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A fossil hunter's guide to the geology of the northern Florida peninsula ( FGS: Open File Report 65)
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Permanent Link: http://ufdc.ufl.edu/UF00003729/00001
 Material Information
Title: A fossil hunter's guide to the geology of the northern Florida peninsula ( FGS: Open File Report 65)
Series Title: Open file report
Physical Description: 12 p. : ill., maps ; 28 cm.
Language: English
Creator: Rupert, Frank
Florida Geological Survey
Publisher: Florida Geological Survey
Place of Publication: Tallahassee
Tallahassee
Publication Date: 1994
Copyright Date: 1994
 Subjects
Subjects / Keywords: Fossils -- Florida   ( lcsh )
Paleontology -- Florida   ( lcsh )
Genre: bibliography   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 12).
General Note: Cover title.
Statement of Responsibility: by Frank R. Rupert.
 Record Information
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: oclc - 37039992
alephbibnum - 002295497
notis - ALP8716
issn - 1058-1391 ;
System ID: UF00003729:00001

Table of Contents
    Front Cover
        Front page 1
        Front page 2
    Main
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Bibliography
        Page 12
Full Text










STATE OF FLORIDA
DEPARTMENT OF ENVIRONMENTAL PROTECTION
Virginia Wetherell, Secretary








DIVISION OF ADMINISTRATIVE AND TECHNICAL SERVICES
Nevin G. Smith, Director







FLORIDA GEOLOGICAL SURVEY
Walter Schmidt, State Geologist and Chief




OPEN FILE REPORT 65




A FOSSIL HUNTER'S GUIDE TO THE GEOLOGY OF THE NORTHERN FLORIDA PENINSULA

By

Frank R. Rupert


FLORIDA GEOLOGICAL SURVEY

Tallahassee
1994


?' -i~i ?~r~t~ L

























SCIENCE
LIBRARY









A Fossil Hunter's Guide to the

Geology of the Northern Florida Peninsula

Frank R. Rupert, P.G. 149


The northern Florida peninsula extends, for
the purposes of this paper, from Madison
County eastward to Nassau County, and
southward to a west-to-east line corresponding
to the southern county boundaries of Pasco,
Sumter, Lake, and Orange Counties. This
region contains its own unique character, and
is transitional from the hilly, topographic
highlands of the panhandle to the low, flat
terrain characteristic of southernmost Florida.
Based on the work of White (1970), the
northern peninsula is generally subdivided into
four broad geomorphic zones: the Northern
Highlands, comprised of topographically higher
uplands; the Gulf Coastal Lowlands, a flat, low-
lying plain bordering the Gulf coast; the Central
Highlands, a series of topographic ridges
punctuated by elevationally-lower valleys, and
the Atlantic Coastal Lowlands, a zone of low,
flat topography bordering the east coast, and
fringed by the persistent Atlantic Coastal Ridge
system. Figure 1 is a geomorphic map of the
northern peninsular region. For interested
readers, White (1970) provides a more detailed
discussion of many of the features mentioned
herein.
The northwestern and north-central
portions of the peninsula are comprised of
elevational highlands of the Northern Highlands
zone. These stream-dissected, gently-rolling
hills are remnants of an extensive upland
spanning the northern edge of the state and
extending into southern Alabama and Georgia.
In the northern peninsula, these highlands are
typically elevationally-lower vestiges of the
highest hills in the state, which are situated to
the west in the north-central panhandle.
Madison County contains the eastern end of
the Tallahassee Hills subzone of the Northern
Highlands, which extend to the Madison-
Hamilton County line. To the east, the
remaining hills generally become lower and
more gently-rolling. At the eastern edge of the
Northern Highlands is a relict marine feature,
possibly a beach ridge, named the Trail Ridge.


This ancient sand body is mined for both quartz
sand and heavy minerals.
Bounding the southern and western edges
of the Northern Highlands is a relict marine
escarpment named the Cody Scarp. It forms
the most persistent topographic break in the
state and marks the former shoreline position of
a high-standing Pleistocene sea. The Cody
Scarp serves as a boundary between the
Northern Highlands and the elevationally-lower
Gulf Coastal Lowlands to the south and
southwest.
The Gulf Coastal Lowlands ring much of
Florida's Gulf coast. In general, this zone
consists of a flat, sandy, gently sea ward-
sloping plain associated with Pleistocene marine
erosion. It is a region of pine flatwoods, moist
hammocky terrain, and coastal salt marshes.
Surface rivers and streams flow to the Gulf in
channels incised in the limestone bedrock.
Some connect through sinkholes with an
extensive subsurface karst drainage system,
comprised of interconnected water-filled sinks,
caves, and springs.
Eocene and Oligocene limestones are near
or at the surface over much of the lowlands
area. These limestones are typically covered by
a variably-thick veneer of Quaternary sands,
clayey sands, and discontinuous shelly sands
left behind by high-standing Pleistocene seas.
Relict marine features such as sand bars, beach
ridges, and dunes are still visible in many areas
of the Gulf Coastal Lowlands. Numerous
limestone and dolostone mines dot the
lowlands region, and where accessible, offer
invertebrate fossil collecting opportunities.
The Central Highlands collectively comprise
a series of coast-parallel ridges and intervening
valleys. In general, the various ridges and
valleys, as the names imply, are differentiated
primarily on elevation. Elevations along
portions of higher ridges, such as the
Brooksville Ridge reach 300 feet above mean
sealevel. In the valleys, elevations between 50
and 100 feet above mean sealevel are typical.





















-N-









10 0 10 40 MI
I- -[ -- J I i


SCHLE


Figure 1. Geomorphic map of the northern Florida peninsula.
(modified from White, 1970)


0
A-

\
Y







Marine and fluvial erosion, coupled with
karst dissolution of the carbonate bedrock,
were major factors shaping the geomorphology
of this region. In some areas, such as the
Central Valley, lowering of the land surface
likely occurred due to extensive dissolution of
the underlying carbonate rocks. Carbonates are
commonly very close to the land surface in the
lowland valleys on the western side of the
peninsula. Karst features, such as springs and
large sinkhole lakes, occur throughout the
Central Valley. Silver Springs, near Ocala is the
larger of the numerous freshwater springs
dotting the Central Valley area. Smaller
springs, flowing crystal clear freshwater from
the Ocala Limestone, provide popular swimming
areas throughout the local Ocala National
Forest. The valleys also typically contain the
major surface water streams, such as the
Oklawaha River, which snakes its way
northward through central Marion County.
The shallow nature of the carbonate
bedrock in areas such as portions of the Central
Valley make them suitable regions for economic
mining of limestone. A number of older mines
are scattered over the Central Valley, especially
in Marion County, north and south of the city
of Ocala. A few still operate in the vicinity of
Ocala.
Many of the topographic features in the
Central Highlands were shaped, at least in part,
by high-standing Miocene through Pleistocene
seas. Elongate highlands such as the
Brooksville and Mount Dora Ridges trend
southeastward at nearly the same orientation
as the modern peninsula. The ridges may have,
at one time, been part of an extensive highland
area subsequently divided by erosional and
dissolutional valleys into discreet highland
segments. These ridges are typically comprised
of Miocene and Pliocene siliciclastic sediments,
overlain by variably-thick Quaternary sands.
Interior hills and ridges such as the Fairfield
Hills and Marion Upland are comprised of
essentially in-place, older sediments. Others,
like the Brooksville Ridge, are built in part of
sediments reworked from older formations by
marine currents and wave activity.
The Atlantic Coastal Lowlands are
comprised of several distinct geomorphic zones.
Along the eastern edge of the northern Florida
peninsula, the Eocene and Miocene formations


dip, and hence deepen, to the northeast. Thick
deposits of undifferentiated sands, clayey
sands, and shell beds are the predominant near-
surface sediments. At the northeastern corner
of the state, the St. Mary's Meander Plain is, as
its name implies, a low, flat fluvial plain shaped
largely by the meandering of the St. Mary's and
Nassau Rivers. Further south, the Eastern
Valley comprises a generally flat, sandy region
lying 25-30 feet above mean sealevel.
Numerous relict beach ridges throughout the
extent of the Eastern Valley suggest it may
represent a Pleistocene beach ridge plain.
Bordering the Atlantic edge of the Eastern
Valley is a narrow ridge comprised of sand and
shelly sands named the Atlantic Coastal Ridge.
This ridge extends, with a few breaks, from
east-central St. Johns County southward to the
vicinity of the town of Homestead, in southern
Dade County. Seaward of the ridge lie the
sandy beaches, barrier islands, and lagoons of
the Atlantic Coast.
Both the geomorphology and the geology of
the northern Florida peninsula are strongly
influenced by subsurface structural features.
Figure 2 illustrates the major structures
affecting this region. Perhaps the most
significant is a broad, structurally


Figure 2. Geologic structures in northern Florida
(from Schmidt, 1984 and Scott, 1988)


positive feature named the Ocala Platform
(Scott, 1988), centered under the central Big
Bend area. Cenozoic formations lap up onto
the western flank of this feature, and dip
northeastward off the eastern flank into a broad
sedimentary basin named the Southeast







Georgia Embayment. The Ocala Platform brings
Eocene carbonate rocks to the surface over the
crest of the structure in Levy and Citrus
Counties. Oligocene and Miocene units lap up
onto the edges of the platform in a younger-
outward concentric pattern. The shallow
Eocene and Oligocene carbonates form
extensive karst plains over much of the western
portion of the northern peninsula. To the east
the Oligocene sediments are absent. As the
Eocene carbonates and overlying Miocene
sediments dip away off the eastern flank of the
platform, siliciclastic sediments become the
predominant near surface sediments.
Three other positive structural features,
situated along the eastern edge of the northern
peninsula, also influence the Eocene and
younger sediments. The Sanford High is
located under Seminole and Volusia Counties;
Ocala Limestone and Hawthorn Group
sediments are missing from the crest of this
feature, presumably due to erosion. The Avon
Park Formation directly underlies the thick Plio-
Pleistocene sediments in this area. The St.
Johns Platform and Brevard Platform are low,
broad ridges on the erosional surface of the
Ocala Limestone. None of these features
directly influence the surface geology.
Figure 3 is a generalized geologic map of
the northern peninsula, and Figure 4 illustrates
two cross sections through the area. The
geologic map is constructed to show the extent
of the formations as they occur within 20 feet
of land surface. Each formation may be more
extensive in the subsurface, but because each
eventually dips below the arbitrary 20 foot
depth or pinches out, their entire extent is
hidden by shallower units shown on the map.
Areas underlain by more than 20 feet of
undifferentiated Quaternary sands are shown as
white areas on the map.
Cross section A-A' in Figure 4 curves
southward from Jefferson County,
approximately following the eastern periphery
of the Ocala Platform. This section shows the
"high" attained by the top of the Eocene Ocala
Limestone over the flank of the platform, as
well as the on-lap of the Oligocene Suwannee
Limestone at the western edge of the platform.
Section B-B' trends southwest-to-northeast
across the peninsula, illustrating the
northeastward dip of the Eocene Avon Park


Formation, the Ocala Limestone, and the
overlying Miocene Hawthorn Group as they lap
off the eastern edge of the Ocala Platform. A
cursory comparison of Figures 1 and 3 reveals
coincidence between many of the geomorphic
zones and features and the areal extent of
certain geologic units. For example, the Gulf
Coastal Lowlands and the interior valleys are
largely underlain by Eocene and Oligocene
carbonates, while the Northern Highlands and
many of the upland areas of the Central
Highlands are comprised of Miocene or Pliocene
siliciclastics.
The karst plain areas of the Big Bend coast
are primarily composed of Middle Eocene to
Oligocene marine limestones and dolostones.
The oldest exposed rock in Florida, the Middle
Eocene Avon Park Formation, occurs near the
surface over the crest of the Ocala Platform in
southern Levy and northern Citrus Counties.
Here it is typically a cream to tan dolostone.
The Upper Eocene Ocala Limestone
unconformably overlies the Avon Park
Formation, and comprises the bedrock over a
broad area of the coastal Big Bend. It also
floors many of the valleys of the western part
of the Central Highlands zone. This white to
cream-colored marine limestone typically
contains abundant foraminifera, bryozoans,
mollusks, and echinoids. It is mined in many of
the counties situated over the Ocala Platform
for use in cement and as roadbed material.
Paleo-sinkholes and crevices encountered
during mining may contain Pleistocene sediment
fill, which has proven to be a source for
excellent Pleistocene vertebrate material. Most
of the karst plain areas in the Big Bend are
overlain by undifferentiated sands of variable
thickness. These sands may locally be thick
enough to form mappable units.
The Oligocene Suwannee Limestone is
brought to the surface along the northwestern
flank of the Ocala Platform, in Taylor, Madison
and Hamilton Counties, and at the southern
edge of the platform in Pasco and Hernando
Counties. It forms the shallow bedrock in most
of Taylor County, and crops out along the
Suwannee River between the towns of White
Springs and Ellaville. This unit is also mined for
roadbase material in Taylor, Hernando, and
Pasco Counties. The Suwannee is typically a
fossiliferous marine limestone containing











EXPLANATION


UNDIFFERENTIATED QUATERNARY SAND AND CLAY

ANASTASIA FORMATION


WEATHERED HAWTHORN (ALACHUA FM.)

MICCOSUKEE FORMATION

CYPRESSHEAD FORMATION

HAWTHORN GROUP


SUWANNEE LIMESTONE;

OCALA LIMESTONE

AVON PARK FORMATION


10 0 10 40 MI

0 60 KM

SCALE


Figure 3. Geologic map of the northern Florida peninsula
(modified from Arthur, 1993; Campbell, 1992a-c; Campbell, 1993a-c; Campbell and Scott, 1992 and 1993;
Rupert and Campbell, 1993; Rupert et al., 1993; Scott, 1992a-j; Scott, 1993a-d; Scott and Campbell, 1992)


F--
ElI


















CYPRESSHEAD FM.


FEET
- 200



- 100


-0


--100



--200


FORMATION


CROSS SECTION


LOCATION


Figure 4. Geologic cross sections in the northern Florida peninsula.


OCALA LIMESTONE


FEET B
-200


100


-0



- -100


- -200


- -300


- -400


g







mollusk molds and occasional specimens of the
characteristic guide fossil echinoid
Ryncholampus gouldii.
The Miocene Hawthorn Group overlies the
Ocala Limestone and, where present, the
Suwannee Limestone. It forms the hilly terrain
of the Northern Highlands and comprises
selected ridges in the Central Highlands,
including the Fairfield Hills, Ocala Hill, and the
southern end of the Brooksville Ridge. The
Hawthorn is generally missing in the Gulf
coastal portions of the northern peninsula, and
dips and thickens under northeastern Florida.
Commercial deposits of phosphate are mined
from the Hawthorn in Hamilton County. Fullers
earth clay, which is crushed to make cat litter,
is also mined from the Hawthorn in central
Marion County. Numerous vertebrate fossils
have been found in Hawthorn sediments
statewide. These range from shark teeth and
dugong bones to horse fossils to the famous
gomphotheres of the Moss Acres site in Marion
County. The Hawthorn is commonly exposed
in stream banks in the Northern Highlands zone,
offering some easily-accessible fossil hunting
sites.
Many of the ridges of the eastern part of
the Central Highlands are comprised of the
Pliocene Cypresshead Formation. This
generally unfossiliferous unit consists primarily
of clayey, gravelly sands, thought to be an
ancient marginal marine deposit. The deeper
water equivalent of the Cypresshead Formation
is a molluskan-fossiliferous shelly sand named
the Nashua Formation. The Nashua crops out
in a small area along the St. John's River, near
the town of Nashua in Putnam County.
A similar age unit, the Miccosukee
Formation, caps hill tops in Madison County, at
the eastern end of the Tallahassee Hills. As
with the Cypresshead Formation, the clayey
sands of the Miccosukee Formation are
generally unfossiliferous, although Olsen (1963)
reports one vertebrate fossil site in this unit in
Jefferson County.
The northern portion of the Brooksville
Ridge is comprised of interbedded clay, sand,
and sandy clay of varying lithologic character,
and containing vertebrate fossils ranging from
Middle Miocene to Plio-Pleistocene in age.
Older literature assigned these sediments to a
unit named the Alachua Formation. These


diverse sediments are now thought to represent
weathered and/or reworked Hawthorn Group
sediments (Scott, 1988).
Large areas of the eastern half of the
northern Florida peninsula are mapped as
undifferentiated Quaternary deposits, primarily
sands and clays. These sediments attain
substantial thicknesses as the older Eocene
through Miocene units dip northeastward into
the Southeast Georgia Embayment. Portions of
the Atlantic Coastal Ridges, are formed of
sands, shelly sands, and mollusk coquina of the
Pleistocene Anastasia Formation. Anastasia
coquina is comprised largely of fossil mollusk
shells cemented together into a porous rock. It
was quarried on Anastasia Island by the
Spaniards and used to build the Castillo de San
Marcos, a 17th century fort in St. Augustine.
The Anastasia Formation crops out sporadically
along the Atlantic coast. An excellent exposure
is present on the beach at Washington Oaks
State Park, south of Marineland in Flagler
County.

Fossil Hunting Opportunities

Fossil collecting sites in the northern Florida
peninsula are many and varied, but typically
require diligent searching on the part of the
fossil hunter. The region offers both
invertebrate collecting, particularly in quarries
and along river banks, and vertebrate fossils in
river beds, on beaches and in sinkhole fill
material from quarries. Figure 5 provides a
generalized location map for some of the ideas
presented here. Some additional detail is
provided by Figure 6, a figure from Puri and
Vernon (1964) showing classic geologic sites of
the region. Keep in mind that the latter figure
is 30 years old, and was prepared as a field trip
guide. Much of the site ownership and access
information is likely obsolete.
As with most of the state, many potential
fossil sites are on private property, or else
require traversing private property to get to
them. Therefore, please use discretion and
common sense when hunting, and respect the
property rights of others. Always seek
permission before entering anyone's land,
posted or not. Once there, respect the integrity
of the land, avoid destructive digging, and leave
it as you found it. This will ensure continued




























51 DIXIE GC ...PUTNAM
fe19G 1 GA L u/ T, JOHNS MARINELAND
FLAGLER
24 ALACHUA NAS A

0-N- 144MARIN DAYTONA BEACH
SGU OCALA VOLUSIA



LAKE

CITRUS SEMINOLE



HERNANDO ORLANDO CAPE
CANAVERAL
ORANGE I L

10 0 10 40 MI ASO "



0 60 KM
SCALE GENERAL AREAS OF LIMESTONE AND DOLOMITE MINES
^ U mI_ t


Figure 5. Generalized road and location map for fossil collecting sites described in text.






























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L~HOLDE R - ,,, STC- 44 -







future access to the sites, a very important
consideration in these days of rapidly dwindling
collecting areas.
For those seeking Eocene and Oligocene
invertebrates such as mollusks and echinoids,
exposures of Ocala and Suwannee Limestones
occur along stream banks and in quarries. At
low water, Suwannee Limestone is accessible
along the Suwannee River between the towns
of White Springs and Ellaville (Hamilton and
Suwannee Counties). Ocala Limestone crops
out along parts of the lower portion of the
Suwannee River, from approximately Mayo
southward.
Quarries throughout the western part of the
northern peninsula expose fossiliferous
limestones and may offer potential collecting
sites. A few are operating; others may be
abandoned, overgrown, or water filled. There
are no commercial fossil hunting quarries in the
region. It is essential to get permission to enter
any quarry from the landowner or operator, and
to use adequate caution when hunting in
quarries. Active mines may refuse entry to
fossil hunters due to insurance and liability
concerns. Others might allow access to non-
working areas upon receipt of a signed liability
waiver. As quarry ownership and status
changes frequently, it is not generally feasible
to direct collectors to any particular site.
Middle Eocene fossil echinoids, primarily
Periarchus lye/li floridanus, and the seagrass
Lepidodendron have been uncovered in the
Avon Park Formation in quarries near Gulf
Hammock in Levy County. This small region
situated in southern Levy and northernmost
Citrus Counties is the only area in the state
where Avon Park Formation is close to the
surface.
Invertebrate fossils are abundant in the
Ocala Limestone quarries, scattered throughout
the Gulf coast Big Bend counties, as well as
both north and south of Ocala in Marion
County, and in western Alachua, and southern
Columbia and Suwannee Counties. Some of
these quarries are easily visible from the road.
Mollusks, echinoids and the large foraminifera
Lepidocyclina are among the most abundant
fossils in the Ocala Limestone. The fossils are
typically locked in the rock matrix, requiring
some tedious removal. It is not uncommon,
however, to find loose fossils as well,


especially the larger echinoids.
During dredging of the first leg of the ill-
fated Cross-Florida Barge Canal, high dredge
spoil piles were created along either side of the
cut near U.S. Highway 19 in Citrus County.
Fossils from the lower Ocala Limestone and
Avon Park Formation were once quite common
in these piles; today the piles are overgrown,
and in some areas fenced off. A few clear
areas remain, however, and are worth checking
out.
The Miocene Hawthorn Group sediments
sometimes yield rare invertebrate fossils,
primarily mollusks, from the carbonate portions
of the unit. There are also reports of silicified
corals being found in the stream banks of the
Withlacoochee River (between Madison and
Hamilton Counties) near where the State Road
6 bridge crosses the river.
Fossiliferous portions of the late Tertiary
and Quaternary sediments along the eastern
portion of the northern peninsula also provide
invertebrate collecting opportunities. Both old
and new shell pits along the eastern half of the
peninsula typically penetrate molluskan-
fossiliferous units such as the Nashua
Formation. Many of these pits are closed or are
private. Another possibility is to check creeks
and streams that may have cut down into these
units in this area.
The northern Florida peninsula also offers
the vertebrate fossil collector numerous
opportunities. Although the Eocene and
Oligocene limestones occasionally yield rare
shark teeth or whale bones, it is the Miocene
Hawthorn Group sediments and Pleistocene
deposits that offer the richest finds. The
Hawthorn Group sediments underlie the
Northern Highlands, and comprise the core of
isolated hills and ridges throughout the Central
Highlands. Many of the vertebrate fossil
discoveries occur along river and creek banks,
where streams have cut downward into the
sediments. Hawthorn exposures are common
along the northern stretch of the Aucilla,
Withlacoochee, Alapaha, and Suwannee Rivers,
but numerous other smaller creeks dissect
these sediments as well. One amateur collector
found a Miocene long-beaked dolphin jaw in a
small creek bank in downtown Gainesville.
Manatee ribs are fairly common in Alachua
County as well. While there are no well known







public sites as such, the sheer area covered by
Miocene sediments provides exceptional
opportunities to the collector willing to wade
local streams.
Weathered Hawthorn Group sediments,
which include the Alachua Formation, are
another source of finds. These sediments
commonly occur as reworked paleo-sinkhole
and channel fill materials in the underlying
limestone. Perhaps the most famous such site
is Thomas Farm in Gilchrist County, noted for
its fossil horse fauna. The weathered
Hawthorn sediments typically show a wide age
range, likely owing to their reworking and
redeposition through several epochs of geologic
time. They are most commonly encountered
west of the Northern Highlands in the Gilchrist-
Alachua-Levy County area, where they may
occupy karst depressions.
Younger Pliocene and Pleistocene
vertebrate fossils are found primarily in two
types of settings: in undifferentiated sinkhole
fill material, usually discovered during mining in
limerock quarries, and as streambed deposits.
Some spectacular finds have come from the
sediments filling ancient karst features, but
finding such features in the walls of a quarry is
somewhat of a hit or miss proposition. Better
success is had by snorkeling or diving the
numerous streams traversing the karst plain
areas of the Gulf Coastal Lowlands. Here
water has eroded Pliocene and Pleistocene land
mammal material out of the sediments and
deposited them in the gravel pockets on the
streambed. Occasional Eocene shark teeth,
eroded from the underlying limestone, may also
be mixed in with the bottom material.
Brown (1988) describes four river sites in
the area that he has worked with success; the
first, the Steinhatchee, flows between Taylor
and Dixie Counties. It is accessible via a small
recreation area located off State Road 51.
From Highway 19, turn south on S.R. 51 and
proceed about 2 miles. Turn left on a dirt road,
go about .3 miles, then take the right fork of
the road for another mile to the park. Search
the banks and bottom gravels above the falls
for Pleistocene land animal and bird fossils, as
well as Eocene shark teeth. A second river site
is along the Santa Fe, which flows between
Columbia, Alachua, and Gilchrist Counties. It
may be entered at the State Road 47 bridge, 6


miles south of Ft. White. Search the gravel
along the north bank, upstream of the bridge,
for Eocene shark teeth and manatee teeth. The
river may also be canoed by putting in at the
U.S. 27 bridge and floating 10 miles to the S.R.
47 bridge. Similarly, the Wacasassa River my
be explored by putting in at the S.R. 24 bridge
and floating downstream to the U.S. 19 bridge.
Finally, the other Withlacoochee River (there are
two) between Citrus and Marion and Sumter
Counties offers Pleistocene fossils in its
streambed as well. One stretch allows canoe
access at the S.R. 44 bridge in Sumter County
and takeout at the S.R. 200 bridge in Marion
County.
Vertebrate fossils are sometimes found in
the undifferentiated Quaternary sediments
along the eastern edge of the peninsula. An
extensive bone bed, including a complete giant
sloth skeleton, was accidentally discovered
near Daytona Beach years ago. Such
discoveries are typically found during
excavation work, and surface sites are few to
nil. Stream cuts may offer some potential
finds, particularly in the upper portions of shell
beds. Collectors have found vertebrate material
along the Atlantic beaches, predominantly in
the Ponte Vedra Beach area of St. Johns
County. Brown (1988) advises parking at
Mickler Landing, or off Highway A1A just south
of this park, and checking both the surf zone
and the shell piles on the beach. Collectors
have, in the past, found vertebrate material in
dredge spoil material along the St. Johns River.
There are undoubtedly numerous other
possible fossil sites throughout the northern
peninsula. The ones presented here are just a
sampling of typical sites. Many of the same
fossil hunting techniques that work elsewhere
will work here as well. Check stream bottoms
and banks, excavations, mines, and beaches.
And be prepared to do some screen washing,
particularly in the Miocene sediments.
If you travel to this part of the state, be
sure the visit the Florida Museum of Natural
History, located on the University of Florida
campus in Gainesville. Signs along 1-75 in
Gainesville direct you to the proper exit. The
museum features outstanding natural history
displays, including a recently-revamped Florida
fossil exhibit.







References


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Brown, R., 1988, Florida's Fossils, Guide to
Location, Identification, and Enjoyment:
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Campbell, K., 1992a, Geologic map of Dixie County,
Florida: Florida Geological Survey Open File
Map Series No. 35.

1992b, Geologic map of Lafayette
County, Florida: Florida Geological Survey
Open File Map Series No. 34.

1992c, Geologic map of Levy County,
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Map Series No. 11.

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1993b, Geologic map of Sumter
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Puri, H., and Vernon, R/, 1964, Summary of the
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S1992a, Geologic map of Alachua
County, Florida: Florida Geological Survey
Open File Map Series No. 12.

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Florida: Florida Geological Survey Open File
Map Series No. 38.

1992c, Geologic map of Clay County,
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1992d, Geologic map of Duval County,
Florida: Florida Geological Survey Open File
Map Series No. 4.

S1992e, Geologic map of Flagler
County,Florida: Florida Geological Survey Open
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S1992i, Geologic map of Union and
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1993a, Geologic map of Brevard
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1993b, Geologic map of Columbia
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1993c, Geologic map of Orange
County, Florida: Florida Geological Survey
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1993d, Geologic map of Seminole
County, Florida: Florida Geological Survey
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Scott, T., and Campbell, K., 1992, Geologic map of
Nassau County, Florida: Florida Geological
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White, W., 1970, Geomorphology of the Florida
peninsula: Florida Geological Survey Bulletin 51,
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