Hampton Springs ·····----------·············-------------- 185 

Hardness of water ---------------------------- 140, 143, 207 

Hardpan. See Soils. 

Harney, Lake ------------------------------------- 15, 16, 1'7, 86 

Harris, Lake --------------------------------··········-· 16, 17, 86 

Hatchetigbee Formation ----------------------------- 86 

Hawthorn escarpment --------------------------------- 84 

Hawthorn Formation ........ 10, 11, 14, 16, 18, 20, 

21, 55, 95 

Florida 58 

fluoride content ---------------------------------- 141, 207 

Georgia ---·-···········--·-········-···-----------········ 6 9 

Hazlehurst marine terrace -------------····--------- 10, 69 

Hazlehurst shoreline ------------------------------·-···· 8, 18 

Hellen Blazes, Lake -------------·······------------------ 15 

Hernando County, Fla --------------------············· 175 

Herzberg lens ····-·················-·······-----------······-·· 155 

Herzberg principle --------···--------------------·-······· 155 

High Hills of Santee, S.C ................ ------------- 12 

Pasre 

High Springs ----------------··------------------------------ 14. 

Highlands County, Fla .. 39, 42, 48, 53, 57, 60, 103 

Hillsborough Bay -----·······--·---------------------··---- 14 

Hillsborough County Area, Florida............ 129 

Hillsborough County, Fla ........ 42, 48, 54, 57, 61, 

103, 174 

Hillsborough River .................................. 14, 15, 16 

History, geologic ............................................. 7 

Hydraulic gradient ---···················----------------- 98 

Hydroelectric plant, Withlacoochee River 191 

Hydrogen-ion concentration, defined -------- 144 

Hydrogen sulfide content ············---------- 144, 207 

Iamonia, Lake ········----------------------------············ 86, 88 

Ichatucknee Springs -------------------------------------- 14 

Illinoian Glaciation ---------------------------------- 8, 18, 68 

Indian River --------------·-······················-------------- 18 

Indian River County, Fla ............... .40, 48, 61, 172 

Inglis Formation ---···-··········· 41, 45, 46, 47, 49, 50 

Ion exchange, ground water ------·-········-···· . 148 

Iron content ----------------------·············------------- 137, 206. 

Iron Ladder Cave ---------············--------------------- 81 

Iron Mountain ------------------············------------------ 9 

Irrigation ····-------------- 107, 129, 170, 172, 187, 191, 

208, 209 

artesian wells ------------------------------------------ 192 

ground water ----------------------------------------- 192 

Irrigation water ----------·-·····----------------------------- 104 

classification of ········------------------------------ 146 

high-salinity --------------------------------·······-··· 146 

high-sodium -------------------------------------------- 146 

low-salinity ---------------------------------------------- 146 

low-sodium --------------------------------------------- 146 

medium-salinity ·--------------------- ------------- 146 

medium-sodium -------··············----------------- 146 

quality of -------------····-···-··········----------------- 145 

very high salinity ----·-··········-------------····· 146 

very high sodium ---------------------------------- 146 

Irvington soils. See Soils. 

Istokpoga, Lake --------------------------------------------- 17 

.J 

.Jackson age ·····-··-············-··········------------········ .!,.!, 

.Jackson County area, Florida -------------------- 125 

.Jackson, Lake -----------------------------------------······· 86, 88 

.Jacksonville, Fla ........... -------------------------- 110 

.Jessup, Lake -------------------·-·····------------------------·- 86 

.Joints ····-------------------------------- 76, 181, 133, 134, 202 

K 

Kansan Glaciation ·····--·····-······----------------------- 8, 68 

Karst cycle ----------------------------------··----------- 79, 82, 84 

Karst topography -------------------------------------- 194, 201 

Kerr, Lake ··--------------·····-------------------------------- 16 

Kershaw soils. See Soils. 

Key Largo Limestone ---------------------------- 67, 7!J, 94 

Kissimmee flexure ------------------------------- 45, 75,200 

Kissimmee, Lake ----------------------------------------- 1 '7 

Kissimmee River ------------------------------------------ 14, 17 

L 

Lafayette, Lake ---------------------------------------------- 86, 88 

Lake basins, origin -------------------------------------- 16 

Lake City Limestone ------------------------------------ 37, 95 

Florida --------------------------------------------------- 88 

Lake Flirt Marl ····------------------------------------------ 67, 79 

Lakeland soil. See Soils. 

Lakes, relation to aquifer recharge ---------- 100 

sinkholes ----·-····------------·········· 86, 126, 127, 201 

solution basins .................... 87, 107, 127, 201 

Laminar flow --········-·-···········-------------------------- 109 

Lawson Limestone ············-·-------------------------- 86 

Leakance, coefficient of, defined ---------------- 92 

Lee County, Ga .............. -------·······-------------------- 51 

Leon-Bladen soils. See Soils. 

Lisbon Formation ·····-········-········------------------- 87 

Little Manatee River ········------········-·-···------- 14 
.. 

.~· 

Page 

Little Salt Springs, Fla ............ ------------------- 85, 185 

Live Oak uplift--------------------------------------------- 73 

Louisville Plateau, Ga ........................ 9, 10, 11, 12 

M 

McBean Formation -------------------·-----·········-··-- 12, 37 

Madison County area, Florida .................... 124 

Magnesium content ·····················---···--·-- 137, 206 

Magnitude of springs, classification.......... 175 

Magnolia soils. Sec Soils. 

Manatee County, Fla ........ 42, 49, 57, 61, 104, 173 

Manatee River ................ -------------·-··-------··--·· 14 

Marianna Limest.one .................................... 52, 95 

Mnrinnnn Lowlands, Fla .............................. 10, 21 

Murine terraces, Pleistocene ...................... 68 

Marion County area, Florida ...................... 128 

Martin County, Fla ............ 42, 49, 54, 57, 61, 104 

Miami canal .................................................... 15 

Miami Oolite ...................................... 18, 20, 67, 7£ 

Miccosukee,, Lake .......................................... 86, 88 

Midway Age .................................................... 1!4 

Miocene Series ........................ _...................... 55 

Monroe, Lake .................................................. 15, 86 

Moodys Branch Formation .................... 44, 45, 52 

Mossy Head ...................................................... 10 

Murphy Creek ............................... -............ 16 

Myakka River ................................................ 14 

N 

Nnheola Formation ........................................ 24 

Nnnnfalin Formation .................................... 36 

Nassau County, Fla .................................... 102, 169 

Natural flow, relation to water levels, 

artesian wells ...................... 116, 204 

Natural Well .................................................. 83 

N ebrnsknn Glaciation .................................. 68 

New Smyrna arch .......................................... 45, 75 

Nitrate content .............................................. 143 

Norfolk-Binnton soils. Sec Soils. 

Norfolk-Ruston soils. Sec Soils. 

0 

Oak Grove Snnd Member ............................ 55, 59 

Ocala dome ...................................................... 75 

Ocain Group .................................................... 45 

Ocala Limestone ............ 10, 11, 14, 15, 38, 44, 95 

Escnmbin County, Ala ........ -............... 5S 

Florida ...................................................... 45 

Georgia ...................................................... 50 

Ocala uplift ................ 8, 15, 24, 45, 55, 73, 75, 76, 

84,131,133,195,200,202 

Ochlocknee River ................ - ........................ 11, 13 

Ocmulgee River .............................................. 11, 13 

Oconee River .................................................... 11, 13 

Ogeechee River ................................................ 13 

Okeechobee, Lake .. 9, 14, 15, 16, 17, 18, 20, 72, 87 

Okeechobee Waterway _................................ 14 

Okefenokee marine terrace .......................... 69 

Okefenokee shoreline .................................... 8 

Okefenokee Swamp ................ 9, 10, 14, 17, 18, 20 

Oklnwnha River .............................. -........... 16· 

Oldsmar Limestone .......................... 96, 38, 39, 95 

Oligocene Series ............................................ 5£ 

Orange Lake .................................................. 88 

Osceola low .............................................. 75, 76, 200 

p 

Paleocene Series ............................................ 1!4 

Pamlico estuaries .......................................... 17 

Pamlico marine terrace .............. 9, 12, 69, 86, 87 

Pnmlico Sand .................................................. 94 

Pamlico sen .............................................. 15, 16, 17 

Pnmlico shoreline .......................................... 8 

Pamlico time _................................................ 85 

Pascagoula Formation .................................. 67 

Pasco County area, Florida -----···--····-------- 126 

Paynes Hammock Sand ................................ 55 

INDEX 

Paynes Prairie ............................................... . 

Pea River ....................... - ............................ .. 

Page 

88 

13 

Peace River ...................................................... 14, 15 

Penholoway marine terrace .................... -- 9, 69 

Penholoway shoreline ........................ ------· 8 

Peninsular arch .......................... 8, 73, 75, 76, 1!00 

Perdido River .............................................. 9, 10, 13 

Permeability, coefficient of, defined .......... 91 

Perrine silt loam. See Soils. 

pH .................................................................. 144,208 

Phosphate deposits, hard-rock, Alachua 

Formation ................................ 64 

pebble, Bone Valley Formation .......... 66 

Physical divisions, Florida ................ -....... 9 

Georgia .................................................... 11 

South Carolina ........................................ 11l 

Piedmont Plateau .......................................... 12 

Piezometric surface .......................... 119, 186, 205 

defined ...................................................... 109 

Pinellas County, Fla ......... 49, 54, 57, 62, 105, 174 

Pinelog Creek ................................................. . 

Pleistocene marine terraces ....................... . 

Pleistocene Series 

Pliocene Series ............................................... . 

Pocket valleys. See Steepheads. 

89 

68 

67 

64 

Polk County area, Florida .......................... 126 

Polk County, Fla ................. 43, 49, 54, 58, 62, 105 

Porters Creek Formation ....................... _. 24 

Potassium content .................................... 139, 207 

Pourtales Terrace .......................................... 76 

Principal artesian aquifer. See Artesian 

aquifer, principal. 

Pumping, relation to water levels, 

artesian wells ...................... 116, 204 

Pumping test .................................................. 43 

Putnam County area, Florida .................... 127 

Putnam County, Fla ........ 40, 44, 50, 103, 106, 170 

Q 

Quaternary formations, salty groundwater areas .............................. 165 

Quaternary System ...................................... 67 

R 

Radioactive contamination .......................... 147 

Radiocarbon dating ........................................ 85, 86 

Radiochemical elements ................................ 149 

Radium .......................................................... 151, 208 

Rainbow Springs ........................................ 128, 185 

Rainfall, artesian-aquifer recharge 

areas --··-···········----······---··---- 111, 204 

Recent Series .................................................. 67 

Recharge. See Aquifer and Artesian aquifer. 

Recreation use, springs ................................ 191 

Red Bluff Clay ................................................ 52 

Resistivity survey ...................................... 157, 158 

Richland Red Hills, S.C................................ 12 

Rivers, relation to aquifer recharge ........ 100 

relation to water levels, artesian 

wells ...................................... 113, 204 

Rock Springs .................................................. 185 

s 

Saber-Tooth Cave .......................................... 81 

Saddle Creek .................................................... 62 

St. Johns County, Fla .............................. 103, 169 

St. Johns 'River .................................. 13, 15, 16, 42 

St. Johns River valley .................................. 20 

St. Lucie River ................................................ 15 

St. Marys River .................................... - ....... 14, 18 

Salinity hazard ................................................ 145 

Salt beds .................................. - ................. 154, 208 

Salt domes ............ ,........................................... 154 

Salt Mountain Limestone ............................ 36 

Salt Springs .............................................. -. 16, 185 

Salt water .................................................... 154, 208 

Salt-water encroachment ...... 139, 141, 146, 147, 

154, 156, 157, 158, 167. 175, 192, 194, 208 

225 

Page 

Salt water, relation to artesian head...... 158 

relation to fresh ground water ........ 155 

sources in fresh-water aquifers .... 154, 208 

Sand Hills ........................................................ 19 

Sanford high .................................................... 45, 75 

Sangamon Interglaciation .......................... 8, 69 

Sanitary wells ................................................ .. 191 

Santa Fe River ........................................ 13, 14, 16 

Santee Limestone .......................................... 37, 38 

Sarasota County, Fla...................................... 173 

Satilla River .................................................... 14, 66 

Saturation zone ............................................ 84, 201 

Savannah area, Georgia ...................... 50, 58, 167 

Savannah area, South Carolina .................. 167 

Savannah River ........................................ 11, 12, 13 

Sea-level changes, eustatic .............. 15, 68, 79, 82 

relation to glaciation. See Glaciation. 

Sea water, chemical composition .............. 155 

concentrated by evaporation .... 154, 169, 208 

entered in Pleistocene 

time .............. 154, 169, 170, 171, 208 

entered prior to Recent time ............ 154, 169 

Seminole County, Fla ........ 40, 44, 50, 62, 106, 171 

Seminole high .................................................. 200 

Ship canal ........................................................ 193 

Ships, relation to water levels, 

artesian wells .......................... 116 

Shoal River Formation ................................ 55, 58 

Silica content .............................................. 136, 206 

Silver Bluff marine terrace .......................... 9, 69 

Silver Bluff shoreline .................................... 8 

Silver Springs ...................................... 16, 128, 185 

Sinkholes ................ 82, 98, 105, 107, 126, 194, 201 

Siphon wells. See Wells. 

Sodium-adsorption-ratio, defined ................ 146 

Sodium bicarbonate water 135, 136, 138, 142, 206 

Sodium chloride water .............................. 135, 206 

Sodium content .......................................... 139, 207 

Sodium hazard ................................................ 146 

Softening, ground water .............................. 148 

Soils .................................................... 19, 20, 21, 107 

Solution cavities .................................. 77, 133, 200 

horizontal .............................................. 84, 201 

Orlando area, Florida ............................ 80 

Polk County, Fla .................................... 80 

vertical .................................................... 84, 201 

Wakulla Springs, Fla ............................ 80 

Solution channels ...................................... 133, 134 

Solution in limestone .................................. 76, 200 

South Carolina, piezometric surface.......... 1££ 

Southeastern Florida .................................... 6£ 

Southern Florida ........................................ 130, 173 

artesian-flow areas ................................ 119 

Southwestern Georgia ............................ · 51, 55, 58 

Specific capacity ............................................ 189 

defined ...................................................... 94 

Specific gravity, sea water .......................... 155 

Specific yield, defined .................................... 92 

Spring Bayou .................................................. 174 

Springs ................................................ 100, 175, 209 

Florida ........................ -........................... 179 

Georgia ...................................................... 179 

recreation use .......................................... 191 

submarine .. 100, 161, 172, 176, 178, 182, 209 

water supply ............................................ 191 

Steepheads ........................................................ 10, 84 

Still Lake .......................................................... 87 

Storage, coefficient of, defined .................... 92 

Stream types _................................................. 12 

Strontium content .......................................... 138 

Structure, geologic · .................................. 7, 78, 1!00 

relation to sinkholes .............................. 131 

relation to solution channels .............. 131 

Submarine discharge .................................... 170 

Sulfate content .................... - ................... 140, 207 

Sulphur Springs ............................................ 129 

Sumter County, Fla........................................ 175 

Sumte~.· County, Ga.......................................... 51 
226 ARTESIAN WATER IN TERTIARY LIMESTONE IN THE SOUTHEASTERN STATES 

Page 

Sunderland marine terrace ........ 9, 10, 14, 16, 69 

Sunderland sea ------------------------------------------------ 10 

Sunderland shoreline ------------------------------- 8 

Sunniland oil field -------------------------------------- 77, 200 

Surface electrical-resistivity survey. See 

Resistivity survey. 

Suwannee Limestone ---------------- 10, 14, 15, 52, 95 

Florida --------------------------------------------······· 5!1 

Savannah area, Georgia ··-···------- 54 

Suwannee River ········-···-···············- 13, 14, 16, 18 

Suwannee River area, Florida ··············----- 130 

Suwannee River valkr ·-----·----------------···- 53 

Sylvia Lake ...................................................... 10 ·, 

T 

Talbot marine terrace ····--------------------------- 9, 69 

Talbot shoreline ----------------------------------------·- 8 

Tallahassee Hills ------------------ 10, 13, 17, 20, 21, 84 

Tallahassee Limestone -------------------- 37, 38, 4o, 95 

Tallahassee syncline -------------------------------·-···· 73 

Tallahatta Formation ----------------------------------- 37 

Tamiami Formation -·---------------------- 55, 69, 64, 94 

Tamiami Trail ·----------------------------------------------- 87 

Tampa Bay ----------------------------------·········--·-·· 9, 14,20 

Tampa Formation -----------------------------------·----- 56 

Tampa Limestone --------····------------------ 10, 15, 55, 95 

Florida ------------------------------------------------------ 55 

Georgia --------------------·-···-········-··-----······-- 58 

Tampa stage -------------·········------------------------------ 55 

Tarpon Lake --------·--····----------------·······----- 127, 17 4 

Tarpon Springs -----------------------------------··-·· 54 

Temperature, artesian water ................ 152, 208 

spring water ·--------------·-------------- 179, 185, 209 

submarine spring discharge ................ 183 

Terrell County Ga ................. -------------------------· 51 

Tertiary formations, salty ground-water 

areas --------------------------·······------- 185 

Theis, C. V., quoted --------------------------------·---- 115 

Thermal gradient. ·------------------------------------ 153, 208 

Tidal efficiency -------------------------------------···--··· 115 

Tides, relation to water levels, artesian 

wells ----·····------------·-··-··------ 114, 204 

Tifton-Irvington soils. See Soils. 

Tifton Upland --------·-···----·····- 9, 10, 11, 13, 21, 51 

Tohopekaliga, Lake ------------····--------- 17 

Topography ······------------------------------------·-·-···· 8, 194 

Tortugas Terrace ------------------------------------- 76 

Trail Ridge --------------------------------·-------·-··-·· 10, 14, 18 

Trains, relation to water levels, artesian 

wells --------········--------------- 115,204 

Page 

Transmissibility, coefficient of, defined...... 91 

Tritium ------------------------------------···---------------· 150, 208 

Tsala Apopka Lake --------····-------------------- 14, 15, 87 

Tuscahoma Sand -----------····------------------------- 36 

u 

Uranium 151,208 

v 

Venturi tube 188 

V ero man ······---·-··--------------·--------------·-·· -···--·--·· 86 

Vertical shafts --------------------------------·-·····-·-- 131, 133 

Volusia County area, Florida ------------------- 128 

Volusia County, Fla ................ 40, 44, 50, 107, 171 

w 

Waacasassa Flats 75 

Waccamaw Formation ·---·---····---------------------- 13 

Wakulla Cave ------------------········---------------------·· 80, 86 

Wakulla County area, Florida -------------------- 124 

Wakulla Spring ---------------------------------·--·-------- 80, 88 

Warley Hill Marl -----------------·······--------····----··· 87 

Warm Mineral Springs, Fla ...................... 85, 185 

Warm Salt Spring. See Warm Mineral 

Springs. 

Water-bearing properties. See Artesian 

aquifer, principal and 

Formations, geologic. 

Water, chemical quality. See Chemical 

quality. 

consumption -------------------------------------------- 192 

Water supplies, public --------·······-·-------------- 192 

Water supply, Hillsborough River ------------ 191 

springs -----------------··-------------------------···------- 191 

wells --------------------------------------------------------- 191 

Water-table conditions -------------------------------- 91 

Water use ------------·----------------·····-----------------· 191 

Wateree River --------------------------------------------- 12 

Well, Effingham County, Ga., No. 7________ 114 

Florida Geological Survey No. W-20.. 66 

Fort Screven, Ga. No. 328 ------------- 114 

Hilliard 1 ------------------------------------------ 59 

Humble Oil Co., No. W-820.................. 77 

J. S. Cosden's Lawson 1 ...................... 40 

Jacksonville, Fla., No. 7 .. -------------------- 110 

Jacksonville, Fla., No. 10 --------····-------- 110 

Oldsmar ---------------------------------------------- 87,41 

Well, Parris Island, S.C., No. 1 ----------------

Parris Island, S.C., No. 2, log of ..... . 

Peninsular Oil and Refining Co., 

J. W. Cory 1 in Monroe 

Page 

162 

163 

County ···---------------------------------- 37, 77 

Ponce de Leon Hotel, St. Augustine, 

Fla --------------------······················· 110 

South Lake -----------····---------------------------· 167 

Wells ---------------------------------------·-··················-· 185, 209 

artesian ---------------------------------·----·---------· 185 

artesian, depths. of ------------------------------ 209 

artesian, to generate electricity -------- 191 

drainage -------------------------·-·······-········- 188, 191 

history of drilling ---------------------------·----- 185 

irrigation ------------------------------------------------ 187 

methods of easing ----------------·----------------- 187 

natural -----------------------------------········· 8!, 201, 202 

natural flow of ------------------------------------ 189, 209 

nonftowing ----------------------------------------· 189, 209 

records of -------------------------·-········--------------- 186 

sanitary ·······----------·········--····----·-·······-----·- 191 

siphon -----------------·--···------------------····--····----- 188 

spacing of --------·-·········-------------------------- 94 

specific capacity of ___________ :____________________ 189 

subsurface leakage in ··················--···-·· 189 

surface drainage into -------------- 112, 191, 204 

water supply from ------------------------·····--- 191 

yields of ·----------------------------------··········- 189, 209 

Western Florida ------------·····--·---------·······-···--- 124. 

Western Highlands, Fla ................................ 10, 84 

White Head ------------------------·-·························· 10 

White Springs ····----------------··················--··--·- 14 

Wicomico marine terrace ···························- 9, 69 

Wicomico shoreline ···------------------------··------- 8, 14 

Wilcox age -----------------------------------------············· 36 

Williston Formation ------------------ 45, 46, 47, 49, 50 

Wind velocity, relation to water levels, 

artesian wells ···········--·--·-·· 114, 204 

Wisconsin Glaciation -----------------····-----------·--· 68 

Wisconsin time----------------·------------·········-···-- 8 

Withlacoochee River -------------------------- 9, 13, 14, 16 

Fla __ ----------------------------------------------------------- 16 

Ga ·--------------------------------------------------------- 16 

y 

Yarmouth Interglaeiation ------------········-------- 8, 69 

Yazoo Clay ----------------------------------------··---------- 44, 52 

Yellow River -----------············---·······------------------ 10, 18 

Yoldia zone ... :·-----------------·-········--------------------- 63 

'1:! U.S. GOVERNMENT PRINTING OFFICE· 1966-Q 21!1·141 

72 3656 3 09 

-<1·