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 Copyright
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 Part 2 Phosephate concentrations...
 Part 3 An analysis of Ochlockonee...


FGS






STATE OF FLORIDA


STATE BOARD OF CONSERVATION
Ernest Mitts, Director


FLORIDA


GEOLOGICAL


SURVEY


Herman Gunter, Director






REPORT OF INVESTIGATIONS NO. 16








MISCELLANEOUS STUDIES

















TALLAHASSEE, FLORIDA


1958










FLORIDA STATE BOARD

OF

CONSERVATION


LEROY COLLINS
Governor


R. A. GRAY
Secretary of State



J. EDWIN LARSON
Treasurer



THOMAS D. BAILEY
Superintendent of Public Instruction


RICHARD ERVIN
Attorney General



RAY E. GREEN
Comptroller



NATHAN MAYO
Commissioner of Agriculture


ERNEST MITTS
Director of Conservation






LETTER OF TRANSMITTAL


7i0tiLa Q a1 ieca1 S atvef

Tallahassee

December 5, 1957





Mr. Ernest Mitts, Director
Florida State Board of Conservation
Tallahassee, Florida

Dear Mr. Mitts:

I am forwarding to you a report entitled, MISCELLANEOUS
STUDIES, which includes the following papers: "Geology of the Area
in and Around the Jim Woodruff Reservoir" by Charles W. Hendry, Jr.
and J. William Yon, Jr.; "Phosphate Concentrations near Bird Rookeries
in South Florida" by Dr. Ernest H. Lund, Department of Geology,
Florida State University; and "An Analysis of Ochlockonee River Channel
Sediments" by Dr. Ernest H. Lund, Associate Professor and Patrick
C. Haley, Graduate Assistant, Department of Geology, Florida State
University.

These three papers contribute to our knowledge of the geology and
economic resources of Florida and are being published as Report of
Investigations No. 16.

Respectfully submitted,
Herman Gunter, Director
























CONTENTS

Part I Geology of the area in and around the Jim Woodruff
reservoir --.----.----___.. -- -----......-----_ .. ...--... ------..........-----.- .....--.- 1

Part II Phosphate concentrations near bird rookeries
in South Florida ......--------------..----------------- 53

Part III An analysis of Ochlockonee river channel
deposits ..--..-- ....----.. ---...-.- ----..-.........-----....... 69










Part I


GEOLOGY OF THE AREA


IN AND AROUND


THE JIM WOODRUFF RESERVOIR


By

Charles W. Hendry, Jr.

and


J. William Yon, Jr.














Florida Geological Survey

Tallahassee, Florida

1958


1



















(










TABLE OF CONTENTS


Page


Acknowledgments ............


Introduction
Purpose
Location
The Jim

Physiography
Introduc
Tallahass

Dougher
Maj
















Stre

Structure ..
Chattah

Linear
Stratigraphy
Introdu'
Tertiary
Eocene

Jackson

Ocala g
Cr











Oligoc<
Su


and scope of study .....................


Woodruff lock and dam ................
W oodo o . k .. am . . ... . .

tion .............................
see Tertiary Highlands ....................

rty River Valley Lowlands .................
jor streams ........ ................. ..
Chattahoochee River .....................
Flint River ............................

Apalachicola River ......................
Flood plain ... ....................
Natural levees ...........................

Rim swamps ...........................
Tributary streams .......................
Stream terraces .... ....................
Jim Woodruff Reservoir area.........
eam capture .........................


.oochee anticline .........................

trends ............. ............ ...... .
. . . . . . . . . .
action ................... .............. .
S system ................................
series .................................

stage ...............................

group ................................
ystal River formation .....................
Historical ............................
Distribution ...........................

Lithology .............................
Thickness and structure ................
Stratigraphic relationship ................
Geologic exposures ....................


ene series .................
iwannee limestone .........


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


. . .
. .

. . .


.. ..
. . .

.. . .

. . .

. . .

0 6 a 0

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

. . . .

. . . .


.. . .


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

. . . .


................... 24


. ................ 25


................................ 25


Historical ..............
Distribution ............


..

3


7
7
7
8
10
10
10
11
12
13
13
13
13

14
14
15

15
16
17
20
20

22
23
23
23
23

23

23
23
23
23
24
24
24


..... i







Lithology .............

Thickness and structure .

Stratigraphic relationship

Geologic exposures .....

Miocene series .................

Tampa stage ..................

Chattahoochee facies .......

Historical .............


Distribution


Lithology ............

Thickness ............

Stratigraphic relationship

Geologic exposures ....

Alum Bluff stage ..............
Hawthorn faces ..........

Historical ............

Distribution ..........

Lithology ............

Thickness ............

Stratigraphic relationship


................ .26
................ 26
.............. 26
................ 26


..





. .


. . .








. . .

. . .


. .. .. .. . .


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


)















I


. . .

. .. .. .

. .

. .

. .. . .

. . .

. .. .

. .. .. ..

. . . .


. .. .. .. .. ..


28

28

28

28

28

28

29

29

30

34

34

34

34

34


........... ........... ...... oo. 34


Geologic exposures .....

Post-Miocene stratigraphy ....
Silicified limestone .........

Historical .............

Present concept .....

Geologic exposures .....

Geologic exposures along Chattahoochee

Insoluble residue study ..............
Introduction ...................
Procedure .. .. .. .. .. .. ..

Insoluble residues ..............

Conclusion ...........,..... .

Localities ....,.....................


34
35

35

35

35

36

36

43

43
44

44

45

47


. . . . . .

. . . .








and Flint rivers .................... ((

. 0 4 6 4 4 . . . . . 4 0

I .............

0 0. 0 6. 0 .. o ff.

00 .......... .......~1~( ~


50





8

9

16'

19

22

24

26

46


Figure
1

2

3
4

5

6

7

8


Map showing area of investigation.................

Map showing phlysiographic regions ................

Reconstructed composite of terrace surfaces.............
Diagramnmatic stream capture sequence...............

Map showing linear trends along the Chattahoochee and Flint rivers ....
Geologic map of area investigated .....,.........,........... Facing

Geologic cross sections ..................................... Facing

Chart showing insoluble residue percentages in three wells ...........


Selected bibliography ........................

ILLUSTRATIONS

















ACKNOWLEDGMENTS

Dr. Robert O. Vernon, Assistant Director, Florida Geological Survey,
assisted the writers many times in the field investigation and offered many
helpful suggestions during the preparation of this report.
Staff members of the Florida Geological Survey offered assistance
and advice during the course of the study. Special recognition is given
to Mrs. Ruth Shuler and Miss Betty Youngblocd for the time they spent
typing and editing the report. Assistance was given by Mr. Kenneth
Highsmith who helped in the preparation of the illustrations and maps.
Appreciation is expressed to the staff of the Resident Engineer's office,
U. S. Army Corps of Engineers, Chattahoochee, Florida, for making
available maps and elevations of the Jim Woodruff reservoir area.
Citizens of Jackson and Gadsden counties, Florida, and Seminole and
Decatur counties, Georgia, were very cooperative and helpful.































































































I





Part I


GEOLOGY OF THE AREA
IN AND AROUND
THE JIM WOODRUFF RESERVOIR

INTRODUCTION

PURPOSE AND SCOPE OF STUDY
In December 1953 Vernon, Hendry, and Yon1 made a study of the
outcropping Tertiary sediments along the lower portions of the Chatta-
hoochee and Flint rivers in the area of the Jim Woodruff reservoir. This
investigation was conducted prior to the conclusion of the Jim Woodruff
Dam project. The completion of this dam has created a 37,000-acre lake
which has masked from future investigations much of those sediments
that were previously exposed in the area. This study along the rivers
brought to light inconsistencies in the present concept of the geology of
this area and the writers thought it wise to undertake a more thorough
investigation of the surface geology.
The data collected through the study of surface exposures were
supplemented by examination of cuttings from three oil test wells and
six water supply wells that were drilled in the area and samples from
three core holes which were obtained from the field office of the U. S.
Army Corps of Engineers, Chattahoochee, Florida. The absence of
samples from a sufficient number of wells to give a good coverage
influenced the writers to put down 17 auger holes in locations where
little or no subsurface information was available.
This report presents the results of the studies on the geology in and
around the Jim Woodruff reservoir that have been conducted inter-
mittently since December 1953.

LOCATION
The area of this investigation is located in southwest Georgia, Decatur
and Seminole counties, and in the adjoining portions of Jackson and Gads-
den counties, Florida. It is roughly rectangular in shape, bounded by
30o40' and 31O00' north latitude and 84o30' and 8500' west longitude.
The east-west dimension is approximately 30 miles, and the north-south
dimension is approximately 20 miles (fig. 1). The investigation was
confined principally to the area between and around the Chattahoochee
and Flint rivers.
1Dr. R. O. Vernon, Assistant Director, C. W. Hendry, Jr. and J. W. Yon, Jr.,
Geologists, Florida Geological Survey.







FLORIDA GEOLOGICAL SURVEY


ALABAMA
quA L A-A A
Lb INa' V/// E 0 R G A
N i (hMA IOmOcl00 AWoqr _r Jt-,

AV~V

'VM A;
CAAP~


G UL F


0


V4
VpA
0
0


FLORIDA
$W. e ,,soWi s
krrIogok Ylleo


Figure 1. Map showing location of the area in and around the Jim Woodmrff
reservoir.


THE JIM WOODRUFF LOCK AND DAM
For nearly half a century Mr. Jim Woodruff, Sr., of Columbus, Georgia,
sought development of the Apalachicola, Chattahoochee, and Flint rivers
for navigation. In tribute to Mr. Woodruff's persistence, the first of the
projects in the plan for improving these rivers was named the Jim
Woodruff Lock and Dam. This project was authorized as a part of the
River and Harbor Act of July 24, 1946, and was dedicated in 1957.

The dam is located northwest of Chattahoochee, Florida about 300
yards below the point where the Chattahoochee and Flint rivers unite
to form the Apalachicola River. The normal level of the water in the
reservoir is at an elevation of 77 feet with the tailwater at 44 feet.


VA
k 0-






REPORT OF INVESTIGATIONS No. 16


This dam provides channels, nine feet deep and 100 feet wide, in
the Chattahoochee River to Columbia, Alabama, and in the Flint River
to Bainbridge, Georgia. In addition to this navigational facility, the dam,
having a shoreline of 243 miles, provides an area for recreational activities
such as boating, camping, fishing, picnicking, and sightseeing (U.S.C.E.
Pamphlet, 1953).






FLORIDA GEOLOGICAL SURVEY


PHYSIOGRAPHY
INTRODUCTION
The sediments studied in this investigation lie within the East Gulf
Coastal Plain, a subunit of the Coastal Plain Province (Fenneman 1938,
p. 65-68). The recognizable physiographic subdivisions of this area were
mapped as: (1) the Tallahassee Tertiary Highlands, and (2) the Dough-
crtv River Valley Lowlands (fig. 2).
On the basis of origin, Vernon (1951, p. 16), subdivided the phy-
siography of Florida into two general groups, each of which is sub-
divided into two units. These are the Delta Plain Highlands, the Tertiary
Hlighlands, the Terraced Coastal Lowlands, and the River Valley Low-
,lnds. He defined his highlands as sediments formed either as a part
of a high-level, widespread, aggradational delta plain or of Tertiary land
masses rising above this plain, and his lowlands as being formed by
imarille erosion and deposition along coastlines and by alluviation and
stream erosion along stream valleys. Vernon proposed that where these
stlbdlivisions are mapped, local names may be appropriately applied.
TALLAHASSEE TERTIARY HIGHLANDS
The topography and composition of the Tallahassee Tertiary High-
lailds is considerably different from that of the surrounding terrain. The
area abruptly rises 200 to 250 feet above the adjacent lowlands and the
excellent soils developed oil the highlands support lush, natural vegetation
and give rise to many prosperous farms.
The Tallahassee Tertiary Highlands arc characterized by erosional-
remn'llant lills with relief up to 250 feet, except in the northwestern part
of (adsden County and in the adjoining southwestern portion of Decatur
(Cotuty, (Georgia, where the highest hills are comparatively flat-topped
witi elevations slightly exceeding 300 feet. Because of the flat crests,
remnlant drainages and depositional sequences, these hills are interpreted
as remnants of the original depositional surface of the Hawthorn delta.
To thle west, south and east of this flat-topped section, the cycle of erosion
is miore advanced, having reduced the highlands to a lower, more dis-
sected topography. -The highlands are composed of sands and clays of
the lHawthorn formation with impure limestone of the Chattahoochee
formation cropping out along the bluffs of the major streams, in road cuts,
in small stream valleys, and in sinks that penetrate through the Hawthorn.
)Descriptions of portions of the Tallahassee Tertiary Highlands area
are numerous in the literature. Not until Cooke (19'9, p. 14-21) divided
the State into five physiographic divisions, was most of this highlands
area grouped together and named.






REPORT OF INVESTIGATIONS No. 16


Cooke (1939, p. 20) applied the name Tallahassee Hills to an area,
approximately 25 by 100 miles, delineated by the Georgia-Florida state
line on the north, the coastal lowlands on the south, and the Withla-
coochee and Apalachicola rivers, respectively, on the east and west. He
described the area as being characterized by long gentle slopes with
rounded summits, the highest part of which is believed to be a plain
with a maximum elevation of about 300 feet in the vicinity of north-
western Gadsden County. Cooke stated the geologic composition of
these "hills" was impure limestone of the "Tampa limestone" overlain
by the sands and clays of the Hawthorn formation. Later (1945, p. 9-10),
he assigned the red surface sands to the Citronelle formation and the
underlying sandy clays and clays to the Hawthorn formation.
Vernon considered that his definition of Tertiary highlands included
Cooke's Tallahassee Hills, which he thought to be a general term and
proposed the local name Tallahassee Tertiary Highlands, as more appro-
priate. The writers, conforming to Vernon's "locality-origin" terminology,
have adopted the term Tallahassee Tertiary Highlands to include Cooke's
Tallahassee Hills as bounded on the south and east, but extended on
the west into Jackson County, Florida, and north into Decatur County,
Georgia, where it is bounded by an escarpment facing the Dougherty
River Valley Lowlands.
That part of the Tallahassee Tertiary Highlands in southeastern
Jackson County, Florida, has been disjoined from the eastern part by
the Apalachicola River. Previous investigators have found little dispute
in assigning the sandy limestones underlying this highlands area to the
lower Miocene; however, the capping clastics west of the Apalachicola
River in Jackson County have been disassociated from the similar Miocene
deposits on the eastern side of the river and generally assigned to the
Pleistocene series in previous literature. The writers find no material
lithologic differences in the clastics of these two areas and therefore
include these western hills in their Tallahassee Tertiary Highlands.
Also, it is the impression of the writers that the northern limits of the
highlands should exceed Cooke's political boundary limit, the Gadsden-
Decatur county line (Florida-Georgia state line), and be extended to the
northward-facing escarpment overlooking the Flint River valley, a
part of the Dougherty River Valley Lowlands.

DOUGHERTY RIVER VALLEY LOWLANDS
The Dougherty River Valley Lowlands is the largest physiographic
unit in the area, consisting of sediments at relatively low elevations
which occur north and west of the Tallahassee Tertiary Highlands. In





FLORIDA GEOLOGICAL SURVEY


1911, Veatch (p. 30-31) applied the name Dougherty Plain to the low-
lands of southwestern Georgia. In 1938, Fenneman (p. 76-77) expanded
the term to include that portion of Florida which was later called the
Marianna Lowlands by Cooke (1939), p. 18-19). Moore (1955, p. 6-8),
using Vernon's terminology based on origin, called Cooke's Marianna
Lowlands the Marianna River Valley Lowlands. Since the largest portion
of the lowlands of this report is a part of Veatch's Dougherty Plain,
the writers have used the term Dougherty River Valley Lowlands for
this geomorphic unit.

The area assigned to the lowlands includes the flood plains and ter-
races of the present Apalachicola, Chattahoochee and Flint rivers, and
also the topographically low area in Jackson County which is probably
the result of ancestral streams of the Choctawhatchee and Chattahoochee
river systems. Moore (1955, p. 7) briefly discusses the agencies forming
these lowlands.

This westward extension has been traced through Jackson County
into Hlolmes County by Moore (1955, p. 8, 13, 14) to where it joins the
Ilood plains of the Choctawhatchee and Holmes rivers (Vernon 1942,
p. 5-6) in Holmes and Washington counties. The sediments are clastics
ranging in size from clays to large silicified boulders measuring up to 15
feet across (see Flood Plain, p. 13).

MAJOR STREAMS
There are portions of three major streams flowing within the area
of this investigation. Two of these streams, the Chattahoochee and the
Flint rivers, originate from outside the area, having their headwaters
in the piedmont of northern Georgia. The third major stream, the
.\palachicola River, has its headwaters within the area of this investi-
gation, being formed by the confluence of the Chattahoochee and Flint
rivers.

The channel banks of the Chattahoochee and Flint rivers are excep-
tionally steep for rivers as old and as well established as they appear to
l)e, when compared to streams elsewhere in Panhandle Florida.

Northward in Georgia and Alabama, tributary streams join the Chatta-
hoochee with valley floors standing much higher and out of adjustment
at their point of confluence with the Chattahoochee. This evidence would
indicate rejuvenation of the Flint and Chattahoochee system in the late
Pleistocene or Recent.






REPORT OF INVESTIGATIONS No. 16


Chattahoochee River
The Chattahoochee River flows southward near the western edge of
the area. This stream is heavily laden with suspended sediment, as is
evidenced by its turbidity and red color. It is an active river with a
gradient of about 0.65 foot per mile in the lower 26 miles. Only at
locality 34 do silicified boulders constrict the channel, a marked contrast
to the Flint River channel, which is strewn with boulders and obstructed
by boulder bars that create a definite hazard to river travel, especially
during periods of low water.
Flint River
The Flint River flows southward along the eastern boundary of the
area and is deflected westward by the high scarp along the north edge
of the Tallahassee Tertiary Highlands. In contrast to the Chattahoochee
River it carries much less load in suspension. This is readily noticeable
at their confluence where, for some distance down the Apalachicola River,
the discharge from each river is easily distinguishable by the color.
The Flint River has a gradient of approximately 0.55 foot per mile
for the lower 26 miles. Rapids and islands of boulders or bedrock of
silicified limestone of Eocene and Oligocene age are not uncommon in
the area from locality 52 (Lamberts Island) to the northern limit of
the area.
Apalachicola River
The Apalachicola River, formed by the union of the Chattahoochee
and Flint rivers about one mile northwest of the town of Chattahoochee,
Gadsden County, Florida, flows southward and empties into the Gulf of
Mexico at Apalachicola, Florida. Only about five miles of this river lies
within the area covered by this report. However, the writers feel it has
played an important part in the evolution of the present landforms, and
is, therefore, discussed more fully under stream capture.
Flood Plain
The deposits comprising the flood plains of the Chattahoochee and
Flint rivers range in thickness from a thin veneer to over 80 feet. Near
the Alabama state line, ledges of bedrock visible at stages of low water
underlie 20 or 30 feet of flood-plain sediment which was deposited in
a more shallow part of the valley. Two auger holes located about one
mile west of the right bank of the Chattahoochee River (see auger hole
localities AS-2422 and AS-244) penetrated 80 feet of sand and pea-
size gravel with small amounts of clay without reaching bedrock. At
auger hole locality AS-243, a depth of 71 feet was reached before bed-
2Florida Geological Survey auger sample numbers.


18





FLORIDA GEOLOGICAL SURVEY


rock was encountered. This alluvium was deposited in deep abandoned
channels probably formed in an older Chattahoochee system which were
cut during a preceding interglacial period and subsequently filled.
The Hood plain along the left bank of the lower section of the Chatta-
hoochee River merges with that of the Flint River, giving a broad
relatively low area between the two rivers in this region. Within this
broad low area, auger holes AS-246, AS-247 and AS-249 did not pene-
trate bedrock at depths of 73.5, 67.5 and 73.5 feet, respectively; whereas,
bedrock was reached in holes AS-248, AS-250 and AS-251 at depths of
63, 26 and 70 feet. This varying thickness of alluvium points up the highly
eroded surface of the bedrock.
Natural Levees
Natural levees are present along the Apalachicola, Chattahoochee and
Flint rivers. These natural levees are formed during flood stages of the
rivers. As the high water rises above the confines of the channels and
flows onto the flood plain, its velocity is sharply decreased and the
increased load, transported by the higher velocity, is largely deposited
immediately adjacent to the streams. At the time the field work was
done, the flood plains of the Chattahoochee and Flint rivers had been
cleared as part of the project of preparing the reservoir. The removal of
trees and brush had exposed the levees over a wide vista and they
were easily identified. Toward the upper limits of the reservoir, where
the levees stand higher than the cleared, adjacent part of the flood plain,
they are marked by elongated wooded islands and strips.
Rim Swamps
Natural levees, normally the highest part of any flood plain, slope
gently toward the base of the valley walls, and low marginal areas are
present along the base of the escarpment rising above the flood plain.
During the wet season, when the ground-water level rises high enough,
these low marginal areas become swampy and are termed rim swamps.
As the local irregularities (basins) in the rim swamp area become full to
overflowing, the drainage collects in a stream, called a rim swamp stream,
which forms along the base of the valley wall (Russell 1938, p. 72-73).
Him swamps are common along the flood plains of the streams within
the area. Vernon (1942, p. 8) described rim swamp streams along the
marginal valleys of the Choctawhatchee River in central Holmes County;
however, rim swamp streams are not sharply delineated in the reservoir
area.
Terraces, deposited as flood plains, have these same aggradational
features. The higher terraces, having been subjected to erosion for a






REPORT OF INVESTIGATIONS No. 16


longer time, have fewer, if any, recognizable aggradational patterns pre-
served; whereas, the younger terraces still possess excellent examples.
On the lower terraces, the marginal areas are marked by sinkhole
alignment.
Tributary Streams
In the area of this investigation, the Flint River has five tributaries
only one of which could be considered a major tributary. The major
tributary, Spring Creek, originates about 10 miles southeast of Fort
Gaines, Georgia, and flows southward to its junction with the Flint River.
It is a very sluggish stream in its lower reaches, the channel being
drowned and in many stretches unidentifiable through swamp vegetation.
The stream carries almost no sediment, but is darkly colored by organic
acids. It is locally reported that this stream is partially spring fed. The
mouth of Spring Creek is obscured by cypress trees, giving the appear-
ance of a drowned swampy area along the Flint River.
Butlers, Sanborn and Fourmile creeks, and Big Slough, are the
four principal small tributary streams of the Flint River. All of these
streams are located along the left side of the Flint, and contrary to the
small tributaries of the lower Chattahoochee River, they are in adjustment
at their point of confluence with the Flint. They drain relatively small
areas, having an average length of only a few miles.
Butlers and Sanborn creeks originate in the Tallahassee Tertiary
Highlands of southern Decatur County, Georgia. They flow northward
and join the Flint River at the base of the northward facing highlands
escarpment. Fourmile Creek and Big Slough originate in the Dougherty
River Valley Lowlands and trend in a westerly direction, uniting with the
Flint near the town of Bainbridge, Decatur County, Georgia.
The small segment of the Apalachicola River covered in this report
has only one tributary. This is Mosquito Creek which drains the area
northeast, east, and south of the town of Chattahoochee and enters the
Apalachicola in the southern part of the area of this investigation.
There are no principal tributaries of the Chattahoochee River below
the Alabama-Florida state line; however, mention has been made above
of the tributaries of the Chattahoochee just north of this area.
Stream Terraces
The first published account of stream terraces in Florida was by
Vernon (1942, p. 9-15). He reported four definite levels above the
present flood plains of all the major streams in Holmes and Washington
counties, Florida. Prior to Vernon's work on stream terraces in West
Florida, H. N. Fisk (1938, 1939, 1940) reported on the occurrences of





FLORIDA GEOLOGICAL SURVEY


stream terraces in Louisiana The reader is referred to these two workers'
reports for a discussion on the origin and description of stream terraces.
Jim Woodruff Reservoir Area: The writers found four really defined
levels associated with stream-cut scarps bordering the Chattahoochee
and Flint rivers. These four fluvial surfaces occur above the modern
flood plain at heights of 10, 40, 60 and 90 feet. To substantiate the number
of existing terraces and their heights above the flood plain the writers
compiled, normal to the river axis, many land-surface profiles using
U. S. Geological Survey topographic quadrangles and aneroid elevations
taken in the field. Figure 3 represents a reconstructed composite of the
terrace su-rfaces associated with the Chattahoochee and Flint rivers.

-200 200-





1 I .... -
100 I-- -


E3 STREAM -CUT VALLEYS
El ALLUVIAL FILL
[ TERTIARY SEDIMENT

Figmur 3. generalizedd and diagrammatic profile across the Chattahoochee River
Valley in Jackson County, Florida and Seminole County, Georgia.

Two terrace surfaces above the flood plain of the Flint River con-
sistently show up in profiles drawn across the valley. These fluvial
surfaces occur at 10 and 40 feet. Between these two levels there occur
several levels at varying altitudes that may be traced only for short
distances. They very probably are attributable to erosion and perhaps to
rejuvenation of the river by stream capture.
Erosion and probably stream course change have so altered the land
surface in this area that the highest terrace is not as well preserved in
Jackson County, Florida, as it is in Seminole County, Georgia. Only
sparsely scattered hilltops in the northern part of Jackson County reach
this level, whereas in Seminole County the average elevation exceeds 160
feet with some hills reaching 180 feet. As this is the only level that






REPORT OF INVESTIGATIONS No. 16


doesn't fit into the system described by Vernon (1942) -there is a possi-
bility that the few remaining hilltops that mark this level were once
higher and are now uniformly eroded to 90-100 feet above the modern
flood plain.
The 60-foot level is extensively developed in central and northern
Jackson County, but it is less distinguishable in Georgia because of the
shorter areal distance between the lower terraces and the 90-foot level.
The 40-foot level is conspicuously developed along both the Chatta-
hoochee. and Flint rivers. In addition to the many flats which represent
this terrace surface there are also many hilltops at this altitude that help
substantiate the level.
In the vicinity of the juncture of the Chattahoochee and Flint rivers
the 10-foot terrace is broadly developed but now flooded by the Jim
Woodruff reservoir. Upstream this terrace narrows considerably, rarely
exceeding two miles in width.
The stream terraces are very poorly defined or absent along the
left side of the Flint River from Southlands Ferry to the dam. The
presence of the steeply sloping, high Tertiary escarpment immediately
to the left of the river makes identification of terrace levels impossible.
That section of the Apalachicola River covered in this report is
bounded on each side by fairly high Miocene hills. There are no hilltops
or extended flats that correspond to the levels described above that occur
above the modern flood plain. The presence of only a recent flood plain
indicated that the river did not occupy this course during the time the
terraces were being formed (see Stream Capture).

STREAM CAPTURE
Paralleling the western edge of the Tallahassee Tertiary Highlands
in Jackson.County, Florida, is a broad, terraced, shallow valley which is
characteristic of a flood plain commensurate with a system comparable
to the Chattahoochee and Flint rivers. The western side of this valley is
bounded by high Pleistocene plastic sediments. The valley trends in a
inorth-south direction and merges at its southern end with the lowlands
associated with the present Apalachicola River flood plain in the vicinity
of northern Calhoun County. Its northern limit joins the lowlands asso-
ciated with the Chattahoochee River lowlands, now inundated by the
Jim Woodruff reservoir.
There are no perennial streams in the valley at the present time, but
small tributaries of the Apalachicola River are present at its southern





FLORIDA GEOLOGICAL SURVEY


extremity. Most of the valley is drained by sinks and during periods of
heavy rainfall and high water-table level the many ponds and swampy
areas are connected by intermittent streams.
Moore (1955, p. 13) reports a buried stream channel in north central
Jackson County that extends in a north-northeast direction into Alabama
towards the Chattahoochee River. Along the right side of the Chatta-
hoochee River, the depth to bedrock, as determined by auger holes,
would indicate that formerly the Chattahoochee was several miles to
the west of its present course. The writers believe that this river flowed
through the remnant valley described above. If this is true, the Flint
River would have extended beyond its present entry into the highlands to
a point of juncture with the Chattahoochee several miles north or north-
west of the town of Sneads (fig. 4-1).
Four and one-half miles north of the Jim Woodruff Dam the direction
of the southward trending Chattahoochee River veers sharply to the
left for approximately one mile and then again southward (right) to
where it joins the Flint River. The axis of this jog in the river is in
perfect alignment with the Flint River where it flows along the base of
the high escarpment which marks the northern limits of the Tallahassee
Tertiary Highlands. Because the location of this jog is not controlled by
the high Miocene hills and because there is an exact alignment with the
Flint River channel, it is possible that the jog may represent a portion
of a former extension of the Flint River which drained to the west.
The geomorphic conditions that exist in the Chattahoochee-Sneads
area at the present time strongly suggest the possibility of stream capture
in the late Pleistocene or early Recent time. The relationship of the
Apalachicola River with the Flint and Chattahoochee rivers indicates that
the Apalachicola has advanced its headwaters northward into the high
Miocene sediments and diverted the Chattahoochee and Flint rivers
(fig. 4-2).
The Apalachicola, because of its steeper gradient along the south-
western edge of the Tallahassee Tertiary Highlands, cut back through
these highlands into the drainage area of the Flint and Chattahoochee
rivers. This stream capture caused a change in the direction of flow of
these rivers at the point of capture (fig. 4-2).
The Flint River diverted by the captor stream, the Apalachicola
River, now turns sharply at the point of capture, exhibiting a well-
defined elbow of capture. The increased volume of the Apalachicola
River after the capture of the Flint River allowed rejuvenation to enlarge
the valley through the Tallahassee Tertiary Highlands.









REPORT OF INVESTIGATIONS No. 16


E -
fV ilnii


Figure 4. Four diagrammatic panels illustrating progressive stages in the stream capture of the
Chattahoochee and Flint rivers by the Apalachicola River.

4-1. Hypothetical courses of the Chattahoochee and Flint rivers (A) which flowed around the
Tallahassee Tertiary Highlands, the northern and western limit of which is shown by
the hachured line (B). At this stage the Apalachicola River (C) was a small tributary to
the Chattahoochee River and had just begun to cut headward into the highlands. The
dashed line (D) represents the most recent courses of the three rivers.

4.2. The Apalachicola River (A), still tributary to the Chattahoochee River (B), has cut
headward through the Tallahassee Tertiary Highlands and captured the Flint River (C).
The captured stream (C) has been diverted by the captor stream (A) and now turns
sharply at the point of capture (E), exhibiting a well-defined elbow of capture. The
beheaded portion of the Flint River (D) has turned back into the captor stream, and
thus has been transformed into an inverted stream.

4-3. The Chattahoochee River (A) has been diverted by the enlarged inverted stream (B).
The combined flows of the Chattahoochee and Flint rivers rapidly enlarged the youthful
valley of the Apalachicola River (C).

4-4. This panel illustrates the positions of the Chattahoochee (A), Flint (B), and Apalachi-
cola (C) rivers just prior to the erection of the Jim Woodruff Dam. The dashed lines
represent the former courses of the Chattahoochee and Flint rivers.


- --I I--- -, 1


_ ___ ___
__ ___


i


I





FLORIDA GEOLOGICAL SURVEY


The Chattahoochee River, having lost most of its volume after the
capture of the Flint, became a misfit stream. Probably the smaller tribu-
taries, below the old point of juncture with the Flint River, built alluvial
fans on the valley floor because the Chattahoochee could no longer
transport the customary load. Lakes and marshes probably formed, and,
subsequently, the development of sinks along this valley captured what
surface drainage remained.
The writers believe that in the region south and southwest of the
Tallahassee Tertiary Highlands the Apalachicola River now occupies or is
closely associated with the former Chattahoochee River valley. The
development of sinks along the valley to the west of Sneads has cap-
tured the surface drainage along this valley and the deposition of
plastic sediments derived from the greatly dissected highlands on each
side of the valley has caused the Chattahoochee to be deflected to the
point of confluence with the Flint and Apalachicola rivers.

STRUCTURE
CHATTAHOOCHEE ANTICLINE
The largest geological structure occupying the region in southwestern
Georgia, southeastern Alabama, and the adjoining portion of Florida
is the Chattahoochee anticline. This broad flexure was first suggested
and named by Veatch (1911, p. 62-64). He observed local disturbances of
Cretaceous and Eocene beds along the Chattahoochee River and noticed
inequalities in the drainage divides of the Chattahoochee and Flint
rivers. Veatch reasoned that the shorter tributary streams of the much
larger Chattahoochee River were developed along the crest of an anti-
cline, whereas the longer tributaries of the Flint flowed down the eastern
flank of the anticline. His interpretation of the somewhat parallel courses
of the rivers was that the Chattahoochee flowed southward along the
crest of the anticline and that the Flint flowed down the trough of a
broad syncline complementary to this anticline.
Veatch noted that the much greater depth of the Chattahoochee valley
and steepness of the channel walls indicated a greater magnitude of
earth movement along the Chattahoochee than along the other rivers
in the region.
A press release issued by the Federal Survey in 1917 stated that the
available evidence was not adequate to substantiate this anticline.
Prettyman and Cave (1923, p. 107-111) did not believe that the
geological evidence indicated crustal folding of the magnitude implied


20






REPORT OF INVESTIGATIONS No. 16


by Veatch in his description of the Chattahoochee anticline. In their
opinion, it pointed only to gentle regional Pleistocene or later movement
with some local reversals in dips.
Stephenson (1928, p. 295) in a description of local flexures in the
coastal plain monocline, agreed that an anticline in this area existed, and
dated (1928a, p. 892) the movement that caused this crustal disturbance
as late Tertiary or early Quaternary.
In 1929 George I. Adams (p. 201-202) published a report on his
investigation of the streams of the coastal plain of Alabama in which he
stated he had examined the area of the Chattahoochee anticline and
did not believe the geological facts supported the existence of this
anticline.
Postley (1938, p. 809-810) presented a paper on the oil and gas
possibilities in the Atlantic Coastal Plain and included the Chattahoochee
anticline in his discussion on structure.
Leet (1940, p. 875) recognized the existence of the Chattahoochee
anticline and described it as a broad upwarp with its axis trending along
the Georgia-Alabama state line.
Cooke (1943, p. 4-5) explained the difference of the greater number
of exposed geological formations along the Chattahoochee River as com-
pared to the Ocmulgee and Savannah rivers as the result of progressive
overlay which indicated a progressive uplift of that part of the coastal
plain of Georgia.
An upwarp in the vicinity of Jackson County, Florida, was one of
several structural features in the subsurface of Florida and southern
Georgia described by Applin and Applin (1944, p. 1727).

The first deviation from the term Chattahoochee as a place-name for
the uplift seems to have been made by Pressler (1947, p. 1852, fig. 1).
He made no mention nor included any discussion of the upwarp in the
text of his article; however, he did use the name Decatur Arch for the
area of the uplift on the text figure which accompanied his article.

Applin (1951, p. 407) and Gunter (1953, p. 42, 48) continued the
use of the term Decatur Arch.

Jordan (1954) recognized the priority of the term Chattahoochee
and applied it in a discussion of the structure of the area. Toulmin (1955,
p. 209-210) used the term -Chattahoochee anticline in preference to
Decatur Arch.





FLORIDA GEOLOGICAL SURVEY


LINEAR TRENDS
Vernon (1951, p. 47) first recognized large scale fracturing in the
subsurface of Florida and mapped these fractures from their physio-
graphic expressions as shown on mosaics of aerial photographs. In Citrus
and Levy counties the regional fractures parallel the axis of the Ocala
uplift with a northwest-southeast trend. This system of fracturing is
crossed by a secondary system which trends in a northeast-southwest
direction. Vernon reports that stream patterns commonly parallel these
two systems of fracturing.
Rectangular stream patterns have been reported in Jackson County
by Moore (1955, p. 15-16). He stated that this pattern observed along the
Chipola River and D)ry Creek suggests a control by fracturing. He re-
ports a similar pattern in west central Jackson County of the creeks that
flow on alluvium 30 to 100 feet thick.
Examination of large scale prints made from aerial photographs of
the Jim Woodruff Dam area shows a linear relationship existing among
certain portions of the courses of the Flint and Chattahoochee rivers
(fig. 5). The scarcity of well and core hole samples prevented the
preparation of detailed geologic sections; the identification of fracturing


Figure 5. Map showing linear trends along the Chattahoochee and Flint rivers.






REPORT OF INVESTIGATIONS No. 16


in relation to such linear trends, without the aid of detailed geologic
sections, was impossible. However, the linear trends are closely similar
to trends associated with fracturing reported by Vernon and Moore.
There is a possibility that fracturing has resulted from the Chattahoochee
anticline, and that the linear trends in the Chattahoochee and Flint
rivers may be the result of fractures in the bedrock that extend through
the alluvium.
STRATIGRAPHY
INTRODUCTION
The surface formations in the area of the Jim Woodruff Dam reservoir
range in age from upper Eocene through Recent. The bedrock is com-
posed of the Crystal River formation, Jackson Stage, in the northern
part; the Oligocene, Suwannee limestone, in the central section; and the
Chattahoochee facies, Tampa Stage, in the southern part. The plastics
that mantle the bedrock in the northern and central parts are of Pleisto-
cene and Recent age and the plastic Hawthorn formation of the Alum
Bluff Stage, overlies the bedrock in the southern part of the area.
TERTIARY SYSTEM
EOCENE SERIES
JACKSON STAGE
OCALA GROUP
CRYSTAL RIVER FORMATION
Historical: The early history of the terms upper Eocene, Jackson
group and "Ocala limestone," has been adequately discussed by Vernon
(1942, p. 40-41) and Cooke (1945, p. 53). The Applins (1944, p. 1683-84)
separated the Ocala limestone in peninsular Florida into an upper and
lower member. Vernon (1951, p. 111-112) divided the Ocala limestone
into two formations, the "Ocala limestone" (restricted) for the upper
portion and the Moodys Branch formation for the lower portion. He
further subdivided the Moodys Branch formation into a lower Inglis
member and an upper Williston member.
Puri (1953, p. 130; 1957, p. 31) proposed the term Crystal River
formation to replace the term "Ocala limestone" (restricted) of Vernon.
He abandoned the name Moodys Branch formation of Vernon and raised
the Williston and Inglis members of the Moodys Branch to formational
rank.
Distribution: The oldest rocks cropping out in the area of this inves-
tigation are those of the Crystal River formation (fig. 6). The formation





FLORIDA GEOLOGICAL SURVEY


is exposed along the banks of the Chattahoochee and Flint rivers from
the northern boundary of the area to about the center of this region
where it dips under younger sediments. Completely silicified limestone,
occurring as boulders and possibly pinnacles throughout the northern
two-thirds of the area, contain Ocala fossils and, although the boulders
are incorporated in clastics ranging in age from Pleistocene to Recent,
they were probably derived from a former greater areal extension of
the Crystal River formation.
Lithology: The Crystal River formation is predominantly a white to
cream, soft to hard, porous to dense, crystalline, marine, generally friable,
coquinoid limestone composed chiefly of foraminifers, bryozoans and
mollusks. The formation has been locally replaced by silica to form a
white to reddish-brown, hard, moldic (porous) crystalline to occasionally
chalky, fossiliferous mass of chert with occasional zones of dense chert.
luring silicification the tests of the smaller microfauna were almost
entirely destroyed and those retained are rarely identifiable. The larger
microfossils are generally retained as molds and casts, and can usually
be identified generically, but seldom specifically.
Thickness and Structure: The complete thickness of the Crystal
River formation is not exposed in the area of this investigation. However,
in Jackson County, Florida, Puri (personal communication, 1955) reports
the Crystal River formation to be about 300 feet thick.
The top of the Crystal River formation as determined from exposures
and well cuttings in Decatur County, Georgia, and in extreme eastern
and southeastern Jackson County, Florida, indicates that the Crystal
River dips south-southeast at approximately 17 feet per mile.
Stratigraphic Relationship: In the northern half of the area, the
Crystal River formation is overlain unconformably by Pleistocene to
Recent clastics which contain silicified limestone rubble derived from
upper Eocene limestones. The elevation of the top of this formation
is very irregular due to solution and sinkhole activity. In the southern
portion of the area, the Crystal River formation is unconformably overlain
by the Oligocene, Suwannee limestone.
Geologic Exposures: Decatur County, Georgia. The best exposures
of the Crystal River formation along the Flint River are found from Bain-
bridge northward to High Bluff, about seven miles above Bainbridge.
The thickest section is found at High Bluff where 17 feet are exposed
(see Flint River traverse locality 4, p. 37, this report for description).
Seminole County, GeQrgia. The best and thickest exposure of the
Crystal River formation on the Chattahoochee River is found at.a bluff




-- '--'-~~-------~~.,_.~ --- - -; I--- :~
-'`-`-' `'-c--- --- -'c-LL~.- Li
--------- -----~. _.., _.._~. ~~
------c-









KK K>\ >.,.t;~


\ 2.\
\" '\

\" '"'
\~\N'




,.\; ''"
i i-N
rN

''N ~ ~
~ ''k"

~ \ \~. ~ yv449


FLORIDA GEOLOGICAL SURVEY


LAMBERTS


GEOLOGIC MAP


AS-251
0


+ +


W.1364
,q-0--


+ MIOCENE SERIES
49
Chattahoochee Facies
Hawthorn Facies


OLIGOCENE SERIES
Suwannee Limestone


EOCENE SERIES
Crystal River Formation


JIM WOODRUFF DAM


1 0 1 2 3 4 5

SScale in miles


REPORT OF INVESTIGATIONS NO. 16, PART I, FIGURE 6
"'.





N a
^ '"' 84 i



N\ \ iit






,:\, /,+ ,,> ,.. .,, .. +.. -,>. '., s \ S".* .,







'. -"" *' +'- ': +.+ *:, t--:,
NjN


O


r


400-








REPORT OF INVESTIGATIONS No. 16


on the left bank of the river about 15 miles above the Jim Woodruff Dam,
where 15 feet are exposed (see Chattahoochee River traverse locality 32,
p. 42, this report for description).
In the J. R. Sealy, Seminole Naval Stores Company well no. 1
(W-37373), Land Lot 142, Land District 21, bedrock was encountered at
40 feet. These sediments represent the Crystal River formation and have
yielded Asterociclina species.
Based on the presence of Operculinoides ocalanus, the top of the
Crystal River formation was identified at a depth of 60 to 70 feet in the
Mont Warren, Grady Bell well no. 1A (W-2149), located 560 feet north
of the south line and 660 feet east of the west line of Land Lot 61, Land
District 27.
Decatur and Seminole counties, Georgia. Nowhere between the Flint
and the Chattahoochee rivers in Decatur and Seminole counties, did the
writers find an outcrop of the Crystal River formation. However, large
chert masses scattered throughout this area may possibly represent eroded
pinnacles of this formation (see post-Miocene section of this report), but
are more probably chert boulders derived by solution from limestone of
the Crystal River formation and incorporated in later sediments.
Jackson County, Florida. Some of the silicified boulders found in
the northeastern portion of Jackson County, were identified as upper
Eocene in age. However, in most cases, the fossil component of the rock
was not identifiable because of the poor state of preservation; therefore,
the age of the rock was not positively established.
Ten feet of Crystal River formation, overlain by five feet of Oligocene
limestone, is exposed in a sink in the south central part of sec. 14, T. 5 N.,
R. 9 W. (locality 38). An oil well test (W-3627) in the SE/ NE3 sec. 11,
T. 5 N., R. 8 W., penetrated, at a depth of 25 feet, limestone of the
Crystal River formation immediately beneath the clastic overburden.

OLIGOCENE SERIES
SUWANNEE LIMESTONE
Historical: Florida Geological Survey bulletins 21 and 29 are cited
.s references for excellent historical reviews of the use of the term
'Suwannee limestone."
Distribution: The Suwannee limestone underlies the southern half
)f the area. Locality 53 represents the only Suwannee limestone outcrop
.ound and, for this reason, the Suwannee was primarily mapped on the
3Florida Geological Survey well sample number.





FLORIDA GEOLOGICAL SURVEY


basis of subsurface information (fig. 6). The dip, as determined in wells,
was projected to intersect the ground surface and provide a means of
delimiting the formational boundary.
Lithology: The Suwannee limestone is a white to cream, granular,
crystalline, soft to hard, porous, frequently dolomitic, fossiliferous lime-
stone. Locally, the fossils are poorly preserved and are difficult to identify.
The formation has been eroded and segments of it remain as completely
silicified limestone boulders incorporated in terrace material (p. 86).
Thickness and Structure: A water well (W-.8442) drilled in south-
eastern Jackson County, Florida, in the SW)1 sec. 12, T. 3 N., R. 7 W.,
penetrated 120 feet of sediment that were assigned to the Suwannee lime-
stone. In the area above the confluence of the Chattahoochee and Flint
rivers, the top of the formation, as penetrated in auger holes, is very irreg-
ular (fig. 7). These auger holes did not pass through the complete thick-
ness of the Suwannee. The top has been eroded in this area and it is
believed the thickness is probably somewhat less than 120 feet.
The dip of the Suwannee limestone in the area of the Jim Woodruff
i)am reservoir trends south-southeast at approximately 25 feet per mile.
Stratigraphic Relationship: The Suwannee limestone lies uncon-
formably upon the Crystal River formation, and unconformably below
the younger Chattahoochee faces, or below younger plastics, where the
Chattahoochee has been removed by erosion. In the central portion of
the area the Suwannee is overlain unconformably by Pleistocene to
Recent river alluvium.
Geologic Exposures: Decatur County, Georgia. Twenty-three feet of
Suwannee limestone are exposed in the bank and in a gully on the
slope of the escarpment on the left side of the Flint River at Southlands
Ferry (locality 53).
On the right bank of the Flint River at Lamberts Island, silicified
limestone boulders of Suwannee age were found incorporated in Pleisto-
cene to Recent sediments.
Seminole County, Georgia. Along the right bank of Spring Creek at
locality 51, about two and one-half miles due south of Reynoldsville,
silicified limestone boulders, Suwannee age, were found embedded in
Pleistocene to Recent sediments.
About one mile east of the left bank of the Chattahoochee River and
four miles northwest of the Jim Woodruff Dam, a depth of 70 feet (+8')
was reached with an auger (AS-251) without penetrating bedrock. How-
ever, rock fragments, probably from a weathered limestone surface, were










































































































































































*1






































LOCATION MAP


EXPLANATION

Section A-A' drawn approxi-
mately parallel to dip of
Tertiary strata.


Section B-B' drawn approxi-
S mately parallel to strike of
Tertiary strata.


ISO


100


50


A






150







*4










*.I3 50


AND


SUWANNEE -..
CRYSTAL RIER FORMATION LISTONE
CRYSTAL RIVER FORMATION


t 0 I
HORIZONiAL SCALE M- MILES


Figure 7. Geologic sections drawn north to south and west to east
Woodruff reservoir.
I *


in area of Jim


- N
z z


I.


SUWANNEE


CRYSr4


RIVER


b~0


.1 1 0


LIMESro


F.R pmriot


1 2


HORIZONTAL SCALE IN MILES


L.--.--------


8'


LIMES1OHE


__


--


A'
as.


LOG


350


100


50


0


.30


.100


.100























































4


p
p

I





REPORT OF INVESTIGATIONS No. 16


found in the samples which were identified as Suwannee limestone in
age by the presence of Rotalia mexicana.
Jackson County, Florida. At localities 39, 40, 41, 42 and 43, silicified
boulders were identified as Suwannee in age.

Gadsden County, Florida. The section described below was measured
in the powerhouse coffer dam excavation at the Jim Woodruff Dam site
(locality 54). The top of the section is at an elevation of +12 feet.
Between the top of this section and the bottom of the section measured
on the west side of the Apalachicola River there are 62.6 feet of section
that are covered.

Bed Description Thickness
(feet)
Miocene Series
Tampa Stage-Chattahoochee facies
5 Limestone, white to light cream, crystalline calcite, soft, chalky,
argillaceous, dendritic manganese in fractures. The middle two
feet of the bed are hard and the bottom two feet are very argil-
laceous and soft.......................................................................... 6.0
4 Limestone, light buff, chalky to very finely crystalline, hard to
soft, argillaceous, dense, slightly dolomitic, dendritic manga-
nese in fractures in the rock. Some isolated flakes of mica......... 4.0
Oligocene Series
Suwannee limestone-elevation +2 feet
3 Limestone, light buff, cryptocrystalline to very finely crystalline,
with more crystalline calcite than bed 2, hard, dendritic man-
ganese, dolomitic moldic porosity in part, dense in part. Kuphus
incrassatus. Upper two feet of bed has small pea-size voids
filled with soft green clay.................................... .................... 5.0
2 Limestone, cream to light buff, very finely crystalline with some
voids filled with crystalline calcite, dense, hard, dolomitic,
fossiliferous. Kuphus incrassatus .............................................. 4.0
1 Limestone, cream to light buff, finely crystalline, porous, hard,
dolomitic, fossiliferous, but microfossils indistinct. Kuphus
incrassatus ........................................................................................ 2.0

Total thickness .............................................................................................. 21.0
Base of section elevation -9 feet.
Near the contact the Chattahoochee is brecciated with masses of
clay and angular dolomitic boulders incorporated together. Some of these
basal boulders appear to have haloes of clay which grade into the
Suwannee limestone and may represent alteration of the limestone to
clay. At the top of the Suwannee limestone and extending into the





FLORIDA GEOLOGICAL SURVEY


Chattahoochee formation are green clay deposits occurring as lenses,
irregular masses, and vertical pipe fills. This green clay is not useful
for widespread correlation as its vertical distribution in the base of the
Tampa is perhaps as great as 30 feet, while its horizontal distribution
is sometimes only a few feet.

MIOCENE SERIES
TAMPA STAGE
CHATTAHOOCHEE FACIES
Historical: Puri (1953a, p. 17) revised the terminology of the Miocene
sediments in Panhandle Florida and included under his term Tampa
Stage those sediments previously assigned to the Tampa formation. For
a historical review of the Tampa formation the reader is referred to
Florida Geological Survey Bulletin 21, pages 67-68.
Puri recognized two distinct lithofacies within the Tampa Stage,
the downdip calcareous facies, called the St. Marks, and the updip silty
and clayey facies, for which he revived the term Chattahoochee. The
writers found no sediments within the area of this study that could be
assigned to the St. Marks facies; therefore, only those sediments of the
(Chattahoochee facies are discussed.
Distribution: The Chattahoochee facies forms a part of the Talla-
hassee Tertiary Highlands in the southern part of the area of this in-
vestigation and underlies the clastics of the Hawthorn formation (fig. 6).
The formation is exposed on the slopes of the bluffs trending along the
Chattahoochee, Flint and Apalachicola rivers, in valleys cut by tribu-
taries of the Flint River, and in sinkholes and road cuts.
Lithology: The Chattahoochee facies consists chiefly of lenses of
clay within a white to cream, very silty to sandy, chalky to crystalline,
soft to hard limestone, containing molluscan casts, several species of
Foraminifera and a burrowing mollusk similar to Kuphus incrassatus
Gabb, but generally smaller. Locally, at the base of the formation, is
found a tan, brown and cream, finely sucrosic, hard, sometimes argilla-
ceous and silty to sandy, usually dense, partially moldic dolomite. At
localities 44, 45, 47 and 55 the formation is a cream, slightly hard, sandy,
chalky, porous, finely crystalline, angular to slightly rounded limestone
pebbles in a cream, slightly hard, finely crystalline, very microfossiliferous
limestone. These two limestones exhibit the appearance of an intra-
formational conglomerate or, according to Tanner (1956, p. 309-311),
a beach rock, which appears to represent only transgressive-regressive
phases of the Tampa Stage.





REPORT OF INVESTIGATIONS No. 16


Thickness:.- The top of the Chattahoochee faces, determined by the
study of water well cuttings and outcrop samples, was found to be
eroded and irregular in elevation. This erosional surface accounts for
the variable thickness of the formation.
The thickness of the Chattahoochee sediments in well no. W-2254,
located in the SE, SEM sec. 28, T. 4 N., R. 7 W., Jackson County, is 30
feet. The excavation and escarpment at the Jim Woodruff Dam exposed
approximately 160 feet of Chattahoochee sediments. The top of the
Chattahoochee faces was encountered at an elevation of 192 feet in
an auger hole (AS-126) drilled on the east side of the town of Chatta-
hoochee, Gadsden County, Florida, in the SW, NE, sec. 33, T. 4 N.,
R. 6 W. This is the highest known point for the top of the formation in the
area. One-half mile south of this auger hole in the city of Chattahoochee
well (W-3482), located in the SW, SEX sec. 33, T. 4 N., R. 6 W., the
bottom of the Chattahoochee facies occurs at an elevation of -35 feet.
The cumulative thickness, 227 feet, between the top and bottom of
these two wells may more nearly represent the true thickness of the
Chattahoochee facies in this area.
Stratigraphic Relationship: The Chattahoochee facies was observed
to lie unconformably upon the Suwannee limestone in an excavation pit
at the site of the Jim Woodruff Dam powerhouse. Chattahoochee and
Suwannee sediments were observed in a gully near Southlands Ferry
(locality 53), but the contact between the two formations was obscured
in 22 feet of the section that was covered by slumped sediments.
Lithologic homogeneity of limestone beds 1 through 14, exposed at
the Jim Woodruff Dam section, influenced Puri (1953a, p. 20) to place
the upper limit of the Chattahoochee facies at the top of bed 14. He
also mentioned the possibility that the rubble bed (bed 7), may represent
a continental phase of the Alum Bluff Stage, probably the Chipola facies.
Later, on the basis of the well-developed unconformable contact between
beds 6 and 7, Puri and Vernon (1956, p. 56) placed the boundary between
the Chattahoochee and the Hawthorn facies at the top of bed 6.
In this report, the boundary between the Chattahoochee and Haw-
thorn sediments is moved back to the top of bed 14. Recognizing that
this boundary may only represent a lithologic and not a time break, this
procedure is followed because:
1. Sediments represented by beds 1 through 14 are similar limestones.
2. There is difficulty in establishing which of the several rubble beds occurring
in the section represent a major unconformity.
3. The rubble beds are not recognizable in well sections.
4. Rubble beds were not observed at other outcrops of the Chattahoochee facies
within the limits of this report.


29






30


FLORIDA GEOLOGICAL SURVEY


Geologic Exposures: Decatur County, Georgia. Fifty-two feet of
Chattahoochee sediments were found along an abandoned road on the
northeast-southwest trending escarpment on the left side of the Flint
River about eight and one-half miles by river above the Jim Woodruff
Dam (locality 48).

The following section was measured on the right bank of Sanborn
Creek, approximately one mile upstream from its junction with the Flint
River (locality 50):

Bed Description Thickness
(feet)
Miocene Series
Tampa Stage-Chattahoochee facies
5 Limestone, buff, soft but tough, argillaceous, silty, moldic. This
bed is exposed in a road 30 feet from creek bank.................... 1.0
4 Limestone, cream to tan, nodular, conglomeratic, very weath-
ered material, seemingly composed of chert boulders, indurated,
and green clay nodules.................................................................. 4.0
3 Very light olive green and cream to tan, silty to finely sandy,
argillaceous material, containing thin laminae running irregu-
larly through the bed. Probably originally horizontal with
slum ping, causing distortion.......................................................... 3.0
2 Limestone, gray to cream, hard, cryptocrystalline, questionably
silty, containing sparsely distributed coarse quartz sand............ 1.5
1 Cream to tan, silty to finely sandy, argillaceous, calcareous
material, weathered surface soft, nonweathered surface hard.... 3.0

T otal exposed .................................................................................................... 12.5

Jackson County, Florida. The following descriptions are of samples
taken from ledges of rock cropping out on the slope of the escarpment
in the SWM sec. 15, T. 4 N., R. 7 W. (locality 44):

Sample No. Description Elevation
(feet)
Miocene Series
Tampa Stage-Chattahoochee facies
2 Limestone, white to cream, soft, porous, argillaceous, silty to
finely sandy, chalky, with veinlets of crystalline calcite................ 124
3 Limestone, very light cream, slightly hard, porous, argillaceous,
silty to finely sandy, chalky to very finely crystalline, micro-
fossiliferous. Archaias floridanus, Sorites sp., Miliolids............ 116
4 Sam e as lim estone above................................................................ 113
5 Limestone, light cream, slightly hard, porous, silty to finely
sandy, chalky to finely crystalline, with green nodules of clay
that appear to be weathered from microfossils................................. 110
6 Limestone, cream, slightly hard, sandy, porous, chalky to finely
crystalline, occurring as angular to slightly rounded pebbles in
a cream, slightly hard, finely crystalline, very microfossiliferous,






REPORT OF INVESTIGATIONS No. 16


Sample No. Description Elevation
(feet)
porous, limestone. The rock displays the appearance of an
intraformational conglomerate or beach rock ......................... 100.5
7 Limestone, light cream, slightly hard, porous, silty to finely
sandy, moldic; this sample was taken from a boulder which had
probably moved down from above...............---------------------- 100
8 Same as sample 6......... ..... ....---------................. 89
9 Limestone, cream, hard, porous, finely sandy, finely crystalline,
m icrofossiliferous .............................................................................. 83
10 Sam e as sam ple 9......................................................................... 65

The thickest exposure of Chattahoochee sediments in the area of
this study is found in the following combined geologic sections in Decatur
County, Georgia, and Jackson County, Florida:
The Decatur County part is located on the access road to the earth
dike of the Jim Woodruff Dam, directly below the U. S. Engineers office
on the east side of the Apalachicola River. Measured in February, 1953,
by Robert 0. Vernon, C. W. Hendry, Jr., Harbans S. Puri, and J. William
Yon, Jr.
Bed Description Thickness
(feet)
Miocene Series
Alumn Bluff Stage-Hawthorn facies (deltaic)
21 Quartz sand; red, yellow and white, fine to coarse-grained,
poorly developed, graded bedding. Contains more quartz gravel
at the base than at the top. Topped by about five feet of deep
red soil profile which contains polished sandy, limonitic nodules,
some of which occur along a definite zone................................. 16.0
20 Quartz sand; mottled, light gray, purple and yellow, fine to
medium-grained, very argillaceous............................................. 6.5
19 C covered ......................................................................................... 29.0
Alum Bluff Stage-Hawthorn facies (marine)
18 Marl; variegated, cream and light gray. Contains fine-grained
quartz sand, abundant Pecten and oyster shells within the bed 1.0
17 Quartz sand; tan to light brownish-gray, medium to fine-
grained, argillaceous and becomes more argillaceous toward
the top.................................................... .............. ....... ............... 8.1
16 Clay; dark greenish-gray, blocky, silty and contains fine-
grained quartz sand..................................................................... 3.0
15 Siltstone; light greenish-gray, which contains bright, waxy, clay
nodules and hard, brown, crystalline, dolomitic limestone.
Oyster reef development within the bed.................................... 4.5
Section discontinuous-beds 14 to I measured about 40 yards to the west.
Tampa Stage-Chattahoochee facies
14 Limestone; tan, dolomitic, hard, cryptocrystalline, thinly bed-
ded, pasty........................................................................ ............... 6.0






32 FLORIDA GEOLOGICAL SURVEY

Bed Description Thickness
(feet)
13 Limestone; thinly bedded and interbedded with green, cal-
careous, silty clay......................................................................... 0.5
12 Limestone; light brownish-gray to cream, dolomitic, soft,
tough, blocky, and contains quartz sand................................. 1.5
11 Limestone; rubble of white, dolomitic, hard, pasty, with ir-
regular lenses of fossils within the bed. Top of bed has irregular
surface along which light green, crystalline calcite has been
developed (Diastem?) ---------- ...........-------.-----.-----------.............. 2.5
10 Limestone; light brownish-gray to cream, dolomitic, soft,
tough, blocky and contains quartz sand..................................... 4.5
9 Limestone; rubble of white, hard, pasty, with irregular lenses
of fossils within the bed. Top of bed has irregular sur-
face along which light green crystalline calcite has been de-
veloped. Bed lies irregularly upon bed 8 (Diastem?)............ 2.5
tains quartz sand; within the bed are irregular tunnels filled
with calcareous, harder, green sand and clay. Contains irreg-
ular lenses and nodules of the above sand and clay. Lenses and
nodules of crystalline calcite are present. Occurring at the top
of the bed is a layer of medium gray crystalline calcite about
eight inches thick. The Gastropod Ampulella is found within
the bed (D iastem ?) ..................................................................... 4.2
7 Limestone; rubble of white, dolomitic, hard, pasty, slightly
fossiliferous, somewhat nodular, intermixed with sand and
nodules of limestone. Possible Chipola equivalent..................... 2.8
NOTE: At the base of bed 7 and the top of bed 6 the contact between
the beds is wavy. There is a one-inch calcite enrichment which
may indicate that bed 7 overlies bed 6 unconformably. The Gas-
tropod Ampulella? was found along the contact between beds
7 and 8.
6 Limestone; white, pasty, silty, blocky, spherical weathering.
Top four inches harder............................................. .................... 0.8
5 Clay; light greenish-gray, containing thin seams and partings of
sand and silt. Also contains limestone nodules appearing
to be fossiliferous............................... ...................................... 0.8
.1 Limestone; very light brownish-gray, dolomitic, hard, and tough
where exposed. Contains numerous mollusk molds. Upper two
and one-half feet contain greenish-gray silt and light green clay
nodules which are fossiliferous. Weathers slightly harder than
bed 3.... ................................................ ......................... ....... 8.1
:3 Limestone; cream to white, soft, pasty. Contains quartz sand.
Numerous molds of Turritella sp. and other mollusks, Sorites
sp., and Archaias sp., are present in the bed. Blebs of green
clay are disseminated throughout.......................................... 2.0
2 Limestone; white to cream, dolomitic, pasty......................... 0.1
1 Clay; light brownish-gray, silty, calcareous, blebs of green clay
disseminated throughout. Gradually becomes more calcareous







REPORT QF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
and approaches a hard white marl near the top........................... 13.6

T total exposedl..........................................................................................................119.2
The base of bed 1 is at an elevation of 108.85 feet.
The Jackson County part is located west of Apalachicola River
Bridge on access road at the end of Victory Bridge NEMi sec. 31, T. 4 N.,
11. 6 W. The top of bed 7 is at an elevation of 118.0 feet. Elevation at the
top of spillway is 84.4 feet.
Bed Description Thickness
(feet)
Tampa Stage-Chattahoochee faces
7 Clay; blocky, waxy, greenish-gray................................................ 2.0
6 Limestone; cream to white, pasty, soft but tough, sandy, dolo-
mitic, containing irregular bodies of light green, calcitic sand
and a very indurated ledge in the center...................... 11.0
5 Clay; light tan, very slightly calcareous, blocky and grades
upward to a medium brownish-gray sandy, blocky clay.............. 2.5
4 Limestone; light tan to cream, soft but tough, dolomitic, very
fossiliferous, containing irregularities of gray silt and clay.
Abundant specimens of regular and irregular echinoids.
Ampulella and other mollusks within the bed. Irregular con-
cretions of sandy brown limestone are also present.......--..........------.. 4.0
3 Limestone; light gray, tan to cream, soft but tough, pasty,
dolomitic, containing greenish clay-filled borings and green ir-
regular masses of crystalline calcite................................................ 5.0
2 Clay; mottled, light greenish-gray to tan, very sandy, blocky,
containing dugong bones and irregular lenses of hard, appar-
ently crystalline clay........................................................................ 4.0
1 Limestone; light brownish-gray, soft but tough, pasty, honey-
combed, sandy, dolomitic, containing nodules, lenses, thin beds
and irregular veins of light gray to greenish waxy, silty, blocky,
clay. Kuphus sp. found in both the clay and limestone. The bed
is more nodular, less honeycombed and with fewer definitely
clay lenses near the top. This bed was apparently deposited as
a beach-rock rubble. There are remains of numerous boring
mollusks that lived in coral head of Siderastraea sp. although
there are few well-preserved heads of the coral. Ampulella
sp. is found throughout the bed. Five feet exposed here and an
additional 9.9 feet is present on the lake side of the dam......... 14.9

Total exposed-east and west sections............................................................ 162.6
At the time the powerhouse coffer dam excavation was open there
were exposed ten feet of Chattahoochee faces unconformably overlying
11 feet of Suwannee limestone (see geologic section under Suwannee
limestone, locality 54).


33






FLORIDA GEOLOGICAL SURVEY


ALUM BLUFF STAGE
HAWTHORN FACIES
Historical: The reader is referred to page 144 of the Florida Geo-
logical Survey Bulletin 29, for a historical review of the term Hawthorn.
Puri (1953a, p. 21) described the Hawthorn in the Florida Panhandle
as a lithofacies of the Alum Bluff Stage.
Distribution: The Hawthorn formation is present in the entire south-
crn portion of the area of this investigation (fig. 6). The eastern and
southern limits of the Hawthorn exceed those of this report. The most
northern extension of the Hawthorn sediments ends at the escarpment
facing the left bank of the Flint River in Decatur County, Georgia, and
its western limit is marked by the termination of the Tallahassee Tertiary
Highlands in Jackson County, Florida.
Lithology: The Hawthorn formation is a highly varied assemblage
of lenticular sand and clay beds that have only slight lateral persistence.
The Hawthorn sediments consist of sorted to nonsorted, coarse to fine-
grained, argillaceous, quartz sand, and rust-brown, gray-green, cream,
red and tan arenaceous clays, some of which are calcareous and contain
pelecypod shells. Irregularly distributed throughout these sediments
are small phosphorite grains of varying colors.
Thickness: The Hawthorn formation in the area of this investigation
has a variable thickness. In the area surrounding Sneads, Jackson Coun-
ty, Florida, and at Chattahoochee, Gadsden County, Florida, the Haw-
thorn formation is represented by approximately 70 feet of sediments. At
locality 56 near Georgia State Highway 97, southward to the intersection
of U.S. Highway 90, the writers measured 135 feet of Hawthorn deposits.
Near Faceville, Decatur County, Georgia, at locality 49, 48 feet of
sediments were assigned to the Hawthorn formation. Sixty-eight feet
of Hawthorn sediments are exposed at the Jim Woodruff Dam section
described on page 81.
Stratigraphic Relationship: The contact of the Hawthorn with the
underlying Chattahoochee facies is unconformable.
Geologic Exposures: The Hawthorn formation mantles almost the
entire area mapped as the Tallahassee Tertiary Highlands. Geologic
sections of formations can be seen in many places in the area along the
west-facing escarpment of the Flint and Apalachicola rivers, and around
Chattahoochee, Gadsden County, and Sneads, Jackson County, Florida.






REPORT OF INVESTIGATIONS No. 16


POST-MIOCENE STRATIGRAPHY
SILICIFIED LIMESTONE
Historical: Cooke (1929, p. 67) extended the name "Glendon lime-
stone" from Alabama to Florida to include limestone of Oligocene age
and what he felt were equivalent fossiliferous chert beds. Later, Cooke
(1935, p. 1170-71) proposed the name Flint River formation for the
fossiliferous chert beds in Florida, Georgia and southeastern Alabama,
and continued the name "Glendon" for Oligocene limestones. Both the
Glendon and Flint River formations were tentatively correlated with the
Chickasawhay limestone of Mississippi. Vernon (1942, p. 130-133)
presented evidence that these silicified boulders were enclosed in Pleis-
tocene alluvium. They represent silicified portions of Oligocene and
Eocene formations released during periods of valley cutting and incor-
porated in alluvium during later intervals of valley fill. Vernon did not
recognize Cooke's "Glendon limestone" or "Flint River formation" in the
counties west of the dam site. Cooke (1945, p. 104-107) again referred
the boulders to formational rank and extended the Flint River formation
to include beds of similar lithology in Florida, and mapped the formation
from Walton County, Florida, eastward to the Chattahoochee River and
across Georgia to Allendale, South Carolina.

MacNeil (1946, p. 64) stated that for the most part the materials in
the Flint River formation are of Miocene age which became intermixed
with limestone residue upon slumping into sinks during the process of
solution. He established the age of the chert in Georgia as middle and
upper Oligocene. Where the "Ocala limestone" has been dissolved, the
residuum of the Oligocene and "Ocala" cannot be separated (MacNeil,
1946, p. 64). MacNeil (1946, p. 64) further states that, "In view of these
findings, and because it is not the policy of the U. S. Geological Survey
to apply formation names to residuum, the name Flint River has been
abandoned and the heterogeneous beds to which it was applied are
designated the residuum of the Jackson, Oligocene, and Miocene,
undifferentiated."

Present Concept: In the area of this study Cooke's "Flint River
formation," is a heterogeneous mass of silicified limestone boulders of
upper Oligocene and possibly upper Eocene age. The boulders are
embedded in Pleistocene to Recent sands and clays and as Vernon and
MacNeil have stated should not be considered a single unit of deposition
as previously supposed by Cooke (1935, p. 1170-71). Seventeen auger
holes were drilled to determine if these boulders, some of which are 18
feet in diameter, were actually outcrops or merely boulders occurring at
!


35






FLORIDA GEOLOGICAL SURVEY


irregular horizons and haphazardly throughout a elastic matrix. The
evidence obtained from these holes show that the boulders indiscrimi-
nately lie 26 to 78 feet above bedrock (fig. 7).
These silicified deposits represent the remnants of a higher limestone
surface which probably became incorporated in the alluvium during
valley cutting and filling by the present major streams or their ancestral
equivalents.
The boulders occur most frequently along the Chattahoochee and
Flint rivers and Spring Creek. Recent degrading by the streams have
cut through the alluvium and have exposed the silicified limestone
boulders and concentrated them by downstream sapping and accumu-
lations in boulder bars at obstructions in the channel and along the inside
of bends in the streams, where velocity is least.
Geologic Exposures: Decatur County, Georgia. On the right bank of
the Flint River at Lamberts Island, silicified limestone boulders of
Suwannee age were found incorporated in Pleistocene to Recent sedi-
ments.
Seminole County, Georgia. Along the right bank of Spring Creek at
locality 51, about two and one-half miles due south of Reynoldsville,
Seminole County, Georgia, silicified limestone boulders, Suwannee age,
were found embedded in Pleistocene to Recent sediments.
Jackson County, Florida. At localities 89, 40, 41, 42 and 43, in Jack-
son County, Florida, silicified boulders occurring in Pleistocene to Recent
sediments, were identified as Suwannee age.

GEOLOGIC EXPOSURES ALONG CHATTAHOOCHEE
AND FLINT RIVERS
Traverse of a portion of the Flint River beginning at High Bluff,
approximately seven miles upstream from Bainbridge, Georgia, and
extending to the junction with the Chattahoochee River, approximately
one mile north of Chattahoochee, Florida:
December 1-2, 1953
R. 0. Vernon, C. W. Hendry, Jr. and J. W. Yon, Jr.
Bed Description Thickness
(feet)
Locality 1
Oligocene? and upper Eocene
Suwannee limestone? and Crystal River formation
Silicified limestone boulders, approximately 12x20 feet, ap-
parently not in place and restricting the channel in part.







REPORT OF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
Locality 2
Upper Eocene-Crystal River formation
Limestone, cream to tan, fragmental, granular, marine, porous,
soft, coquinoid. Very cavernous with horsebone weathering and
a tendency to laminate............................................................... 10.0
Locality 3
Post-Eocene
2 Sand, varicolored, medium to coarse-grained and contains clay
lenses, quartz gravel, silicified limestone boulders and a cal-
careous, clayey, sandstone which contains numerous molds of
mollusks and nodules of a more calcareous material............... 10.0
Upper Eocene-Crystal River formation
1 Limestone as found at locality 2.......................................... 15.5

T otal exposed............................................................. ......................................... 25.5
Locality 4
Post-Eocene
7 Sandy soil zone, tan to brown, weathered................................. 4.0
6 Clay, variegated, gray, tan, red, white, blocky, sandy, and
has a tendency to laminate......................................................... 7.8
5 Sand, variegated, gray, tan, red, white, blocky, clayey, very
fine-grained, and contains lenses of blocky clay of overlying
bed 6............................................................................................... 13.7
4 Slum p ............................................................................................. 17.2
3 Clay, light gray, very sandy, blocky............................................. 11.4
2 C covered .................................................................... .................. 9.4
Upper Eocene-Crystal River formation
1 Limestone as found at locality 2............................................... 17.0

T otal exposed.................................................................................................... 80.5
Locality 5
Upper Eocene-Crystal River formation
Pinnacles of limestone protruding through tan, fine-grained,
sandy alluvium .............................................................................. 10.0-12.0
Also ledges of limestone overlain by alluvium. Scattered boul-
ders of silicified limestone, approximately 6x8 feet. Further
downstream these boulders become more abundant in the
river bed.
Locality 6
Post-Eocene (flood-plain alluvium)
4 Sand, dark gray, with a thin sandy soil zone............................. 0.5
3 Sand, yellow to orange, very fine-grained, slightly clayey........ 4.0
2 Bed 3 grades downward into seven feet of thinly bedded,
orange, fine-grained sand, increasing in coarseness toward the
base and merges with a one to three foot zone of thinly bedded,
fine to coarse-grained sand containing numerous quartz pebbles
and large silicified boulders of Crystal River age. Very irregular
contact with bed below ............................................................... 1.0-7.0


37






38


FLORIDA GEOLOGICAL SURVEY


Bed Description Thickness
(feet)
1 Siltstone, light gray, very clayey, very sandy............................. 9.6

T otal exposedl.................................................................................................. 15.1-21.1
Between localities 6 and 7 is flood-pl"'n alluvium composed of fine-grained, light
yellow sand with scattered silicified l,. stone boulders.

Locality 7
Post-Eocene
2 Sand, orange, fine-grained............................................................8.0-14.0
1 Siltstone, light gray, very sandy, very clayey. Very irregular con-
tact with bed above..................................................................... 3.0-3.5

T total exposed .................................................................................................. 11.0-17.5
Just downstream from locality 7 are scattered boulders of silicified limestone, 6 to
8 feet in diameter in river bed.
Locality 8
Post-Eocene
Clay, gray, with incorporated silicified limestone boulders,
3x4 feet, lying on gray, sandy clay or siltstone........................... 5.0
Locality 9
Post-Focene (flood-plain alluvium)
2 Sand, poorly sorted, crossbedded, fine to coarse-grained, but
generally coarsest at base......................................................... 14.0
1 Clay, light gray, blocky, slightly silty.
Locality 10
Post-Eocene (flood-plain alluvium)
3 Sand, fine to coarse-grained, crossbedded and reworked clayey
alluvium ......................................................................................... 10.0
2 Clay, very silty and sandy, blocky, grading laterally into clay,
variegated, sandy, weathered and mottled................................. 9.8
Upper Eocene-Crystal River formation
1 Limestone, tan, fragmental, granular, marine, hard, fossil-
iferous. Crystalline on exposed surfaces and occurring as pin-
nacles protruding through Led 2............................................. 7.8

T otal exposed...................................................................................................... 27.6
Just downstream from locality 10 is ;s6edded, sandy alluvium overlain by five
feet of sandy, silty clay.
Locality 11
Silty clay overlaying gray clay and through which protrudes
several pinnacles of limestone (upper Eocene?). Several
large, 6x8 feet, boulders in river bed.
Locality 12
Upper Eocene-Crystal River formation
Limestone, tan to brown, fragmental, marine, very porous, soft,







REPORT OF INVESTIGATIONS No. 16


Bed


Description

loose, coquinoid. Abundant large foraminifers and Amusium
sp. .......... ... .......... ............ ........................ ......... ............ ................


Locality 13
Lim estone, recrystallized............... ................................................


Just downstream from locality 13 are largo Ibulders of recrystallized and
limestone incorporated in very loamy flood-plain deposits.
Locality 14
Post-Eocene (flood-plain alluvium)
2 Sand, fine to coarse-grained, crossbedded, slightly clayey, with
a gravel and boulder bed at base-.............................................-
1 Clay, gray, silty.................................... ............ ...................

T otal exposed.......................................................................................................
Locality 15
9 Soil zone.....................................................................................
8 Sand, yellow, fine-grained, oxidized and leached.....................
7 Sand, red, very fine-grained, slightly clayey, oxidized, but


not leached..................................................................................
Sand, dark brownish-gray, slightly clayey, very fine-grained
and contains a four-inch freshwater clam bed.. ------......................
Sand, brown, very fine-grained, slightly clayey...........................
C covered ............................................................... .......... ...............
Sand, tan, fine-grained, slightly clayey, crossed by laminae of
deep reddish-brown, very fine-grained moderately clayey sand
C covered ....................................................................................... ..
Sand, mottled tan, gray, brown, fine-grained, very clayey and
contains two eight-inch grit beds in the middle grading down-
ward into a more clayey material with similar characteristics
to top of bed ...................................................... ......... .................


Total exposed-................. .. ...-- .. ..- ...- ... .....-.. .........................--
Locality 16
Post-Eocene (flood-plain alluvium)
3 Clay, loamy, blocky, very sandy-......................... ................
2 Sand, light brown, slightly clayey" fine to coarse-grained, cross-
bedded and contains pea-size gravel and boulders of silicified
lim estone (see basal bed) ..............................................................
1 Clay, bluish-gray, blocky, silly grading laterally into light
grayish-green, very clayey silt. Wiiiee the bluish-gray clay forms
a ledge there is a cascade of boulders of quartz up to one foot
in diameter and silicified limestone of Crystal River, Suwannee
and possibly Tampa age lying oni the ledge and having fallen
from the light brown silty sand of bed 2......................................


Thickness
(feet)

8.0


T otal exposed........................................................................... ....................... 18.0
One-quarter mile downstream from locality 16 are low islands of silicified lime-
stone. River banks composed of eight feet of loams.


4.5
silicified




12.0
10.0

22.0

0.67
1.0

0.75

1.5
1.0
2.0

3.0
2.0



8.5

21.42


8.0


4.0





6.0






FLORIDA GEOLOGICAL SURVEY


Bed Description Thickness
(feet)
Further below locality 16-
Silt, greenish-gray, above which thick limonite has developed
containing numerous silicified boulders and overlain by 12
feet of sandy alluvium.
Locality 17
Silicifled boulders forming a jetty extending into river channel
and protecting the left bank.
Locality 18
Post-Eocene (flood-plain alluvium)
2 Sand, red, crossbedded, fine to coarse-grained, poorly sorted
with abundant boulders in base............................................ 10.0-14.0
1 C lay, gray ................................................................................... 3.0- 5.0

T otal exposed....................................... .. ...................................................... 13.0-19.0
Locality 19
Post-Eocene
Clay, gray. Collected to check fossil content. Contained one
small Cardium sp.
Locality 20
Post-Eocene (flood-plain alluvium)
2 Sand .......................................................................................... ..... 12.0
1 Clay. Very irregular contact between these two beds along
which are numerous limonite pebbles....................................... 8.0

T otal exposed................................................... .............................................. 20.0
Locality 21 (Southlands Ferry)
Oligocene Series-Suwannee limestone
Limestone, cream to tan, hard, crystalline, weathers cavernous.
Crops out at base of Hawthorn hill........................................... 8.0

Locality 22
Oligocene Series-Suwannee limestone
Limestone, cream to gray, hard, dense, finely crystalline, brec-
ciated texture and contains very rare fossils. This limestone
exposed in temporary road cut made by bulldozer part way
up hill................................................................................................ 5.0
C covered ......................................................................................... 17.0
This limestone exposed at small spring at base of hill............. 3.0

T otal exposed................................................................................................... 25.0

Locality 23
Post-Eocene (flood-plain alluvium)
2 Sand, reddish-brown, fine to very coarse-grained, crossbedded
with irregular lenses of grit and pea-size gravel covering pin-
nacles of greenish-gray, massive sand....................................... 21.4


40






REPORT OF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
1 Sand, light greenish-gray, massive, slightly clayey, micaceous,
jointed northeast-southwest........................................................... 5.8

T total exposed ...................................................................................................... 27.2
Locality 24
Oligocene Series-Suwannee limestone
Hill of limestone similar to lithology at locality 22.
Locality 25
Oligocene Series-Suwannee limestone
On right bank of river, several boulders of tan to cream, frag-
mental, marine limestone containing numerous echinoid frag-
ments and specimens of Lepidocyclina, Sorites, and Camerina.
Boulders are apparently dislodged by machinery used in clear-
ing Jim Woodruff reservoir area.

Traverse of a portion of the Chattahoochee River beginning at
Florida Highway 2-Georgia Highway 91 Bridge, and extending to
the junction with the Flint River, approximately one mile north of
Chattahoochee, Florida:
December 2-3, 1953
Locality 26
Post-Eocene
Sandy alluvium ............................................................................. 10.0
Clay, light greenish-gray, and purple, sandy, overlain by boul-
ders of limonite and silicified limestone............................. 5.0

T otal exposed................................................................................................ .... 15.0
Locality 27
Upper Eocene-Crystal River formation
Limestone, white to cream, fragmental, marine, porous, soft but
tough, very finely crystalline, coquinoid and contains numerous
mollusks mostly as molds. Olygopygus abundant-....--.------- 6.8
Locality 28
Two feet of limestone as at locality 27 cropping out overlain
by thin bed of limonite.
Two-thirds mile below locality 28, four feet of limestone as at locality 27.
Locality 29
Upper Eocene-Crystal River formation
2 Limestone, cream, granular, marine, dense, hard, cryptocrystal-
line to very finely crystalline And weathers extremely cavernous
and marked by a white, speckled, chalky, nodular material,
which may represent calcite dust from fossils............................. 3.0
1 Limestone, tan, fragmental, marine, soft, coquinoid. Olygopy-
gus sp...--------.................-----...........................- .... ... ..... .. 0.5

Total exposed.................................................................................................... 3.5






FLORIDA GEOLOGICAL SURVEY


Bed Description Thickness
(feet)
Locality 30
Upper Eocene-Crystal River formation
I Limestone, cream, fragmental, granular, marine, soft, weather-
ing hard, miliolid bed contains numerous Lepidocyclinas and
A m usium ocalanum ........................................ ............................... 1.9
3 Limestone of above bed and weathered into hard ledge con-
taining O lygopygus sp............................................................ ..... 1.6
2 Limestone of bed 3, but very soft, cream to tan, very porous
and extremely microfossiliferous................................................. 1.5
1 Limestone, cream, fragmental, marine, very hard, weathers cav-
ernous and contains specks of chalky nodules representing cal-
cite dust from weathered fossils. This bed similar to limestone
at locality 29.......................................................................... ...... 4.0

T total exposed .................................................................... ........................... 9 .0
Locality 31
Upper Eocene-Crystal River formation
Limestone, white to cream, marine, dense, moldic porosity,
cryptocrystalline to very finely crystalline, hard, microfossil-
iferous. Weathers cavernous and locally altered to green clay-- 5.5
Locality 32
UIpper Eocene-Crystal River formation
*2 Limestone, tan, fragmental, marine, coquinoid, contains abun-
dant Lepidocyclinas, Camerinas, Olygopygus sp., small fora-
minifers, mollusks, and echinoids, weathers red......................... 3.0
I Limestone, cream to tan, fragmental, hard, coquinoid, contains
small to large chalky nodules which are apparently calcite
dust derived from weathered fossils. This type of limestone is
apparently a subsequent product of the coquinoid limestone
of bed 2 and the bed when traced laterally to a fresh exposure
is the sam e as bed 2.................................................................. 12.0

T otal exposed .................................................... ...................................... ..... 15 .0
Upstream and adjacent to above described limestone are 10 feet of extremely variable,
massive, highly colored, purple, red, brown, gray, sandy clay and fine sand overlain
by 10 feet of sandy alluvium. This area appears to be disturbed.
Locality 33
Post-Eocene
Clay as described at locality 32.
Locality 34
Upper Eocene-Crystal River formation
Limestone, cream, marine, dense, hard, tough, fossiliferous.
Weathers cavernous and microcoquinoid in places---.-------..-....... 5.6
One hundred yards downstream from locality 34, mottled clay as at locality 32, and
limestone as at locality 34. Large limonite boulders 12 to 15 inches in diameter.






REPORT OF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
Scattered large boulders of limestone as bed 1, locality 32, and with fossiliferous,
porous zones throughout. Boulders appear to have recrystallized and almost prohibit
navigation because of abundance.
Locality 35
Post-Eocene
3 Sandy alluvium ........................................................................... 12.0-13.0
2 Sand and clay, variegated light greenish-gray, purple, red------9.0
1 Limestone, coquinoid, badly weathered and covered by consid-
erable amount of limonite.......................................................... 5.0

Total exposed ------------------------------------------.---.-- -----------....... .......---. 26.0-27.0
Just downstream from locality 35 are five feet of limonite.
Locality 36
Upper Eocene-Crystal River formation
Limestone, white to cream, fragmental, marine, very finely
crystalline, soft, weathers cavernous.......................................... 2.0
Locality 37
Upper Eocene-Crystal River formation
Limestone, cream to tan, fragmental, marine, very fossil-
iferous-composed largely of molds of mollusks and merges
laterally with light gray mottled reddish-brown sandy clays.
Limestone composed of boulders and possible pinnacles.


INSOLUBLE RESIDUE STUDY
INTRODUCTION
Lithologic examination of the cuttings and core samples of carbonate
rocks from wells in and near the area of this investigation indicated that
the lower part of the Chattahoochee facies and the upper part of the
Suwannee limestone have undergone secondary crystallization, thereby
destroying the characteristic lithologic appearance of the respective
formations and the diagnostic fossil content of the rock. The lack of
these criteria for differentiating between the formations makes it ex-
tremely difficult to determine the contact between these two units.
Because the identifying paleontologic and lithologic characteristics had
been destroyed, the writers felt that the determination of insoluble resi-
dues might assist in stratigraphic correlation. Three U. S. Corps of Engi-
neers core holes and 43 outcrop samples were selected to be used in the
experimental work. The three core holes, W-1562, W-1775 and W-1779,
are located in Jackson County, Florida, and range in depth from 126 feet
to 164 feet. The outcrop samples were collected at six discontinuous





FLORIDA GEOLOGICAL SURVEY


exposures along the east-west trending bluff, marking the northern
limit of the Tallahassee Tertiary Highlands at localities 45 and 54,
Jackson County, Florida, and localities 21, 46, 47 and 55, Decatur County,
Georgia (fig. 6).
PROCEDURE
Twenty-five gram portions were used from each outcrop sample
and from intervals of approximately two feet from the cores. These
samples were digested in dilute hydrochloric acid at room temperature.
The insoluble residues were filtered, thoroughly washed with water, dried,
and weighed.
The clay content of the insoluble residue was removed by flocculation.
The silt and sand-size material from two U.S. Corps of Engineers core
holes (W-1775 and W-1779) was treated with bromoform to separate
the heavy minerals from the quartz and mica. The writers felt that
because W-1775 and W-1779 were close together, they would depict
any similarities or dissimilarities and W-1562 would be used only to
verify or disprove any zonational sequences that might show up.
A binocular microscope was used in the examination of the nonheavy
minerals and a standard petrographic microscope was used for the
mineralogic determination of the heavy minerals. The close proximity of
W-1775 and W-1779 influenced the writers to use only these two for
preliminary comparison.
INSOLUBLE RESIDUE
ARENACEOUS MATERIAL
Quartz sand was present as a part of the insoluble residue in all of
the outcrop samples and in all of the core samples of W-1775, and in the
upper 85 and 87 feet of W-1779 and W-1562 respectively.
The detrital quartz grains ranged in size from silt to medium sand
with traces of coarse sand. Except for a few variations, the shape of the
detrital quartz grains was angular to subangular. Frosting of the
grains was absent or very slight in all of the samples examined.
SECONDARY SILICA
Silt-size to very fine sand-size aggregates of crystalline secondary
silica were found to exist in the lower 48 feet of W-1775, and also in
the lower 39 feet of W-1562.
SILICEOUS OOLITES
Texturally the oolites ranged from fine to medium sand-size, and
occurred either singularly or in clusters of three or more. .






REPORT OF INVESTIGATIONS No. 16


MUSCOVITE
Fine to very fine sand-size muscovite was present as a part of all
samples examined for insoluble material.
HEAVY MINERALS
The most common heavy minerals that existed as part of the residue
were:
1. Tourmaline 6. Monazite
2. Garnet 7. Staurolite
3. Kyanite 8. Ilmenite
4. Zircon 9. ?Hematite
5. Rutile 10. Leucoxene

CONCLUSION
This investigation has shown that insoluble residues do exist in the
sediments examined. Some of these insoluble constituents are useful in
establishing local correlation zones. In the following discussion the
overall value of the insoluble residues and insoluble residue zones is
analyzed in relation to their value for establishing the Miocene-Oligocene
boundary.
To help in visualizing graphically the range of the insolubles, the
percentages of the insoluble residues of the core holes were calculated
and plotted as the abscissa and the corresponding depths of the residue
samples as the ordinate (fig. 8). The conclusion reached from this part
of the experiment was that the upper part of the Chattahoochee formation
has zones which are high in insoluble material, but percentages of
insoluble residues gave no clue to the contact between the Chattahoochee
faces and the Suwannee limestone.
The Suwannee limestone sometimes contains detrital sands and a
detailed study was made of the detrital quartz grains to determine if the
characteristics of the quartz sand revealed any differences which could
be used in establishing the boundary between .the Suwannee limestone
and the Chattahoochee faces. All of the quartz sand present was
angular to subangular and usually clear. The grain size ranged from
silt to medium sand, with traces of coarse sand. The results of the
examination of the detrital quartz grains indicated that if any apparent
differences existed, they were insignificant and could not be used in
determining the Miocene and Oligocene contact.
The aggregates of secondary crystalline quartz found in W-1562 and
W-1779 occurred in a very badly leached foraminiferal coquina, some


45






FLORIDA GEOLOGICAL SURVEY


go- .


20 .







PERCENTAGE OF INDIGESTIBLE RESIDUE

Figure 8. Diagrammatic representation of insoluble residue from three sampled
wells. Percentages shown refer to insoluble residues.


of which were identified as Oligocene forms. By determining the ele-
vation of the crystalline quartz, it was found that in both core holes,
the elevations of the aggregates were practically the same. In the opinion
of the writers, this zone is not the top of the Suwannee sediments even
though the fossils indicate that it is Oligocene in age, but only a probable
correlative zone within the Suwannee limestone.

The siliceous oolites proved to be of no help in separating the Chatta-
hoochee and Suwannee formations because of their occurrence at
irregular depths in only one well, W-1562, and because of their spasmodic
appearance in the outcrop formations of locality 47.

The quantity of the mica was in most cases very small and not a
useful criterion for establishing the bottom of the Chattahoochee facies
and the top of the Suwannee limestone.

Heavy minerals from the core samples of W-1775 and W-1779 were
mounted and identified. After computing and plotting the frequency
percentages of the individual mineral species against the respective
depths at which they occurred, no trends or suites appeared to be
present which could be used in determining the contact between the
Chattahoochee and the Suwannee formations.


46






REPORT OF INVESTIGATIONS No. 16


LOCALITIES

Listed below are the locations of all outcrops, well and auger hole
samples used in the preparation of this report. All locations of outcrop
samples are listed chronologically; references to locations contained in
the text are indicated by the index number which precedes each entry.
Florida Geological Survey accession numbers precede all well and
auger hole locations.


OUTCROP SAMPLES

1. Crystal River formation. Right bank of Flint River, approximately one mile
upstream from locality 4, Decatur County, Georgia.
2. Crystal River formation. Left bank of Flint River, 50 yards downstream from
locality 1, Decatur County, Georgia.
3. Post-Eocene. Left bank of Flint River, approximately one-half mile upstream
from locality 4, Decatur County, Georgia.
4. Post-Eocene. Right bank of Flint River (High Bluff), center of L. L. 263,
L. D. 15, Decatur County, Georgia.
5. Crystal River formation. Right bank of Flint River, SW,1 L. L. 264, L. D. 15,
Decatur County, Georgia.
6. Post-Eocene. Left bank of Flint River, SEX L. L. 214, L. D. 15, Decatur
County, Georgia.
7. Post-Eocene. Right bank of Flint River, W/2 L. L. 291, L. D. 15, Decatur
County, Georgia.
8. Post-Eocene. Right bank of Flint River, NW,4 L. L. 292, L. D. 15, Decatur
County, Georgia.
9. Post-Eocene. Left bank of Flint River, SE/4 L. L. 217, L. D. 15, Decatur
County, Georgia.
10. Crystal River formation. Left bank of Flint River, NW,4 L. L. 219, L. D. 15,
Decatur County, Georgia.
11. Crystal River formation. Left bank of Flint River, NW,1 L. L. 223, L. D. 15,
Decatur County, Georgia.
12. Crystal River formation. Right bank of Flint River, NE?3 L. L. 331, L. D. 15,
Decatur County, Georgia.
13. Crystal River formation. Right bank of Flint River, NE), L. L. 332, L. D. 15;
Decatur County, Georgia.
14. Post-Eocene. Right bank of Flint River, SE,1 L. L. 873, L. D. 15, Decatur
County, Georgia.
15. Post-Eocene. Left bank of Flint River, SE,4 L. L. 359, L. D. 20, Decatur
County, Georgia.
16. Post-Eocene. Right bank of Flint River, SWi L. L. 394, L. D. 20, Decatur
County, Georgia.
17. Suwannee? limestone. Left bank of Flint River, SE1, L. L. 250, L. D. 21,
Decatur County, Georgia.
18. Post-Eocene. Left bank of Flint River, SW., L. L. 250, L. D. 21, Decatur
County, Georgia.
19. Post-Eocene. Left bank of Flint River, NEi L. L. 257, L. D. 21, Decatur
County, Georgia.






FLORIDA GEOLOGICAL SURVEY


20. Post-Eocene. Right bank of Flint River, SW% L. L. 262, L. D. 21, Decatur
County, Georgia.
21. Oligocene. Left bank of Flint River, SW)4 L. L. 262, L. D. 21, Decatur
County, Georgia.
22. Oligocene. Left bank of Flint River, NEA4 L. L. 267, L. D. 21, Decatur
County, Georgia.
2:1. Post-Eocene. Right bank of Flint River, SE3 L. L. 203, L. D. 21, Decatur
County, Georgia.
21. Oligocene. Left bank of Flint River, NE%3 L. L. 301, L. D. 21, Decatur
County, Georgia.
25. Oligocene. Right bank of Flint River, SWM L. L. 240, L. D. 21, Decatur
County, Georgia.
26. Post-Eocene. Right bank of Chattahoochee River, SWN3 sec. 26, T. 7 N., R. 8 W.,
Jackson County, Florida.
27. Crystal River formation. Right bank of Chattahoochee River, SE4 sec. 26,
T. 7 N., R. 8 W., Jackson County, Florida.
28. Crystal River formation. Left bank of Chattahoochee River, SE14 L. L. 332,
I,. D. 14, Seminole County, Georgia.
29. Crystal River formation. Left bank of Chattahoochee River, NE, L. L. 328,
L. D. 14, Seminole County, Georgia.
30. Crystal River formation. Left bank of Chattahoochee River, SWV4 L. L. 326,
I,. D. 14, Seminole County, Georgia.
:31. Crystal River formation. Right bank of Chattahoochee River, SWX see. 28,
T. 6 N., R. 7 W., Jackson County, Florida.
32. Crystal River formation. Left bank of Chattahoochee River, NWXi L. L. 242,
L. D. 14, Seminole County, Georgia.
33. Post-Eocene. Right bank of Chattahoochee River, NWV'4 sec. 4, T. 5 N., R. 7 W.,
Jackson County, Florida.
34. Crystal River formation. Left bank of Chattahoochee River, SEA L. L. 244,
i,. D. 14, Seminole County, Georgia.
35. Post-Eocene. Left bank of Chattahoochee River, NW) L. L. 196, L. D. 14,
Seminole County, Georgia.
36. Crystal River formation. Right bank of Chattahoochee River, SE04 sec. 21,
T. 5 N., R. 7 W., Jackson County, Florida.
37. Crystal River formation. Right bank of Chatthoochee River, SE34 sec. 10,
T. 4 N., R. 7 W., Jackson County, Florida.
38. Suwannee limestone. Small sink in south central part of sec. 14, T. 5 N.,
R. 9 W., Jackson County, Florida.
39. Suwannee limestone. Residual boulder in small depression in SE/4 sec. 14,
T. 5 N., R. 9 W., Jackson County, Florida.
40. Suwannee limestone. Pinnacles and/or boulders cropping out in edge of
field, SWM sec. 15, T. 5 N., R. 8 W., Jackson County, Florida.
41. Suwannee limestone. Pinnacles and/or boulders exposed in side of hill on
right bank of Chattahoochee River, NW\}4 sec. 21, T. 5 N., R. 7 W., Jackson
County, Florida.
42. Suwannec limestone. Pinnacles and/or boulders cropping out along rim of
shallow depression, SW corner NEi. sec. 18, T. 5 N., R. 7 W., Jackson County,
Florida.
43. Suwannee limestone. Residual boulders scattered around rim of depression,
SE corner, SW)4 sec. 18, T. 5 N., R. 7 W., Jackson County, Florida.


48







REPORT OF INVESTIGATIONS No. 16


44. Chattahoochee facies. Ledges of rock exposed along bluff, SE corner, NEI
sec. 16, T. 4 N., R. 7 W., Jackson County, Florida.
45. Chattahoochee facies. Residual boulders and ledges of rock exposed along
bluff, SWX sec. 15, T. 4 N., R. 7 W., Jackson County, Florida.
46. Chattahoochee facies. Pinnacles and/or boulders exposed along bluff, SW%
L. L. 336, L. D. 21, Decatur County, Georgia.
47. Chattahoochee facies. Pinnacles and/or boulders exposed along bluff, SEX
L. L. 299, L. D. 21, Decatur County, Georgia.
48. Chattahoochee facies. Exposed along bluff, NEM L. L. 302, L. D. 21, De-
catur County, Georgia.
49. Chattahoochee faces. Exposed along both banks of small creek, SE,4 L. L.
284, L. D. 21, Decatur County, Georgia.
50. Chattahoochee facies. Exposed along right bank of Sanborn Creek, SE corner
SW% L. L. 265, L. D. 21, Decatur County, Georgia.
51. Crystal River formation. Ledges and boulders exposed along right bank of
Spring Creek, center L. L. 131, L. D. 21, Seminole County, Georgia.
52. Suwannee limestone. Exposed along right bank of Flint River and on
island in river, SW% L. L. 258, L. D. 21, Decatur County, Georgia.
53. Suwannee limestone overlain by Chattahoochee facies in small gully along left
bank of Flint River, SW,4 L. L. 262, L. D. 21, Decatur County, Georgia.
54. Suwannee limestone overlain by Chattahoochee facies in powerhouse excava-
tion, Jim Woodruff dam, SWX sec. 29, T. 4 N., R. 6 W., Gadsden County, Florida.
55. Chattahoochee facies. Exposed along left bank of Sanborn Creek, SWA L. L.
265, L. D. 21, Decatur County, Georgia.
56. Hawthorn facies. Exposed along road cut on Florida 269A-Georgia 97, L. L.
429, L. D. 21, Decatur County, Georgia, Gadsden County, Florida.

AUGER HOLES

AS-126 SW,4 NE,4 sec. 33, T. 4 N., R. 6 W., Gadsden County, Florida.
AS-238 SW, sec. 16, T. 4 N., R. 7 W., Jackson County, Florida.
AS-239 SW)i sec. 9, T. 4 N., R. 7 W., Jackson County, Florida.
AS-240 SE corner sec. 5, T. 4 N., R. 7 W., Jackson County, Florida.
AS-241 NW,% sec. 5, T. 4 N., R. 7 W., Jackson County, Florida.
AS-242 SE, sec. 29, T. 5 N., R. 7 W., Jackson County, Florida.
AS-243 NEX sec. 7, T. 5 N., R. 7 W., Jackson County, Florida.
AS-244 NW corner NEI SWX sec. 13, T. 6 N., R. 8 W., Jackson County, Florida.
AS-245 NE?4 NEX sec. 34, T. 7 N., R. 8 W., Jackson County, Florida.
AS-246 SEI, L. L. 11, L. D. 21, Seminole County, Georgia.
AS-247 NW%, L. L. 130, L. D. 21, Seminole County, Georgia.
AS-248 SW, L. L. 212, L. D. 21, Seminole County, Georgia.
AS-249 NEI L. L. 101, L. D. 21, Seminole County, Georgia.
AS-250 SWV L. L. 206, L. D. 21, Decatur County, Georgia.
AS-251 NWX L. L. 118, L. D. 14, Seminole County, Georgia.

WELLS

W-1364 NE, SW, sec. 8, T. 4 N., R. 8 W., Jackson County, Florida.
W-1562 SE3, SW,4 sec. 30, T. 4 N., R. 6 W., Jackson County, Florida.
W-1775 SE,4 SE3, NE34 sec. 28, T. 4 N., R. 7 W., Jackson County, Florida.
f.






FLORIDA GEOLOGICAL SURVEY


1944 (and Applin, E. R.) Regional subsurface stratigraphy and structure of
Florida and southern Georgia: Am. Assoc. Petroleum Geologists Bull.,
vol. 28, no. 12, p. 1673-1753.
1951 Possible future petroleum provinces of North America, Symposium: Am.
Assoc. Petroleum Geologists Bull., vol. 35, no. 2, p. 407.
Calver, James L. (see Gunter)
Cave, H. S. (see Prettyman)
Cooke, C. Wythe
1929 (and Mossom, Stuart) Geology of Florida: Florida Geol. Survey 20th Ann.
Rept., p. 67.
1935 Notes on Vicksburg group: Am. Assoc. Petroleum Geologists Bull., vol.
19, no. 8, p. 1162-72.
1939 Scenery of Florida interpreted by a geologist: Florida Geol. Survey Bull.
17, p. 14-21, 25.
1943 Geology of the coastal plain of Georgia: U. S. Geol. Survey Bull. 941,
p. 4, 5.
1945 Geology of Florida: Florida Geol. Survey Bull. 29, 339 p.
Fenneman, Nevin M.
1938 Physiography of eastern United States: McGraw-Hill Publ. Co., Inc.,
New York and London, p. 65-68, 76, 77.
Fisk, H. N.
1938 GeologU of Grant and LaSalle parishes: Louisiana Dent. Cons. Geonl.


CI, .- .. .. .... .
Bull. 10, p. 13-75.
1938a Pleistocene exposures in western Florida parishes, Louisiana: Louisiana
Geol. Survey Bull. 12, p. 3-25.
1939 Depositional terrace slopes in Louisiana: Jour. Geomorphology, vol. 2, p.
181-200.
1940 Geology of Avoyelles and Rapides parishes: Louisiana Geol. Survey Bull.
18, p. 17-116.
Gunter, Herman
1953 (and Vernon, R. 0., and Calver, J. L.) Interpretation of Florida geology:
Georgia Geol. Survey Bull. 60, p. 40-48.


0


W-1779 SE)X SW% sec. 30, T. 4 N., R. 6 W., Jackson County, Florida.
W-2149 L. L. 61, L. D. 27, Seminole County, Georgia.
W-2247 NWMI NE% sec. 12, T. 3 N., R. 7 W., Jackson County, Florida.
W-2254 SE)4 SEJ sec. 28, T. 4 N., R. 7 W., Jackson County, Florida.
W-2306 SE%4 sec. 17, T. 4 N., R. 7 W., Jackson County, Florida.
\V-3442 SWV sec. 12, T. 3 N., R. 7 W., Jackson County, Florida.
W-3482 SW% SEMI sec. 33, T. 4 N., R. 6 W., Gadsden County, Florida.
W-3627 SE% NE34 sec. 11, T. 5 N., R. 8 W., Jackson County, Florida.
W-3737 L. L. 142, L. D. 21, Seminole County, Georgia.



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Applin, E. R. (see Applin, Paul, 1944)
Applin, Paul






REPORT OF INVESTIGATIONS No. 16


Ireland, H. A.
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Geologists Bull., vol. 31, p. 1479-1490.
Hamblin, Ralph H. (see Sloss)
Jordan, Louise
1954 A critical appraisal of oil possibilities in Florida: Oil and Gas Journal,
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Leet, L. D.
1940 Status of geological and geophysical investigations on the Atlantic and
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MacNeil, F. Steams
1946 Southeastern Alabama: Fourth Field Trip Guidebook, Southeastern Geol.
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1955 Geology of Jackson County, Florida: Florida Geol. Survey Bull. 37, 101 p.
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Postley, 0. C.
1938 Oil and gas possibilities in Atlantic coastal plain from New Jersey to
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Pressler, E. D.
1947 Geology and occurrence of oil in Florida: Am. Assoc. Petroleum Geologists
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Prettyman, T. M.
1923 (and Cave, H. S.) Petroleum and natural gas possibilities in Georgia:
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1953 Zonation of the Ocala group in peninsular Florida (abstract): Jour.
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1956 (and Vernon, R. 0.) A summary of the geology of Florida with empha-
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Russell, Richard J.
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FLORIDA GEOLOGICAL SURVEY


Tanner, William F.
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1955 Cenozoic geology of southeastern Alabama, Florida and Georgia: Am.
Assoc. Petroleum Geologists Bull., vol. 39, no. 2, p. 207-235.
U. S. Army Corps of Engineers (Mobile District, South Atlantic Division)
1953 Jim Woodruff Lock and Dam Project, Apalachicola River, Florida: In-
formation folder.
U. S. Geological Survey (author unknown)
1917 Exploration for oil in southern Georgia: Press release dated July 30, 1917.
Veatch, Otto
1911 (and Stephenson, L. W.)Preliminary report on the geology of the coastal
plain of Georgia: Georgia Geol. Survey Bull. 26, p. 30-31, 62-64.
Vernon, Robert 0. (also see Gunter; Puri, 1956)
1942 Geology of Holmes and Washington counties, Florida: Florida Geol.
Survey Bull. 21, 151 p.
1951 Geology of Citrus and Levy counties, Florida: Florida Geol. Survey
Bull. 33, p. 14-16, 47.


52











Part II



PHOSPHATE CONCENTRATIONS NEAR

BIRD ROOKERIES IN

SOUTH FLORIDA






By
Ernest H. Lund
Associate Professor, Department of Geology
Florida State University







Prepared for the
Florida Geological Survey







Tallahassee, Florida
1958





53
















TABLE OF CONTENTS
Page
Abstract ................................................... ....... 57
Acknowledgm ents ..................................................... 57
Introduction .......................................................... 57
Sampled localities ...... .................. .............. ....... 60
Green Key Rookery ................................................ 60
D uck Rock ....................................................... 60
East River Rookery ............................................... 61
Cuthbert Lake Rookery ........................................... 62
Summary and conclusions .............................................. 64
References ........................................................... 64






ILLUSTRATIONS
Figure
1 Index map of sampled localities ................................... 59



Table
1 Analyses of samples from Green Key vicinity ........... ............. 65
2 Analyses of samples from Duck Rock vicinity ....................... 65
3 Analyses of samples from East River ............................. 66
4 Analyses of samples from Cuthbert Lake ............................ 66
5 Analyses of samples from miscellaneous localities ..................... 67









Part II


PHOSPHATE CONCENTRATIONS NEAR BIRD
ROOKERIES IN SOUTH FLORIDA

ABSTRACT
Sediments collected from the vicinity of four bird rookeries along
the coast of southwest Florida were analyzed for their P205 content
to determine the effect of a colony of large birds on the concentration
of phosphate in the sediments near the rookeries. Samples were also
taken from localities away from areas of dense bird population for
comparison. In three of the sample rookery localities the amount of
P205 was not significantly higher than in other nearby areas. In the
fourth, the Cuthbert Lake rookery, dried sediments contain up to 24.55
percent P205. Samples of material near the edges of Cuthbert Lake
contain less than one percent down to a trace. The comparison indicates
that the bird colony has appreciably increased the phosphate content
of the sedimentary material in the near vicinity of the rookery, but the
effects are very local.
ACKNOWLEDGMENTS
The writer is indebted to Herman Gunter, Director, and R. 0. Vernon
of the Florida Geological Survey for assistance with the field work and to
J. J. Taylor, State Chemist, for the analyses. The cooperation of Daniel
Beard, Superintendent of Everglades National Park, and other members
of the park staff in getting to localities in the park is greatly appreciated.
The writer is equally grateful for help given by Wardens Hank Bennett
and Fred Schultz in sampling at rookeries protected by the Audubon
Society.
INTRODUCTION
The numerous guano deposits on islands off the coast of South
America, in the south and mid-Pacific, and in a number of other places
demonstrate the ability of a large bird population to concentrate large
amounts of phosphate in comparatively small areas. The Guanape
Islands, latitude 834'S, longitude 78056'W, off the coast of Peru, had
a total estimated reserve of 1,300,000 tons of guano with P205 content
of 12.75 percent (Hutchinson, p. 30). This quantity of guano had accumu-
lated principally on two islands, North Island which is 1050 meters long
and 700 meters wide and South Island which is 690 meters long and
570 meters wide.
A number of Pacific atolls have larger deposits of phosphate related
57





FLORIDA GEOLOGICAL SURVEY


to a more remote period of bird activity. Ocean Island and Nauru afford
good examples of this type. Both of these islands are in the equatorial
Pacific and lie within 1S of the equator and between longitude 1760E
and longitude 1700E. Neither has a guano-producing bird population
at the present time. Ocean Island which is 2780 meters long and 2200
meters wide had an initial reserve estimated by Ellis (Hutchinson, p. 217)
at 20,000,000 tons. Three analyses of this phosphate give a mean P205
content of 40.51 percent. Nauru, 6 kilometers long and 4.7 kilometers
wide had an even larger reserve estimated by the British Phosphate
Commissioners at 87,500,000 tons, with a mean P20, content of about
39 percent. Much of the phosphate of Ocean and Nauru islands consists
of phosphatized coral rock and limestone debris.
Though limestone is the most favorable rock for phosphate replace-
ment, there are numerous examples of other rock types that have been
phosphatized. Echel and Milton (1953, p. 437-446) describe a deposit
of phosphate which they believe was formed by the influence of guano
on felsite. Chemical analyses by Teall (Hutchinson, p. 198) of trachyte
from Clipperton Island in the East Pacific show replacement by phos-
phate with a highly altered specimen of the rock containing 38.5 percent
P2O:,. Basalt on Necker Island, one of the Hawaiian Leeward Islands,
is considerably replaced by phosphate according to Elscher (Hutchinson,
p. 203). None of the deposits of phosphate resulting from replacement
of rocks other than limestone appears to be commercially important.
The present study is concerned with the influence of a large bird
population on the phosphate content of sediments adjacent to the areas
of bird concentration. Bird rookeries and roosts on small mangrove
islands along the southwest coast of Florida are suitable for this sort
of study, because there is a periodic removal of the bird droppings by
rain and high tides. Accumulations such as those found on the many
guano islands are not possible, and the material becomes available for
distribution by wave and current action. The amount of droppings is
large and highly localized in most cases, for as many as 80,000 large
wading and swimming birds may be concentrated on a mangrove key
no larger than five or six acres. Mills (1944) estimates that about 50 tons
are added to the waters of Tampa Bay every 24 hours by the several
rookeries and roosts located there.
Sampling was done with a cylindrical scoop of about one-quart
capacity mounted on a stem of one-half inch pipe. This method of
sampling recovered only surficial material, and all samples were taken
where the water was less than 10 feet deep. Where sampling was done
in the vicinity of a mangrove key, samples were taken at the edge of the


58






REPORT OF INVESTIGATIONS No. 16


Key West ,XBohio Hondao Key


Figure 1. Index map of sampled localities.
mangrove and outward at predetermined intervals of 15 feet up to 300
feet. Lines of samples were taken in all directions from the key. At the
East River (fig. 1) locality samples were taken from the channels between


_ I ____


59





FLORIDA GEOLOGICAL SURVEY


the mangrove islands. As a basis for comparison some samples were taken
from a short distance above and below the rookery.

SAMPLED LOCALITIES
GREEN KEY ROOKERY
Green Key (fig. 1) is a mangrove island of about six acres located
about 10 miles south of Tampa on the east side of Tampa Bay. The
island has been the site of a bird rookery since about 1921 and has been
under the protection of the Audubon Society since 1934. It is mainly
a nesting place for herons, ibis, pelicans, and cormorants and is used
by a small number of birds as a roost after the nesting period. According
to Mills the population of the colony has grown from 700 to 50,000
iiunder the Audubon Society's protection.
The sediment in the vicinity of Green Key is predominantly quartz
sand with varying amounts of silt and clay-size material. The amount
of fine material diminishes away from the island. Six samples (table 1)
have P..O., content, based on dry sample, ranging from 0.18 percent to
0.46 percent. The maximum value is less than the average of 40 samples
more or less evenly spaced over Tampa Bay. According to Gould
(personal communication) the P20, content of these 40 samples ranges
from 0.06 percent to 6.24 percent and averages 0.55 percent. Two
samples from near the mouth of Alafia River, about 4 miles north of
Green Key, have P20,5 contents of 0.30 percent and 0.93 percent. This
locality of high phosphorus concentration is probably affected consider-
ably by the Alafia River which flows through one of the principal phos-
phate areas of the State. This river has a high phosphorus content and
samples of its water analyzed by Odum (1953, p. 12) contained up to 3.55
ppm total phosphorus. The organic and particulate fractions of the
river's phosphorus are less susceptible to removal from the water by
plant activity than the dissolved phosphorus, and are more subject
to settling out and becoming part of the sediment. The proximity of
Green Key and the mouth of the Alafia River suggests that the phos-
phorus in the sediment around Green Key has been contributed in its
major part by the river, with the bird colony perhaps contributing a
small amount.
DUCK ROCK
Duck Rock (fig. 1), one of the Ten Thousand Islands, is a mangrove
key of about five acres located about 10 miles south of the town of
Everglades. The substratum of this island is oyster shell and coquina,
and apparently it once stood above high tides, for ducks are said to have
nested there prior to 1910. Establishment of mangrove made roosting


60





REPt)iT OF iNVESTIGATIONS NO. 16


possible, and it is now principally a roost for an estimated 75,000 to
80,000 white ibis and rtiliierous brown pelicans, cormorants, egrets and
other herons, and frigate birds. A number of birds including the egrets,
Louisiana heron, brown pieblicah; and double-crested cormorant nest there.
It has been under the protection of the Audubon Society for over 20
years.
Duck Rock is on the outer edge of the Ten Thousand Islands chain
and its exposed southwest side shows considerable effects of storm-wave
erosion. The sedimerit on the southwest side is mainly quartz sand, and
that on the sheltered northeast side is a mixture of calcareous mud and
sand. Bottofi conditions permit the growth of organisms, and a number
of live mollusks were picked Uip in the samples.
Eight samples (table 2, nos. 7-14) from the vicinity of Duck Rock
have P205 content ranging from a trace to 0.29 percent based on dry
samples. For comparative purposes three samples (table 2, no. 15-17)
were taken from the vicinity of another key1 located about a mile north
of Duck Rock. This key is not known to have been a center of bird
population. Three samples frmni this locality show respectively a trace,
0.20 percent, and 0.41 percent. The 0.41 percent noticeably exceeds the
highest value obtained in the Duck Rock samples. These data suggest
that the bird colony has had little influence on the phosphorus content
in the sediments at Duck Rock.

EAST RIVER ROOKERY
East River (fig. 1), flowing sluggishly toward Whitewater Bay from
the east, is characterized by a network of channels separated by numer-
ous small mangrove islands. A number of these islands form the nesting
site of some 20,000 or more wood and white ibis, American egret,
cormorant, anhinga and snowy egret.
The mangrove of the East River area grows on a substratum of peat
about 1 to 2 feet thick. The peat lies on a layer of soft calcareous mud,
referred to in this paper as marl, of about the same thickness, and below
the marl is hard Miami limestone.
Samples taken from near the center of the channels at a number
of points consist of miitiires of marl with abundant mollusk shells and
peat. The high loss on ignition, up to nearly 20 percent, reflects the
amount of peat in the samples. The sediment smells very strongly of
hydrogen sulphide which may account for the fact that no live mollusks
Designated Beiine't Key for piirpose of this paper.





FLORIDA GEOLOGICAL SURVEY


were found in it. Four samples (table 3) from this locality have P205
contents that range from a trace to 0.24 percent.

CUTHBERT LAKE ROOKERY
Cuthbert Lake Rookery (fig. 1) is on a small mangrove key about 500
feet long by 300 feet wide near the middle of Cuthbert Lake. This
lake, which is about two miles long by one mile wide, is one of a large
number of shallow brackish-water lakes located at the southern edge
of the Florida mainland within a few miles of Florida Bay. The man-
grove of Cuthbert Key grows on a substratum of peat which is three
feet thick at the center of the island. This is underlain by a 14-inch
layer of marl very similar to that under the peat at East River. The
bedrock is Miami limestone.
The rookery is populated predominantly by wood ibis which, ac-
cording to Moore (1953, p. 181-188), make up about nine-tenths of the
total. American egrets, cormorants, anhinga, and snowy egret constitute
the remainder. The total population varies between 2000 and 5000. A
plume hunter named Cuthbert discovered the rookery in 1890, but no
one has any idea how long the rookery had been in use prior to that.
Bird protection laws passed by the State Legislature in 1901 virtually
stopped the slaughter of birds for their plumes. In 1902 Guy M.
Bradley, who was a few years later shot by a plume hunter, was em-
ployed by the National Audubon Society to protect the rookery. It
remained under the protection of the Audubon Society until the estab-
lishment of the Everglades National Park.
Over most of its area the Cuthbert Lake bottom is on Miami lime-
stone. The limestone has a solution pitted surface, and in many of
the depressions there is an accumulation of shells, limestone fragments
and other debris. The limestone is covered by marl only around the
margins of the rookery key and around the fringes of the lake. The
marl is thinner away from the edge of the mangrove and usually extends
less than 100 feet out into the lake. This condition suggests that erosion
instead of sedimentation is noneffective in the main body of the lake.
In some of the small embayments, however, there is an accumulation
up to two feet thick of a gelatinous sort of material. It is largely organic,
for the analysis (table 4, no. 40) shows nearly 42 percent ignition loss.
Although in the vicinity of the rookery key there is essentially no
deposition, there is some precipitation of phosphate. In addition to peat
and marl, samples from this locality contain small concretion-like particles
of phosphatic material. A sample submitted to J. B. Cathcart and






REPORT OF INVESTIGATIONS No. 16


analyzed by George Ashby of the U. S. Geological Survey showed apatite
as the major mineral phase. Fluor-apatite is indicated by its fluorine con-
tent. The particles range in size from less than one mm. to about two
cm. They accumulate in limestone solution pits beyond the edge of the
marl and on the island's beach which is exposed at low tide. None of
this material was found in the peat and marl samples taken near the
middle of the island. Samples of sediment from the edges of Cuthbert
Lake and from nearby West Lake and Long Lake contain none, although
the sediment is otherwise similar to that near the rookery key. The locali-
zation of phosphatic material in the vicinity of the rookery indicates
that the bird colony plays an important part in its accumulation.
Eleven samples (table 4, no. 22-32) collected at a distance of 20 feet
to 70 feet from the edge of the mangrove on the rookery key contain
varying amounts of peat, marl with shell fragments, fragments of bed-
rock, and phosphatic particles. The P205 contents of these samples
range from 0.48 percent to 7.92 percent with an average of 4.10 percent.
The amount of phosphorus varies with the quantity of the phosphatic
particles in the sample. A sample from the island's beach (table 4, no.
33), consisting almost entirely of ground-up peat and phosphate parti-
cles, has 24.55 percent P205 based on dry sample. This sample has a
25.50 percent loss on ignition, and when the P20s percentage is based
on ash, the value is 33.77 percent.

Some indication of replacement of the marl substratum by phosphate
is given by a comparison of its P205 content with that of marl from
other localities. A single sample of marl (table 4, no. 35) from near
the middle of the island contains 0.85 percent P205. Four marl samples
(table 5, no. 41-44), two each from nearby Long Lake and West Lake
contain P205 ranging from a trace to 0.39 percent, one from near the
beach at East Cape (table 5, no. 45) 0.18 percent and a sample of marl
dredged up for fill on Bahia Honda Key (table 5, no. 46) has only a
trace. There is further indication of replacement in the shell material
located near the island. An analysis of oyster shell (table 4, no. 34)
picked from the samples and washed clean of marl and other material
shows 0.50 percent P205. Analyses of pelecypod shells by Clarke and
Wheeler (1922) show CasP208 ranging from a trace to only 0.07 percent.
There is a distinct difference in the amount of phosphorus in the sedi-
ment around the edge of the lake and the amount in the sediment from
the near vicinity of the rookery. Four samples of marl (table 4, no.
36-39) from widely separated points near the lake's edge contain P205
ranging from a trace to 0.18 percent. A fifth sample (table 4, no. 40),


63





FLORIDA GEOLOGICAL SURVEY


consisting of a somewhat gelatinous organic material and whose analysis
shows 41.85 ignition loss, contains 0.27 percent P205.

SUMMARY AND CONCLUSIONS
The lack of significant concentration of P205 in the Green Key, Duck
Rock, and East River localities is probably due to several factors. The
bird colonies may be too recent to have had much effect, currents may
carry the material away and distribute it sparsely, or plant life may take
up the soluble phosphorus before it has a chance to precipitate.
At Cuthbert Lake conditions have favored accumulation of phos-
phorus in the near vicinity of the rookery key. A large colony of birds
has occupied the key for a long time providing an adequate source of
phosphorus. Currents in the lakes are not as strong as in the other
sampled localities, so the phosphorus has a better chance to accumulate.
Without a specific study of the flora of the water in the different lo-
calities, it is not possible to evaluate the effects plant life had in removing
phosphorus from solution. Much algae had been growing around the
rookery key in Cuthbert Lake, but when sampling was done in August,
the algae was dead and largely disintegrated. A high H2S content in
the samples may have had some inhibiting effect on plant life, especially
on forms near the bottom. In any case there was phosphorus in excess
of that needed by plants and part of the excess was precipitated as
apatite in small concretion-like particles.
The relatively high concentration of phosphorus in the sediments at
the Cuthbert Lake rookery and the low concentration in other parts
of this lake and in nearby lakes indicates that the bird colony has been a
major factor in its accumulation.

REFERENCES
Clarke, F. VW.
1922 (and Wheeler, W. C.) The inorganic constituents of marine inverte-
brates: U. S. Geol. Survey Prof. Paper 124, 62 p.
Echel, E. B.
1953 (and Milton, Charles) Reconnaissance of superficial phosphate deposit
near Minas, Uruguay: Econ. Geol., vol. 48, p. 437-446.
Hutchinson, G. E.
1950 Survey of contemporary knowledge of biochemistry vertebrate excretion:
Am. Mus. Nat. Hist. Bull., vol. 96, p. 30-217.
Mills, H. R.
1944 The log of whiskey stump: The Florida Naturalist, vol. 18, no. 1, 8 p.
Milton, Charles (see Echel)


64






REPORT OF INVESTIGATIONS No. 16


65


Moore, Joseph C.
1953 A story of Cuthbert Rookery: Everglades Nat. Hist., vol. 1, no. 4, p.
181-188.
Odum, H. T.
1953 Dissolved phosphorus in Florida waters: Florida Geol. Survey Rept.
Inv. 9, p. 12.
Wheeler, W. C. (see Clarke)


TABLE 1. ANALYSES OF SAMPLES FROM GREEN KEY VICINITY
Sample P20, based on *P20, based Moisture Ignition A
air dried sample on ash loss (65C
1 0.43 0.45 1.08 '3.99 94
2 0.46 0.47 1.13 3.72 95
3 0.30 0.31 0.63 2.37 97
4 0.18 0.18 0.30 1.37 98
5 0.30 0.33 0.45 7.42 92
6 0.20 0.20 0.48 1.67 97


40
200
500
40
200
500


feet east of Green Key
feet east of Green Key
feet east of Green Key
feet south of Green Ke
feet south of Green Ke
feet south of Green Ke


ksh
* C)
1.93
;.15
t.00
3.33
1.13
'.85


y
y
y


*Calculated by Author


TABLE 2. ANALYSES OF SAMPLES
Sample P20, based on *P205 based
air dried sample on ash
7 0.29 0.34
8 0.24 0.29
9 0.19 0.23
10 0.20 0.25
11 0.19 0.22
12 0.21 0.25
13 0.18 0.20
14 Trace Trace
15 Trace Trace
16 0.41 0.49
17 0.20 0.22
7 At north edge of Duck Rock
8 40 feet north of Duck Rock
9 100 feet north of Duck Rock
10 200 feet north of Duck Rock
11 500 feet north of Duck Rock
12 100 feet east of Duck Rock
13 150 feet south of Duck Rock
14 150 feet west of Duck Rock
15 40 feet north of Bennett Key
16 100 feet north of Bennett Key
17 100 feet west of Bennett Key
*Calculated by Author


FROM DUCK ROCK VICINITY


Moisture

2.65
2.85
3.58
1.95
2.90
4.80
0.70
0.23
0.60
3.60
1.95


Ignition
loss
14.40
18.80
17.04
17.07
14.40
15.75
8.10
6.89
10.47
14.17
7.92


Ash
(6500 C)
82.95
78.35
79.38
80.98
82.70
79.45
91.20
92.88
88.93
82.23
90.13






FLORIDA GEOLOGICAL SURVEY


TABLE 3. ANALYSES OF SAMPLES FROM EAST RIVER
Sample P205 based on *P205 based Moisture Ignition
air dried sample on ash loss
18 0.24 0.29 4.33 17.22
19 0.10 0.12 2.45 16.52
20 Trace Trace 3.30 17.45
21 0.11 0.13 5.65 19.87
18 Channel sample from upper edge of rookery
19 Channel sample from middle of rookery
20 Channel sample from lower edge of rookery
21 Channel sample from below rookery
*Calculated by Author


TABLE 4. ANALYSES OF SAMPLES FROM CUTI
Sample P20. based on *P20, based Moisture ]
air dried sample on ash
22 6.49 8.18 4.73
23 2.22 2.87 4.25
24 2.52 5.36 10.75
25 6.21 8.05 4.25
26 4.68 5.95 5.28
27 3.45 4.55 5.83
28 5.99 7.75 4.38
29 0.48 0.68 6.20
30 7.92 10.53 7.15
31 1.66 2.10 3.55
32 3.43 4.17 2.90
33 24.55 33.77 6.60
34 0.50 0.54 0.65
35 0.85 1.06 2.43
36 0.18 0.20 1.63
37 0.15 0.17 0.60
38 Trace Trace 8.30
39 Trace Trace 2.85
40 0.27 0.49 6.70
22 20 feet north of Cuthbert Key
23 40 feet north of Cuthbert Key
24 60 feet north of Cuthbert Key
25 40 feet northeast of Cuthbert Key
26 40 feet east of Cuthbert Key
27 40 feet southeast of Cuthbert Key
28 40) feet south of Cuthbert Key
29 30 feet southwest of Cuthbert Key
:30 70 feet southwest of Cuthbert Key
31 70 feet west of Cuthbert Key
32 40 feet northwest of Cuthbert Key
33 Beach material from Cuthbert Rookery
34 Oyster shell from vicinity of Cuthbert Rookery
35 Marl from middle of Cuthbert Rookery
36 Southwest margin of lake, northwest of Cuthbert Cre
.37 At north edge of lake
38 At southeast margin of lake
39 At southwest margin of lake, east of Cuthbert' Creek
40 Southwest margin of lake at Cuthbert Creek


IBERT
Ignition
loss
19.72
21.80
47.30
21.87
20.27
22.79
21.64
27.75
23.05
20.40
17.15
25.50
6.50
19.24
10.04
11.67
14.20
12.92
41.85


LAKE
Ash
(6500 C)
75.55
73.95
41.95
73.88
74.45
71.38
73.98
66.05
69.80
76.05
79.95
67.90
92.85
78.33
88.33
87.73
77.50
83.23
51.45


ek


Ash
(6500 C)
78.45
81.03
79.25
74.48


66






REPORT OF INVESTIGATIONS No. 16


TABLE 5. SAMPLES FROM MISCELLANEOUS LOCALITIES-


Sample P20, based on
air dried sample
41 0.18
42 Trace
43 0.34
44 0.39
45 0.18
46 Trace


41 East end of West
42 Northwest corner
43 East end of Long
44 West end of Loni
45 Marl from near b
46 Dredgings from 1
*Calculated by Author


*P205 based
on ash
0.23
Trace
0.43
0.51
0.24
Trace


Moisture

1.70
2.05
2.20
3.48
1.95
3.40


Ignition
loss
18.65
23.05
21.10
21.67
22.65
11.07


t Lake, 200 yards west of small island
of West Lake, near the channel opening
Lake
g Lake
each at East Cape
Bahia Honda Key


Ash
(6500 C)
79.65
74.90
76.70
74.85
75.40
85.53












Part III




AN ANALYSIS OF OCHLOCKONEE

RIVER CHANNEL SEDIMENTS







By
Ernest H. Lund
Associate Professor, Department of Geology
Florida State University
and
Patrick C. Haley
Graduate Assistant, Department of Geology
Florida State University
On Special Grant from Coastal Petroleum Company








Prepared for the
Florida Geological Survey



Tallahassee, Florida
1958
























TABLE OF CONTENTS


Abstract .....................................

Acknowledgments .............................

Purpose of investigation .....................

Method of sampling ........................

Mechanical analysis of sediments ................

Heavy mineral analysis ........................


Table

1
2

3


Page

........................ 73

........................ 73

........................ 73

........................ 73

............. ........... 74

........................ 76


Sedimentary parameters .......................................... 74

Percentage of total heavy minerals in each sample ................... 75

Relative abundance of heavy minerals in all samples ................. 76









Part III


AN ANALYSIS OF
OCHLOCKONEE RIVER. CHANNEL SEDIMENTS

ABSTRACT
Channel sediments from the Ochlockonee River between Ochlockonee
Bay and the dam at Lake Talquin, Florida, were examined to determine
sedimentary parameters and heavy-mineral content. Most samples show
a unimodal grain-size distribution. There is considerable fluctuation in
the median diameter and mean grain size, but there is a noticeable
tendency for these values to decrease downstream. Total heavy-mineral
content ranges from about 0.05 per cent to 0.46 per cent with magnetite-
ilmenite the most abundant and rutile second in abundance.

ACKNOWLEDGMENTS
The writers are indebted to Mr. John Bates and the Coastal Petroleum
Company for the generous financial assistance given to this project and
to Dr. Stephen Winters of the Florida State University for his helpful
criticisms and suggestions in the preparation of the thesis from which this
paper is derived.

PURPOSE OF INVESTIGATION
The objectives of this study were to learn something of the physical
characteristics of the Ochlockonee River channel sediments between
Ochlockonee Bay and Lake Talquin and to determine the heavy-mineral
content of these sediments.

METHOD OF SAMPLING
Samples were collected from the river channel at two-mile intervals,
beginning at the entrance of the river into Ochlockonee Bay. A coring
tube 2 inches in diameter and 18 inches long attached to a stem made up
of 22-foot sections was lowered into the water and forced into the channel
deposits. The depth of penetration into the sediment was to the full
length of the coring tube where the thickness of the sediment layer
permitted. In a few places compaction of the material in the tube allowed
a penetration in excess of 18 inches. Water depths ranged from 1 foot
to 21 feet.





FLORIDA GEOLOGICAL SURVEY


MECHANICAL ANALYSIS OF SEDIMENTS

A representative 100-gram portion of each sample was separated
through a battery of 26 Tyler screens, the finest with an opening of .048
mm. and the coarsest with an opening of 6.680 mm. The data were
plotted in histograms and cumulative frequency curves, and from these
graphs the sedimentary parameters of table 1 were derived.


TABLE 1. SEDIMENTARY PARAMETERS*


Sample
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32


.115
.126
.173
.202
.200
.238
.305
.160
.268
.390
.350
.360
.360
.260
.269
.430
.225
.324
.154
.375
.315
.600
.215
.335
.590
.370
.295
.426
.370
.254
.345
.250


Median

.149
.204
.228
.254
.260
.286
.369
.196
.352
.484
.410
.498
.460
.350
.318
.723
.298
.470
.220
.477
.385
.790
.295
.422
.775
.530
.437
.610
.508
.441
.475
.430


Averages .409


Q3

.184
.315
.320
.340
.284
.336
.470
.250
.520
.680
.530
.568
.625
.480
.395
1.050
.410
.700
.290
.610
.495
1.120
.410
.570
1.050
.748
.700
.830
.700
.680
.712
.985


Mean


.156
.165
.247
.294
.246
.287
.438
.203
.430
.534
.461
.521
.553
.401
.360
.767
.365
.546
.256
.519
.429
.937
.358
.490
.871
.607
.550
.675
.590
.605
.587
.849


.478


1.26
1.58
1.36
1.30
1.19
1.19
1.24
1.25
1.39
1.32
1.23
1.25
1.31
1.35
1.21
1.56
1.35
1.47
1.37
1.27
1.25
1.36
1.38
1.30
1.33
1.42
1.54
1.39
1.37
1.63
1.43
1.98


1.36


* All figures except So are expressed in mm.


____


I





REPORT OF INVESTIGATIONS No. 16


With few exceptions the Ochlockonee channel deposits have a uni-
modal grain-size distribution and are very well sorted. The least well-
sorted sample, with a sorting coefficient of 1.98, was taken just below
the Lake Talquin Dam. Sorting coefficient values range from 1.98 to 1.19.

The median diameters range from 0.14 mm. to 0.790 mm. with con-
siderable fluctuation from one locality to the next but with a noticeable
decrease downstream. Sample number 1, taken at the river's mouth, has
the lowest value. The mean grain sizes range from 0.156 mm. to 0.937
mm., and there is a fluctuation that almost parallels that of the median
grain sizes. Like the median diameter, the mean grain size tends to
decrease downstream.

TABLE 2. PERCENTAGE OF TOTAL HEAVY MINERALS IN EACH SAMPLE
Sample Percent of
Number Heavies
1 0.46
2 0.12
3 0.06
4 0.05
5 0.13
6 0.10
7 0.10
8 0.25
9 0.10
10 0.05
11 0.08
12 0.09
13 0.07
14 0.11
15 0.16
16 0.21
17 0.22
18 0.25
19 0.24
20 0.10
21 0.14
22 0.11
23 0.24
24 0.24
25 0.05
26 0.12
27 0.12
28 0.10
29 0.20
30 0.16
31 0.16
32 0.38





FLORIDA GEOLOGICAL SURVEY


HEAVY MINERAL ANALYSIS
The heavy minerals were separated from the sands by allowing a
20-gram portion of each sample to settle in bromoform for a period of
30 minutes with agitation every five minutes. A representative part of
each heavy fraction was mounted in balsam and a grain count was made
using a mechanical stage on a petrographic microscope.
The amount of heavy minerals (table 2) in the Ochlockonee channel
deposits is small, ranging from 0.05 percent to 0.46 percent. The opaque
minerals, chiefly ilmenite but with some magnetite, are the most abundant
(table 3). They make up from 10 percent to 34 percent of the total
heavies, and the average for the 32 samples is about 22 percent. Rutile
is the second most abundant, ranging from about 8 percent to 26 percent
and averaging about 20 percent. Other minerals in decreasing order of
abundance are kyanite, zircon, tourmaline, hornblende, leucoxene, silli-
manite, staurolite, garnet and epidote.
'AmI.E 3. RELATIVE ABUNDANCE OF HEAVY MINERALS IN ALL SAMPLES
Average Percent
Percent Range
Magnetite-
ilhnenite 22.4 10-34
Rutile 19.8 8-26
Kyanite 16.9 9-29
Zircon 12.8 5-25
Tourmaline 11.1 1-27
Hornblende 7.0 0-20
Leucoxene 5.3 1-21
Sillimanite 1.9 0-6
Staurolite 1.3 0-11
Garnet 0.8 0-5
Epidote 0.7 0-4

A study' by Alfred Larsen and Steve Revell of the heavy-mineral
content of the Pleistocene terrace sands east of the Ochlockonee River
shows a close similarity in the heavy-mineral suites of the terrace deposits
and the river deposits. A notable difference is in the high percentage
of hornblende in some of the river material and its scarcity in the terrace
material. No monazite was noted in the river material, but in some of
the terrace localities monazite makes up to 10 percent of the total heavy-
mineral content.
Close similarity in the heavy minerals of the river deposits and the
adjacent terrace deposits indicates that a major source of the river's


SFor Master's degree at Florida State University.





REPORT OF INVESTIGATIONS No. 16 77

present bed load is the terrace material. Since the construction of the
Talquin dam, the upstream sources of material have been cut off. The
load below the dam is now obtained mainly by reworking of the flood
plain and through contributions of Pleistocene terrace material from
tributary streams and by slumping of this material along the banks of
the Ochlockonee River. The limestone bedrock over which the river
flows probably contributes a very small amount of plastic material to
the bed load.




Miscellaneous studies ( FGS: Report of investigations 16 )
CITATION SEARCH THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00001200/00001
 Material Information
Title: Miscellaneous studies ( FGS: Report of investigations 16 )
Series Title: ( FGS: Report of investigations 16 )
Physical Description: iv, 77 p. : maps (part fold., 1 col.) tables. ; 23 cm.
Language: English
Creator: Florida Geological Survey
Publisher: s.n.
Place of Publication: Tallahassee
Publication Date: 1958
 Subjects
Subjects / Keywords: Geology -- Florida   ( lcsh )
Sediments (Geology) -- Florida   ( lcsh )
Guano   ( lcsh )
Phosphates -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographies.
 Record Information
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Table of Contents
    Copyright
        Copyright
    Front Cover
        Page i
    Florida State Board of Conservation
        Page ii
    Transmittal letter
        Page iii
    Contents
        Page iv
    Part 1 Geology of the area in and around the Jim Woodruff Reservoir
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        24a
        Page 25
        Page 26
        26a
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
    Part 2 Phosephate concentrations near bird rookeries in South Florida
        Page 53
        Page 55
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
    Part 3 An analysis of Ochlockonee River channel sediments
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
Full Text






FLRD GEOLIOWC( ICA SURflViEWY~


COPYRIGHT NOTICE
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information and permissions.







STATE OF FLORIDA


STATE BOARD OF CONSERVATION
Ernest Mitts, Director


FLORIDA


GEOLOGICAL


SURVEY


Herman Gunter, Director






REPORT OF INVESTIGATIONS NO. 16








MISCELLANEOUS STUDIES

















TALLAHASSEE, FLORIDA


1958










FLORIDA STATE BOARD

OF

CONSERVATION


LEROY COLLINS
Governor


R. A. GRAY
Secretary of State



J. EDWIN LARSON
Treasurer



THOMAS D. BAILEY
Superintendent of Public Instruction


RICHARD ERVIN
Attorney General



RAY E. GREEN
Comptroller



NATHAN MAYO
Commissioner of Agriculture


ERNEST MITTS
Director of Conservation






LETTER OF TRANSMITTAL


7i0tiLa Q a1 ieca1 S atvef

Tallahassee

December 5, 1957





Mr. Ernest Mitts, Director
Florida State Board of Conservation
Tallahassee, Florida

Dear Mr. Mitts:

I am forwarding to you a report entitled, MISCELLANEOUS
STUDIES, which includes the following papers: "Geology of the Area
in and Around the Jim Woodruff Reservoir" by Charles W. Hendry, Jr.
and J. William Yon, Jr.; "Phosphate Concentrations near Bird Rookeries
in South Florida" by Dr. Ernest H. Lund, Department of Geology,
Florida State University; and "An Analysis of Ochlockonee River Channel
Sediments" by Dr. Ernest H. Lund, Associate Professor and Patrick
C. Haley, Graduate Assistant, Department of Geology, Florida State
University.

These three papers contribute to our knowledge of the geology and
economic resources of Florida and are being published as Report of
Investigations No. 16.

Respectfully submitted,
Herman Gunter, Director
























CONTENTS

Part I Geology of the area in and around the Jim Woodruff
reservoir --.----.----___.. -- -----......-----_ .. ...--... ------..........-----.- .....--.- 1

Part II Phosphate concentrations near bird rookeries
in South Florida ......--------------..----------------- 53

Part III An analysis of Ochlockonee river channel
deposits ..--..-- ....----.. ---...-.- ----..-.........-----....... 69










Part I


GEOLOGY OF THE AREA


IN AND AROUND


THE JIM WOODRUFF RESERVOIR


By

Charles W. Hendry, Jr.

and


J. William Yon, Jr.














Florida Geological Survey

Tallahassee, Florida

1958


1



















(










TABLE OF CONTENTS


Page


Acknowledgments ............


Introduction
Purpose
Location
The Jim

Physiography
Introduc
Tallahass

Dougher
Maj
















Stre

Structure ..
Chattah

Linear
Stratigraphy
Introdu'
Tertiary
Eocene

Jackson

Ocala g
Cr











Oligoc<
Su


and scope of study .....................


Woodruff lock and dam ................
W oodo o . k .. am . . ... . .

tion .............................
see Tertiary Highlands ....................

rty River Valley Lowlands .................
jor streams ........ ................. ..
Chattahoochee River .....................
Flint River ............................

Apalachicola River ......................
Flood plain ... ....................
Natural levees ...........................

Rim swamps ...........................
Tributary streams .......................
Stream terraces .... ....................
Jim Woodruff Reservoir area.........
eam capture .........................


.oochee anticline .........................

trends ............. ............ ...... .
. . . . . . . . . .
action ................... .............. .
S system ................................
series .................................

stage ...............................

group ................................
ystal River formation .....................
Historical ............................
Distribution ...........................

Lithology .............................
Thickness and structure ................
Stratigraphic relationship ................
Geologic exposures ....................


ene series .................
iwannee limestone .........


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


. . .
. .

. . .


.. ..
. . .

.. . .

. . .

. . .

0 6 a 0

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

. . . .

. . . .


.. . .


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

. . . .


................... 24


. ................ 25


................................ 25


Historical ..............
Distribution ............


..

3


7
7
7
8
10
10
10
11
12
13
13
13
13

14
14
15

15
16
17
20
20

22
23
23
23
23

23

23
23
23
23
24
24
24


..... i






Lithology ................................................ .
Thickness and structure ....................................
Stratigraphic relationship .......... .................... .
Geologic exposures ....................................... .
M iocene series ..... ... ...... ............................ ..... ...
Tampa stage .............. ............. ......... .. ......... ...
Chattahoochee facies .......... ... ......... ................. .
Historical ..................... ...........................
Distribution ............. ..........................
Lithology ....... ........ ........... .. .... .......
Thickness ............... .............................. .
Stratigraphic relationship ............... ............
Geologic exposures .................................. ... .
Alum Bluff stage .................. .......... .......... ......
Hawthorn facies .......................................... .
Historical .................... ........ ....................
Distribution .......................... ..................
Lithology ................... ................ ........ ...
Thickness ......... .................. ....... ..... ..
Stratigraphic relationship ..................................
Geologic exposures ......................................
Post-Miocene stratigraphy ......... ............ ...................
Silicified limestone ............... ........... ............... .
Historical ............ ...................................
Present concept ................................ ...... .
Geologic exposures ...................................
Geologic exposures along Chattahoochee and Flint rivers ...................
Insoluble residue study ...... ............................................
Introduction ...................................................
Procedure .....................................................
Insoluble residues ........................ ................ ......
Conclusion ..................................... ............


Localities ..........
Selected bibliography


26
26
26
26
28
28
28
28
28
28
29
29
30
34
34
34
34
34
34
34
34
35
35
35
35
36
36
43
. 43
S44
. 44
. 45
. 47


ILLUSTRATIONS


Figure
1
2
3
4
5
6
7
8


Map showing area of investigation ...............................
Map showing physiographic regions ................................
Reconstructed composite of terrace surfaces .........................
Diagrammatic stream capture sequence .............................
Map showing linear trends along the Chattahoochee and Flint rivers ....
Geologic map of area investigated .......................... Facing
Geologic cross sections ................................. Facing
Chart showing insoluble residue percentages in three wells ...........


8
9
16
19
22
24
26
46


. . . 0 0 4 0 4 0 0 0 9 0 0 0 0 a 1 0 a 0 6 0

















ACKNOWLEDGMENTS

Dr. Robert O. Vernon, Assistant Director, Florida Geological Survey,
assisted the writers many times in the field investigation and offered many
helpful suggestions during the preparation of this report.
Staff members of the Florida Geological Survey offered assistance
and advice during the course of the study. Special recognition is given
to Mrs. Ruth Shuler and Miss Betty Youngblocd for the time they spent
typing and editing the report. Assistance was given by Mr. Kenneth
Highsmith who helped in the preparation of the illustrations and maps.
Appreciation is expressed to the staff of the Resident Engineer's office,
U. S. Army Corps of Engineers, Chattahoochee, Florida, for making
available maps and elevations of the Jim Woodruff reservoir area.
Citizens of Jackson and Gadsden counties, Florida, and Seminole and
Decatur counties, Georgia, were very cooperative and helpful.































































































I





Part I


GEOLOGY OF THE AREA
IN AND AROUND
THE JIM WOODRUFF RESERVOIR

INTRODUCTION

PURPOSE AND SCOPE OF STUDY
In December 1953 Vernon, Hendry, and Yon1 made a study of the
outcropping Tertiary sediments along the lower portions of the Chatta-
hoochee and Flint rivers in the area of the Jim Woodruff reservoir. This
investigation was conducted prior to the conclusion of the Jim Woodruff
Dam project. The completion of this dam has created a 37,000-acre lake
which has masked from future investigations much of those sediments
that were previously exposed in the area. This study along the rivers
brought to light inconsistencies in the present concept of the geology of
this area and the writers thought it wise to undertake a more thorough
investigation of the surface geology.
The data collected through the study of surface exposures were
supplemented by examination of cuttings from three oil test wells and
six water supply wells that were drilled in the area and samples from
three core holes which were obtained from the field office of the U. S.
Army Corps of Engineers, Chattahoochee, Florida. The absence of
samples from a sufficient number of wells to give a good coverage
influenced the writers to put down 17 auger holes in locations where
little or no subsurface information was available.
This report presents the results of the studies on the geology in and
around the Jim Woodruff reservoir that have been conducted inter-
mittently since December 1953.

LOCATION
The area of this investigation is located in southwest Georgia, Decatur
and Seminole counties, and in the adjoining portions of Jackson and Gads-
den counties, Florida. It is roughly rectangular in shape, bounded by
30o40' and 31O00' north latitude and 84o30' and 8500' west longitude.
The east-west dimension is approximately 30 miles, and the north-south
dimension is approximately 20 miles (fig. 1). The investigation was
confined principally to the area between and around the Chattahoochee
and Flint rivers.
1Dr. R. O. Vernon, Assistant Director, C. W. Hendry, Jr. and J. W. Yon, Jr.,
Geologists, Florida Geological Survey.







FLORIDA GEOLOGICAL SURVEY


ALABAMA
quA L A-A A
Lb INa' V/// E 0 R G A
N i (hMA IOmOcl00 AWoqr _r Jt-,

AV~V

'VM A;
CAAP~


G UL F


0


V4
VpA
0
0


FLORIDA
$W. e ,,soWi s
krrIogok Ylleo


Figure 1. Map showing location of the area in and around the Jim Woodmrff
reservoir.


THE JIM WOODRUFF LOCK AND DAM
For nearly half a century Mr. Jim Woodruff, Sr., of Columbus, Georgia,
sought development of the Apalachicola, Chattahoochee, and Flint rivers
for navigation. In tribute to Mr. Woodruff's persistence, the first of the
projects in the plan for improving these rivers was named the Jim
Woodruff Lock and Dam. This project was authorized as a part of the
River and Harbor Act of July 24, 1946, and was dedicated in 1957.

The dam is located northwest of Chattahoochee, Florida about 300
yards below the point where the Chattahoochee and Flint rivers unite
to form the Apalachicola River. The normal level of the water in the
reservoir is at an elevation of 77 feet with the tailwater at 44 feet.


VA
k 0-






REPORT OF INVESTIGATIONS No. 16


This dam provides channels, nine feet deep and 100 feet wide, in
the Chattahoochee River to Columbia, Alabama, and in the Flint River
to Bainbridge, Georgia. In addition to this navigational facility, the dam,
having a shoreline of 243 miles, provides an area for recreational activities
such as boating, camping, fishing, picnicking, and sightseeing (U.S.C.E.
Pamphlet, 1953).






FLORIDA GEOLOGICAL SURVEY


PHYSIOGRAPHY
INTRODUCTION
The sediments studied in this investigation lie within the East Gulf
Coastal Plain, a subunit of the Coastal Plain Province (Fenneman 1938,
p. 65-68). The recognizable physiographic subdivisions of this area were
mapped as: (1) the Tallahassee Tertiary Highlands, and (2) the Dough-
crtv River Valley Lowlands (fig. 2).
On the basis of origin, Vernon (1951, p. 16), subdivided the phy-
siography of Florida into two general groups, each of which is sub-
divided into two units. These are the Delta Plain Highlands, the Tertiary
Hlighlands, the Terraced Coastal Lowlands, and the River Valley Low-
,lnds. He defined his highlands as sediments formed either as a part
of a high-level, widespread, aggradational delta plain or of Tertiary land
masses rising above this plain, and his lowlands as being formed by
imarille erosion and deposition along coastlines and by alluviation and
stream erosion along stream valleys. Vernon proposed that where these
stlbdlivisions are mapped, local names may be appropriately applied.
TALLAHASSEE TERTIARY HIGHLANDS
The topography and composition of the Tallahassee Tertiary High-
lailds is considerably different from that of the surrounding terrain. The
area abruptly rises 200 to 250 feet above the adjacent lowlands and the
excellent soils developed oil the highlands support lush, natural vegetation
and give rise to many prosperous farms.
The Tallahassee Tertiary Highlands arc characterized by erosional-
remn'llant lills with relief up to 250 feet, except in the northwestern part
of (adsden County and in the adjoining southwestern portion of Decatur
(Cotuty, (Georgia, where the highest hills are comparatively flat-topped
witi elevations slightly exceeding 300 feet. Because of the flat crests,
remnlant drainages and depositional sequences, these hills are interpreted
as remnants of the original depositional surface of the Hawthorn delta.
To thle west, south and east of this flat-topped section, the cycle of erosion
is miore advanced, having reduced the highlands to a lower, more dis-
sected topography. -The highlands are composed of sands and clays of
the lHawthorn formation with impure limestone of the Chattahoochee
formation cropping out along the bluffs of the major streams, in road cuts,
in small stream valleys, and in sinks that penetrate through the Hawthorn.
)Descriptions of portions of the Tallahassee Tertiary Highlands area
are numerous in the literature. Not until Cooke (19'9, p. 14-21) divided
the State into five physiographic divisions, was most of this highlands
area grouped together and named.






REPORT OF INVESTIGATIONS No. 16


Cooke (1939, p. 20) applied the name Tallahassee Hills to an area,
approximately 25 by 100 miles, delineated by the Georgia-Florida state
line on the north, the coastal lowlands on the south, and the Withla-
coochee and Apalachicola rivers, respectively, on the east and west. He
described the area as being characterized by long gentle slopes with
rounded summits, the highest part of which is believed to be a plain
with a maximum elevation of about 300 feet in the vicinity of north-
western Gadsden County. Cooke stated the geologic composition of
these "hills" was impure limestone of the "Tampa limestone" overlain
by the sands and clays of the Hawthorn formation. Later (1945, p. 9-10),
he assigned the red surface sands to the Citronelle formation and the
underlying sandy clays and clays to the Hawthorn formation.
Vernon considered that his definition of Tertiary highlands included
Cooke's Tallahassee Hills, which he thought to be a general term and
proposed the local name Tallahassee Tertiary Highlands, as more appro-
priate. The writers, conforming to Vernon's "locality-origin" terminology,
have adopted the term Tallahassee Tertiary Highlands to include Cooke's
Tallahassee Hills as bounded on the south and east, but extended on
the west into Jackson County, Florida, and north into Decatur County,
Georgia, where it is bounded by an escarpment facing the Dougherty
River Valley Lowlands.
That part of the Tallahassee Tertiary Highlands in southeastern
Jackson County, Florida, has been disjoined from the eastern part by
the Apalachicola River. Previous investigators have found little dispute
in assigning the sandy limestones underlying this highlands area to the
lower Miocene; however, the capping clastics west of the Apalachicola
River in Jackson County have been disassociated from the similar Miocene
deposits on the eastern side of the river and generally assigned to the
Pleistocene series in previous literature. The writers find no material
lithologic differences in the clastics of these two areas and therefore
include these western hills in their Tallahassee Tertiary Highlands.
Also, it is the impression of the writers that the northern limits of the
highlands should exceed Cooke's political boundary limit, the Gadsden-
Decatur county line (Florida-Georgia state line), and be extended to the
northward-facing escarpment overlooking the Flint River valley, a
part of the Dougherty River Valley Lowlands.

DOUGHERTY RIVER VALLEY LOWLANDS
The Dougherty River Valley Lowlands is the largest physiographic
unit in the area, consisting of sediments at relatively low elevations
which occur north and west of the Tallahassee Tertiary Highlands. In





FLORIDA GEOLOGICAL SURVEY


1911, Veatch (p. 30-31) applied the name Dougherty Plain to the low-
lands of southwestern Georgia. In 1938, Fenneman (p. 76-77) expanded
the term to include that portion of Florida which was later called the
Marianna Lowlands by Cooke (1939), p. 18-19). Moore (1955, p. 6-8),
using Vernon's terminology based on origin, called Cooke's Marianna
Lowlands the Marianna River Valley Lowlands. Since the largest portion
of the lowlands of this report is a part of Veatch's Dougherty Plain,
the writers have used the term Dougherty River Valley Lowlands for
this geomorphic unit.

The area assigned to the lowlands includes the flood plains and ter-
races of the present Apalachicola, Chattahoochee and Flint rivers, and
also the topographically low area in Jackson County which is probably
the result of ancestral streams of the Choctawhatchee and Chattahoochee
river systems. Moore (1955, p. 7) briefly discusses the agencies forming
these lowlands.

This westward extension has been traced through Jackson County
into Hlolmes County by Moore (1955, p. 8, 13, 14) to where it joins the
Ilood plains of the Choctawhatchee and Holmes rivers (Vernon 1942,
p. 5-6) in Holmes and Washington counties. The sediments are clastics
ranging in size from clays to large silicified boulders measuring up to 15
feet across (see Flood Plain, p. 13).

MAJOR STREAMS
There are portions of three major streams flowing within the area
of this investigation. Two of these streams, the Chattahoochee and the
Flint rivers, originate from outside the area, having their headwaters
in the piedmont of northern Georgia. The third major stream, the
.\palachicola River, has its headwaters within the area of this investi-
gation, being formed by the confluence of the Chattahoochee and Flint
rivers.

The channel banks of the Chattahoochee and Flint rivers are excep-
tionally steep for rivers as old and as well established as they appear to
l)e, when compared to streams elsewhere in Panhandle Florida.

Northward in Georgia and Alabama, tributary streams join the Chatta-
hoochee with valley floors standing much higher and out of adjustment
at their point of confluence with the Chattahoochee. This evidence would
indicate rejuvenation of the Flint and Chattahoochee system in the late
Pleistocene or Recent.






REPORT OF INVESTIGATIONS No. 16


Chattahoochee River
The Chattahoochee River flows southward near the western edge of
the area. This stream is heavily laden with suspended sediment, as is
evidenced by its turbidity and red color. It is an active river with a
gradient of about 0.65 foot per mile in the lower 26 miles. Only at
locality 34 do silicified boulders constrict the channel, a marked contrast
to the Flint River channel, which is strewn with boulders and obstructed
by boulder bars that create a definite hazard to river travel, especially
during periods of low water.
Flint River
The Flint River flows southward along the eastern boundary of the
area and is deflected westward by the high scarp along the north edge
of the Tallahassee Tertiary Highlands. In contrast to the Chattahoochee
River it carries much less load in suspension. This is readily noticeable
at their confluence where, for some distance down the Apalachicola River,
the discharge from each river is easily distinguishable by the color.
The Flint River has a gradient of approximately 0.55 foot per mile
for the lower 26 miles. Rapids and islands of boulders or bedrock of
silicified limestone of Eocene and Oligocene age are not uncommon in
the area from locality 52 (Lamberts Island) to the northern limit of
the area.
Apalachicola River
The Apalachicola River, formed by the union of the Chattahoochee
and Flint rivers about one mile northwest of the town of Chattahoochee,
Gadsden County, Florida, flows southward and empties into the Gulf of
Mexico at Apalachicola, Florida. Only about five miles of this river lies
within the area covered by this report. However, the writers feel it has
played an important part in the evolution of the present landforms, and
is, therefore, discussed more fully under stream capture.
Flood Plain
The deposits comprising the flood plains of the Chattahoochee and
Flint rivers range in thickness from a thin veneer to over 80 feet. Near
the Alabama state line, ledges of bedrock visible at stages of low water
underlie 20 or 30 feet of flood-plain sediment which was deposited in
a more shallow part of the valley. Two auger holes located about one
mile west of the right bank of the Chattahoochee River (see auger hole
localities AS-2422 and AS-244) penetrated 80 feet of sand and pea-
size gravel with small amounts of clay without reaching bedrock. At
auger hole locality AS-243, a depth of 71 feet was reached before bed-
2Florida Geological Survey auger sample numbers.


18





FLORIDA GEOLOGICAL SURVEY


rock was encountered. This alluvium was deposited in deep abandoned
channels probably formed in an older Chattahoochee system which were
cut during a preceding interglacial period and subsequently filled.
The Hood plain along the left bank of the lower section of the Chatta-
hoochee River merges with that of the Flint River, giving a broad
relatively low area between the two rivers in this region. Within this
broad low area, auger holes AS-246, AS-247 and AS-249 did not pene-
trate bedrock at depths of 73.5, 67.5 and 73.5 feet, respectively; whereas,
bedrock was reached in holes AS-248, AS-250 and AS-251 at depths of
63, 26 and 70 feet. This varying thickness of alluvium points up the highly
eroded surface of the bedrock.
Natural Levees
Natural levees are present along the Apalachicola, Chattahoochee and
Flint rivers. These natural levees are formed during flood stages of the
rivers. As the high water rises above the confines of the channels and
flows onto the flood plain, its velocity is sharply decreased and the
increased load, transported by the higher velocity, is largely deposited
immediately adjacent to the streams. At the time the field work was
done, the flood plains of the Chattahoochee and Flint rivers had been
cleared as part of the project of preparing the reservoir. The removal of
trees and brush had exposed the levees over a wide vista and they
were easily identified. Toward the upper limits of the reservoir, where
the levees stand higher than the cleared, adjacent part of the flood plain,
they are marked by elongated wooded islands and strips.
Rim Swamps
Natural levees, normally the highest part of any flood plain, slope
gently toward the base of the valley walls, and low marginal areas are
present along the base of the escarpment rising above the flood plain.
During the wet season, when the ground-water level rises high enough,
these low marginal areas become swampy and are termed rim swamps.
As the local irregularities (basins) in the rim swamp area become full to
overflowing, the drainage collects in a stream, called a rim swamp stream,
which forms along the base of the valley wall (Russell 1938, p. 72-73).
Him swamps are common along the flood plains of the streams within
the area. Vernon (1942, p. 8) described rim swamp streams along the
marginal valleys of the Choctawhatchee River in central Holmes County;
however, rim swamp streams are not sharply delineated in the reservoir
area.
Terraces, deposited as flood plains, have these same aggradational
features. The higher terraces, having been subjected to erosion for a






REPORT OF INVESTIGATIONS No. 16


longer time, have fewer, if any, recognizable aggradational patterns pre-
served; whereas, the younger terraces still possess excellent examples.
On the lower terraces, the marginal areas are marked by sinkhole
alignment.
Tributary Streams
In the area of this investigation, the Flint River has five tributaries
only one of which could be considered a major tributary. The major
tributary, Spring Creek, originates about 10 miles southeast of Fort
Gaines, Georgia, and flows southward to its junction with the Flint River.
It is a very sluggish stream in its lower reaches, the channel being
drowned and in many stretches unidentifiable through swamp vegetation.
The stream carries almost no sediment, but is darkly colored by organic
acids. It is locally reported that this stream is partially spring fed. The
mouth of Spring Creek is obscured by cypress trees, giving the appear-
ance of a drowned swampy area along the Flint River.
Butlers, Sanborn and Fourmile creeks, and Big Slough, are the
four principal small tributary streams of the Flint River. All of these
streams are located along the left side of the Flint, and contrary to the
small tributaries of the lower Chattahoochee River, they are in adjustment
at their point of confluence with the Flint. They drain relatively small
areas, having an average length of only a few miles.
Butlers and Sanborn creeks originate in the Tallahassee Tertiary
Highlands of southern Decatur County, Georgia. They flow northward
and join the Flint River at the base of the northward facing highlands
escarpment. Fourmile Creek and Big Slough originate in the Dougherty
River Valley Lowlands and trend in a westerly direction, uniting with the
Flint near the town of Bainbridge, Decatur County, Georgia.
The small segment of the Apalachicola River covered in this report
has only one tributary. This is Mosquito Creek which drains the area
northeast, east, and south of the town of Chattahoochee and enters the
Apalachicola in the southern part of the area of this investigation.
There are no principal tributaries of the Chattahoochee River below
the Alabama-Florida state line; however, mention has been made above
of the tributaries of the Chattahoochee just north of this area.
Stream Terraces
The first published account of stream terraces in Florida was by
Vernon (1942, p. 9-15). He reported four definite levels above the
present flood plains of all the major streams in Holmes and Washington
counties, Florida. Prior to Vernon's work on stream terraces in West
Florida, H. N. Fisk (1938, 1939, 1940) reported on the occurrences of





FLORIDA GEOLOGICAL SURVEY


stream terraces in Louisiana The reader is referred to these two workers'
reports for a discussion on the origin and description of stream terraces.
Jim Woodruff Reservoir Area: The writers found four really defined
levels associated with stream-cut scarps bordering the Chattahoochee
and Flint rivers. These four fluvial surfaces occur above the modern
flood plain at heights of 10, 40, 60 and 90 feet. To substantiate the number
of existing terraces and their heights above the flood plain the writers
compiled, normal to the river axis, many land-surface profiles using
U. S. Geological Survey topographic quadrangles and aneroid elevations
taken in the field. Figure 3 represents a reconstructed composite of the
terrace su-rfaces associated with the Chattahoochee and Flint rivers.

-200 200-





1 I .... -
100 I-- -


E3 STREAM -CUT VALLEYS
El ALLUVIAL FILL
[ TERTIARY SEDIMENT

Figmur 3. generalizedd and diagrammatic profile across the Chattahoochee River
Valley in Jackson County, Florida and Seminole County, Georgia.

Two terrace surfaces above the flood plain of the Flint River con-
sistently show up in profiles drawn across the valley. These fluvial
surfaces occur at 10 and 40 feet. Between these two levels there occur
several levels at varying altitudes that may be traced only for short
distances. They very probably are attributable to erosion and perhaps to
rejuvenation of the river by stream capture.
Erosion and probably stream course change have so altered the land
surface in this area that the highest terrace is not as well preserved in
Jackson County, Florida, as it is in Seminole County, Georgia. Only
sparsely scattered hilltops in the northern part of Jackson County reach
this level, whereas in Seminole County the average elevation exceeds 160
feet with some hills reaching 180 feet. As this is the only level that






REPORT OF INVESTIGATIONS No. 16


doesn't fit into the system described by Vernon (1942) -there is a possi-
bility that the few remaining hilltops that mark this level were once
higher and are now uniformly eroded to 90-100 feet above the modern
flood plain.
The 60-foot level is extensively developed in central and northern
Jackson County, but it is less distinguishable in Georgia because of the
shorter areal distance between the lower terraces and the 90-foot level.
The 40-foot level is conspicuously developed along both the Chatta-
hoochee. and Flint rivers. In addition to the many flats which represent
this terrace surface there are also many hilltops at this altitude that help
substantiate the level.
In the vicinity of the juncture of the Chattahoochee and Flint rivers
the 10-foot terrace is broadly developed but now flooded by the Jim
Woodruff reservoir. Upstream this terrace narrows considerably, rarely
exceeding two miles in width.
The stream terraces are very poorly defined or absent along the
left side of the Flint River from Southlands Ferry to the dam. The
presence of the steeply sloping, high Tertiary escarpment immediately
to the left of the river makes identification of terrace levels impossible.
That section of the Apalachicola River covered in this report is
bounded on each side by fairly high Miocene hills. There are no hilltops
or extended flats that correspond to the levels described above that occur
above the modern flood plain. The presence of only a recent flood plain
indicated that the river did not occupy this course during the time the
terraces were being formed (see Stream Capture).

STREAM CAPTURE
Paralleling the western edge of the Tallahassee Tertiary Highlands
in Jackson.County, Florida, is a broad, terraced, shallow valley which is
characteristic of a flood plain commensurate with a system comparable
to the Chattahoochee and Flint rivers. The western side of this valley is
bounded by high Pleistocene plastic sediments. The valley trends in a
inorth-south direction and merges at its southern end with the lowlands
associated with the present Apalachicola River flood plain in the vicinity
of northern Calhoun County. Its northern limit joins the lowlands asso-
ciated with the Chattahoochee River lowlands, now inundated by the
Jim Woodruff reservoir.
There are no perennial streams in the valley at the present time, but
small tributaries of the Apalachicola River are present at its southern





FLORIDA GEOLOGICAL SURVEY


extremity. Most of the valley is drained by sinks and during periods of
heavy rainfall and high water-table level the many ponds and swampy
areas are connected by intermittent streams.
Moore (1955, p. 13) reports a buried stream channel in north central
Jackson County that extends in a north-northeast direction into Alabama
towards the Chattahoochee River. Along the right side of the Chatta-
hoochee River, the depth to bedrock, as determined by auger holes,
would indicate that formerly the Chattahoochee was several miles to
the west of its present course. The writers believe that this river flowed
through the remnant valley described above. If this is true, the Flint
River would have extended beyond its present entry into the highlands to
a point of juncture with the Chattahoochee several miles north or north-
west of the town of Sneads (fig. 4-1).
Four and one-half miles north of the Jim Woodruff Dam the direction
of the southward trending Chattahoochee River veers sharply to the
left for approximately one mile and then again southward (right) to
where it joins the Flint River. The axis of this jog in the river is in
perfect alignment with the Flint River where it flows along the base of
the high escarpment which marks the northern limits of the Tallahassee
Tertiary Highlands. Because the location of this jog is not controlled by
the high Miocene hills and because there is an exact alignment with the
Flint River channel, it is possible that the jog may represent a portion
of a former extension of the Flint River which drained to the west.
The geomorphic conditions that exist in the Chattahoochee-Sneads
area at the present time strongly suggest the possibility of stream capture
in the late Pleistocene or early Recent time. The relationship of the
Apalachicola River with the Flint and Chattahoochee rivers indicates that
the Apalachicola has advanced its headwaters northward into the high
Miocene sediments and diverted the Chattahoochee and Flint rivers
(fig. 4-2).
The Apalachicola, because of its steeper gradient along the south-
western edge of the Tallahassee Tertiary Highlands, cut back through
these highlands into the drainage area of the Flint and Chattahoochee
rivers. This stream capture caused a change in the direction of flow of
these rivers at the point of capture (fig. 4-2).
The Flint River diverted by the captor stream, the Apalachicola
River, now turns sharply at the point of capture, exhibiting a well-
defined elbow of capture. The increased volume of the Apalachicola
River after the capture of the Flint River allowed rejuvenation to enlarge
the valley through the Tallahassee Tertiary Highlands.









REPORT OF INVESTIGATIONS No. 16


E -
fV ilnii


Figure 4. Four diagrammatic panels illustrating progressive stages in the stream capture of the
Chattahoochee and Flint rivers by the Apalachicola River.

4-1. Hypothetical courses of the Chattahoochee and Flint rivers (A) which flowed around the
Tallahassee Tertiary Highlands, the northern and western limit of which is shown by
the hachured line (B). At this stage the Apalachicola River (C) was a small tributary to
the Chattahoochee River and had just begun to cut headward into the highlands. The
dashed line (D) represents the most recent courses of the three rivers.

4.2. The Apalachicola River (A), still tributary to the Chattahoochee River (B), has cut
headward through the Tallahassee Tertiary Highlands and captured the Flint River (C).
The captured stream (C) has been diverted by the captor stream (A) and now turns
sharply at the point of capture (E), exhibiting a well-defined elbow of capture. The
beheaded portion of the Flint River (D) has turned back into the captor stream, and
thus has been transformed into an inverted stream.

4-3. The Chattahoochee River (A) has been diverted by the enlarged inverted stream (B).
The combined flows of the Chattahoochee and Flint rivers rapidly enlarged the youthful
valley of the Apalachicola River (C).

4-4. This panel illustrates the positions of the Chattahoochee (A), Flint (B), and Apalachi-
cola (C) rivers just prior to the erection of the Jim Woodruff Dam. The dashed lines
represent the former courses of the Chattahoochee and Flint rivers.


- --I I--- -, 1


_ ___ ___
__ ___


i


I





FLORIDA GEOLOGICAL SURVEY


The Chattahoochee River, having lost most of its volume after the
capture of the Flint, became a misfit stream. Probably the smaller tribu-
taries, below the old point of juncture with the Flint River, built alluvial
fans on the valley floor because the Chattahoochee could no longer
transport the customary load. Lakes and marshes probably formed, and,
subsequently, the development of sinks along this valley captured what
surface drainage remained.
The writers believe that in the region south and southwest of the
Tallahassee Tertiary Highlands the Apalachicola River now occupies or is
closely associated with the former Chattahoochee River valley. The
development of sinks along the valley to the west of Sneads has cap-
tured the surface drainage along this valley and the deposition of
plastic sediments derived from the greatly dissected highlands on each
side of the valley has caused the Chattahoochee to be deflected to the
point of confluence with the Flint and Apalachicola rivers.

STRUCTURE
CHATTAHOOCHEE ANTICLINE
The largest geological structure occupying the region in southwestern
Georgia, southeastern Alabama, and the adjoining portion of Florida
is the Chattahoochee anticline. This broad flexure was first suggested
and named by Veatch (1911, p. 62-64). He observed local disturbances of
Cretaceous and Eocene beds along the Chattahoochee River and noticed
inequalities in the drainage divides of the Chattahoochee and Flint
rivers. Veatch reasoned that the shorter tributary streams of the much
larger Chattahoochee River were developed along the crest of an anti-
cline, whereas the longer tributaries of the Flint flowed down the eastern
flank of the anticline. His interpretation of the somewhat parallel courses
of the rivers was that the Chattahoochee flowed southward along the
crest of the anticline and that the Flint flowed down the trough of a
broad syncline complementary to this anticline.
Veatch noted that the much greater depth of the Chattahoochee valley
and steepness of the channel walls indicated a greater magnitude of
earth movement along the Chattahoochee than along the other rivers
in the region.
A press release issued by the Federal Survey in 1917 stated that the
available evidence was not adequate to substantiate this anticline.
Prettyman and Cave (1923, p. 107-111) did not believe that the
geological evidence indicated crustal folding of the magnitude implied


20






REPORT OF INVESTIGATIONS No. 16


by Veatch in his description of the Chattahoochee anticline. In their
opinion, it pointed only to gentle regional Pleistocene or later movement
with some local reversals in dips.
Stephenson (1928, p. 295) in a description of local flexures in the
coastal plain monocline, agreed that an anticline in this area existed, and
dated (1928a, p. 892) the movement that caused this crustal disturbance
as late Tertiary or early Quaternary.
In 1929 George I. Adams (p. 201-202) published a report on his
investigation of the streams of the coastal plain of Alabama in which he
stated he had examined the area of the Chattahoochee anticline and
did not believe the geological facts supported the existence of this
anticline.
Postley (1938, p. 809-810) presented a paper on the oil and gas
possibilities in the Atlantic Coastal Plain and included the Chattahoochee
anticline in his discussion on structure.
Leet (1940, p. 875) recognized the existence of the Chattahoochee
anticline and described it as a broad upwarp with its axis trending along
the Georgia-Alabama state line.
Cooke (1943, p. 4-5) explained the difference of the greater number
of exposed geological formations along the Chattahoochee River as com-
pared to the Ocmulgee and Savannah rivers as the result of progressive
overlay which indicated a progressive uplift of that part of the coastal
plain of Georgia.
An upwarp in the vicinity of Jackson County, Florida, was one of
several structural features in the subsurface of Florida and southern
Georgia described by Applin and Applin (1944, p. 1727).

The first deviation from the term Chattahoochee as a place-name for
the uplift seems to have been made by Pressler (1947, p. 1852, fig. 1).
He made no mention nor included any discussion of the upwarp in the
text of his article; however, he did use the name Decatur Arch for the
area of the uplift on the text figure which accompanied his article.

Applin (1951, p. 407) and Gunter (1953, p. 42, 48) continued the
use of the term Decatur Arch.

Jordan (1954) recognized the priority of the term Chattahoochee
and applied it in a discussion of the structure of the area. Toulmin (1955,
p. 209-210) used the term -Chattahoochee anticline in preference to
Decatur Arch.





FLORIDA GEOLOGICAL SURVEY


LINEAR TRENDS
Vernon (1951, p. 47) first recognized large scale fracturing in the
subsurface of Florida and mapped these fractures from their physio-
graphic expressions as shown on mosaics of aerial photographs. In Citrus
and Levy counties the regional fractures parallel the axis of the Ocala
uplift with a northwest-southeast trend. This system of fracturing is
crossed by a secondary system which trends in a northeast-southwest
direction. Vernon reports that stream patterns commonly parallel these
two systems of fracturing.
Rectangular stream patterns have been reported in Jackson County
by Moore (1955, p. 15-16). He stated that this pattern observed along the
Chipola River and D)ry Creek suggests a control by fracturing. He re-
ports a similar pattern in west central Jackson County of the creeks that
flow on alluvium 30 to 100 feet thick.
Examination of large scale prints made from aerial photographs of
the Jim Woodruff Dam area shows a linear relationship existing among
certain portions of the courses of the Flint and Chattahoochee rivers
(fig. 5). The scarcity of well and core hole samples prevented the
preparation of detailed geologic sections; the identification of fracturing


Figure 5. Map showing linear trends along the Chattahoochee and Flint rivers.






REPORT OF INVESTIGATIONS No. 16


in relation to such linear trends, without the aid of detailed geologic
sections, was impossible. However, the linear trends are closely similar
to trends associated with fracturing reported by Vernon and Moore.
There is a possibility that fracturing has resulted from the Chattahoochee
anticline, and that the linear trends in the Chattahoochee and Flint
rivers may be the result of fractures in the bedrock that extend through
the alluvium.
STRATIGRAPHY
INTRODUCTION
The surface formations in the area of the Jim Woodruff Dam reservoir
range in age from upper Eocene through Recent. The bedrock is com-
posed of the Crystal River formation, Jackson Stage, in the northern
part; the Oligocene, Suwannee limestone, in the central section; and the
Chattahoochee facies, Tampa Stage, in the southern part. The plastics
that mantle the bedrock in the northern and central parts are of Pleisto-
cene and Recent age and the plastic Hawthorn formation of the Alum
Bluff Stage, overlies the bedrock in the southern part of the area.
TERTIARY SYSTEM
EOCENE SERIES
JACKSON STAGE
OCALA GROUP
CRYSTAL RIVER FORMATION
Historical: The early history of the terms upper Eocene, Jackson
group and "Ocala limestone," has been adequately discussed by Vernon
(1942, p. 40-41) and Cooke (1945, p. 53). The Applins (1944, p. 1683-84)
separated the Ocala limestone in peninsular Florida into an upper and
lower member. Vernon (1951, p. 111-112) divided the Ocala limestone
into two formations, the "Ocala limestone" (restricted) for the upper
portion and the Moodys Branch formation for the lower portion. He
further subdivided the Moodys Branch formation into a lower Inglis
member and an upper Williston member.
Puri (1953, p. 130; 1957, p. 31) proposed the term Crystal River
formation to replace the term "Ocala limestone" (restricted) of Vernon.
He abandoned the name Moodys Branch formation of Vernon and raised
the Williston and Inglis members of the Moodys Branch to formational
rank.
Distribution: The oldest rocks cropping out in the area of this inves-
tigation are those of the Crystal River formation (fig. 6). The formation





FLORIDA GEOLOGICAL SURVEY


is exposed along the banks of the Chattahoochee and Flint rivers from
the northern boundary of the area to about the center of this region
where it dips under younger sediments. Completely silicified limestone,
occurring as boulders and possibly pinnacles throughout the northern
two-thirds of the area, contain Ocala fossils and, although the boulders
are incorporated in clastics ranging in age from Pleistocene to Recent,
they were probably derived from a former greater areal extension of
the Crystal River formation.
Lithology: The Crystal River formation is predominantly a white to
cream, soft to hard, porous to dense, crystalline, marine, generally friable,
coquinoid limestone composed chiefly of foraminifers, bryozoans and
mollusks. The formation has been locally replaced by silica to form a
white to reddish-brown, hard, moldic (porous) crystalline to occasionally
chalky, fossiliferous mass of chert with occasional zones of dense chert.
luring silicification the tests of the smaller microfauna were almost
entirely destroyed and those retained are rarely identifiable. The larger
microfossils are generally retained as molds and casts, and can usually
be identified generically, but seldom specifically.
Thickness and Structure: The complete thickness of the Crystal
River formation is not exposed in the area of this investigation. However,
in Jackson County, Florida, Puri (personal communication, 1955) reports
the Crystal River formation to be about 300 feet thick.
The top of the Crystal River formation as determined from exposures
and well cuttings in Decatur County, Georgia, and in extreme eastern
and southeastern Jackson County, Florida, indicates that the Crystal
River dips south-southeast at approximately 17 feet per mile.
Stratigraphic Relationship: In the northern half of the area, the
Crystal River formation is overlain unconformably by Pleistocene to
Recent clastics which contain silicified limestone rubble derived from
upper Eocene limestones. The elevation of the top of this formation
is very irregular due to solution and sinkhole activity. In the southern
portion of the area, the Crystal River formation is unconformably overlain
by the Oligocene, Suwannee limestone.
Geologic Exposures: Decatur County, Georgia. The best exposures
of the Crystal River formation along the Flint River are found from Bain-
bridge northward to High Bluff, about seven miles above Bainbridge.
The thickest section is found at High Bluff where 17 feet are exposed
(see Flint River traverse locality 4, p. 37, this report for description).
Seminole County, GeQrgia. The best and thickest exposure of the
Crystal River formation on the Chattahoochee River is found at.a bluff









KK K>\ >.,.t;~


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\" '\

\" '"'
\~\N'




,.\; ''"
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''N ~ ~
~ ''k"

~ \ \~. ~ yv449


FLORIDA GEOLOGICAL SURVEY


LAMBERTS


GEOLOGIC MAP


AS-251
0


+ +


W.1364
,q-0--


+ MIOCENE SERIES
49
Chattahoochee Facies
Hawthorn Facies


OLIGOCENE SERIES
Suwannee Limestone


EOCENE SERIES
Crystal River Formation


JIM WOODRUFF DAM


1 0 1 2 3 4 5

SScale in miles


REPORT OF INVESTIGATIONS NO. 16, PART I, FIGURE 6
"'.





N a
^ '"' 84 i



N\ \ iit






,:\, /,+ ,,> ,.. .,, .. +.. -,>. '., s \ S".* .,






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r


400-





REPORT OF INVESTIGATIONS No. 16


on the left bank of the river about 15 miles above the Jim Woodruff Dam,
where 15 feet are exposed (see Chattahoochee River traverse locality 32,
p. 42, this report for description).
In the J. R. Sealy, Seminole Naval Stores Company well no. 1
(W-37373), Land Lot 142, Land District 21, bedrock was encountered at
40 feet. These sediments represent the Crystal River formation and have
yielded Asterociclina species.
Based on the presence of Operculinoides ocalanus, the top of the
Crystal River formation was identified at a depth of 60 to 70 feet in the
Mont Warren, Grady Bell well no. 1A (W-2149), located 560 feet north
of the south line and 660 feet east of the west line of Land Lot 61, Land
District 27.
Decatur and Seminole counties, Georgia. Nowhere between the Flint
and the Chattahoochee rivers in Decatur and Seminole counties, did the
writers find an outcrop of the Crystal River formation. However, large
chert masses scattered throughout this area may possibly represent eroded
pinnacles of this formation (see post-Miocene section of this report), but
are more probably chert boulders derived by solution from limestone of
the Crystal River formation and incorporated in later sediments.
Jackson County, Florida. Some of the silicified boulders found in
the northeastern portion of Jackson County, were identified as upper
Eocene in age. However, in most cases, the fossil component of the rock
was not identifiable because of the poor state of preservation; therefore,
the age of the rock was not positively established.
Ten feet of Crystal River formation, overlain by five feet of Oligocene
limestone, is exposed in a sink in the south central part of sec. 14, T. 5 N.,
R. 9 W. (locality 38). An oil well test (W-3627) in the SE/ NE3 sec. 11,
T. 5 N., R. 8 W., penetrated, at a depth of 25 feet, limestone of the
Crystal River formation immediately beneath the clastic overburden.

OLIGOCENE SERIES
SUWANNEE LIMESTONE
Historical: Florida Geological Survey bulletins 21 and 29 are cited
.s references for excellent historical reviews of the use of the term
'Suwannee limestone."
Distribution: The Suwannee limestone underlies the southern half
)f the area. Locality 53 represents the only Suwannee limestone outcrop
.ound and, for this reason, the Suwannee was primarily mapped on the
3Florida Geological Survey well sample number.





FLORIDA GEOLOGICAL SURVEY


basis of subsurface information (fig. 6). The dip, as determined in wells,
was projected to intersect the ground surface and provide a means of
delimiting the formational boundary.
Lithology: The Suwannee limestone is a white to cream, granular,
crystalline, soft to hard, porous, frequently dolomitic, fossiliferous lime-
stone. Locally, the fossils are poorly preserved and are difficult to identify.
The formation has been eroded and segments of it remain as completely
silicified limestone boulders incorporated in terrace material (p. 86).
Thickness and Structure: A water well (W-.8442) drilled in south-
eastern Jackson County, Florida, in the SW)1 sec. 12, T. 3 N., R. 7 W.,
penetrated 120 feet of sediment that were assigned to the Suwannee lime-
stone. In the area above the confluence of the Chattahoochee and Flint
rivers, the top of the formation, as penetrated in auger holes, is very irreg-
ular (fig. 7). These auger holes did not pass through the complete thick-
ness of the Suwannee. The top has been eroded in this area and it is
believed the thickness is probably somewhat less than 120 feet.
The dip of the Suwannee limestone in the area of the Jim Woodruff
i)am reservoir trends south-southeast at approximately 25 feet per mile.
Stratigraphic Relationship: The Suwannee limestone lies uncon-
formably upon the Crystal River formation, and unconformably below
the younger Chattahoochee faces, or below younger plastics, where the
Chattahoochee has been removed by erosion. In the central portion of
the area the Suwannee is overlain unconformably by Pleistocene to
Recent river alluvium.
Geologic Exposures: Decatur County, Georgia. Twenty-three feet of
Suwannee limestone are exposed in the bank and in a gully on the
slope of the escarpment on the left side of the Flint River at Southlands
Ferry (locality 53).
On the right bank of the Flint River at Lamberts Island, silicified
limestone boulders of Suwannee age were found incorporated in Pleisto-
cene to Recent sediments.
Seminole County, Georgia. Along the right bank of Spring Creek at
locality 51, about two and one-half miles due south of Reynoldsville,
silicified limestone boulders, Suwannee age, were found embedded in
Pleistocene to Recent sediments.
About one mile east of the left bank of the Chattahoochee River and
four miles northwest of the Jim Woodruff Dam, a depth of 70 feet (+8')
was reached with an auger (AS-251) without penetrating bedrock. How-
ever, rock fragments, probably from a weathered limestone surface, were






































LOCATION MAP


EXPLANATION

Section A-A' drawn approxi-
mately parallel to dip of
Tertiary strata.


Section B-B' drawn approxi-
S mately parallel to strike of
Tertiary strata.


ISO


100


50


A






150







*4










*.I3 50


AND


SUWANNEE -..
CRYSTAL RIER FORMATION LISTONE
CRYSTAL RIVER FORMATION


t 0 I
HORIZONiAL SCALE M- MILES


Figure 7. Geologic sections drawn north to south and west to east
Woodruff reservoir.
I *


in area of Jim


- N
z z


I.


SUWANNEE


CRYSr4


RIVER


b~0


.1 1 0


LIMESro


F.R pmriot


1 2


HORIZONTAL SCALE IN MILES


L.--.--------


8'


LIMES1OHE


__


--


A'
as.


LOG


350


100


50


0


.30


.100


.100





REPORT OF INVESTIGATIONS No. 16


found in the samples which were identified as Suwannee limestone in
age by the presence of Rotalia mexicana.
Jackson County, Florida. At localities 39, 40, 41, 42 and 43, silicified
boulders were identified as Suwannee in age.

Gadsden County, Florida. The section described below was measured
in the powerhouse coffer dam excavation at the Jim Woodruff Dam site
(locality 54). The top of the section is at an elevation of +12 feet.
Between the top of this section and the bottom of the section measured
on the west side of the Apalachicola River there are 62.6 feet of section
that are covered.

Bed Description Thickness
(feet)
Miocene Series
Tampa Stage-Chattahoochee facies
5 Limestone, white to light cream, crystalline calcite, soft, chalky,
argillaceous, dendritic manganese in fractures. The middle two
feet of the bed are hard and the bottom two feet are very argil-
laceous and soft.......................................................................... 6.0
4 Limestone, light buff, chalky to very finely crystalline, hard to
soft, argillaceous, dense, slightly dolomitic, dendritic manga-
nese in fractures in the rock. Some isolated flakes of mica......... 4.0
Oligocene Series
Suwannee limestone-elevation +2 feet
3 Limestone, light buff, cryptocrystalline to very finely crystalline,
with more crystalline calcite than bed 2, hard, dendritic man-
ganese, dolomitic moldic porosity in part, dense in part. Kuphus
incrassatus. Upper two feet of bed has small pea-size voids
filled with soft green clay.................................... .................... 5.0
2 Limestone, cream to light buff, very finely crystalline with some
voids filled with crystalline calcite, dense, hard, dolomitic,
fossiliferous. Kuphus incrassatus .............................................. 4.0
1 Limestone, cream to light buff, finely crystalline, porous, hard,
dolomitic, fossiliferous, but microfossils indistinct. Kuphus
incrassatus ........................................................................................ 2.0

Total thickness .............................................................................................. 21.0
Base of section elevation -9 feet.
Near the contact the Chattahoochee is brecciated with masses of
clay and angular dolomitic boulders incorporated together. Some of these
basal boulders appear to have haloes of clay which grade into the
Suwannee limestone and may represent alteration of the limestone to
clay. At the top of the Suwannee limestone and extending into the





FLORIDA GEOLOGICAL SURVEY


Chattahoochee formation are green clay deposits occurring as lenses,
irregular masses, and vertical pipe fills. This green clay is not useful
for widespread correlation as its vertical distribution in the base of the
Tampa is perhaps as great as 30 feet, while its horizontal distribution
is sometimes only a few feet.

MIOCENE SERIES
TAMPA STAGE
CHATTAHOOCHEE FACIES
Historical: Puri (1953a, p. 17) revised the terminology of the Miocene
sediments in Panhandle Florida and included under his term Tampa
Stage those sediments previously assigned to the Tampa formation. For
a historical review of the Tampa formation the reader is referred to
Florida Geological Survey Bulletin 21, pages 67-68.
Puri recognized two distinct lithofacies within the Tampa Stage,
the downdip calcareous facies, called the St. Marks, and the updip silty
and clayey facies, for which he revived the term Chattahoochee. The
writers found no sediments within the area of this study that could be
assigned to the St. Marks facies; therefore, only those sediments of the
(Chattahoochee facies are discussed.
Distribution: The Chattahoochee facies forms a part of the Talla-
hassee Tertiary Highlands in the southern part of the area of this in-
vestigation and underlies the clastics of the Hawthorn formation (fig. 6).
The formation is exposed on the slopes of the bluffs trending along the
Chattahoochee, Flint and Apalachicola rivers, in valleys cut by tribu-
taries of the Flint River, and in sinkholes and road cuts.
Lithology: The Chattahoochee facies consists chiefly of lenses of
clay within a white to cream, very silty to sandy, chalky to crystalline,
soft to hard limestone, containing molluscan casts, several species of
Foraminifera and a burrowing mollusk similar to Kuphus incrassatus
Gabb, but generally smaller. Locally, at the base of the formation, is
found a tan, brown and cream, finely sucrosic, hard, sometimes argilla-
ceous and silty to sandy, usually dense, partially moldic dolomite. At
localities 44, 45, 47 and 55 the formation is a cream, slightly hard, sandy,
chalky, porous, finely crystalline, angular to slightly rounded limestone
pebbles in a cream, slightly hard, finely crystalline, very microfossiliferous
limestone. These two limestones exhibit the appearance of an intra-
formational conglomerate or, according to Tanner (1956, p. 309-311),
a beach rock, which appears to represent only transgressive-regressive
phases of the Tampa Stage.





REPORT OF INVESTIGATIONS No. 16


Thickness:.- The top of the Chattahoochee faces, determined by the
study of water well cuttings and outcrop samples, was found to be
eroded and irregular in elevation. This erosional surface accounts for
the variable thickness of the formation.
The thickness of the Chattahoochee sediments in well no. W-2254,
located in the SE, SEM sec. 28, T. 4 N., R. 7 W., Jackson County, is 30
feet. The excavation and escarpment at the Jim Woodruff Dam exposed
approximately 160 feet of Chattahoochee sediments. The top of the
Chattahoochee faces was encountered at an elevation of 192 feet in
an auger hole (AS-126) drilled on the east side of the town of Chatta-
hoochee, Gadsden County, Florida, in the SW, NE, sec. 33, T. 4 N.,
R. 6 W. This is the highest known point for the top of the formation in the
area. One-half mile south of this auger hole in the city of Chattahoochee
well (W-3482), located in the SW, SEX sec. 33, T. 4 N., R. 6 W., the
bottom of the Chattahoochee facies occurs at an elevation of -35 feet.
The cumulative thickness, 227 feet, between the top and bottom of
these two wells may more nearly represent the true thickness of the
Chattahoochee facies in this area.
Stratigraphic Relationship: The Chattahoochee facies was observed
to lie unconformably upon the Suwannee limestone in an excavation pit
at the site of the Jim Woodruff Dam powerhouse. Chattahoochee and
Suwannee sediments were observed in a gully near Southlands Ferry
(locality 53), but the contact between the two formations was obscured
in 22 feet of the section that was covered by slumped sediments.
Lithologic homogeneity of limestone beds 1 through 14, exposed at
the Jim Woodruff Dam section, influenced Puri (1953a, p. 20) to place
the upper limit of the Chattahoochee facies at the top of bed 14. He
also mentioned the possibility that the rubble bed (bed 7), may represent
a continental phase of the Alum Bluff Stage, probably the Chipola facies.
Later, on the basis of the well-developed unconformable contact between
beds 6 and 7, Puri and Vernon (1956, p. 56) placed the boundary between
the Chattahoochee and the Hawthorn facies at the top of bed 6.
In this report, the boundary between the Chattahoochee and Haw-
thorn sediments is moved back to the top of bed 14. Recognizing that
this boundary may only represent a lithologic and not a time break, this
procedure is followed because:
1. Sediments represented by beds 1 through 14 are similar limestones.
2. There is difficulty in establishing which of the several rubble beds occurring
in the section represent a major unconformity.
3. The rubble beds are not recognizable in well sections.
4. Rubble beds were not observed at other outcrops of the Chattahoochee facies
within the limits of this report.


29






30


FLORIDA GEOLOGICAL SURVEY


Geologic Exposures: Decatur County, Georgia. Fifty-two feet of
Chattahoochee sediments were found along an abandoned road on the
northeast-southwest trending escarpment on the left side of the Flint
River about eight and one-half miles by river above the Jim Woodruff
Dam (locality 48).

The following section was measured on the right bank of Sanborn
Creek, approximately one mile upstream from its junction with the Flint
River (locality 50):

Bed Description Thickness
(feet)
Miocene Series
Tampa Stage-Chattahoochee facies
5 Limestone, buff, soft but tough, argillaceous, silty, moldic. This
bed is exposed in a road 30 feet from creek bank.................... 1.0
4 Limestone, cream to tan, nodular, conglomeratic, very weath-
ered material, seemingly composed of chert boulders, indurated,
and green clay nodules.................................................................. 4.0
3 Very light olive green and cream to tan, silty to finely sandy,
argillaceous material, containing thin laminae running irregu-
larly through the bed. Probably originally horizontal with
slum ping, causing distortion.......................................................... 3.0
2 Limestone, gray to cream, hard, cryptocrystalline, questionably
silty, containing sparsely distributed coarse quartz sand............ 1.5
1 Cream to tan, silty to finely sandy, argillaceous, calcareous
material, weathered surface soft, nonweathered surface hard.... 3.0

T otal exposed .................................................................................................... 12.5

Jackson County, Florida. The following descriptions are of samples
taken from ledges of rock cropping out on the slope of the escarpment
in the SWM sec. 15, T. 4 N., R. 7 W. (locality 44):

Sample No. Description Elevation
(feet)
Miocene Series
Tampa Stage-Chattahoochee facies
2 Limestone, white to cream, soft, porous, argillaceous, silty to
finely sandy, chalky, with veinlets of crystalline calcite................ 124
3 Limestone, very light cream, slightly hard, porous, argillaceous,
silty to finely sandy, chalky to very finely crystalline, micro-
fossiliferous. Archaias floridanus, Sorites sp., Miliolids............ 116
4 Sam e as lim estone above................................................................ 113
5 Limestone, light cream, slightly hard, porous, silty to finely
sandy, chalky to finely crystalline, with green nodules of clay
that appear to be weathered from microfossils................................. 110
6 Limestone, cream, slightly hard, sandy, porous, chalky to finely
crystalline, occurring as angular to slightly rounded pebbles in
a cream, slightly hard, finely crystalline, very microfossiliferous,






REPORT OF INVESTIGATIONS No. 16


Sample No. Description Elevation
(feet)
porous, limestone. The rock displays the appearance of an
intraformational conglomerate or beach rock ......................... 100.5
7 Limestone, light cream, slightly hard, porous, silty to finely
sandy, moldic; this sample was taken from a boulder which had
probably moved down from above...............---------------------- 100
8 Same as sample 6......... ..... ....---------................. 89
9 Limestone, cream, hard, porous, finely sandy, finely crystalline,
m icrofossiliferous .............................................................................. 83
10 Sam e as sam ple 9......................................................................... 65

The thickest exposure of Chattahoochee sediments in the area of
this study is found in the following combined geologic sections in Decatur
County, Georgia, and Jackson County, Florida:
The Decatur County part is located on the access road to the earth
dike of the Jim Woodruff Dam, directly below the U. S. Engineers office
on the east side of the Apalachicola River. Measured in February, 1953,
by Robert 0. Vernon, C. W. Hendry, Jr., Harbans S. Puri, and J. William
Yon, Jr.
Bed Description Thickness
(feet)
Miocene Series
Alumn Bluff Stage-Hawthorn facies (deltaic)
21 Quartz sand; red, yellow and white, fine to coarse-grained,
poorly developed, graded bedding. Contains more quartz gravel
at the base than at the top. Topped by about five feet of deep
red soil profile which contains polished sandy, limonitic nodules,
some of which occur along a definite zone................................. 16.0
20 Quartz sand; mottled, light gray, purple and yellow, fine to
medium-grained, very argillaceous............................................. 6.5
19 C covered ......................................................................................... 29.0
Alum Bluff Stage-Hawthorn facies (marine)
18 Marl; variegated, cream and light gray. Contains fine-grained
quartz sand, abundant Pecten and oyster shells within the bed 1.0
17 Quartz sand; tan to light brownish-gray, medium to fine-
grained, argillaceous and becomes more argillaceous toward
the top.................................................... .............. ....... ............... 8.1
16 Clay; dark greenish-gray, blocky, silty and contains fine-
grained quartz sand..................................................................... 3.0
15 Siltstone; light greenish-gray, which contains bright, waxy, clay
nodules and hard, brown, crystalline, dolomitic limestone.
Oyster reef development within the bed.................................... 4.5
Section discontinuous-beds 14 to I measured about 40 yards to the west.
Tampa Stage-Chattahoochee facies
14 Limestone; tan, dolomitic, hard, cryptocrystalline, thinly bed-
ded, pasty........................................................................ ............... 6.0






32 FLORIDA GEOLOGICAL SURVEY

Bed Description Thickness
(feet)
13 Limestone; thinly bedded and interbedded with green, cal-
careous, silty clay......................................................................... 0.5
12 Limestone; light brownish-gray to cream, dolomitic, soft,
tough, blocky, and contains quartz sand................................. 1.5
11 Limestone; rubble of white, dolomitic, hard, pasty, with ir-
regular lenses of fossils within the bed. Top of bed has irregular
surface along which light green, crystalline calcite has been
developed (Diastem?) ---------- ...........-------.-----.-----------.............. 2.5
10 Limestone; light brownish-gray to cream, dolomitic, soft,
tough, blocky and contains quartz sand..................................... 4.5
9 Limestone; rubble of white, hard, pasty, with irregular lenses
of fossils within the bed. Top of bed has irregular sur-
face along which light green crystalline calcite has been de-
veloped. Bed lies irregularly upon bed 8 (Diastem?)............ 2.5
tains quartz sand; within the bed are irregular tunnels filled
with calcareous, harder, green sand and clay. Contains irreg-
ular lenses and nodules of the above sand and clay. Lenses and
nodules of crystalline calcite are present. Occurring at the top
of the bed is a layer of medium gray crystalline calcite about
eight inches thick. The Gastropod Ampulella is found within
the bed (D iastem ?) ..................................................................... 4.2
7 Limestone; rubble of white, dolomitic, hard, pasty, slightly
fossiliferous, somewhat nodular, intermixed with sand and
nodules of limestone. Possible Chipola equivalent..................... 2.8
NOTE: At the base of bed 7 and the top of bed 6 the contact between
the beds is wavy. There is a one-inch calcite enrichment which
may indicate that bed 7 overlies bed 6 unconformably. The Gas-
tropod Ampulella? was found along the contact between beds
7 and 8.
6 Limestone; white, pasty, silty, blocky, spherical weathering.
Top four inches harder............................................. .................... 0.8
5 Clay; light greenish-gray, containing thin seams and partings of
sand and silt. Also contains limestone nodules appearing
to be fossiliferous............................... ...................................... 0.8
.1 Limestone; very light brownish-gray, dolomitic, hard, and tough
where exposed. Contains numerous mollusk molds. Upper two
and one-half feet contain greenish-gray silt and light green clay
nodules which are fossiliferous. Weathers slightly harder than
bed 3.... ................................................ ......................... ....... 8.1
:3 Limestone; cream to white, soft, pasty. Contains quartz sand.
Numerous molds of Turritella sp. and other mollusks, Sorites
sp., and Archaias sp., are present in the bed. Blebs of green
clay are disseminated throughout.......................................... 2.0
2 Limestone; white to cream, dolomitic, pasty......................... 0.1
1 Clay; light brownish-gray, silty, calcareous, blebs of green clay
disseminated throughout. Gradually becomes more calcareous







REPORT QF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
and approaches a hard white marl near the top........................... 13.6

T total exposedl..........................................................................................................119.2
The base of bed 1 is at an elevation of 108.85 feet.
The Jackson County part is located west of Apalachicola River
Bridge on access road at the end of Victory Bridge NEMi sec. 31, T. 4 N.,
11. 6 W. The top of bed 7 is at an elevation of 118.0 feet. Elevation at the
top of spillway is 84.4 feet.
Bed Description Thickness
(feet)
Tampa Stage-Chattahoochee faces
7 Clay; blocky, waxy, greenish-gray................................................ 2.0
6 Limestone; cream to white, pasty, soft but tough, sandy, dolo-
mitic, containing irregular bodies of light green, calcitic sand
and a very indurated ledge in the center...................... 11.0
5 Clay; light tan, very slightly calcareous, blocky and grades
upward to a medium brownish-gray sandy, blocky clay.............. 2.5
4 Limestone; light tan to cream, soft but tough, dolomitic, very
fossiliferous, containing irregularities of gray silt and clay.
Abundant specimens of regular and irregular echinoids.
Ampulella and other mollusks within the bed. Irregular con-
cretions of sandy brown limestone are also present.......--..........------.. 4.0
3 Limestone; light gray, tan to cream, soft but tough, pasty,
dolomitic, containing greenish clay-filled borings and green ir-
regular masses of crystalline calcite................................................ 5.0
2 Clay; mottled, light greenish-gray to tan, very sandy, blocky,
containing dugong bones and irregular lenses of hard, appar-
ently crystalline clay........................................................................ 4.0
1 Limestone; light brownish-gray, soft but tough, pasty, honey-
combed, sandy, dolomitic, containing nodules, lenses, thin beds
and irregular veins of light gray to greenish waxy, silty, blocky,
clay. Kuphus sp. found in both the clay and limestone. The bed
is more nodular, less honeycombed and with fewer definitely
clay lenses near the top. This bed was apparently deposited as
a beach-rock rubble. There are remains of numerous boring
mollusks that lived in coral head of Siderastraea sp. although
there are few well-preserved heads of the coral. Ampulella
sp. is found throughout the bed. Five feet exposed here and an
additional 9.9 feet is present on the lake side of the dam......... 14.9

Total exposed-east and west sections............................................................ 162.6
At the time the powerhouse coffer dam excavation was open there
were exposed ten feet of Chattahoochee faces unconformably overlying
11 feet of Suwannee limestone (see geologic section under Suwannee
limestone, locality 54).


33






FLORIDA GEOLOGICAL SURVEY


ALUM BLUFF STAGE
HAWTHORN FACIES
Historical: The reader is referred to page 144 of the Florida Geo-
logical Survey Bulletin 29, for a historical review of the term Hawthorn.
Puri (1953a, p. 21) described the Hawthorn in the Florida Panhandle
as a lithofacies of the Alum Bluff Stage.
Distribution: The Hawthorn formation is present in the entire south-
crn portion of the area of this investigation (fig. 6). The eastern and
southern limits of the Hawthorn exceed those of this report. The most
northern extension of the Hawthorn sediments ends at the escarpment
facing the left bank of the Flint River in Decatur County, Georgia, and
its western limit is marked by the termination of the Tallahassee Tertiary
Highlands in Jackson County, Florida.
Lithology: The Hawthorn formation is a highly varied assemblage
of lenticular sand and clay beds that have only slight lateral persistence.
The Hawthorn sediments consist of sorted to nonsorted, coarse to fine-
grained, argillaceous, quartz sand, and rust-brown, gray-green, cream,
red and tan arenaceous clays, some of which are calcareous and contain
pelecypod shells. Irregularly distributed throughout these sediments
are small phosphorite grains of varying colors.
Thickness: The Hawthorn formation in the area of this investigation
has a variable thickness. In the area surrounding Sneads, Jackson Coun-
ty, Florida, and at Chattahoochee, Gadsden County, Florida, the Haw-
thorn formation is represented by approximately 70 feet of sediments. At
locality 56 near Georgia State Highway 97, southward to the intersection
of U.S. Highway 90, the writers measured 135 feet of Hawthorn deposits.
Near Faceville, Decatur County, Georgia, at locality 49, 48 feet of
sediments were assigned to the Hawthorn formation. Sixty-eight feet
of Hawthorn sediments are exposed at the Jim Woodruff Dam section
described on page 81.
Stratigraphic Relationship: The contact of the Hawthorn with the
underlying Chattahoochee facies is unconformable.
Geologic Exposures: The Hawthorn formation mantles almost the
entire area mapped as the Tallahassee Tertiary Highlands. Geologic
sections of formations can be seen in many places in the area along the
west-facing escarpment of the Flint and Apalachicola rivers, and around
Chattahoochee, Gadsden County, and Sneads, Jackson County, Florida.






REPORT OF INVESTIGATIONS No. 16


POST-MIOCENE STRATIGRAPHY
SILICIFIED LIMESTONE
Historical: Cooke (1929, p. 67) extended the name "Glendon lime-
stone" from Alabama to Florida to include limestone of Oligocene age
and what he felt were equivalent fossiliferous chert beds. Later, Cooke
(1935, p. 1170-71) proposed the name Flint River formation for the
fossiliferous chert beds in Florida, Georgia and southeastern Alabama,
and continued the name "Glendon" for Oligocene limestones. Both the
Glendon and Flint River formations were tentatively correlated with the
Chickasawhay limestone of Mississippi. Vernon (1942, p. 130-133)
presented evidence that these silicified boulders were enclosed in Pleis-
tocene alluvium. They represent silicified portions of Oligocene and
Eocene formations released during periods of valley cutting and incor-
porated in alluvium during later intervals of valley fill. Vernon did not
recognize Cooke's "Glendon limestone" or "Flint River formation" in the
counties west of the dam site. Cooke (1945, p. 104-107) again referred
the boulders to formational rank and extended the Flint River formation
to include beds of similar lithology in Florida, and mapped the formation
from Walton County, Florida, eastward to the Chattahoochee River and
across Georgia to Allendale, South Carolina.

MacNeil (1946, p. 64) stated that for the most part the materials in
the Flint River formation are of Miocene age which became intermixed
with limestone residue upon slumping into sinks during the process of
solution. He established the age of the chert in Georgia as middle and
upper Oligocene. Where the "Ocala limestone" has been dissolved, the
residuum of the Oligocene and "Ocala" cannot be separated (MacNeil,
1946, p. 64). MacNeil (1946, p. 64) further states that, "In view of these
findings, and because it is not the policy of the U. S. Geological Survey
to apply formation names to residuum, the name Flint River has been
abandoned and the heterogeneous beds to which it was applied are
designated the residuum of the Jackson, Oligocene, and Miocene,
undifferentiated."

Present Concept: In the area of this study Cooke's "Flint River
formation," is a heterogeneous mass of silicified limestone boulders of
upper Oligocene and possibly upper Eocene age. The boulders are
embedded in Pleistocene to Recent sands and clays and as Vernon and
MacNeil have stated should not be considered a single unit of deposition
as previously supposed by Cooke (1935, p. 1170-71). Seventeen auger
holes were drilled to determine if these boulders, some of which are 18
feet in diameter, were actually outcrops or merely boulders occurring at
!


35






FLORIDA GEOLOGICAL SURVEY


irregular horizons and haphazardly throughout a elastic matrix. The
evidence obtained from these holes show that the boulders indiscrimi-
nately lie 26 to 78 feet above bedrock (fig. 7).
These silicified deposits represent the remnants of a higher limestone
surface which probably became incorporated in the alluvium during
valley cutting and filling by the present major streams or their ancestral
equivalents.
The boulders occur most frequently along the Chattahoochee and
Flint rivers and Spring Creek. Recent degrading by the streams have
cut through the alluvium and have exposed the silicified limestone
boulders and concentrated them by downstream sapping and accumu-
lations in boulder bars at obstructions in the channel and along the inside
of bends in the streams, where velocity is least.
Geologic Exposures: Decatur County, Georgia. On the right bank of
the Flint River at Lamberts Island, silicified limestone boulders of
Suwannee age were found incorporated in Pleistocene to Recent sedi-
ments.
Seminole County, Georgia. Along the right bank of Spring Creek at
locality 51, about two and one-half miles due south of Reynoldsville,
Seminole County, Georgia, silicified limestone boulders, Suwannee age,
were found embedded in Pleistocene to Recent sediments.
Jackson County, Florida. At localities 89, 40, 41, 42 and 43, in Jack-
son County, Florida, silicified boulders occurring in Pleistocene to Recent
sediments, were identified as Suwannee age.

GEOLOGIC EXPOSURES ALONG CHATTAHOOCHEE
AND FLINT RIVERS
Traverse of a portion of the Flint River beginning at High Bluff,
approximately seven miles upstream from Bainbridge, Georgia, and
extending to the junction with the Chattahoochee River, approximately
one mile north of Chattahoochee, Florida:
December 1-2, 1953
R. 0. Vernon, C. W. Hendry, Jr. and J. W. Yon, Jr.
Bed Description Thickness
(feet)
Locality 1
Oligocene? and upper Eocene
Suwannee limestone? and Crystal River formation
Silicified limestone boulders, approximately 12x20 feet, ap-
parently not in place and restricting the channel in part.







REPORT OF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
Locality 2
Upper Eocene-Crystal River formation
Limestone, cream to tan, fragmental, granular, marine, porous,
soft, coquinoid. Very cavernous with horsebone weathering and
a tendency to laminate............................................................... 10.0
Locality 3
Post-Eocene
2 Sand, varicolored, medium to coarse-grained and contains clay
lenses, quartz gravel, silicified limestone boulders and a cal-
careous, clayey, sandstone which contains numerous molds of
mollusks and nodules of a more calcareous material............... 10.0
Upper Eocene-Crystal River formation
1 Limestone as found at locality 2.......................................... 15.5

T otal exposed............................................................. ......................................... 25.5
Locality 4
Post-Eocene
7 Sandy soil zone, tan to brown, weathered................................. 4.0
6 Clay, variegated, gray, tan, red, white, blocky, sandy, and
has a tendency to laminate......................................................... 7.8
5 Sand, variegated, gray, tan, red, white, blocky, clayey, very
fine-grained, and contains lenses of blocky clay of overlying
bed 6............................................................................................... 13.7
4 Slum p ............................................................................................. 17.2
3 Clay, light gray, very sandy, blocky............................................. 11.4
2 C covered .................................................................... .................. 9.4
Upper Eocene-Crystal River formation
1 Limestone as found at locality 2............................................... 17.0

T otal exposed.................................................................................................... 80.5
Locality 5
Upper Eocene-Crystal River formation
Pinnacles of limestone protruding through tan, fine-grained,
sandy alluvium .............................................................................. 10.0-12.0
Also ledges of limestone overlain by alluvium. Scattered boul-
ders of silicified limestone, approximately 6x8 feet. Further
downstream these boulders become more abundant in the
river bed.
Locality 6
Post-Eocene (flood-plain alluvium)
4 Sand, dark gray, with a thin sandy soil zone............................. 0.5
3 Sand, yellow to orange, very fine-grained, slightly clayey........ 4.0
2 Bed 3 grades downward into seven feet of thinly bedded,
orange, fine-grained sand, increasing in coarseness toward the
base and merges with a one to three foot zone of thinly bedded,
fine to coarse-grained sand containing numerous quartz pebbles
and large silicified boulders of Crystal River age. Very irregular
contact with bed below ............................................................... 1.0-7.0


37






38


FLORIDA GEOLOGICAL SURVEY


Bed Description Thickness
(feet)
1 Siltstone, light gray, very clayey, very sandy............................. 9.6

T otal exposedl.................................................................................................. 15.1-21.1
Between localities 6 and 7 is flood-pl"'n alluvium composed of fine-grained, light
yellow sand with scattered silicified l,. stone boulders.

Locality 7
Post-Eocene
2 Sand, orange, fine-grained............................................................8.0-14.0
1 Siltstone, light gray, very sandy, very clayey. Very irregular con-
tact with bed above..................................................................... 3.0-3.5

T total exposed .................................................................................................. 11.0-17.5
Just downstream from locality 7 are scattered boulders of silicified limestone, 6 to
8 feet in diameter in river bed.
Locality 8
Post-Eocene
Clay, gray, with incorporated silicified limestone boulders,
3x4 feet, lying on gray, sandy clay or siltstone........................... 5.0
Locality 9
Post-Focene (flood-plain alluvium)
2 Sand, poorly sorted, crossbedded, fine to coarse-grained, but
generally coarsest at base......................................................... 14.0
1 Clay, light gray, blocky, slightly silty.
Locality 10
Post-Eocene (flood-plain alluvium)
3 Sand, fine to coarse-grained, crossbedded and reworked clayey
alluvium ......................................................................................... 10.0
2 Clay, very silty and sandy, blocky, grading laterally into clay,
variegated, sandy, weathered and mottled................................. 9.8
Upper Eocene-Crystal River formation
1 Limestone, tan, fragmental, granular, marine, hard, fossil-
iferous. Crystalline on exposed surfaces and occurring as pin-
nacles protruding through Led 2............................................. 7.8

T otal exposed...................................................................................................... 27.6
Just downstream from locality 10 is ;s6edded, sandy alluvium overlain by five
feet of sandy, silty clay.
Locality 11
Silty clay overlaying gray clay and through which protrudes
several pinnacles of limestone (upper Eocene?). Several
large, 6x8 feet, boulders in river bed.
Locality 12
Upper Eocene-Crystal River formation
Limestone, tan to brown, fragmental, marine, very porous, soft,







REPORT OF INVESTIGATIONS No. 16


Bed


Description

loose, coquinoid. Abundant large foraminifers and Amusium
sp. .......... ... .......... ............ ........................ ......... ............ ................


Locality 13
Lim estone, recrystallized............... ................................................


Just downstream from locality 13 are largo Ibulders of recrystallized and
limestone incorporated in very loamy flood-plain deposits.
Locality 14
Post-Eocene (flood-plain alluvium)
2 Sand, fine to coarse-grained, crossbedded, slightly clayey, with
a gravel and boulder bed at base-.............................................-
1 Clay, gray, silty.................................... ............ ...................

T otal exposed.......................................................................................................
Locality 15
9 Soil zone.....................................................................................
8 Sand, yellow, fine-grained, oxidized and leached.....................
7 Sand, red, very fine-grained, slightly clayey, oxidized, but


not leached..................................................................................
Sand, dark brownish-gray, slightly clayey, very fine-grained
and contains a four-inch freshwater clam bed.. ------......................
Sand, brown, very fine-grained, slightly clayey...........................
C covered ............................................................... .......... ...............
Sand, tan, fine-grained, slightly clayey, crossed by laminae of
deep reddish-brown, very fine-grained moderately clayey sand
C covered ....................................................................................... ..
Sand, mottled tan, gray, brown, fine-grained, very clayey and
contains two eight-inch grit beds in the middle grading down-
ward into a more clayey material with similar characteristics
to top of bed ...................................................... ......... .................


Total exposed-................. .. ...-- .. ..- ...- ... .....-.. .........................--
Locality 16
Post-Eocene (flood-plain alluvium)
3 Clay, loamy, blocky, very sandy-......................... ................
2 Sand, light brown, slightly clayey" fine to coarse-grained, cross-
bedded and contains pea-size gravel and boulders of silicified
lim estone (see basal bed) ..............................................................
1 Clay, bluish-gray, blocky, silly grading laterally into light
grayish-green, very clayey silt. Wiiiee the bluish-gray clay forms
a ledge there is a cascade of boulders of quartz up to one foot
in diameter and silicified limestone of Crystal River, Suwannee
and possibly Tampa age lying oni the ledge and having fallen
from the light brown silty sand of bed 2......................................


Thickness
(feet)

8.0


T otal exposed........................................................................... ....................... 18.0
One-quarter mile downstream from locality 16 are low islands of silicified lime-
stone. River banks composed of eight feet of loams.


4.5
silicified




12.0
10.0

22.0

0.67
1.0

0.75

1.5
1.0
2.0

3.0
2.0



8.5

21.42


8.0


4.0





6.0






FLORIDA GEOLOGICAL SURVEY


Bed Description Thickness
(feet)
Further below locality 16-
Silt, greenish-gray, above which thick limonite has developed
containing numerous silicified boulders and overlain by 12
feet of sandy alluvium.
Locality 17
Silicifled boulders forming a jetty extending into river channel
and protecting the left bank.
Locality 18
Post-Eocene (flood-plain alluvium)
2 Sand, red, crossbedded, fine to coarse-grained, poorly sorted
with abundant boulders in base............................................ 10.0-14.0
1 C lay, gray ................................................................................... 3.0- 5.0

T otal exposed....................................... .. ...................................................... 13.0-19.0
Locality 19
Post-Eocene
Clay, gray. Collected to check fossil content. Contained one
small Cardium sp.
Locality 20
Post-Eocene (flood-plain alluvium)
2 Sand .......................................................................................... ..... 12.0
1 Clay. Very irregular contact between these two beds along
which are numerous limonite pebbles....................................... 8.0

T otal exposed................................................... .............................................. 20.0
Locality 21 (Southlands Ferry)
Oligocene Series-Suwannee limestone
Limestone, cream to tan, hard, crystalline, weathers cavernous.
Crops out at base of Hawthorn hill........................................... 8.0

Locality 22
Oligocene Series-Suwannee limestone
Limestone, cream to gray, hard, dense, finely crystalline, brec-
ciated texture and contains very rare fossils. This limestone
exposed in temporary road cut made by bulldozer part way
up hill................................................................................................ 5.0
C covered ......................................................................................... 17.0
This limestone exposed at small spring at base of hill............. 3.0

T otal exposed................................................................................................... 25.0

Locality 23
Post-Eocene (flood-plain alluvium)
2 Sand, reddish-brown, fine to very coarse-grained, crossbedded
with irregular lenses of grit and pea-size gravel covering pin-
nacles of greenish-gray, massive sand....................................... 21.4


40






REPORT OF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
1 Sand, light greenish-gray, massive, slightly clayey, micaceous,
jointed northeast-southwest........................................................... 5.8

T total exposed ...................................................................................................... 27.2
Locality 24
Oligocene Series-Suwannee limestone
Hill of limestone similar to lithology at locality 22.
Locality 25
Oligocene Series-Suwannee limestone
On right bank of river, several boulders of tan to cream, frag-
mental, marine limestone containing numerous echinoid frag-
ments and specimens of Lepidocyclina, Sorites, and Camerina.
Boulders are apparently dislodged by machinery used in clear-
ing Jim Woodruff reservoir area.

Traverse of a portion of the Chattahoochee River beginning at
Florida Highway 2-Georgia Highway 91 Bridge, and extending to
the junction with the Flint River, approximately one mile north of
Chattahoochee, Florida:
December 2-3, 1953
Locality 26
Post-Eocene
Sandy alluvium ............................................................................. 10.0
Clay, light greenish-gray, and purple, sandy, overlain by boul-
ders of limonite and silicified limestone............................. 5.0

T otal exposed................................................................................................ .... 15.0
Locality 27
Upper Eocene-Crystal River formation
Limestone, white to cream, fragmental, marine, porous, soft but
tough, very finely crystalline, coquinoid and contains numerous
mollusks mostly as molds. Olygopygus abundant-....--.------- 6.8
Locality 28
Two feet of limestone as at locality 27 cropping out overlain
by thin bed of limonite.
Two-thirds mile below locality 28, four feet of limestone as at locality 27.
Locality 29
Upper Eocene-Crystal River formation
2 Limestone, cream, granular, marine, dense, hard, cryptocrystal-
line to very finely crystalline And weathers extremely cavernous
and marked by a white, speckled, chalky, nodular material,
which may represent calcite dust from fossils............................. 3.0
1 Limestone, tan, fragmental, marine, soft, coquinoid. Olygopy-
gus sp...--------.................-----...........................- .... ... ..... .. 0.5

Total exposed.................................................................................................... 3.5






FLORIDA GEOLOGICAL SURVEY


Bed Description Thickness
(feet)
Locality 30
Upper Eocene-Crystal River formation
I Limestone, cream, fragmental, granular, marine, soft, weather-
ing hard, miliolid bed contains numerous Lepidocyclinas and
A m usium ocalanum ........................................ ............................... 1.9
3 Limestone of above bed and weathered into hard ledge con-
taining O lygopygus sp............................................................ ..... 1.6
2 Limestone of bed 3, but very soft, cream to tan, very porous
and extremely microfossiliferous................................................. 1.5
1 Limestone, cream, fragmental, marine, very hard, weathers cav-
ernous and contains specks of chalky nodules representing cal-
cite dust from weathered fossils. This bed similar to limestone
at locality 29.......................................................................... ...... 4.0

T total exposed .................................................................... ........................... 9 .0
Locality 31
Upper Eocene-Crystal River formation
Limestone, white to cream, marine, dense, moldic porosity,
cryptocrystalline to very finely crystalline, hard, microfossil-
iferous. Weathers cavernous and locally altered to green clay-- 5.5
Locality 32
UIpper Eocene-Crystal River formation
*2 Limestone, tan, fragmental, marine, coquinoid, contains abun-
dant Lepidocyclinas, Camerinas, Olygopygus sp., small fora-
minifers, mollusks, and echinoids, weathers red......................... 3.0
I Limestone, cream to tan, fragmental, hard, coquinoid, contains
small to large chalky nodules which are apparently calcite
dust derived from weathered fossils. This type of limestone is
apparently a subsequent product of the coquinoid limestone
of bed 2 and the bed when traced laterally to a fresh exposure
is the sam e as bed 2.................................................................. 12.0

T otal exposed .................................................... ...................................... ..... 15 .0
Upstream and adjacent to above described limestone are 10 feet of extremely variable,
massive, highly colored, purple, red, brown, gray, sandy clay and fine sand overlain
by 10 feet of sandy alluvium. This area appears to be disturbed.
Locality 33
Post-Eocene
Clay as described at locality 32.
Locality 34
Upper Eocene-Crystal River formation
Limestone, cream, marine, dense, hard, tough, fossiliferous.
Weathers cavernous and microcoquinoid in places---.-------..-....... 5.6
One hundred yards downstream from locality 34, mottled clay as at locality 32, and
limestone as at locality 34. Large limonite boulders 12 to 15 inches in diameter.






REPORT OF INVESTIGATIONS No. 16


Bed Description Thickness
(feet)
Scattered large boulders of limestone as bed 1, locality 32, and with fossiliferous,
porous zones throughout. Boulders appear to have recrystallized and almost prohibit
navigation because of abundance.
Locality 35
Post-Eocene
3 Sandy alluvium ........................................................................... 12.0-13.0
2 Sand and clay, variegated light greenish-gray, purple, red------9.0
1 Limestone, coquinoid, badly weathered and covered by consid-
erable amount of limonite.......................................................... 5.0

Total exposed ------------------------------------------.---.-- -----------....... .......---. 26.0-27.0
Just downstream from locality 35 are five feet of limonite.
Locality 36
Upper Eocene-Crystal River formation
Limestone, white to cream, fragmental, marine, very finely
crystalline, soft, weathers cavernous.......................................... 2.0
Locality 37
Upper Eocene-Crystal River formation
Limestone, cream to tan, fragmental, marine, very fossil-
iferous-composed largely of molds of mollusks and merges
laterally with light gray mottled reddish-brown sandy clays.
Limestone composed of boulders and possible pinnacles.


INSOLUBLE RESIDUE STUDY
INTRODUCTION
Lithologic examination of the cuttings and core samples of carbonate
rocks from wells in and near the area of this investigation indicated that
the lower part of the Chattahoochee facies and the upper part of the
Suwannee limestone have undergone secondary crystallization, thereby
destroying the characteristic lithologic appearance of the respective
formations and the diagnostic fossil content of the rock. The lack of
these criteria for differentiating between the formations makes it ex-
tremely difficult to determine the contact between these two units.
Because the identifying paleontologic and lithologic characteristics had
been destroyed, the writers felt that the determination of insoluble resi-
dues might assist in stratigraphic correlation. Three U. S. Corps of Engi-
neers core holes and 43 outcrop samples were selected to be used in the
experimental work. The three core holes, W-1562, W-1775 and W-1779,
are located in Jackson County, Florida, and range in depth from 126 feet
to 164 feet. The outcrop samples were collected at six discontinuous





FLORIDA GEOLOGICAL SURVEY


exposures along the east-west trending bluff, marking the northern
limit of the Tallahassee Tertiary Highlands at localities 45 and 54,
Jackson County, Florida, and localities 21, 46, 47 and 55, Decatur County,
Georgia (fig. 6).
PROCEDURE
Twenty-five gram portions were used from each outcrop sample
and from intervals of approximately two feet from the cores. These
samples were digested in dilute hydrochloric acid at room temperature.
The insoluble residues were filtered, thoroughly washed with water, dried,
and weighed.
The clay content of the insoluble residue was removed by flocculation.
The silt and sand-size material from two U.S. Corps of Engineers core
holes (W-1775 and W-1779) was treated with bromoform to separate
the heavy minerals from the quartz and mica. The writers felt that
because W-1775 and W-1779 were close together, they would depict
any similarities or dissimilarities and W-1562 would be used only to
verify or disprove any zonational sequences that might show up.
A binocular microscope was used in the examination of the nonheavy
minerals and a standard petrographic microscope was used for the
mineralogic determination of the heavy minerals. The close proximity of
W-1775 and W-1779 influenced the writers to use only these two for
preliminary comparison.
INSOLUBLE RESIDUE
ARENACEOUS MATERIAL
Quartz sand was present as a part of the insoluble residue in all of
the outcrop samples and in all of the core samples of W-1775, and in the
upper 85 and 87 feet of W-1779 and W-1562 respectively.
The detrital quartz grains ranged in size from silt to medium sand
with traces of coarse sand. Except for a few variations, the shape of the
detrital quartz grains was angular to subangular. Frosting of the
grains was absent or very slight in all of the samples examined.
SECONDARY SILICA
Silt-size to very fine sand-size aggregates of crystalline secondary
silica were found to exist in the lower 48 feet of W-1775, and also in
the lower 39 feet of W-1562.
SILICEOUS OOLITES
Texturally the oolites ranged from fine to medium sand-size, and
occurred either singularly or in clusters of three or more. .






REPORT OF INVESTIGATIONS No. 16


MUSCOVITE
Fine to very fine sand-size muscovite was present as a part of all
samples examined for insoluble material.
HEAVY MINERALS
The most common heavy minerals that existed as part of the residue
were:
1. Tourmaline 6. Monazite
2. Garnet 7. Staurolite
3. Kyanite 8. Ilmenite
4. Zircon 9. ?Hematite
5. Rutile 10. Leucoxene

CONCLUSION
This investigation has shown that insoluble residues do exist in the
sediments examined. Some of these insoluble constituents are useful in
establishing local correlation zones. In the following discussion the
overall value of the insoluble residues and insoluble residue zones is
analyzed in relation to their value for establishing the Miocene-Oligocene
boundary.
To help in visualizing graphically the range of the insolubles, the
percentages of the insoluble residues of the core holes were calculated
and plotted as the abscissa and the corresponding depths of the residue
samples as the ordinate (fig. 8). The conclusion reached from this part
of the experiment was that the upper part of the Chattahoochee formation
has zones which are high in insoluble material, but percentages of
insoluble residues gave no clue to the contact between the Chattahoochee
faces and the Suwannee limestone.
The Suwannee limestone sometimes contains detrital sands and a
detailed study was made of the detrital quartz grains to determine if the
characteristics of the quartz sand revealed any differences which could
be used in establishing the boundary between .the Suwannee limestone
and the Chattahoochee faces. All of the quartz sand present was
angular to subangular and usually clear. The grain size ranged from
silt to medium sand, with traces of coarse sand. The results of the
examination of the detrital quartz grains indicated that if any apparent
differences existed, they were insignificant and could not be used in
determining the Miocene and Oligocene contact.
The aggregates of secondary crystalline quartz found in W-1562 and
W-1779 occurred in a very badly leached foraminiferal coquina, some


45






FLORIDA GEOLOGICAL SURVEY


go- .


20 .







PERCENTAGE OF INDIGESTIBLE RESIDUE

Figure 8. Diagrammatic representation of insoluble residue from three sampled
wells. Percentages shown refer to insoluble residues.


of which were identified as Oligocene forms. By determining the ele-
vation of the crystalline quartz, it was found that in both core holes,
the elevations of the aggregates were practically the same. In the opinion
of the writers, this zone is not the top of the Suwannee sediments even
though the fossils indicate that it is Oligocene in age, but only a probable
correlative zone within the Suwannee limestone.

The siliceous oolites proved to be of no help in separating the Chatta-
hoochee and Suwannee formations because of their occurrence at
irregular depths in only one well, W-1562, and because of their spasmodic
appearance in the outcrop formations of locality 47.

The quantity of the mica was in most cases very small and not a
useful criterion for establishing the bottom of the Chattahoochee facies
and the top of the Suwannee limestone.

Heavy minerals from the core samples of W-1775 and W-1779 were
mounted and identified. After computing and plotting the frequency
percentages of the individual mineral species against the respective
depths at which they occurred, no trends or suites appeared to be
present which could be used in determining the contact between the
Chattahoochee and the Suwannee formations.


46






REPORT OF INVESTIGATIONS No. 16


LOCALITIES

Listed below are the locations of all outcrops, well and auger hole
samples used in the preparation of this report. All locations of outcrop
samples are listed chronologically; references to locations contained in
the text are indicated by the index number which precedes each entry.
Florida Geological Survey accession numbers precede all well and
auger hole locations.


OUTCROP SAMPLES

1. Crystal River formation. Right bank of Flint River, approximately one mile
upstream from locality 4, Decatur County, Georgia.
2. Crystal River formation. Left bank of Flint River, 50 yards downstream from
locality 1, Decatur County, Georgia.
3. Post-Eocene. Left bank of Flint River, approximately one-half mile upstream
from locality 4, Decatur County, Georgia.
4. Post-Eocene. Right bank of Flint River (High Bluff), center of L. L. 263,
L. D. 15, Decatur County, Georgia.
5. Crystal River formation. Right bank of Flint River, SW,1 L. L. 264, L. D. 15,
Decatur County, Georgia.
6. Post-Eocene. Left bank of Flint River, SEX L. L. 214, L. D. 15, Decatur
County, Georgia.
7. Post-Eocene. Right bank of Flint River, W/2 L. L. 291, L. D. 15, Decatur
County, Georgia.
8. Post-Eocene. Right bank of Flint River, NW,4 L. L. 292, L. D. 15, Decatur
County, Georgia.
9. Post-Eocene. Left bank of Flint River, SE/4 L. L. 217, L. D. 15, Decatur
County, Georgia.
10. Crystal River formation. Left bank of Flint River, NW,4 L. L. 219, L. D. 15,
Decatur County, Georgia.
11. Crystal River formation. Left bank of Flint River, NW,1 L. L. 223, L. D. 15,
Decatur County, Georgia.
12. Crystal River formation. Right bank of Flint River, NE?3 L. L. 331, L. D. 15,
Decatur County, Georgia.
13. Crystal River formation. Right bank of Flint River, NE), L. L. 332, L. D. 15;
Decatur County, Georgia.
14. Post-Eocene. Right bank of Flint River, SE,1 L. L. 873, L. D. 15, Decatur
County, Georgia.
15. Post-Eocene. Left bank of Flint River, SE,4 L. L. 359, L. D. 20, Decatur
County, Georgia.
16. Post-Eocene. Right bank of Flint River, SWi L. L. 394, L. D. 20, Decatur
County, Georgia.
17. Suwannee? limestone. Left bank of Flint River, SE1, L. L. 250, L. D. 21,
Decatur County, Georgia.
18. Post-Eocene. Left bank of Flint River, SW., L. L. 250, L. D. 21, Decatur
County, Georgia.
19. Post-Eocene. Left bank of Flint River, NEi L. L. 257, L. D. 21, Decatur
County, Georgia.






FLORIDA GEOLOGICAL SURVEY


20. Post-Eocene. Right bank of Flint River, SW% L. L. 262, L. D. 21, Decatur
County, Georgia.
21. Oligocene. Left bank of Flint River, SW)4 L. L. 262, L. D. 21, Decatur
County, Georgia.
22. Oligocene. Left bank of Flint River, NEA4 L. L. 267, L. D. 21, Decatur
County, Georgia.
2:1. Post-Eocene. Right bank of Flint River, SE3 L. L. 203, L. D. 21, Decatur
County, Georgia.
21. Oligocene. Left bank of Flint River, NE%3 L. L. 301, L. D. 21, Decatur
County, Georgia.
25. Oligocene. Right bank of Flint River, SWM L. L. 240, L. D. 21, Decatur
County, Georgia.
26. Post-Eocene. Right bank of Chattahoochee River, SWN3 sec. 26, T. 7 N., R. 8 W.,
Jackson County, Florida.
27. Crystal River formation. Right bank of Chattahoochee River, SE4 sec. 26,
T. 7 N., R. 8 W., Jackson County, Florida.
28. Crystal River formation. Left bank of Chattahoochee River, SE14 L. L. 332,
I,. D. 14, Seminole County, Georgia.
29. Crystal River formation. Left bank of Chattahoochee River, NE, L. L. 328,
L. D. 14, Seminole County, Georgia.
30. Crystal River formation. Left bank of Chattahoochee River, SWV4 L. L. 326,
I,. D. 14, Seminole County, Georgia.
:31. Crystal River formation. Right bank of Chattahoochee River, SWX see. 28,
T. 6 N., R. 7 W., Jackson County, Florida.
32. Crystal River formation. Left bank of Chattahoochee River, NWXi L. L. 242,
L. D. 14, Seminole County, Georgia.
33. Post-Eocene. Right bank of Chattahoochee River, NWV'4 sec. 4, T. 5 N., R. 7 W.,
Jackson County, Florida.
34. Crystal River formation. Left bank of Chattahoochee River, SEA L. L. 244,
i,. D. 14, Seminole County, Georgia.
35. Post-Eocene. Left bank of Chattahoochee River, NW) L. L. 196, L. D. 14,
Seminole County, Georgia.
36. Crystal River formation. Right bank of Chattahoochee River, SE04 sec. 21,
T. 5 N., R. 7 W., Jackson County, Florida.
37. Crystal River formation. Right bank of Chatthoochee River, SE34 sec. 10,
T. 4 N., R. 7 W., Jackson County, Florida.
38. Suwannee limestone. Small sink in south central part of sec. 14, T. 5 N.,
R. 9 W., Jackson County, Florida.
39. Suwannee limestone. Residual boulder in small depression in SE/4 sec. 14,
T. 5 N., R. 9 W., Jackson County, Florida.
40. Suwannee limestone. Pinnacles and/or boulders cropping out in edge of
field, SWM sec. 15, T. 5 N., R. 8 W., Jackson County, Florida.
41. Suwannee limestone. Pinnacles and/or boulders exposed in side of hill on
right bank of Chattahoochee River, NW\}4 sec. 21, T. 5 N., R. 7 W., Jackson
County, Florida.
42. Suwannec limestone. Pinnacles and/or boulders cropping out along rim of
shallow depression, SW corner NEi. sec. 18, T. 5 N., R. 7 W., Jackson County,
Florida.
43. Suwannee limestone. Residual boulders scattered around rim of depression,
SE corner, SW)4 sec. 18, T. 5 N., R. 7 W., Jackson County, Florida.


48







REPORT OF INVESTIGATIONS No. 16


44. Chattahoochee facies. Ledges of rock exposed along bluff, SE corner, NEI
sec. 16, T. 4 N., R. 7 W., Jackson County, Florida.
45. Chattahoochee facies. Residual boulders and ledges of rock exposed along
bluff, SWX sec. 15, T. 4 N., R. 7 W., Jackson County, Florida.
46. Chattahoochee facies. Pinnacles and/or boulders exposed along bluff, SW%
L. L. 336, L. D. 21, Decatur County, Georgia.
47. Chattahoochee facies. Pinnacles and/or boulders exposed along bluff, SEX
L. L. 299, L. D. 21, Decatur County, Georgia.
48. Chattahoochee facies. Exposed along bluff, NEM L. L. 302, L. D. 21, De-
catur County, Georgia.
49. Chattahoochee faces. Exposed along both banks of small creek, SE,4 L. L.
284, L. D. 21, Decatur County, Georgia.
50. Chattahoochee facies. Exposed along right bank of Sanborn Creek, SE corner
SW% L. L. 265, L. D. 21, Decatur County, Georgia.
51. Crystal River formation. Ledges and boulders exposed along right bank of
Spring Creek, center L. L. 131, L. D. 21, Seminole County, Georgia.
52. Suwannee limestone. Exposed along right bank of Flint River and on
island in river, SW% L. L. 258, L. D. 21, Decatur County, Georgia.
53. Suwannee limestone overlain by Chattahoochee facies in small gully along left
bank of Flint River, SW,4 L. L. 262, L. D. 21, Decatur County, Georgia.
54. Suwannee limestone overlain by Chattahoochee facies in powerhouse excava-
tion, Jim Woodruff dam, SWX sec. 29, T. 4 N., R. 6 W., Gadsden County, Florida.
55. Chattahoochee facies. Exposed along left bank of Sanborn Creek, SWA L. L.
265, L. D. 21, Decatur County, Georgia.
56. Hawthorn facies. Exposed along road cut on Florida 269A-Georgia 97, L. L.
429, L. D. 21, Decatur County, Georgia, Gadsden County, Florida.

AUGER HOLES

AS-126 SW,4 NE,4 sec. 33, T. 4 N., R. 6 W., Gadsden County, Florida.
AS-238 SW, sec. 16, T. 4 N., R. 7 W., Jackson County, Florida.
AS-239 SW)i sec. 9, T. 4 N., R. 7 W., Jackson County, Florida.
AS-240 SE corner sec. 5, T. 4 N., R. 7 W., Jackson County, Florida.
AS-241 NW,% sec. 5, T. 4 N., R. 7 W., Jackson County, Florida.
AS-242 SE, sec. 29, T. 5 N., R. 7 W., Jackson County, Florida.
AS-243 NEX sec. 7, T. 5 N., R. 7 W., Jackson County, Florida.
AS-244 NW corner NEI SWX sec. 13, T. 6 N., R. 8 W., Jackson County, Florida.
AS-245 NE?4 NEX sec. 34, T. 7 N., R. 8 W., Jackson County, Florida.
AS-246 SEI, L. L. 11, L. D. 21, Seminole County, Georgia.
AS-247 NW%, L. L. 130, L. D. 21, Seminole County, Georgia.
AS-248 SW, L. L. 212, L. D. 21, Seminole County, Georgia.
AS-249 NEI L. L. 101, L. D. 21, Seminole County, Georgia.
AS-250 SWV L. L. 206, L. D. 21, Decatur County, Georgia.
AS-251 NWX L. L. 118, L. D. 14, Seminole County, Georgia.

WELLS

W-1364 NE, SW, sec. 8, T. 4 N., R. 8 W., Jackson County, Florida.
W-1562 SE3, SW,4 sec. 30, T. 4 N., R. 6 W., Jackson County, Florida.
W-1775 SE,4 SE3, NE34 sec. 28, T. 4 N., R. 7 W., Jackson County, Florida.
f.






FLORIDA GEOLOGICAL SURVEY


1944 (and Applin, E. R.) Regional subsurface stratigraphy and structure of
Florida and southern Georgia: Am. Assoc. Petroleum Geologists Bull.,
vol. 28, no. 12, p. 1673-1753.
1951 Possible future petroleum provinces of North America, Symposium: Am.
Assoc. Petroleum Geologists Bull., vol. 35, no. 2, p. 407.
Calver, James L. (see Gunter)
Cave, H. S. (see Prettyman)
Cooke, C. Wythe
1929 (and Mossom, Stuart) Geology of Florida: Florida Geol. Survey 20th Ann.
Rept., p. 67.
1935 Notes on Vicksburg group: Am. Assoc. Petroleum Geologists Bull., vol.
19, no. 8, p. 1162-72.
1939 Scenery of Florida interpreted by a geologist: Florida Geol. Survey Bull.
17, p. 14-21, 25.
1943 Geology of the coastal plain of Georgia: U. S. Geol. Survey Bull. 941,
p. 4, 5.
1945 Geology of Florida: Florida Geol. Survey Bull. 29, 339 p.
Fenneman, Nevin M.
1938 Physiography of eastern United States: McGraw-Hill Publ. Co., Inc.,
New York and London, p. 65-68, 76, 77.
Fisk, H. N.
1938 GeologU of Grant and LaSalle parishes: Louisiana Dent. Cons. Geonl.


CI, .- .. .. .... .
Bull. 10, p. 13-75.
1938a Pleistocene exposures in western Florida parishes, Louisiana: Louisiana
Geol. Survey Bull. 12, p. 3-25.
1939 Depositional terrace slopes in Louisiana: Jour. Geomorphology, vol. 2, p.
181-200.
1940 Geology of Avoyelles and Rapides parishes: Louisiana Geol. Survey Bull.
18, p. 17-116.
Gunter, Herman
1953 (and Vernon, R. 0., and Calver, J. L.) Interpretation of Florida geology:
Georgia Geol. Survey Bull. 60, p. 40-48.


0


W-1779 SE)X SW% sec. 30, T. 4 N., R. 6 W., Jackson County, Florida.
W-2149 L. L. 61, L. D. 27, Seminole County, Georgia.
W-2247 NWMI NE% sec. 12, T. 3 N., R. 7 W., Jackson County, Florida.
W-2254 SE)4 SEJ sec. 28, T. 4 N., R. 7 W., Jackson County, Florida.
W-2306 SE%4 sec. 17, T. 4 N., R. 7 W., Jackson County, Florida.
\V-3442 SWV sec. 12, T. 3 N., R. 7 W., Jackson County, Florida.
W-3482 SW% SEMI sec. 33, T. 4 N., R. 6 W., Gadsden County, Florida.
W-3627 SE% NE34 sec. 11, T. 5 N., R. 8 W., Jackson County, Florida.
W-3737 L. L. 142, L. D. 21, Seminole County, Georgia.



SELECTED BIBLIOGRAPHY

Adams, George I.
1929 The streams of the coastal plain of Alabama and the Lafayette problem:
Jour. Geology, vol. 37, no. 3, p. 193-203.
Applin, E. R. (see Applin, Paul, 1944)
Applin, Paul






REPORT OF INVESTIGATIONS No. 16


Ireland, H. A.
1947 (and others) Terminology for insoluble residues: Am. Assoc. Petroleum
Geologists Bull., vol. 31, p. 1479-1490.
Hamblin, Ralph H. (see Sloss)
Jordan, Louise
1954 A critical appraisal of oil possibilities in Florida: Oil and Gas Journal,
Nov. 15, 1954, p. 370-375.
Leet, L. D.
1940 Status of geological and geophysical investigations on the Atlantic and
Gulf coastal plain: Geol. Soc. America Bull., vol. 51, p. 873-886.
MacNeil, F. Steams
1946 Southeastern Alabama: Fourth Field Trip Guidebook, Southeastern Geol.
Society, Tallahassee, Florida, p. 64.
Moore, Wayne E.
1955 Geology of Jackson County, Florida: Florida Geol. Survey Bull. 37, 101 p.
Mossom, Stuart (see Cooke, 1929)
Postley, 0. C.
1938 Oil and gas possibilities in Atlantic coastal plain from New Jersey to
Florida: Am. Assoc. Petroleum Geologists Bull., vol. 22, no. 7, p. 799-815.
Pressler, E. D.
1947 Geology and occurrence of oil in Florida: Am. Assoc. Petroleum Geologists
Bull., vol. 31, no. 10, p. 1851-1862.
Prettyman, T. M.
1923 (and Cave, H. S.) Petroleum and natural gas possibilities in Georgia:
Georgia Geol. Survey Bull. 40, p. 107-111.
Puri, Harbans S.
1953 Zonation of the Ocala group in peninsular Florida (abstract): Jour.
Sedimentary Petrology, vol. 23, p. 130.
1953a Contribution to the study of the Miocene of the Florida Panhandle:
Florida Geol. Survey Bull. 36, p. 15-57.
1956 (and Vernon, R. 0.) A summary of the geology of Florida with empha-
sis on the Miocene deposits, and a guidebook to the Miocene exposures:
Guidebook prepared for the Gulf Coast Section, Society of Economic
Paleontologists and Mineralogists, p. 56.
1957 Stratigraphy and zonation of the Ocala group: Florida Geol. Survey
Bull. 38, p. 31.
Russell, Richard J.
1938 Physiography of Iberville and Ascension parishes, in reports on the
geology of Iberville and Ascension parishes: Louisiana Geol. Survey
Bull. 13, p. 3-86.
Sloss, Laurence L.
1942 (and Hamblin, Ralph H.) Stratigraphy and insoluble residues of Madison
group (Mississippian) of Montana: Am. Assoc. Petroleum Geologists Bull.,
vol. 26, p. 305-335.
Stephenson, L. W. (also see Veatch)
1928 Major marine transgressions and regressions and structural features of
the Gulf coastal plain: Am. Jour. Sci., vol. 16, no. 94, p. 281-298.
1928a Structural features of the Atlantic and Gulf coastal plain: Geol. Soc.
America Bull., vol. 39, no. 4, p. 887-900.






FLORIDA GEOLOGICAL SURVEY


Tanner, William F.
1956 Examples of probable lithified beachrock: Jour. Sedimentary Petrology,
vol. 26, no. 4, p. 307-312.
Toulmin, L. D.
1955 Cenozoic geology of southeastern Alabama, Florida and Georgia: Am.
Assoc. Petroleum Geologists Bull., vol. 39, no. 2, p. 207-235.
U. S. Army Corps of Engineers (Mobile District, South Atlantic Division)
1953 Jim Woodruff Lock and Dam Project, Apalachicola River, Florida: In-
formation folder.
U. S. Geological Survey (author unknown)
1917 Exploration for oil in southern Georgia: Press release dated July 30, 1917.
Veatch, Otto
1911 (and Stephenson, L. W.)Preliminary report on the geology of the coastal
plain of Georgia: Georgia Geol. Survey Bull. 26, p. 30-31, 62-64.
Vernon, Robert 0. (also see Gunter; Puri, 1956)
1942 Geology of Holmes and Washington counties, Florida: Florida Geol.
Survey Bull. 21, 151 p.
1951 Geology of Citrus and Levy counties, Florida: Florida Geol. Survey
Bull. 33, p. 14-16, 47.


52











Part II



PHOSPHATE CONCENTRATIONS NEAR

BIRD ROOKERIES IN

SOUTH FLORIDA






By
Ernest H. Lund
Associate Professor, Department of Geology
Florida State University







Prepared for the
Florida Geological Survey







Tallahassee, Florida
1958





53













TABLE OF CONTENTS
Page
Abstract ................................................... ....... 57
Acknowledgm ents ..................................................... 57
Introduction .......................................................... 57
Sampled localities ...... .................. .............. ....... 60
Green Key Rookery ................................................ 60
D uck Rock ....................................................... 60
East River Rookery ............................................... 61
Cuthbert Lake Rookery ........................................... 62
Summary and conclusions .............................................. 64
References ........................................................... 64






ILLUSTRATIONS
Figure
1 Index map of sampled localities ................................... 59



Table
1 Analyses of samples from Green Key vicinity ........... ............. 65
2 Analyses of samples from Duck Rock vicinity ....................... 65
3 Analyses of samples from East River ............................. 66
4 Analyses of samples from Cuthbert Lake ............................ 66
5 Analyses of samples from miscellaneous localities ..................... 67






Part II


PHOSPHATE CONCENTRATIONS NEAR BIRD
ROOKERIES IN SOUTH FLORIDA

ABSTRACT
Sediments collected from the vicinity of four bird rookeries along
the coast of southwest Florida were analyzed for their P205 content
to determine the effect of a colony of large birds on the concentration
of phosphate in the sediments near the rookeries. Samples were also
taken from localities away from areas of dense bird population for
comparison. In three of the sample rookery localities the amount of
P205 was not significantly higher than in other nearby areas. In the
fourth, the Cuthbert Lake rookery, dried sediments contain up to 24.55
percent P205. Samples of material near the edges of Cuthbert Lake
contain less than one percent down to a trace. The comparison indicates
that the bird colony has appreciably increased the phosphate content
of the sedimentary material in the near vicinity of the rookery, but the
effects are very local.
ACKNOWLEDGMENTS
The writer is indebted to Herman Gunter, Director, and R. 0. Vernon
of the Florida Geological Survey for assistance with the field work and to
J. J. Taylor, State Chemist, for the analyses. The cooperation of Daniel
Beard, Superintendent of Everglades National Park, and other members
of the park staff in getting to localities in the park is greatly appreciated.
The writer is equally grateful for help given by Wardens Hank Bennett
and Fred Schultz in sampling at rookeries protected by the Audubon
Society.
INTRODUCTION
The numerous guano deposits on islands off the coast of South
America, in the south and mid-Pacific, and in a number of other places
demonstrate the ability of a large bird population to concentrate large
amounts of phosphate in comparatively small areas. The Guanape
Islands, latitude 834'S, longitude 78056'W, off the coast of Peru, had
a total estimated reserve of 1,300,000 tons of guano with P205 content
of 12.75 percent (Hutchinson, p. 30). This quantity of guano had accumu-
lated principally on two islands, North Island which is 1050 meters long
and 700 meters wide and South Island which is 690 meters long and
570 meters wide.
A number of Pacific atolls have larger deposits of phosphate related
57





FLORIDA GEOLOGICAL SURVEY


to a more remote period of bird activity. Ocean Island and Nauru afford
good examples of this type. Both of these islands are in the equatorial
Pacific and lie within 1S of the equator and between longitude 1760E
and longitude 1700E. Neither has a guano-producing bird population
at the present time. Ocean Island which is 2780 meters long and 2200
meters wide had an initial reserve estimated by Ellis (Hutchinson, p. 217)
at 20,000,000 tons. Three analyses of this phosphate give a mean P205
content of 40.51 percent. Nauru, 6 kilometers long and 4.7 kilometers
wide had an even larger reserve estimated by the British Phosphate
Commissioners at 87,500,000 tons, with a mean P20, content of about
39 percent. Much of the phosphate of Ocean and Nauru islands consists
of phosphatized coral rock and limestone debris.
Though limestone is the most favorable rock for phosphate replace-
ment, there are numerous examples of other rock types that have been
phosphatized. Echel and Milton (1953, p. 437-446) describe a deposit
of phosphate which they believe was formed by the influence of guano
on felsite. Chemical analyses by Teall (Hutchinson, p. 198) of trachyte
from Clipperton Island in the East Pacific show replacement by phos-
phate with a highly altered specimen of the rock containing 38.5 percent
P2O:,. Basalt on Necker Island, one of the Hawaiian Leeward Islands,
is considerably replaced by phosphate according to Elscher (Hutchinson,
p. 203). None of the deposits of phosphate resulting from replacement
of rocks other than limestone appears to be commercially important.
The present study is concerned with the influence of a large bird
population on the phosphate content of sediments adjacent to the areas
of bird concentration. Bird rookeries and roosts on small mangrove
islands along the southwest coast of Florida are suitable for this sort
of study, because there is a periodic removal of the bird droppings by
rain and high tides. Accumulations such as those found on the many
guano islands are not possible, and the material becomes available for
distribution by wave and current action. The amount of droppings is
large and highly localized in most cases, for as many as 80,000 large
wading and swimming birds may be concentrated on a mangrove key
no larger than five or six acres. Mills (1944) estimates that about 50 tons
are added to the waters of Tampa Bay every 24 hours by the several
rookeries and roosts located there.
Sampling was done with a cylindrical scoop of about one-quart
capacity mounted on a stem of one-half inch pipe. This method of
sampling recovered only surficial material, and all samples were taken
where the water was less than 10 feet deep. Where sampling was done
in the vicinity of a mangrove key, samples were taken at the edge of the


58






REPORT OF INVESTIGATIONS No. 16


Key West ,XBohio Hondao Key


Figure 1. Index map of sampled localities.
mangrove and outward at predetermined intervals of 15 feet up to 300
feet. Lines of samples were taken in all directions from the key. At the
East River (fig. 1) locality samples were taken from the channels between


_ I ____


59





FLORIDA GEOLOGICAL SURVEY


the mangrove islands. As a basis for comparison some samples were taken
from a short distance above and below the rookery.

SAMPLED LOCALITIES
GREEN KEY ROOKERY
Green Key (fig. 1) is a mangrove island of about six acres located
about 10 miles south of Tampa on the east side of Tampa Bay. The
island has been the site of a bird rookery since about 1921 and has been
under the protection of the Audubon Society since 1934. It is mainly
a nesting place for herons, ibis, pelicans, and cormorants and is used
by a small number of birds as a roost after the nesting period. According
to Mills the population of the colony has grown from 700 to 50,000
iiunder the Audubon Society's protection.
The sediment in the vicinity of Green Key is predominantly quartz
sand with varying amounts of silt and clay-size material. The amount
of fine material diminishes away from the island. Six samples (table 1)
have P..O., content, based on dry sample, ranging from 0.18 percent to
0.46 percent. The maximum value is less than the average of 40 samples
more or less evenly spaced over Tampa Bay. According to Gould
(personal communication) the P20, content of these 40 samples ranges
from 0.06 percent to 6.24 percent and averages 0.55 percent. Two
samples from near the mouth of Alafia River, about 4 miles north of
Green Key, have P20,5 contents of 0.30 percent and 0.93 percent. This
locality of high phosphorus concentration is probably affected consider-
ably by the Alafia River which flows through one of the principal phos-
phate areas of the State. This river has a high phosphorus content and
samples of its water analyzed by Odum (1953, p. 12) contained up to 3.55
ppm total phosphorus. The organic and particulate fractions of the
river's phosphorus are less susceptible to removal from the water by
plant activity than the dissolved phosphorus, and are more subject
to settling out and becoming part of the sediment. The proximity of
Green Key and the mouth of the Alafia River suggests that the phos-
phorus in the sediment around Green Key has been contributed in its
major part by the river, with the bird colony perhaps contributing a
small amount.
DUCK ROCK
Duck Rock (fig. 1), one of the Ten Thousand Islands, is a mangrove
key of about five acres located about 10 miles south of the town of
Everglades. The substratum of this island is oyster shell and coquina,
and apparently it once stood above high tides, for ducks are said to have
nested there prior to 1910. Establishment of mangrove made roosting


60





REPt)iT OF iNVESTIGATIONS NO. 16


possible, and it is now principally a roost for an estimated 75,000 to
80,000 white ibis and rtiliierous brown pelicans, cormorants, egrets and
other herons, and frigate birds. A number of birds including the egrets,
Louisiana heron, brown pieblicah; and double-crested cormorant nest there.
It has been under the protection of the Audubon Society for over 20
years.
Duck Rock is on the outer edge of the Ten Thousand Islands chain
and its exposed southwest side shows considerable effects of storm-wave
erosion. The sedimerit on the southwest side is mainly quartz sand, and
that on the sheltered northeast side is a mixture of calcareous mud and
sand. Bottofi conditions permit the growth of organisms, and a number
of live mollusks were picked Uip in the samples.
Eight samples (table 2, nos. 7-14) from the vicinity of Duck Rock
have P205 content ranging from a trace to 0.29 percent based on dry
samples. For comparative purposes three samples (table 2, no. 15-17)
were taken from the vicinity of another key1 located about a mile north
of Duck Rock. This key is not known to have been a center of bird
population. Three samples frmni this locality show respectively a trace,
0.20 percent, and 0.41 percent. The 0.41 percent noticeably exceeds the
highest value obtained in the Duck Rock samples. These data suggest
that the bird colony has had little influence on the phosphorus content
in the sediments at Duck Rock.

EAST RIVER ROOKERY
East River (fig. 1), flowing sluggishly toward Whitewater Bay from
the east, is characterized by a network of channels separated by numer-
ous small mangrove islands. A number of these islands form the nesting
site of some 20,000 or more wood and white ibis, American egret,
cormorant, anhinga and snowy egret.
The mangrove of the East River area grows on a substratum of peat
about 1 to 2 feet thick. The peat lies on a layer of soft calcareous mud,
referred to in this paper as marl, of about the same thickness, and below
the marl is hard Miami limestone.
Samples taken from near the center of the channels at a number
of points consist of miitiires of marl with abundant mollusk shells and
peat. The high loss on ignition, up to nearly 20 percent, reflects the
amount of peat in the samples. The sediment smells very strongly of
hydrogen sulphide which may account for the fact that no live mollusks
Designated Beiine't Key for piirpose of this paper.





FLORIDA GEOLOGICAL SURVEY


were found in it. Four samples (table 3) from this locality have P205
contents that range from a trace to 0.24 percent.

CUTHBERT LAKE ROOKERY
Cuthbert Lake Rookery (fig. 1) is on a small mangrove key about 500
feet long by 300 feet wide near the middle of Cuthbert Lake. This
lake, which is about two miles long by one mile wide, is one of a large
number of shallow brackish-water lakes located at the southern edge
of the Florida mainland within a few miles of Florida Bay. The man-
grove of Cuthbert Key grows on a substratum of peat which is three
feet thick at the center of the island. This is underlain by a 14-inch
layer of marl very similar to that under the peat at East River. The
bedrock is Miami limestone.
The rookery is populated predominantly by wood ibis which, ac-
cording to Moore (1953, p. 181-188), make up about nine-tenths of the
total. American egrets, cormorants, anhinga, and snowy egret constitute
the remainder. The total population varies between 2000 and 5000. A
plume hunter named Cuthbert discovered the rookery in 1890, but no
one has any idea how long the rookery had been in use prior to that.
Bird protection laws passed by the State Legislature in 1901 virtually
stopped the slaughter of birds for their plumes. In 1902 Guy M.
Bradley, who was a few years later shot by a plume hunter, was em-
ployed by the National Audubon Society to protect the rookery. It
remained under the protection of the Audubon Society until the estab-
lishment of the Everglades National Park.
Over most of its area the Cuthbert Lake bottom is on Miami lime-
stone. The limestone has a solution pitted surface, and in many of
the depressions there is an accumulation of shells, limestone fragments
and other debris. The limestone is covered by marl only around the
margins of the rookery key and around the fringes of the lake. The
marl is thinner away from the edge of the mangrove and usually extends
less than 100 feet out into the lake. This condition suggests that erosion
instead of sedimentation is noneffective in the main body of the lake.
In some of the small embayments, however, there is an accumulation
up to two feet thick of a gelatinous sort of material. It is largely organic,
for the analysis (table 4, no. 40) shows nearly 42 percent ignition loss.
Although in the vicinity of the rookery key there is essentially no
deposition, there is some precipitation of phosphate. In addition to peat
and marl, samples from this locality contain small concretion-like particles
of phosphatic material. A sample submitted to J. B. Cathcart and






REPORT OF INVESTIGATIONS No. 16


analyzed by George Ashby of the U. S. Geological Survey showed apatite
as the major mineral phase. Fluor-apatite is indicated by its fluorine con-
tent. The particles range in size from less than one mm. to about two
cm. They accumulate in limestone solution pits beyond the edge of the
marl and on the island's beach which is exposed at low tide. None of
this material was found in the peat and marl samples taken near the
middle of the island. Samples of sediment from the edges of Cuthbert
Lake and from nearby West Lake and Long Lake contain none, although
the sediment is otherwise similar to that near the rookery key. The locali-
zation of phosphatic material in the vicinity of the rookery indicates
that the bird colony plays an important part in its accumulation.
Eleven samples (table 4, no. 22-32) collected at a distance of 20 feet
to 70 feet from the edge of the mangrove on the rookery key contain
varying amounts of peat, marl with shell fragments, fragments of bed-
rock, and phosphatic particles. The P205 contents of these samples
range from 0.48 percent to 7.92 percent with an average of 4.10 percent.
The amount of phosphorus varies with the quantity of the phosphatic
particles in the sample. A sample from the island's beach (table 4, no.
33), consisting almost entirely of ground-up peat and phosphate parti-
cles, has 24.55 percent P205 based on dry sample. This sample has a
25.50 percent loss on ignition, and when the P20s percentage is based
on ash, the value is 33.77 percent.

Some indication of replacement of the marl substratum by phosphate
is given by a comparison of its P205 content with that of marl from
other localities. A single sample of marl (table 4, no. 35) from near
the middle of the island contains 0.85 percent P205. Four marl samples
(table 5, no. 41-44), two each from nearby Long Lake and West Lake
contain P205 ranging from a trace to 0.39 percent, one from near the
beach at East Cape (table 5, no. 45) 0.18 percent and a sample of marl
dredged up for fill on Bahia Honda Key (table 5, no. 46) has only a
trace. There is further indication of replacement in the shell material
located near the island. An analysis of oyster shell (table 4, no. 34)
picked from the samples and washed clean of marl and other material
shows 0.50 percent P205. Analyses of pelecypod shells by Clarke and
Wheeler (1922) show CasP208 ranging from a trace to only 0.07 percent.
There is a distinct difference in the amount of phosphorus in the sedi-
ment around the edge of the lake and the amount in the sediment from
the near vicinity of the rookery. Four samples of marl (table 4, no.
36-39) from widely separated points near the lake's edge contain P205
ranging from a trace to 0.18 percent. A fifth sample (table 4, no. 40),


63





FLORIDA GEOLOGICAL SURVEY


consisting of a somewhat gelatinous organic material and whose analysis
shows 41.85 ignition loss, contains 0.27 percent P205.

SUMMARY AND CONCLUSIONS
The lack of significant concentration of P205 in the Green Key, Duck
Rock, and East River localities is probably due to several factors. The
bird colonies may be too recent to have had much effect, currents may
carry the material away and distribute it sparsely, or plant life may take
up the soluble phosphorus before it has a chance to precipitate.
At Cuthbert Lake conditions have favored accumulation of phos-
phorus in the near vicinity of the rookery key. A large colony of birds
has occupied the key for a long time providing an adequate source of
phosphorus. Currents in the lakes are not as strong as in the other
sampled localities, so the phosphorus has a better chance to accumulate.
Without a specific study of the flora of the water in the different lo-
calities, it is not possible to evaluate the effects plant life had in removing
phosphorus from solution. Much algae had been growing around the
rookery key in Cuthbert Lake, but when sampling was done in August,
the algae was dead and largely disintegrated. A high H2S content in
the samples may have had some inhibiting effect on plant life, especially
on forms near the bottom. In any case there was phosphorus in excess
of that needed by plants and part of the excess was precipitated as
apatite in small concretion-like particles.
The relatively high concentration of phosphorus in the sediments at
the Cuthbert Lake rookery and the low concentration in other parts
of this lake and in nearby lakes indicates that the bird colony has been a
major factor in its accumulation.

REFERENCES
Clarke, F. VW.
1922 (and Wheeler, W. C.) The inorganic constituents of marine inverte-
brates: U. S. Geol. Survey Prof. Paper 124, 62 p.
Echel, E. B.
1953 (and Milton, Charles) Reconnaissance of superficial phosphate deposit
near Minas, Uruguay: Econ. Geol., vol. 48, p. 437-446.
Hutchinson, G. E.
1950 Survey of contemporary knowledge of biochemistry vertebrate excretion:
Am. Mus. Nat. Hist. Bull., vol. 96, p. 30-217.
Mills, H. R.
1944 The log of whiskey stump: The Florida Naturalist, vol. 18, no. 1, 8 p.
Milton, Charles (see Echel)


64






REPORT OF INVESTIGATIONS No. 16


65


Moore, Joseph C.
1953 A story of Cuthbert Rookery: Everglades Nat. Hist., vol. 1, no. 4, p.
181-188.
Odum, H. T.
1953 Dissolved phosphorus in Florida waters: Florida Geol. Survey Rept.
Inv. 9, p. 12.
Wheeler, W. C. (see Clarke)


TABLE 1. ANALYSES OF SAMPLES FROM GREEN KEY VICINITY
Sample P20, based on *P20, based Moisture Ignition A
air dried sample on ash loss (65C
1 0.43 0.45 1.08 '3.99 94
2 0.46 0.47 1.13 3.72 95
3 0.30 0.31 0.63 2.37 97
4 0.18 0.18 0.30 1.37 98
5 0.30 0.33 0.45 7.42 92
6 0.20 0.20 0.48 1.67 97


40
200
500
40
200
500


feet east of Green Key
feet east of Green Key
feet east of Green Key
feet south of Green Ke
feet south of Green Ke
feet south of Green Ke


ksh
* C)
1.93
;.15
t.00
3.33
1.13
'.85


y
y
y


*Calculated by Author


TABLE 2. ANALYSES OF SAMPLES
Sample P20, based on *P205 based
air dried sample on ash
7 0.29 0.34
8 0.24 0.29
9 0.19 0.23
10 0.20 0.25
11 0.19 0.22
12 0.21 0.25
13 0.18 0.20
14 Trace Trace
15 Trace Trace
16 0.41 0.49
17 0.20 0.22
7 At north edge of Duck Rock
8 40 feet north of Duck Rock
9 100 feet north of Duck Rock
10 200 feet north of Duck Rock
11 500 feet north of Duck Rock
12 100 feet east of Duck Rock
13 150 feet south of Duck Rock
14 150 feet west of Duck Rock
15 40 feet north of Bennett Key
16 100 feet north of Bennett Key
17 100 feet west of Bennett Key
*Calculated by Author


FROM DUCK ROCK VICINITY


Moisture

2.65
2.85
3.58
1.95
2.90
4.80
0.70
0.23
0.60
3.60
1.95


Ignition
loss
14.40
18.80
17.04
17.07
14.40
15.75
8.10
6.89
10.47
14.17
7.92


Ash
(6500 C)
82.95
78.35
79.38
80.98
82.70
79.45
91.20
92.88
88.93
82.23
90.13






FLORIDA GEOLOGICAL SURVEY


TABLE 3. ANALYSES OF SAMPLES FROM EAST RIVER
Sample P205 based on *P205 based Moisture Ignition
air dried sample on ash loss
18 0.24 0.29 4.33 17.22
19 0.10 0.12 2.45 16.52
20 Trace Trace 3.30 17.45
21 0.11 0.13 5.65 19.87
18 Channel sample from upper edge of rookery
19 Channel sample from middle of rookery
20 Channel sample from lower edge of rookery
21 Channel sample from below rookery
*Calculated by Author


TABLE 4. ANALYSES OF SAMPLES FROM CUTI
Sample P20. based on *P20, based Moisture ]
air dried sample on ash
22 6.49 8.18 4.73
23 2.22 2.87 4.25
24 2.52 5.36 10.75
25 6.21 8.05 4.25
26 4.68 5.95 5.28
27 3.45 4.55 5.83
28 5.99 7.75 4.38
29 0.48 0.68 6.20
30 7.92 10.53 7.15
31 1.66 2.10 3.55
32 3.43 4.17 2.90
33 24.55 33.77 6.60
34 0.50 0.54 0.65
35 0.85 1.06 2.43
36 0.18 0.20 1.63
37 0.15 0.17 0.60
38 Trace Trace 8.30
39 Trace Trace 2.85
40 0.27 0.49 6.70
22 20 feet north of Cuthbert Key
23 40 feet north of Cuthbert Key
24 60 feet north of Cuthbert Key
25 40 feet northeast of Cuthbert Key
26 40 feet east of Cuthbert Key
27 40 feet southeast of Cuthbert Key
28 40) feet south of Cuthbert Key
29 30 feet southwest of Cuthbert Key
:30 70 feet southwest of Cuthbert Key
31 70 feet west of Cuthbert Key
32 40 feet northwest of Cuthbert Key
33 Beach material from Cuthbert Rookery
34 Oyster shell from vicinity of Cuthbert Rookery
35 Marl from middle of Cuthbert Rookery
36 Southwest margin of lake, northwest of Cuthbert Cre
.37 At north edge of lake
38 At southeast margin of lake
39 At southwest margin of lake, east of Cuthbert' Creek
40 Southwest margin of lake at Cuthbert Creek


IBERT
Ignition
loss
19.72
21.80
47.30
21.87
20.27
22.79
21.64
27.75
23.05
20.40
17.15
25.50
6.50
19.24
10.04
11.67
14.20
12.92
41.85


LAKE
Ash
(6500 C)
75.55
73.95
41.95
73.88
74.45
71.38
73.98
66.05
69.80
76.05
79.95
67.90
92.85
78.33
88.33
87.73
77.50
83.23
51.45


ek


Ash
(6500 C)
78.45
81.03
79.25
74.48


66






REPORT OF INVESTIGATIONS No. 16


TABLE 5. SAMPLES FROM MISCELLANEOUS LOCALITIES-


Sample P20, based on
air dried sample
41 0.18
42 Trace
43 0.34
44 0.39
45 0.18
46 Trace


41 East end of West
42 Northwest corner
43 East end of Long
44 West end of Loni
45 Marl from near b
46 Dredgings from 1
*Calculated by Author


*P205 based
on ash
0.23
Trace
0.43
0.51
0.24
Trace


Moisture

1.70
2.05
2.20
3.48
1.95
3.40


Ignition
loss
18.65
23.05
21.10
21.67
22.65
11.07


t Lake, 200 yards west of small island
of West Lake, near the channel opening
Lake
g Lake
each at East Cape
Bahia Honda Key


Ash
(6500 C)
79.65
74.90
76.70
74.85
75.40
85.53












Part III




AN ANALYSIS OF OCHLOCKONEE

RIVER CHANNEL SEDIMENTS







By
Ernest H. Lund
Associate Professor, Department of Geology
Florida State University
and
Patrick C. Haley
Graduate Assistant, Department of Geology
Florida State University
On Special Grant from Coastal Petroleum Company








Prepared for the
Florida Geological Survey



Tallahassee, Florida
1958
























TABLE OF CONTENTS


Abstract .....................................

Acknowledgments .............................

Purpose of investigation .....................

Method of sampling ........................

Mechanical analysis of sediments ................

Heavy mineral analysis ........................


Table

1
2

3


Page

........................ 73

........................ 73

........................ 73

........................ 73

............. ........... 74

........................ 76


Sedimentary parameters .......................................... 74

Percentage of total heavy minerals in each sample ................... 75

Relative abundance of heavy minerals in all samples ................. 76









Part III


AN ANALYSIS OF
OCHLOCKONEE RIVER. CHANNEL SEDIMENTS

ABSTRACT
Channel sediments from the Ochlockonee River between Ochlockonee
Bay and the dam at Lake Talquin, Florida, were examined to determine
sedimentary parameters and heavy-mineral content. Most samples show
a unimodal grain-size distribution. There is considerable fluctuation in
the median diameter and mean grain size, but there is a noticeable
tendency for these values to decrease downstream. Total heavy-mineral
content ranges from about 0.05 per cent to 0.46 per cent with magnetite-
ilmenite the most abundant and rutile second in abundance.

ACKNOWLEDGMENTS
The writers are indebted to Mr. John Bates and the Coastal Petroleum
Company for the generous financial assistance given to this project and
to Dr. Stephen Winters of the Florida State University for his helpful
criticisms and suggestions in the preparation of the thesis from which this
paper is derived.

PURPOSE OF INVESTIGATION
The objectives of this study were to learn something of the physical
characteristics of the Ochlockonee River channel sediments between
Ochlockonee Bay and Lake Talquin and to determine the heavy-mineral
content of these sediments.

METHOD OF SAMPLING
Samples were collected from the river channel at two-mile intervals,
beginning at the entrance of the river into Ochlockonee Bay. A coring
tube 2 inches in diameter and 18 inches long attached to a stem made up
of 22-foot sections was lowered into the water and forced into the channel
deposits. The depth of penetration into the sediment was to the full
length of the coring tube where the thickness of the sediment layer
permitted. In a few places compaction of the material in the tube allowed
a penetration in excess of 18 inches. Water depths ranged from 1 foot
to 21 feet.





FLORIDA GEOLOGICAL SURVEY


MECHANICAL ANALYSIS OF SEDIMENTS

A representative 100-gram portion of each sample was separated
through a battery of 26 Tyler screens, the finest with an opening of .048
mm. and the coarsest with an opening of 6.680 mm. The data were
plotted in histograms and cumulative frequency curves, and from these
graphs the sedimentary parameters of table 1 were derived.


TABLE 1. SEDIMENTARY PARAMETERS*


Sample
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32


.115
.126
.173
.202
.200
.238
.305
.160
.268
.390
.350
.360
.360
.260
.269
.430
.225
.324
.154
.375
.315
.600
.215
.335
.590
.370
.295
.426
.370
.254
.345
.250


Median

.149
.204
.228
.254
.260
.286
.369
.196
.352
.484
.410
.498
.460
.350
.318
.723
.298
.470
.220
.477
.385
.790
.295
.422
.775
.530
.437
.610
.508
.441
.475
.430


Averages .409


Q3

.184
.315
.320
.340
.284
.336
.470
.250
.520
.680
.530
.568
.625
.480
.395
1.050
.410
.700
.290
.610
.495
1.120
.410
.570
1.050
.748
.700
.830
.700
.680
.712
.985


Mean


.156
.165
.247
.294
.246
.287
.438
.203
.430
.534
.461
.521
.553
.401
.360
.767
.365
.546
.256
.519
.429
.937
.358
.490
.871
.607
.550
.675
.590
.605
.587
.849


.478


1.26
1.58
1.36
1.30
1.19
1.19
1.24
1.25
1.39
1.32
1.23
1.25
1.31
1.35
1.21
1.56
1.35
1.47
1.37
1.27
1.25
1.36
1.38
1.30
1.33
1.42
1.54
1.39
1.37
1.63
1.43
1.98


1.36


* All figures except So are expressed in mm.


____


I





REPORT OF INVESTIGATIONS No. 16


With few exceptions the Ochlockonee channel deposits have a uni-
modal grain-size distribution and are very well sorted. The least well-
sorted sample, with a sorting coefficient of 1.98, was taken just below
the Lake Talquin Dam. Sorting coefficient values range from 1.98 to 1.19.

The median diameters range from 0.14 mm. to 0.790 mm. with con-
siderable fluctuation from one locality to the next but with a noticeable
decrease downstream. Sample number 1, taken at the river's mouth, has
the lowest value. The mean grain sizes range from 0.156 mm. to 0.937
mm., and there is a fluctuation that almost parallels that of the median
grain sizes. Like the median diameter, the mean grain size tends to
decrease downstream.

TABLE 2. PERCENTAGE OF TOTAL HEAVY MINERALS IN EACH SAMPLE
Sample Percent of
Number Heavies
1 0.46
2 0.12
3 0.06
4 0.05
5 0.13
6 0.10
7 0.10
8 0.25
9 0.10
10 0.05
11 0.08
12 0.09
13 0.07
14 0.11
15 0.16
16 0.21
17 0.22
18 0.25
19 0.24
20 0.10
21 0.14
22 0.11
23 0.24
24 0.24
25 0.05
26 0.12
27 0.12
28 0.10
29 0.20
30 0.16
31 0.16
32 0.38





FLORIDA GEOLOGICAL SURVEY


HEAVY MINERAL ANALYSIS
The heavy minerals were separated from the sands by allowing a
20-gram portion of each sample to settle in bromoform for a period of
30 minutes with agitation every five minutes. A representative part of
each heavy fraction was mounted in balsam and a grain count was made
using a mechanical stage on a petrographic microscope.
The amount of heavy minerals (table 2) in the Ochlockonee channel
deposits is small, ranging from 0.05 percent to 0.46 percent. The opaque
minerals, chiefly ilmenite but with some magnetite, are the most abundant
(table 3). They make up from 10 percent to 34 percent of the total
heavies, and the average for the 32 samples is about 22 percent. Rutile
is the second most abundant, ranging from about 8 percent to 26 percent
and averaging about 20 percent. Other minerals in decreasing order of
abundance are kyanite, zircon, tourmaline, hornblende, leucoxene, silli-
manite, staurolite, garnet and epidote.
'AmI.E 3. RELATIVE ABUNDANCE OF HEAVY MINERALS IN ALL SAMPLES
Average Percent
Percent Range
Magnetite-
ilhnenite 22.4 10-34
Rutile 19.8 8-26
Kyanite 16.9 9-29
Zircon 12.8 5-25
Tourmaline 11.1 1-27
Hornblende 7.0 0-20
Leucoxene 5.3 1-21
Sillimanite 1.9 0-6
Staurolite 1.3 0-11
Garnet 0.8 0-5
Epidote 0.7 0-4

A study' by Alfred Larsen and Steve Revell of the heavy-mineral
content of the Pleistocene terrace sands east of the Ochlockonee River
shows a close similarity in the heavy-mineral suites of the terrace deposits
and the river deposits. A notable difference is in the high percentage
of hornblende in some of the river material and its scarcity in the terrace
material. No monazite was noted in the river material, but in some of
the terrace localities monazite makes up to 10 percent of the total heavy-
mineral content.
Close similarity in the heavy minerals of the river deposits and the
adjacent terrace deposits indicates that a major source of the river's


SFor Master's degree at Florida State University.





REPORT OF INVESTIGATIONS No. 16 77

present bed load is the terrace material. Since the construction of the
Talquin dam, the upstream sources of material have been cut off. The
load below the dam is now obtained mainly by reworking of the flood
plain and through contributions of Pleistocene terrace material from
tributary streams and by slumping of this material along the banks of
the Ochlockonee River. The limestone bedrock over which the river
flows probably contributes a very small amount of plastic material to
the bed load.