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THE MIDDLE MIOCENE ALUM BLUFF FLORA,
LIBERTY COUNTY, FLORIDA
SARAH LYNN CORBETT
A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE
UNIVERSITY OF FLORIDA
who grew up under the shade of
a big live oak and taught me
the value of all things in nature
The Peace of Wild Things
When despair for the world grows in me
And I wake in the night at the least sound
In fear of what my life and my children's lives may be,
I go and lie down where the wood drake
Rests in his beauty on the water, and the great heron feeds.
I come into the peace of wild things
Who do not tax their lives with forethought
Of grief. I come into the presence of still water.
And I feel above me the day-blind stars
Waiting with their light. For a time
I rest in the grace of the world, and am free.
I would like to thank my advisor and committee chair, Dr. Steven R.
Manchester, for help with fieldwork, processing samples, examining leaf material
critically, and for general advice along the way. I also thank my committee
members, Dr. Walter Judd, Dr. David Dilcher, and Dr. Michelle Mack, for
reviewing my work and making much needed suggestions. Several other
persons and organizations deserve acknowledgment as well. The Nature
Conservancy provided a permit for me and others to collect fossil plants on their
property, and Greg Seamon of The Nature Conservancy helped to arrange
access to the property. The Florida Paleontological Society Gary Morgan Award
committee and the Southwest Florida Fossil Club provided monetary support for
fieldwork and research. Dr. David Jarzen provided help with identification of
some palynomorphs, provided access to modern reference pollen collections and
palynological reprints, and made revisions to the pollen section. Student
assistant, Sabrina Khouri helped with pollen counts, cuticle extraction,
databasing, and photography. Global Geolabs of Medicine Hat, Alberta, Canada,
and Russ Harms processed pollen samples and generously processed those
samples for free. The University of Florida Electron Microscopy Core Laboratory
provided their facilities at no cost, and Fred Bennett and Karen Kelly of the EM
lab provided excellent training and technical support. Roger Portell answered
questions on Alum Bluff geology and reviewed revisions of the geology section.
Dr. Jon Bryan and Harley Means offered useful conversations on panhandle
geology and allowed me to accompany them on several field trips. Dr. Bill Elsik,
Dr. Vaughn Bryant, Dr. John Wrenn, and Dr. Fred Rich shared information and
reprints on eastern Miocene palynofloras. J. Yoder, R. Portell, K. Schindler, T.
Sweet, S. R. Manchester, T. A. Lott, the 1999 Paleobotany Class, the 2002
Phytogeography Class, and members of the Florida Paleontological Society
(2003) collected fossils from Alum Bluff. Laura Corbett McGuire provided her
photographic efforts and an occasional push in the right direction. Tamika
Robinson offered advice and answered many late night frantic phone calls.
Lastly, I would like to recognize my parents. I extend appreciation to my mother,
Janice Corbett, for extensive photocopying of references, support through this
project and always, and an enormous amount of tolerance and patience. And to
my father, the late Richard Larry Corbett, I express deep gratitude for always
providing much needed graduate school survival advice, being interested in my
work, being attentive to my questions, and instilling the interest in me to begin
TABLE OF CONTENTS
ACKNOW LEDG M ENTS................................. ........................ ii
LIST OF TABLES ............. ..................... .............. vi
LIST OF FIGURES ............................ .......... ............ vii
A BST RA C T ..... .............................................. ........... ix
INTRO DUCTIO N ................................... ................. 1
Modern Flora of Apalachicola Bluffs and Ravines.................... 2
Geology............. .................... ............. ......... 4
MATERIALS AND METHODS ...... ..... ........... ... ....................... 8
RESULTS ................................... ................. ................ 13
Leaf M acrofossils................. ............ ............... .......... 13
Fruits and Seeds ......... ........................ ..... ......... 22
Spores and Pollen................ .................. ... .... ........ 23
Spores .............. ................ ............... .......... 23
Pollen ............... ........ ........ ......... ....... .......... 27
Fungi ................ ......... ....................... ............. 36
DISCUSSION..................... ...... ................ ......... 71
Comparison with Other Miocene Floras................. .............. 71
Paleoecological Im plications ........ ... ..... ........ .. ......... ... 73
Biogeographical Im plications ........ ... ..... ........ .. ......... ... 77
C O N C LU S IO N S .......................................................... .......... 79
APPENDIX A SELECTED WOODY TAXA OCCURRING IN AND
AROUND THE APALACHICOLA BLUFFS AND RAVINES AREA AND
THEIR TYPICAL HABITATS...... ...... ...................... ..... ............ 82
APPENDIX B EXPLANATION OF PALYNOMORPH TERMINOLOGY...... 85
REFERENCES. .............. .. ......... ........... .............. ... 90
BIOGRAPHICAL SKETCH................... ... ........... 96
LIST OF TABLES
1 Examples of historical names of the stratum currently known as the
Alum Bluff Group, undifferentiated and their corresponding
publication ................................. ........ . ...... 7
2 Terrestrial Miocene palynomorph localities from eastern North
America used for comparison with Alum Bluff palynomorphs......... 24
3 Taxa shared between Alum Bluff and other Miocene localities ........74
4 Summary of taxa identified at Alum Bluff.............. ... ........... 81
LIST OF FIGURES
1 Map showing Alum Bluff and surrounding area.............. .......... 38
2 Apalachicola River and Alum Bluff exposure.............. ............. 39
3 Alum Bluff exposures showing Pleistocene to Miocene age
sediments. ............ ............. ......... ...... .... ...... 39
4 Lithostratigraphy of Alum Bluff......... .. ........... ....................... 40
5 Summary of geochronology, showing temporal relationships
between Torreya and Chipola Formations, and the Alum Bluff
Group, undifferentiated ................................................. 41
6 Fossil plant strata at the Alum Bluff exposure.............. .............42
7 Leaflets of Carva (Juglandaceae) .................. ............. ................43
8 Lauraceous leaf ............... ................ ........... .... ......... 44
9 Leaves of Paliurus (Rhamnaceae) .. ........................................ 45
10 Leaves and 'wood' of Sabalites (Arecaceae)............................... 46
11 Graduate student Xin Wang with a very large example of a
Sabalites leaf from Alum Bluff .... ....... ... ................. ......... 47
12 Leaves of Ulmus (Ulmaceae) ............ ........ ......... .......... 48
13 Alum Bluff leaf Morphotype AB1 ............ ..... ... ...... ....... 49
14 Alum Bluff leaf Morphotype AB2 ........... .. ......... ......... 50
15 Alum Bluff leaf Morphotype AB3 ..................... ... ...... ......... 51
16 Alum Bluff leaf Morphotypes AB4, 5, 6, and 7.............. ............ 53
17 Alum Bluff leaf Morphotypes AB8 and 9 ......... .................. 54
18 Alum Bluff leaf Morphotypes AB10, 11, and 12................ ..........55
19 Fruits and seeds from Alum Bluff.................... .......... ...... 56
20 Pie chart showing pollen count summary for Alum Bluff ............... 57
21 Fern spores from Alum Bluff ............. ... ....... ...........59
22 Gymnosperm and Poaceae type pollen from Alum Bluff ................61
23 Liliaceae, Magnoliaceae type, and miscellaneous dicotyledonous
pollen from Alum Bluff............. ........ ...... ......... ... ... 63
24 Fagaceae and Ulmaceae pollen from Alum Bluff...................... 64
25 Miscellaneous dicotyledonous pollen from Alum Bluff........ ......... 66
26 Unknown palynomorphs and dinoflagellate cyst from Alum Bluff...... 68
27 Fungal sporomorphs from Alum Bluff ............. ..................70
Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science
THE MIDDLE MIOCENE ALUM BLUFF FLORA,
LIBERTY COUNTY, FLORIDA
Sarah Lynn Corbett
Chair: Steven R. Manchester
Major Department: Botany
The Miocene flora of Alum Bluff, Liberty County, Florida, is significant
because of the relative rarity of Tertiary, and especially Miocene, fossil plant
localities in eastern North America. After conducting a paleofloristic study
including leaves, seeds, fruits, and pollen at Alum Bluff, implications for
understanding Miocene climate, biogeography, and paleoecology of the region
were inferred. The first study of the flora of the Alum Bluff site was conducted on
leaf impressions by E.W. Berry in the early twentieth century. Berry studied only
leaf macrofossils and identified 12 leaf species. Recent collections and further
examination of specimens reveals 22 identified taxa, 7 morphotypes of uncertain
taxonomic affinity, and 21 examples of unknown taxonomic affinity are also
present in the flora. Berry described the flora as being tropical with some
temperate elements found in the Florida panhandle today; however, recent finds
such as Paliurus, which is extinct in North America but present in Eurasia today,
suggest different floristic affinities and indicate that the flora was warm-
temperate. The composition of the flora was compared with modern floras and
other Miocene floras to determine the environmental conditions present at Alum
Bluff in the Miocene. It was found that the Alum Bluff flora an elm-hickory-
cabbage palm forest (similar to that of North central Florida today) occurring
along a river or near a river delta. Biogeographical implications of the Florida
panhandle region during the Miocene were inferred based on the floral
composition of Alum Bluff. The use of fruit, seeds, pollen, and leaves increased
the known diversity of the Alum Bluff flora, making it a paleobotanically important
Miocene floras are poorly known in eastern North America. In the
southeast U.S., Tertiary paleobotanical deposits are even less common, though
there are a number of marine Tertiary deposits in the region. The Brandon
lignite flora of Vermont, the Brandywine flora of Maryland, and the Alum Bluff
flora of Florida are some examples of the few eastern North American Miocene
localities with good preservation of macrofossils (Berry 1916, McCartan et al.
1990, Tiffney 1994, Tiffney and Traverse 1994). Due to the rarity of Tertiary
fossil plant localities in the southeastern coastal plain and especially in Florida,
the Alum Bluff flora is of special interest. Alum Bluff is located in the Florida
panhandle about 2 miles north-northwest of Bristol, Florida
(30028'08"N/84059'10"W) (Fig. 1). The exposure is a steep river cut bluff along
the Apalachicola River and is part of a property owned by the Nature
Conservancy known as Apalachicola Bluffs and Ravines Preserve.
The pioneering work on the Alum Bluff flora was done by Berry (1916). He
identified 12 plant species (based on leaf forms) and one fungal species from the
site. Recently collected leaf, seed, and pollen for this study from the same site
reveal new taxa not treated by Berry. Berry's work characterized the Alum Bluff
flora as being subtropical to tropical, and he made his identifications by
comparing the leaves with modern North American genera. Some of the newer
finds from the site evaluated in this study, however, suggest other floristic
relationships. A temperate Eurasian genus, Paliurus (Rhamnaceae), extinct in
North America today, was recently noted from the site by Manchester (1999).
Paliurus has also been found in Eocene to Miocene strata in the Western U.S.,
since the Eocene in Asia, and in the Oligocene and Miocene of Europe
(Manchester 1999). This study also revealed other taxa present at Alum Bluff,
including members of the Juglandaceae, Ulmaceae, Fagaceae, Altingiaceae,
Pinaceae, Cupressaceae, and a temperate member of the Aquifoliaceae. The
presence of Paliurus and the other temperate genera represented suggests more
temperate affinities than those Berry described based on his identifications.
The goals of this project were 1) to investigate the overall biodiversity of
Alum Bluff based on recent collections, 2) to interpret past climatological and
paleoecological conditions of the Alum Bluff region based on the floristic
assemblage, and 3) to examine the biogeographical implications and evidence
for floral change presented by the Alum Bluff floristic assemblage. To investigate
these goals, pollen, fruits, seeds, and leaves were examined from the Alum Bluff
Modern Flora of Apalachicola Bluffs and Ravines
In order to gain an appreciation of late Tertiary floristic change in
southeastern North America, it is useful to compare the Miocene Alum Bluff flora
with the flora existing in the region today. The modern flora of the area
surrounding Alum Bluff is botanically distinctive (Clewell 1977, James 1961,
Harper 1914, Leonard and Baker 1982, Means 1985, 1977, Ward 1979, Wolfe et
al. 1988, Wunderlin and Hansen 2003). In a study using a rarity-weighted
richness index to identify hot spots of rarity and richness, the Apalachicola River
Valley region of the Panhandle was identified as one of the five hot spots of
diversity for the United States (Stein et al. 2000). Also according to Stein et al.
(2000), the forests of the Florida panhandle region possess the "largest number
of tree species per unit area of any forests in the United States." Compared with
the number of taxa in the fossil flora examined by the author, the modern flora of
the area is much more diverse (see Appendix A), however this difference is likely
partially due to preservation factors which prevented the entire diversity of the
Miocene flora from being preserved.
Today, numerous endemic species are known from the Apalachicola River
Valley, and the region also contains many northern species at the southern
extreme of their range (or with disjunct occurrences). The reason for this
geographic isolation of more northern species along the Apalachicola River
corridor is largely because the Apalachicola corridor has been connected to the
Appalachian region almost continuously since the late Miocene (Clewell 1977,
Harper 1914). The Apalachicola River is the only river in Florida whose
watershed is fed mostly by areas outside the coastal plain, namely the Piedmont
and Appalachian Region, and thus the route for migration of species has
primarily been from these areas. The high proportion of endemic species may be
related to both genetic isolation and topography of the area (James 1961, Myers
and Ewel 1990, Ward 1979, Wolfe et al. 1988). Unlike most of peninsular
Florida, the Apalachicola River Valley is largely protected from fire. Fires cannot
approach from the west because of the river, and fires are slow to spread
downslope in the gully-eroded ravines along the eastern bank. Thus, humus
accumulates creating a rich growing environment (Clewell 1977, Harper 1914).
These conditions would not have been present during the Middle Miocene,
however, since the Apalachicola River Valley began to form around this time
The Apalachicola River is formed by the confluence of the Chattahochee
and Flint rivers at the Georgia/Florida border near the town of Chatahoochee and
Lake Seminole. It extends through the Northern Highlands geographic province
of Florida and down through the Gulf Coastal Lowlands near Apalachicola,
Florida. According to Harper (1914, p. 228),
From its beginning at the southwestern corner of Georgia to about the
latitude of Bristol the Apalachicola River has on its east side some of the highest
land in Florida ..., which comes out to the river in several places, making steep
bluffs. Between these bluffs are deep rich valleys, some of which extend back
several miles from the river.
Alum Bluff, first described by Langdon (1889), is one of the bluff
exposures characteristic along the Apalachicola. It is considered probably the
most conspicuous topographic feature in Florida (Harper 1914, Schmidt 1986),
and is characterized by a precipitous face that is about 170 feet high.
The bluff exposes a stratigraphic sequence of Miocene to Pleistocene
age sediments (Fig. 2, 3). There are five lithologic units exposed at Alum Bluff
including Miocene Alum Bluff Group (Chipola Formation and unconformably
overlying undifferentiated beds) (Gardner 1926, Johnson 1989b), the Pliocene
Jackson Bluff Formation, the Plio-Pleistocene Citronelle Formation, and a section
of undifferentiated surficial clastics (Schmidt 1986) (Fig. 4). The plant-bearing
horizon is in the upper part of the Alum Bluff Group in unnamed beds
(undifferentiated stratum) above the Early Miocene Chipola Formation and below
the Pliocene Jackson Bluff Formation, and is inferred to be middle Miocene (15-
18 million years old) in age (Bryant et al. 1992, Johnson 1989a, Schmidt 1986)
(Fig. 5). This stratum is characterized by gray to yellow and white clayey sands
(Schmidt 1986). Within the upper portion of this stratum, fossil leaves, roots,
seeds, pollen, and wood have been collected. It was observed that there are
approximately five fossil plant layers within a half-meter stratigraphic interval in
the upper portion of the Alum Bluff Group (undifferentiated stratum) (Fig. 6). A
number of age-significant mammals (Hemingfordian or early Barstovian) have
also been isolated from the undifferentiated stratum of the Alum Bluff Group
including Prosynthetoceras texanas, a protoceratid mammal (Webb et al. 2003),
a small anchitherine horse (Bryant et al. 1992, Olsen 1964, 1968), a small
rhinocerotid, and an equid known as Merychippus gunteri (Bryant et al. 1992). It
is important to note that mammal fossils have not been found in situ with the
plant fossils, but rather as outwash from the Alum Bluff Group (undifferentiated)
stratum. The underlying Chipola Formation has a rich molluscan fauna, and has
been estimated to be about 18.3-18.9 million years old giving a maximum bound
for the age of the leaf deposit (Bryant et al. 1992). The Alum Bluff Group
(undifferentiated) however, due to the presence of late Hemingfordian or early
Barstovian mammals, is estimated to be between 15-18 million years old. The
overlying Jackson Bluff Formation is also a fossiliferous stratum, however it
yields marine fossils including bone fragments of dugong, sharks teeth, and
The Alum Bluff Group (undifferentiated) is thought to represent deltaic or
pro-deltaic sediments (Schmidt 1986). Also, the sandy matrix surrounding fossil
plants at Alum Bluff and the presence of trunks of Sabalities in the fossil beds
suggests a high energy riverine depositional environment capable of carrying and
depositing heavy sediment particles and plant materials (pers. comm. Dilcher
2004). The conspicuous lack of megaspores of heterosporous ferns in sieved
material or sediment processed for pollen also indicates a moving-water
depositional environment as opposed to a still-water lake or pond environment
(pers. comm. Dilcher 2004).
The nomenclatural history of geologic units exposed at Alum Bluff is
somewhat confusing and has changed numerous times since the Alum Bluff
lithostratigraphy was first described. The Alum Bluff Group, undifferentiated, has
been called the "Fort Preston Sand," the Alum Bluff Formation, the Hawthorne
Formation, and the Choctawhatchie Stage, among others (Table 1).
Table 1. Examples of historical names of the stratum currently known as the
Alum Bluff Group, undifferentiated and their corresponding publication
Oak Grove Sand Berry 1916
Choctawhatchie Stage Olsen 1964, 1968
Hawthorne Formation Campbell 1985, Schmidt 1986
Fort Preston Sand Puri and Vernon 1964, Bryant et al. 1992
Alum Bluff Group Gardner 1924, Johnson 1989b
Alum Bluff Group/ Rupert 1994
Hawthorn Group sands
Alum Bluff Formation Webb et al. 2003
MATERIALS AND METHODS
Macrofossils were collected haphazardly from the plant-fossil bearing
strata by exposing fossiliferous platforms on the hillside at Alum Bluff. Care was
then taken to extract mostly complete specimens from the excavated areas.
Some specimens were collected as very large (ca. 0.3m2) chunks which were
allowed to dry in the lab, then broken apart to expose macrofossils. Most of the
collections from Alum Bluff were made at the northernmost end of the exposure.
Macrofossils collected from Alum Bluff were photographed with oblique lighting
using a Nikon Coolpix 995 digital camera. Due to the fragile nature of the
specimens from Alum Bluff, some were treated with Paleo-bond Penetrant
Stabilizer (manufactured by Paleo-bond, Inc. of St. Paul, MN) to prevent the
sandy matrix from crumbling. Others were stabilized with a diluted solution of
Elmer's white glue. No glue or Paleo-bond was applied to the face of the fossil
itself, but only to the attached matrix. Leaf descriptions were developed using
the categorization and terminology set forth in the Manual of Leaf Architecture
Some sediment was processed for pollen in the Paleobotany lab at the
Florida Museum of Natural History (FLMNH) using a technique modified from
Traverse (1988). Other samples were outsourced for processing by Global
Geolabs, Ltd. of Medicine Hat, Alberta, Canada. At FLMNH, the outer surface of
30-200g sediment samples were first scraped away to avoid potential
contamination with modern pollen. The samples were then ground with a mortar
and pestle until only loose, coarse particles remained. The sediment was
transferred to a plastic beaker, and distilled water was added to make a sediment
slurry. Enough 5% HCI was added to cover the sample. No reaction was
observed indicating that no carbonates were present, so the HCI was decanted.
The sample was washed with distilled water and decanted three times. A volume
of 49% HF equaling about one and a half times as much as the sample was then
added. The beaker was covered and allowed to sit under a fume hood for 2-4
days. Periodically, the sample was agitated. The sample was then separated
into plastic centrifuge tubes and centrifuged for 15 minutes. The HF was
decanted and the samples were washed with distilled water three times. Zinc
Chloride at a specific gravity of 1.7 was then added. Samples were agitated and
centrifuged for 30-45 minutes. Samples were allowed to sit in a test tube rack for
4-10 days without being disturbed. After this period, a small amount of distilled
water was added and then siphoned off with the organic matter that had
separated from the sediment. The siphoned material was placed in a separate
centrifuge tube and washed several times. Several drops of 30% EtOH was
added to each tube to retard fungal growth. One to three drops of the organic
slurry were then placed on a glass slide with one to two drops of glycerine. The
sample was covered with a coverslip, which was rimmed with clear fingernail
polish or Canada balsam. Pollen grains and spores were photographed via light
microscopy with a Nikon SLR using black and white Technical Pan (ISO 25) or
color print film (ISO 100). X and Y coordinates were recorded from the Nikon
Eclipse E600 microscope. For comparison with coordinates of other
microscopes, a point placed on a standard biological microscope slide 3 cm from
the left edge and 1.5 cm from the bottom edge gives coordinates of 44.2x,
Observations were also made using scanning electron microscopy (SEM).
Some preparations were made by placing a 12mm round smooth adhesive pad
onto a standard SEM stub, and then placing a drop of pollen slurry on the pad.
These SEM stubs were placed in a closed SEM stub box and then allowed to dry
on a slide warmer. Other SEM stubs were prepared by placing a small 1.3 cm2
piece of tinfoil with adhesive onto a standard 12mm SEM stub. A 12mm round
glass coverslip was then placed in the center of the tinfoil square, and the
corners of the square were crimped around the coverslip to hold it in place. A
drop of pollen slurry was placed on the coverslip. The stubs were placed in a
closed SEM stub box and then on a slide warmer or in incubator for several
hours to dry. This second method was developed after it was found that the
pollen grains and spores tended to sink into the adhesive, obscuring part of the
structure. Also, the second method was advantageous in that it enabled a
permanent slide to be prepared that can be accessioned into the UF
paleobotanical collections. Stubs were sputter coated and observations were
made using a Hitachi S-400 Fe-SEM at the University of Florida Electron
Microscopy Core Laboratory. After SEM observations were completed, the
coverslips were removed from the stubs and inverted onto a drop of Canada
balsam on a standard glass microscope slide.
Pollen, pteridophyte spores, and fungi (fruiting bodies and spores) were
described using a synthesis of terminology defined by the AASP Workgroup on
Fossil Fungal Palynomorphs (1983), Huang (1981), Moore et al. (1991), Traverse
(1988), and Weber (1998) (see Appendix B).
Pollen counts were conducted by tallying all pollen grains of specific
genera or morphotypes on four slides. The slides were prepared from sediment
that was either clay-rich or sand-rich from different levels in the exposure. At
least 250 individual grains were counted on each slide. A total of 1,072 grains or
spores were included in the percentage calculations. Because this was a
random sampling technique, not all genera or morphotypes identified are
described in the pollen count summary.
Cuticle analysis was preformed on some specimens. The cuticle
preparation method used was that of Kva6ek (pers. comm. w/ S. R. Manchester
2003), which was modified from Dilcher (1974). Loose cuticle samples were
removed carefully from fossils with forceps. The samples were then transferred
to a water droplet on a glass slide. A fresh Schulz' solution was then prepared
by adding several crystals of Potassium Chlorate to a few drops of concentrated
Nitric Acid, making sure the solution was saturated (crystals remained at bottom).
Monocot cuticle was treated for 10 minutes, while dicot cuticle was treated for 2-5
minutes. Timing was determined by carefully watching the sample, and then
quickly diluting the Schultz solution with distilled water when the cuticles had
cleared to a pale brown color (eudicots and magnoliids), or had cleared partially
(from black to chocolate brown)(monocot). After diluting the Schulz' solution, it
was pipetted off, and the specimen was washed two to three more times in a
Euicot and magnoliid cuticle was then transferred in water to a slide and
observed via a dissecting microscope. The abaxial and adaxial cuticles were
carefully teased apart with fine needles and the mesophyll was carefully scraped
away. A drop of glycerine jelly was added to the slide and a slipcover was
placed over it with a ring of clear fingernail polish to keep it in place and to
Monocot cuticle was still dark and was treated with a couple drops of NH3
(ammonia) after the Schulz treatment. The cuticle quickly cleared with this
treatment, but remained very fragile. Repeated attempts were made to extract
monocot cuticle, each time successively shortening the time in Schultz solution
from 10 to 5 to 2 minutes and reducing the amount of ammonia and then
eliminating the ammonia treatment entirely. However, despite these efforts, the
cuticle disintegrated easily when the attempts were made to pry the cuticle layers
apart. SEM observations were also attempted on monocot cuticle, but the
cellular structure was obscured. No successful observations of monocot cuticle
Some sediment from Alum Bluff was sieved previous to the start of my
investigations. Some of the grey, siltstone bearing black leaf compressions was
disaggregated in Hydrogen Peroxide and washed through a series of screens
with mesh size grading from 1 mm to 0.33 mm. Only one specimen obtained
from the sieving method was found to be taxonomically identifiable.
From the leaf, spore, pollen, fruit and seed observations that were made,
30 taxa have been recognized (Table 4). Seven morphotypes of uncertain
taxonomic affinity, and 22 examples of unknown taxonomic affinity were
described (Table 4). In addition, 11 leaf morphotypes of uncertain taxonomic
affinity, and 17 pollen or spore morphotypes of uncertain affinity were
Sixteen morphotypes were identified from Alum Bluff. Only two of the
morphotypes are named to genus, one morphotype is tentatively named to genus
(Table 4), and the remaining 12 morphotypes are designated "Morphotype AB1-
In the current description of the flora, most leaves were not named to a
specific genus, though the morphology of the leaves is certainly that of species
belonging to a more temperate climate, as evidenced by the small leaf size and
frequency of leaves with serrate margins.
Carva (Juglandaceae). 10+ specimens. Fig. 7a-f. Leaves presumably
compound. Lamina elliptic to ovate, asymmetrical, unlobed microphyll-
notophylls, length to width ratio 2-2.4:1. Apex straight to cuneate, base cuneate.
Margin serrated, 1 tooth order, 4 teeth/cm, spacing regular, teeth are straight
above and may be straight or convex below, sinus angular. Primary vein straight
to curved. Secondaries pinnate, craspedodromous. All secondaries terminate in
a tooth. Spacing of secondaries increasing toward base, angle relative to the
primary vein also increasing toward base. Tertiaries opposite percurrent, straight
vein course, obtuse vein angle relative to primary. Quaternary and higher order
veins not well preserved.
The identification of this foliage as Carva is supported by the abundant
pollen and nut evidence of the genus at Alum Bluff. The leaves are fragmentary
in most cases, however the distinct character of the venation and the
asymmetrical lamina base and overall asymmetrical shape of the leaf also lend
support to the identification as Carva. Of the modern reference material I
observed, characteristic opposite percurrent tertiaries are very similar to the fossil
material from Alum Bluff. Also, the tendency of the secondaries to dichotomize
near the margin, and the dichotomous branches to enervate two teeth is
characteristic of modern Carya. In modern material, occasionally, one or both of
the secondary branches branch again and feed into the teeth as well (thus one
secondary enervates up to 3-4 teeth). This was observed in the fossil material as
Extant Carva ranges from eastern North America to Central America and
a few species occur in eastern Asia. There are six species of living Carva in the
Apalachicola River Valley. Macrofossils of Carva are known from the Miocene of
the eastern U.S. in the Brandon Lignite of Vermont (Tiffney 1994).
Lauraceae. 1 specimen. Fig. 8a-c. Leaves simple. Lamina elliptical,
entire microphyll. Apex and base missing. Secondary veins weak
brochidodromous. Tertiary and higher order veins not well preserved. Stomata
paracytic, oil cells common.
Cuticle was successfully recovered and processed from this fragmentary
Alum Bluff specimen. Before removal, the cuticular material appeared
coriaceous (Fig. 8c). Several characteristics of this cuticle suggest that it may
belong to a member of the Lauraceae. Before the abaxial and adaxial cuticles
were separated, it was noted that the mesophyll contained numerous, large oil
cells. One oil cell remained attach with some mesophyll remnant to one cuticle
surface (Fig. 8a).
Paliurus (Rhamnaceae). 3 specimens. Fig. 9a-d. Leaves simple.
Lamina elliptical, symmetrical, unlobed microphylls to notophylls. Length to width
ratio approximately 1.3:1. Apex missing in all specimens, base acute, straight to
slightly concave. Leaf serrate with possibly gland-tipped teeth, 1 tooth order, 3
teeth/cm, spacing regular. Primary veins basal actinodromous with 3 basal
veins. Secondaries craspedodromous. Tertiary and higher order veins not well
The identification of Paliurus leaves at Alum Bluff is tenuous. Though a
convincing winged fruit has been found at the site (Fig. 19g) (Manchester 1999),
leaves have proven more troublesome. Though the leaves illustrated here as
Paliurus share some common characters with that of modern Paliurus, namely
three basal veins arising from the same point and arching toward the leaf apex
and serrate margins, identification cannot be confirmed in the leaves due to lack
of preservation of higher order venation and the absence of a leaf apex. The
identification presented here is provided as a possible taxon for this morphotype.
Sabalites (Arecaceae). 20+ specimens. Fig. 10a-e, Fig. 11. Large
plicate leaved, costapalmate (rachis of leaf continues through where leaf
segments begin to diverge to form a narrow point near the midpoint of the leaf)
palm fronds, up to 50X50+mm. Individual leaf segments display a prominent
midvein. Veins arise at an acute angle from the costa and continue to the of the
leaf apex. A small hastula (ligule-like appendage) is evident at the base of the
leaf (Fig. 10c). Petiole of leaf large without spines or otherwise armed edges.
Sabalites is probably the most common megafossil found at Alum Bluff.
Fan palms of similar form are noted from Tertiary sites from the gulf coastal plain
Florida to Texas and from Kentucky and Tennessee (Berry 1916, Daghlian
1978). The large, coriaceous leaves occur in dense overlapping mats within the
fossil plant strata. Repeated efforts were made to extract cuticle from Sabalites
specimens for more precise generic and species determination with no success.
Several large trunks of palm were also observed, and a portion of one of these is
illustrated in Fig. 10d. In viewing the trunks in cross section, large, conspicuous
fibers typical of palm stems were evident.
The form genus, Sabalites, is used here to describe the costapalmate
palm leaves from Alum Bluff. Sabalites was also the name used by Berry in his
original description of the flora. Lacking diagnostic characters found in fruits,
flowers, or leaf cuticle, identification to a modern genus can not and should not
be made (Daghlian 1978, Read and Hickey 1972). Palm leaves from Alum Bluff
may be erroneously named if assigned to a modern costapalmate palm genus
such as Sabal in the absence of distinctive fruit, flower, or cuticle characters.
Berry named the species at Alum Bluff Sabalites apalachicolensis, however he
named this species essentially as a locality morphotype without specifying of
distinctive characters that distinguish the Alum Bluff material of Sabalites from
that of other Tertiary deposits. Thus, this species name cannot be confirmed.
Ulmus (Ulmaceae). 10+specimens. Fig. 12a-f. Leaves simple. Lamina
elliptic to ovate, symmetrical to slightly asymmetrical at the base, unlobed
microphyll-notophylls, length to width ratio 2-2.4:1. Apex straight to cuneate,
base cuneate. Margin serrated, 1 tooth order, 4 teeth/cm, spacing regular, teeth
are straight above and may be straight or convex below, sinus angular.
Secondaries pinnate, craspedodromous, 1 basal vein. All secondaries terminate
in a tooth. Spacing of secondaries increasing toward base, angle relative to the
primary vein also increasing toward base. Tertiaries alternate percurrent, straight
vein course, obtuse vein angle relative to primary. Quaternary and higher order
veins are not well preserved.
This is one of only two genera upheld from Berry's (1916) original work on
the Alum Bluff flora (Berry designated a new fossil species, Ulmus floridana). In
Berry's description of the material, however, he describes the petiole of Ulmus
floridana as being "short and stout, about 2.5 millimeters in length." The material
that I examined, however, exhibited a significantly longer petiole, being at least
4.0-9.0 mm in length (Fig. 12a, b, e, f). Specimens of Ulmus exhibit secondaries
which often dichotomize near the margin. This phenomenon was observed in
modern reference material as well. Unlike the Carya leaves, however, one of the
dichotomous branches enervates the tooth, while the other usually feeds into the
sinus between the teeth and rarely enervates a tooth. In addition, the alternate
percurrent tertiary venation of Ulmus distinguishes it from Carva. This type of
tertiary venation is typical in modern Ulmus.
Morphotype AB1. 6 specimens. Fig. 13a-g. Leaves simple. Lamina
ovate to elliptical, symmetrical, unlobed microphylls to notophylls, length to width
ration 0.8-2.5:1. Apex obtuse, rounded. Only one specimen of an isolated apex
was found (Fig 13g). Apex is missing in all other specimens. Base cuneate to
slightly concave. Only fragmented petiole preserved in some specimens. Margin
crenate with about 1-1.5 crenations/cm, spacing regular, sinuses rounded.
Primary veins are basal actinodromous, five basal veins present. Primaries feed
into the large, broad, rounded teeth. Secondaries enervate remaining teeth
(craspedodromous) (Fig 13f).
Berry (1916) reported observing but being unable to collect a palmately
veined leaf at Alum Bluff that he thought was Ficus. He gave no mention to
whether marginal characters were observed. Berry may have observed the
Morphotype AB1 leaf instead.
Morphotype AB2. 4 specimens. Fig. 14a-d. Leaves simple. Lamina
elongated ovate, symmetrical, unlobed microphylls, length to width ratio 7:1.
Apex missing but likely acute-acuminate. Basal portion and petiole are missing
in all specimens. Margin is serrate, 1 tooth order, 5 teeth/cm, tooth spacing
regular, teeth are straight above and convex below, tooth apex simple, tooth
sinuses angular. Secondaries pinnate, weakly brochidodromous. Secondaries
terminate in some but not all teeth. Spacing of secondaries increasing toward
base, secondary angle relative to the primary vein decreasing toward base.
Tertiaries alternate percurrent, vein course straight. Quaternary and higher order
veins not well preserved.
Morphotype AB3. 3 specimens. Fig. 15a-d. Leaves simple. Lamina
ovate, symmetrical, unlobed microphylls, length to width ratio ca. 2:1. Apex is
missing (straight?) as is basal portion and petiole in all specimens. Margin is
entire. Secondaries pinnate, weakly brochidodromous. Spacing of secondaries
increasing toward base, secondary angle relative to the primary vein smoothly
decreasing toward base. Tertiaries random reticulate, vein course slightly
exmedially ramified. Quaternary veins reticulate. Areolation appears to be well
developed, freely ending ultimate veins appear absent.
Morphotype AB4. 1 specimen. Fig. 16a, b. Leaves simple. Lamina
ovate, symmetrical, unlobed microphyll, length to width ratio 2.75:1. Apex
narrowly rounded, basal portion and petiole missing. Margin entire. Primary
veins basal acrodromous. Secondaries basal acrodromous. Tertiary and higher
order veins are not well preserved.
Morphotype AB5. 1 specimen. Fig. 16c, d. Leaves presumably
compound. Lamina asymmetrical, unlobed microphyll-notophyll (or leaflets from
a compound leaf), length to width ratio ca. 2.33:1. Apex is missing (interpreted
as acuminate/straight?), base cuneate. Petiole ca. 0.5 cm. Margin entire.
Secondaries pinnate, craspedodromous, 1 basal vein. Spacing of secondaries
decreasing slightly toward base, vein angle relative to primary vein is uniform.
Tertiary and higher order veins are not well preserved.
Morphotype AB6. 1 specimen. Fig. 16e-g. Leaves simple. Lamina
obovate, symmetrical, unlobed microphyll, length to width ratio 1.3:1. Apex
obtuse, convex, base concave. Margin serrated, 1 tooth order, 2 teeth/cm,
spacing regular, teeth flexuous or convex above and convex below. Secondary
veins pinnate, craspedodromous, 1 basal vein. Secondary spacing and angle
unclear due to poor preservation. Tertiary and higher order veins also obscure.
This specimen is composed of fragmented segments of cuticle and no clear
impression is evident.
Morphotype AB7. 1 specimen. Fig. 16h, i. Leaves simple. Lamina
ovate, symmetrical, unlobed micropyhll, length to width ratio 1.14:1. Apex
obtuse, acuminate, base obtuse, rounded. Margin entire. Secondaries pinnate,
weak brochidodromous, 1 basal vein. Spacing and vein angle of secondaries
uniform. Tertiary and higher order veins poorly preserved.
Morphotype AB8. 1 specimen. Fig. 17a, b. Leaves simple. Lamina
elliptic, symmetrical, unlobed microphyll, length to width ratio 1.65:1. Apex
obtuse-rounded, base acute-convex. Margin entire. Secondary veins pinnate,
weak brochidodromous, 1 basal vein. Spacing and angle of secondaries
decreasing toward base. Tertiaries random reticulate or regular polygonal
reticulate (preservation makes determination difficult). Higher order veins are not
visible due to poor preservation.
Morphotype AB9. 1 specimen. Fig. 17c-d. Leaves simple. Lamina
elliptical, symmetrical, unlobed microphyll, length to width ratio 2.7:1. Apex
acute-straight, base is missing (perhaps cuneate). Margins serrate, 1 tooth order,
3 teeth/cm, irregular spacing, angular sinus, tooth straight above and convex
below. Only tertiary veins enervate the teeth. Secondary veins pinnate,
semicraspedodromous, 1 basal vein. Spacing and angle of secondary veins
decreasing slightly toward base. Tertiary veins regular polygonal. Quarternary
veins regular polygonal reticulate. Higher order veins lacking or poorly
Morphotype AB10. 2 specimens. Fig. 18a-b. Leaves simple. Lamina
elliptic, symmetrical, unlobed notophyll, length to width ratio 2.6:1. Apex acute,
convex, base acute, cuneate. Margin entire. Secondary veins pinnate,
brochidodromous. 1 basal vein. Spacing and angle of secondaries decreasing
toward base. Tertiaries and higher order viens not well preserved.
Morphotype AB11. 2 specimen. Fig. 18c-e. Leaves simple. Lamina
elliptic, symmetrical, unlobed notophyll, length to width ratio 2:1. Apex acute,
straight, base obtuse, rounded. Margin entire. Secondary pinnate, veins
brochidodromous. 1 basal vein. Spacing of secondaries decreasing toward
base. Angle of secondaries increasing toward base. Tertiaries alternate
percurrent. Higher order veins are not well preserved.
Morphotype AB12: 1 specimen. Fig. 18f. Leaves simple. Lamina
elliptical, symmetrical, unlobed microphyll, length to width ratio 4:1. Apex
convex, base convex. Margin entire. Secondaries pinnate, weak
brochidodromous. Spacing of secondaries increasing toward the base, and vein
angle of secondaries relative to the primary vein is smoothly increasing toward
base. Tertiaries appear randomly reticulated, but are poorly preserved. Petiole
Fruits and Seeds
Carya (Juglandaceae). Fig. 19a-f. Fruits with thick, smooth husks
(averaging ca. 2mm thick) (Fig. 19a, f), nut 13-15X20-30mm, endocarp 12-
15X15-17mm. Husk appears to separate into four valves. Locule cast shows a
pair of longitudinal grooves corresponding to primary and secondary septa with
the the nut (Fig. 19d).
Paliurus (Rhamnaceae). Fig. 19g. Winged fruit, with the wing extending
horizontally outward around the circumference of the fruit. Approximately
10X15mm, seed body 4X6mm. Persistent perianth disk scar present.
The evidence of a persistent perianth disk scar (raised rim below the
wing), distinguishing it this taxa from Cyclocarya (Manchester 1999). Modern
Paliurus occurs primarily in Asia, though some species do occur in southern
Europe. The introduction of this Eurasian endemic group to the Alum Bluff flora
significantly changes the interpretations of Berry (1916), as will be discussed
Scirpus (Cyperaceae). Fig. 19h. Three angled achene, approximately
0.4X1.29mm, apparently not subtended by hyaline scales. Specimen was
unfortunately broken during preparation for SEM, but the three angled nature is
Unknown fruit. Fig. 19i. Globose fruit, 10X10mm. Several examples of
this form exist at Alum Bluff, but none have yet revealed peduncle or perianth
scars, etc. which would aid identification.
Spores and Pollen
Unlike the limited macrofloral assemblages, there are several Miocene
localities in the eastern United States from which pollen is known (Table 2).
Occurrence of palynomorphs at Alum Bluff has been compared with other known
terrestrial Miocene localities in the eastern United States (Table 2).
Approximately 30 palynomorphs have been identified at least to "type" (most
similar systematic group) from Alum Bluff (Table 4). In addition, percentages of
abundance of some of the pollen types identified at Alum Bluff are illustrated (Fig.
20). The most abundant pollen types, based on pollen counts of 1,072 grains, at
Alum Bluff are Carva, Pinus, Ulmus, and an unknown monosulcate pollen
(Magnoliid type). All other pollen types account for 2% or less of the total pollen
abundance at the site. No attempt was made to identify pollen morphotypes to
the species level.
Fern spores are relatively common in the Alum Bluff sediments, and as a
group account for approximately 4-5% of the total palynomorph abundance.
Despite this frequent occurrence in the palynomorph record, ferns are entirely
lacking from the macrofossil assembledge. This is probably due in large part to
the harsh, sandy preservation environment. Herbaceous fern remains likely
decayed quickly in the highly oxic riverine deposits along the Apalachicola River.
Table 2. Terrestrial Miocene pollen localities from eastern North America used
for comparison with Alum Bluff pollen. See Table 3 for details of the occurrence
of individual elements of several of these floras.
Early late Miocene
Rich et al. 2002
Wrenn et al. 2003
McCartan et al.
1994, Tiffney and
Adiantaceae. Fig. 21a, b. Trilete spore, subtriangular., ca. 45X45 pm.
Laesural arms 17-20 pm long, straight, margo flange-like with irregularly sinuous
ridges. Surface verrucate.
In the modern flora of Alum Bluff area, there is one species belonging to
the Adiantaceae that occurs (Adiantum capillus-veneris). The spore closely
resembles Jamesonia, a tropical member of the Adiantaceae. Jamesonia occurs
from Mexico to Bolivia and Brazil at high altitutes. Jamesonia is not known from
Tertiary sites in North America, though it does have a fossil record from the
Pleistocene within it's native range (Hammen and Gonzalez 1960, Hafsten
1960). Graham and Jarzen also noted fossil Jamesonia from Puerto Rico
(1969). The laesural ridges also resemble Anogramma of the Adiantaceae.
Botrychium (Ophioglossaceae). Figure 21c. 1 specimen observed.
Trilete spore, subtriangular, ca. 35X35 pm. Laesura not evident in SEM. Surface
Extant Ophioglossaceae are subcosmopolitan. Fossil records from the
Miocene of eastern North America are not known.
Cyathea (Cyatheaceae). Figure 21d. Trilete spore, subtriangular, ca.
40X40 pm. Laesural arms ca. 12X1 pm long, straight, margo flange-like.
In North America, modern Cyatheaceae are widespread in tropical
montane Mexico to Chile and in the Caribbean. In eastern North America,
Cyathea has been reported from the Miocene in the Legler Lignite of New Jersey
(Rachele 1976). Frederiksen (1984) also reported a Cyathea-like type in the Old
Church Flora of Virginia.
Dryopteris (Dryopteridaceae). Fig. 21e, f. Trilete spore, 30-40X40-55
pm. Laesural arms ca. 15X2 pm long, straight, margo line-like. Surface covered
with large verrucate, almost bladder-like, processes.
Extant Dryopteris are cosmopolitan. Dryopteris ludoviciana occurs in the
modern Alum Bluff area flora. Dryopteris is not known from other Miocene
eastern North American sites.
Polypodiaceae. Fig. 21g-i. Bilateral monolete spore, 20-40X33-60 pm..
Laesurae 20-45 pm, simple commissure. Surface verrucate.
Modern Polypodiaceae are widespread with many speices in temperate
and tropical regions. Two species occur in the modern flora near Alum Bluff
(Pleopeltis polypodioides and Phlebodium aureum). In the Cenozoic fossil
record, Polypodiaceae is well known in North America. Polypodium fertile is
known in the Miocene Weaverville Formation at Redding Creek, California
(Kva6ek et al. 2004). In eastern North America, members of the Polypodiaceae
have been identified from the Brandon Lignite of Vermont (Traverse 1955, 1994,
Tiffney 1994, Tiffney and Traverse 1994), Catahoula formation of Louisiana
(Wrenn et al. 2003), Legler Lignite, New Jersey (Rachele 1976), and the Calvert
Formation, Delaware (Groot 1992).
Pteris (Pteridaceae). Figure 21j. Trilete spores, rounded triangular, ca.
45X47 pm.. Laesurae not evident in SEM. Surface baculate to clavate.
Equitorial ridge present, annulotrilete.
Extant Pteris is cosmopolitan, occurring in both warm and temperate
regions. Three species occur today in the Alum Bluff area flora (Pteris cretica, P.
multifida, and the introduced P. vittata).
Unknown Trilete Spores
Figure 21k, I. Trilete spores, rounded triangular, ca. 15-17X20-25 pm..
Laesural arms ca. 15 pm long, straight, margo lip-like. Surface slightly verrucate.
Perhaps Momipites (an angiosperm pollen type)?
Figure 21m. Trilete spores, rounded triangular, ca. 17X20 pm.. Laesural
arms ca. 10 pm long, straight, margo line-like. Surface psilate.
Figure 21n. 1 specimen observed. Trilete spore, subtriangular, 45X45
pm.. Laesural arms ca. 20 pm long, curved. A large gap (ca. 15 pm) extends
between the laesurae. Margo may be line-like.
Figure 21o. 47X46 pm. Trilete spore, globose. Laesural arms ca 25 pm
long, straight, margo line-like. Surface reticulate.
Figure 21p,q. ca. 45X60 pm. Trilete spore, ellipsoidal. Laesural arms ca
30 pm long, straight, margo line-like. Surface reticulate. May be a member of
Taxodium (Cupressaceae). Fig. 22a-c. Inaperturate pollen grains that
split deeply and fold inwards along their equators, 18-25X15-22 pm. Very small
gemmate ornamentation is evident in SEM (Fig. 22c).
Modern Taxodium is primarily restricted to the eastern North America, with
one species occurring at higher elevations in Mexico. Both North American
species of Taxodium occur near Alum Bluff in the modern flora. Taxodium is
known from several other Miocene sites in eastern North America including the
Brandywine Flora (McCartan et al. 1990), the Ohoopee River dune field (Rich et
al. 2002), the Calvert Formation, Delaware (Groot 1992), and the Legler Lignite
(Rachele 1976). Traverse identified Glyptostrobus, a close relative of Taxodium,
in the Brandon Lignite (1955).
At Alum Bluff, Taxodium is relatively uncommon, accounting for less than
2% of pollen abundance at the site. No macrofossils of Taxodium have been
found at the site.
Pinus (Pinaceae). Fig. 22d-g. Vesiculate pollen grain with bladders
broadly attached to the corpus. Overall-40-55X70-80 pm. Corpus 30-45X45-60
pm. Sacci 30-45X30-45 pm. Bladders reticulate under light microscopy (Fig.
22e, g), psilate under SEM (22d, f). Corpus reticulato-verrucate.
Pine is one of the most abundant and widespread genera in the
palynological record, largely due to its copious pollen production and long-
distance pollen dispersal (Traverse 1988). Seven species are native today in the
Apalachicola River Valley. In the Miocene of the eastern United States, Pinus is
known from the Ohoopee River dune field (Rich et al. 2002), the Catahoula
Formation (Wrenn et al. 2004), the Legler Lignite (Rachele 1976), the
Brandywine Flora of Maryland (McCartan et al. 1990), and the Calvert Formation
of Delaware (Groot 1992).
Despite the abundance of Pinus pollen in the Alum Bluff sediment (26.4%
of the total pollen assemblage), no macrofossils of Pinus were discovered at
Alum Bluff, indicating that Pinus was likely transported to the site from some
distance away. The overabundance of pine pollen in the Alum Bluff sediment,
however, suggests that Pinus was certainly present in the area immediately
surrounding Alum Bluff.
Poaceae. Fig. 22h-k. Monoporate spheroidal-subspheroidal to prolate
pollen grains, 40-45X40-65 pm. Surface psilate. Most examples exhibit a
prominent annulus (Fig. 22i-k), and one shows an operculum still in place (Fig.
Poaceous type pollen has also been identified from the eastern U.S.
Miocene in the Legler Lignite (Rachele 1976), the Catahoula Formation (Wrenn
et al. 2003), the Ohoopee River dune field (Rich et al. 2002), and the Brandon
Lignite (Traverse 1955). In the Alum Bluff sediments, Poaceous type pollen was
identified successfully only with SEM and was rare in the samples overall.
Liliales. Fig. 23a-d. Monosulcate pollen grains, 12-25X20-45 pm.
Surface perforate to foveolate.
Liliaceous pollen has also been reported from the Miocene of the eastern
U.S. at the Catahoula Formation (Wrenn et al. 2003), the Ohoopee River dune
field (Rich et al. 2002), and the Piney Point Formation (Fredericksen 1984). At
Alum Bluff, Liliaceous pollen is rare (>1% of total pollen assemblage).
Magnoliaceae. Fig 23e, f. Monosulcate pollen grains, 15-25X25-28 pm.
These inconspicuous monosulcate grains constitute a large fraction of the
pollen at Alum Bluff (13.0%), though this percentage doubtless includes a
number of unknown taxa. Magnoliid type pollen is also known from the Miocene
localites at the Ohoopee River dune field (Rich et al. 2002), and the Catahoula
Formation (Wrenn 2003).
In the megafossil assemblage at Alum Bluff, there are several examples of
entire margined, pinnately veined leaves that may belong to the Magnoliaceae,
however sufficient characters are lacking to confirm identification of the family
among the megafossils.
Amaranthaceae. Fig. 23g-i. Periporate pollen grains, 15X15 pm.
Surface scabrate to gemmate.
This pollen type is also know from the Calvert Formation (Groot 1992).
Amaranthaceae/Chenopodiaceae type pollen is relatively rare at Alum Bluff and
was probably transported to the site from the surrounding area.
Carya (Juglandaceae). Fig. 23j-m. Triporate pollen grains with the pores
clearly shifted to one hemisphere, 45-50X45-60 pm. Annulus present, but not
prominent. Surface sculpture scabrate.
Carya pollen is known from all the eastern U.S. Miocene localities except
the Brandywine Flora. By far the most abundant pollen type at Alum Bluff, the
presence of Carva pollen corroborates the identification of both leaf and seed
macrofossils recovered from the site. The abundance of both macrofossil and
palynological remains of Carva suggest that hickories were an important
component of the Miocene Alum Bluff forest along with Ulmus and Sabalites.
Diospyros (Ebenaceae). Fig. 23n. Tricolpate pollen grains, ca. 30X30
pm. Surface sculpture psilate. Sculpturing is evident within the broad colpi, and
appears to be baculate.
Diospyros is currently predominantly a tropical genus, with one species
(Diospyros virginiana) occurring in the southeastern U.S. The Diospyros type is
not known from any other Miocene eastern U.S. pollen localities. It is a rare
component of the Alum Bluff flora (>0.5%).
This pollen type resembles some members of the Styracaceae as well,
though it is distinctly different from this family due to the psilate surface
(Styracaceae possess scabrate surface sculpturing.)
Gleditsia (Fabaceae). Fig. 25j-p. Tricolpate pollen grains, ca.30-40X30-
40 pm. Sculpturing reticulate with horizontal striations across reticulum.
Comparison with modern reference material of Gleditsia supports this
identification. Not only do both the fossil and modern material exhibit prominent
reticulate sculpturing, but both exhibit horizontal striations on the reticulum. In
addition, the length to width ratio (ca. 1.5:1) is the same for the modern and fossil
Berry (1916) reported observing fruits very similar to those of Gleditsia
aquatica at Alum Bluff, though he was unsuccessful in collecting them. Gleditsia
aquatica is a component of the modern floodplain forests near Alum Bluff today.
Ilex (Aquifoliaceae). Fig. 23o-u. Tricolpate pollen grains, 25-37X30-40
pm. Surface covered with very large pilate processes (Fig. 23u) with the stalks of
the clubs being very narrow in relation to the head. Surface of club head covered
with rugulate sculpturing.
Modern Ilex is a cosmopolitan genus, though most species are restricted
to tropical and temperate Asia and America. There are 10 species native to the
panhandle region of Florida. Ilex is known from all of the Miocene eastern U.S.
palynofloras surveyed (Table 2). At Alum Bluff, it is a relatively infrequent
Liquidambar (Altingiaceae). Fig. 23v-x. Periporate, spheroidal pollen
grains, ca. 30-40X30-40 pm. Surface sculpturing foveolate. Pore membranes
covered with bead-like sculpturing.
There are only a few extant species of Liquidambar that occur either in
eastern North America (L. styraciflua) or Asia (L. acalycina and L. formosana in
China, and L. orientalis in Asia Minor). Liquidambar styraciflua is a common
component of floodplain habitats in the Apalachicola River Valley. Liquidambar
is known from all of the Miocene eastern U.S. palynofloras (Table 2). At Alum
Bluff, it comprises only 1% of the total palynofloral assemblage. Though
Liquidambar was abundant in the modern environment at the Alum Bluff site,
likelihood of contamination from modern sources is low since Liquidambar was
found in samples processed with sterile techniques at the Canadian Geolabs, Inc
(Liquidambar does not occur in Western Canada), and since grains exhibited no
nucleus and were often corroded or deflated.
Myrica (Myricaceae). Fig. 23y, z. Triporate pollen grains, annulus
present but not prominent, 30-35X30-35 pm. Surface sculpturing scabrate.
Myrica is a subcosmopolitan genus. There are several species native to
the eastern U.S. (Myrica cerifera, M. inodora, and M. caroliniensis). Myrica
pollen is known from the Catahoula Formation (Wrenn et al. 2003), the Ohoopee
River dune field (Rich et al. 2002), and the Brandon Lignite (Traverse 1955). It is
uncommon at Alum Bluff.
It is often difficult to discern the Betulaceous type pollen from the
Myricaceous type pollen by light microscopy, and thus this palynomorph, which
was not observed in SEM may represent Betulaceae.
Quercus (Fagaceae). Fig. 24a-f. Tricolpate pollen grains, ca. 20X30 pm.
Surface sculpturing scrabrato-verrucate.
Oaks occur primarily in northern temperate zones, with some species
occurring at more tropical latitudes at high altitudes. In the panhandle of Florida,
there are 24 native oak species (Clewell 1985, Wunderlin and Hansen 2003).
Quercus is present in all of the Miocene eastern U.S. palynofloral localities. It is
relatively rare at Alum Bluff, occurring at a frequency of about 1 per 1,000.
Ulmus (Ulmaceae). Fig. 24g-l. Stephanoporate, oblate pollen grains, ca.
30-45X30-45 pm. Distinct arci lacking (distinguishing it from Alnus). Surface
sculpturing scabrate and rugulate. May occur with four (Fig. 24g-j), five (Fig.
24k), or six (Fig 241) pores.
Modern elms are found primarily at northern temperate latitudes of North
America and Eurasia. There are three species of Ulmus occurring in the
Apalachicola River Valley (U. alata, U. americana, and U. rubra). Pollen
occurring at Alum Bluff is more likely Ulmus than Planera, because according to
Zavada, Planera possess little to no rugulae at the poles of the grain (1983). The
specimens from Alum Bluff mostly show clear rugulae covering both the
equatorial region as well as the poles (Fig. 24g-l). Present at all eastern U.S.
Miocene localities, Ulmus is particularly abundant at Alum Bluff, comprising more
than 10% of the pollen assemblage.
Asteraceae and Malvaceae. Fig. 25a-e. Two size classes: 18-25X30
pm, 30-45X32-47 pm. Smaller pollen grains tricolporate (Fig. 25a, b). Colpi and
pores unclear in larger grains (Fig. 25c-e). All with echinate surface sculpturing.
Due to their clear tricolporate nature, it is suggested that the smaller
grains (Fig. 25a, b) may be helianthid type pollen (Asteraceae). Similar
helianthid type pollen recovered from the Catahoula Formation is age diagnostic
for that area. Pollen of the helianthid type assigns an age of earliest late
Miocene to the Catahoula Formation based on offshore pollen zonation markers
in the Gulf of Mexico (Styzen 1996, Wrenn 1996, Wrenn et al. 2003). This
reported age is slightly younger (ca. 3 million years) than that of Alum Bluff.
Thus, the presence of the helianthid type pollen in the Alum Bluff assemblage
may suggest a slightly younger age than reported by previous authors (Bryant et
al. 1992, Webb et al. 2003). Until a firm diagnosis of the pollen at Alum Bluff
being the helianthid type, this new assertation regarding age cannot be made
The larger pollen grains (Fig. 25c-e) show some characteristics of the
Malvaceae, particularly small "lines" or "bands" that inervate the echinate
processes. These seem to be lacking in the small grains (Fig. 25a, b). Certain
identification cannot be made, however, due to lack of resolution in determining
present/absence and position of pores and/or colpi. Further examination via
TEM or SEM may be warranted to gain the necessary resolution to distinguish
Vitaceae type. Fig. 25u-x. Tricolporate pollen grain, ca. 18-30X18-30
pm. Surface sculpturing rugulate.
The sculpturing of this palynomorph closely resembles that of Vitis. The
larger sized specimens (Fig. 25v, x) approach the typical size for Parthenocissus.
Uncertain Pollen Forms
Betulaceae type. Fig. 25f. Triporate pollen grain with a distinct annulus
around the pores, 35X35 pm. Surface ornamentation appears scabrate.
Euphorbiaceae type. Fig. 25g, h. Pores and colpi not visible in SEM
(may be inaperturate or have pores or colpi on one hemisphere), 30X35 pm.
Sculpturing appears gemmate.
These morphotypes resemble sculpturing exhibited by some
Fabaceae type. Fig. 25i. Pores and colpi not visible in SEM (may be
inaperturate or have pores or colpi on one hemisphere), 40X45 pm. Sculpturing
This taxon resembles Vigna (Fabaceae) pollen.
Rubiaceae/Rhamnaceae type. Fig. 25q, r. Tricolporate, syncolpate,
15X15 pm. Surface sculpturing verrucate.
These pollen grain resemble some genera of Rubiaceae and
Rosaceae type. Fig. 25s, t. 8X12 pm. Tricolpate pollen grain. Surface
This specimen resembles some members of the Rosaceae due to its
prominent striato-rugulate sculpturing.
Fig. 26a. 60X115 pm. Very large monosulcate pollen (?) grain. Surface
psilate. Possibly an algal cyst.
Fig. 26b-d. Varying sizes. Tricolpate pollen grains. Sculpturing varies.
Fig. 26e, g-j. Varying sizes. Triporate pollen grains. Sculpturing varies.
Fig. 26f. ca. 17X17 pm. Tricolporate pollen grain. Surface verrucate.
Fig. 26k, I. 33X33 pm. Tricolpate pollen grain. Sculpturing perforate.
Fig. 26m, n. 30-45X40-45 pm. Periporate pollen grains. Sculpturing
Fig. 260, p. 30-45X65-75 pm. Apparently inaperturate, "boat shaped"
pollen (?) grains. Surface psilate.
Fig. 26q. A marine dinoflagellate cyst.
Several fungal types have been noted from Alum Bluff. Berry (1916)
described a spot fungus known as Pestalozzites sabalana on leaves of Sabal
from Alum Bluff. He compared it to modern species of Pestalozzites that occur
on leaves of Serenoa and related groups, and his determination seems accurate.
In examining sediment samples processed for pollen and spores at Alum Bluff, a
number of fungal types were noted that occurred with frequency in the samples.
Following are general descriptions of several fungal types, none of which were
identified taxonomically. Descriptions are tentative and were made following the
terminology of AASP Workgroup on Fossil Fungal Palynomorphs (1983).
Fig. 27a. Obovate, psilate, apparently diporate, dicellate fungal spore.
Fig. 27b. Elliptic, psilate, inaperturate, tricellate fungal spore. Axis
Fig. 27c. Rounded rhombic, Slightly longitudinally striate, inaperturate,
dicellate fungal spore. Axis straight, dividing spore into equal proportions.
Fig. 27d. Elliptic, psilate, inaperturate, monocellate fungal spore.
Fig. 27e, f. Rounded obdeltate, psilate, inaperturate, monocellate fungal
Fig. 27g. Partial scutate fruit body. Ostiole/pseudo-ostiole missing in
these fragmented specimens.
Fig. 27h. Circular, psilate, inaperturate, dicellate spore. Axis straight,
dividing the spore into unequal proportions.
Fig. 27i. Elliptic, reticulate, inaperturate, monocellate spore.
Fig. 27j, k. Circular, slightly rugulate, inaperturate, monocellate spore
I o0 1 2 3 4 5Miles
Figure 1. Map showing Alum Bluff and surrounding area. *=Alum Bluff site.
W= Bristol boat landing.
IM-41I& TI Mr
Figure 2. Apalachicola River and Alum Bluff exposure.
Figure 3. Alum Bluff exposures showing Early Miocene lowermostt portion at
water level) to Pleistocene (uppermost portion) age sediments.
TF- :: .. ......... ....
AL A ARGILLACEOUS SANDS
-- --"- ARENACEOUS CLAY
MOLDS OF MOLLUSKS
SAND WrTH CLAY LENSES.
Citronelle Formation and
Jackson Bluff Formation
Alum Bluff Group,
Figure 4. Lithostratigraphy of Alum Bluff. Modified from Schmidt 1986.
AGE (M EPOCH STAGE ZONE NALMA
1 1 _Ir'~7au
Figure 5. Summary of geochronology, showing temporal relationships between
Torreya and Chipola Formations, and the Alum Bluff Group, undifferentiated.
Stippled areas are unrepresented time intervals. Abbreviations: N-ZONE,
planktonic foraminiferal zonation; NALMA, North American land-mammal age.
Modified from Bryant et al. 1992.
Figure 6. Fossil plant strata at the Alum Bluff exposure. Arrows indicate fossil
plant layers. One stratum lies slightly below where photo is cropped.
Figure 7. Leaflets of Carya (Juglandaceae). Scalebar=lcm. A) UF18049-
043542, B) UF18049-043504, C) counterpart of "B," D) UF 18049-043502, E)
UF18049-043588, F) counterpart of "E." G) UF18049-043502
P hj _
., ". ."~f
-" A^- ^ --
.- I,' ...
(" < t .--f / .-
^ *^ >>.
... ...:-^ '5, *. F ... ..-" ,-'
>.- *-, ,. .,. /''
1 .,- ., ,." **^, .
t-i<. ~---' < ,- '
Cr..- -. ^ /
- -rV r
/" ,-i *
**' ~ ~ *-* A'.. L -
\ I I,
~-q. .,, \'
T V '
\' [ ." \
y.- -r '
'/i <\ 2
Figure 8. Lauraceous leaf. A) 200X, Abaxial cuticle at vein, arrow indicates oil
cell from mesophyll, B) 400X, Abaxial cuticle near vein, note paracytic stomata,
C) Specimen from which cuticle was obtained, UF 18049-043550. Note entire
margin, weakly brochidodromous venation, and flaky, coriaceous cuticle.
Figure 9. Leaves of Paliurus (Rhamnaceae). Scale bar=lcm. A) UF18049-
043543, B) UF18049-043505, C) UF18049-043514, D) closeup of venation of C.
Figure 10. Leaves of Sabalites (Arecaceae). A) UF18049-029144, B) UF18049-
?, C) UF18049-029143, D)UF18049-043552.
Figure 11. Graduate student Xin Wang with a very large example of a Sabalites
leaf from Alum Bluff.
Figure 12. Leaves of Ulmus (Ulmaceae). Scale bar=lcm. A) UF18049-043513,
B) UF18049-043531, C) Line drawing illustrating vein course, D) UF18049-
043536, E) UF18049-043515, F) UF18049-029132, E) UF18049-043510.
043536, E) UF18049-043515, F) UF18049-029132, E) UF18049-043510.
Figure 13. Alum Bluff leaf Morphotype AB1. Scale bar=1cm. A) UF18049-
043566 (AB1.2), B) UF18049-043520, C) UF18049-043559, D) UF18049-043558
part, E) closeup of D, note arrows indicating primary and secondary veins, F)
counterpart of D, note dotted line highlighting primary and secondary veins, G)
leaf apex, UF18049-043522.
Figure 14. Alum Bluff leaf Morphotype AB2. Scale bar=lcm. A) UF18049-
043557 part, B) counterpart of A, C) UF18049-043567part, D) counterpart of "C."
Figure 15. Alum Bluff leaf Morphotype AB3. Scale bar=lcm. A) UF18049-
043523, B) UF18049-043587, C) UF18049-043557, D) closeup of C showing
higher order venation.
Figure 16. Alum Bluff leaf Morphotypes AB4, 5, and 6. Scale bar=lcm. A)
Morphotype AB4, UF18049-043575, B) counterpart of "A," C) Morphotype AB5,
UF18049-043573, D) line drawing of C showing vein course, E) Morphotype
AB6, UF18049-043553, F) counterpart of "E," G) line drawing of "E" showing vein
course, H) Morphotype AB7, UF18049-043574), I) line drawing of "H" showing
Figure 17. Alum Bluff leaf Morphotypes AB8 and 9. Scale bar=lcm. A)
UF18049-043512, B) line drawing of A showing vein course and higher order
venation, C) UF18049-043521, D) closeup of C showing higher order venation,
E) line drawing of C showing venation.
Figure 18. Alum Bluff leaf Morphotypes AB10, 11. Scale bar=1cm. A-B
Morphotype AB10, A) UF18049-043527, B) UF18049-043503, C-E, Morphotype
AB11,C) UF18049-029133, D) UF18049-043551, E) counterpart of D, F)
Morphotype AB12, UF 18049-043589.
Figure 19. Fruits and Seeds from Alum Bluff. Scale bar=lcm. A-F, Carva. A)
arrows indicate valves of dehiscent husk. Also note partial husk in lower right
corner, UF18049-043528, B) endocarp, UF18049-043509, C) endocarp,
UF18049-043500, D) endocarp, arrows indicate longitudinal grooves, UF18049-
043525, E) endocarp, UF18049-043524, F) husk valve, UF18049-043526, G)
Paliurus fruit, UF18049-026117, H) Scirpus achene, UF18049-043597, 1)
Unknown fruit, UF18049-043540.
11% Ty pe
1.2% 1 %
1 9% Tricolporate
Triporate / Ulmus
2.1% I 106%
d Jamesonia Type
Dryopteris Type >1 .0%
Unknown Trilete Spc
Figure 20. Pie chart showing pollen count summary for Alum Bluff.
Figure 21. Fern spores from Alum Bluff. Scale bar=15p. LM=Light micrograph,
SEM=Scanning electron micrograph.
A-B. Adiantaceae. A) LM, UF18049-043592, PY02F, coordinates 29,
101.6, B) SEM, UF 18049-043594, PY01, SEM-A.
C. Botrvchium, SEM UF18049-043591, PY01, SEM-B.
D. Cyathea, LM, UF18049-043592, PY02C, coordinates 50.1, 103.1.
E-F. Dryopteris, E) LM, UF18049-043592, PY02C, coordinates 36.9,
98.5, F) SEM UF18049-043591, PY01, SEM-B
G-I. Polypodiaceae. G) LM, UF18049-043593, PY01A, coordinates 37.1,
103.2, H) LM, UF18049-0435596, PY01A, coordinates 41.9, 95, 1) SEM,
UF18049-043591, PY01, SEM-A.
J-L. Pteris, J) SEM UF18049-043593, PY01, SEM-B, K) LM, UF 18049-
043595, PY01A, coordinates 24.6, 104, high focus showing trilete laesural
arms, L) Low focus of "K" showing surface sculpturing.
M. Unknown trilete spore. LM, UF18049-043592, PY02C, coordinates
N. Unknown trilete spore, LM, UF18049-043592, PY02C, coordinates
O. Unknown trilete spore, LM, UF18049-043595, PY01A, coordinates 23,
P. Unknown trilete spore, LM, UF18049-043592, PY02B, no coordinates
Q. Unknown trilete spore, LM, UF18049-0435596, PY01A, coordinates
R-S. Unknown trilete spore, LM, UF18049-043592, PY02A, no
21a '11 21e 21f
.,. .. ....
Figure 22. Gymnosperm and Poaceae type pollen from Alum Bluff. Scale
bar=15p. LM=Light micrograph, SEM=Scanning electron micrograph.
A-C. Taxodium, A) LM, UF18049-043592, PY02C, coordinates 51.8,
96.3), B) LM, UF18049-043592, PY02A, no coordinates available, C)
SEM, UF18049-043594, PY01, SEM-A.
D-G. Pinus, D) SEM UF18049-043591, PY01, SEM-A, E) LM, UF18049-
043592, PY02A, no coordinates available, F) SEM, UF18049-043591,
PY01, SEM-A, G) LM, UF18049-043592, PY02B, no coordinates
H-K. Poaceae, H) SEM, UF18049-043592, PY04, SEM-B, I) SEM,
UF18049-043592, PY04, SEM-B), J) SEM, UF18049-043596, PYO1,
SEM-B, K) SEM, UF18049-043596, PY01, SEM-B.
22a 22b 22c
22f -- 22g
Figure 23. Liliaceae, Magnoliaceae type and miscellaneous dicotyledonous
pollen from Alum Bluff. Scale bar=15p. LM=Light micrograph, SEM=Scanning
A-D. Liliaceae type. A) SEM, UF18049-043595, PY01, SEM-B, B) LM,
UF18049-043591, PY02B, no coordinates available, C) LM, UF18049-
043596, PY01A, coordinates 41.5, 113.6, D) LM, UF18049-043592,
PY02C, coordinates 45.1, 96.2.
E-F. Magnoliaceae type. E) LM, UF18049-043592, PY02B, no
coordinates available, F) LM, UF18049-043592, no coordinates available.
G-I. Amaranthaceae type. G) LM, UF18049-043592, PY02C, coordinates
28.4, 100.1, H) LM, UF18049-043592, PY02C, coordinates 45.2, 106.9, 1)
SEM, UF18049-043593, PY01, SEM-D.
J-M. Carva. J) LM, UF18049-043591, PY02B, no coordinates available,
K) LM, UF18049-043592, PY02C, coordinates 47.3, 113.6), L) SEM,
UF18049-043594, PY01, SEM-A, M) SEM, UF18049-043593, PYO1,
N. Diospyros, SEM, UF18049-043596, PYO1, SEM-B.
O-U. Ilex. O) LM, high focus, UF18049-043593, PY01A, coordinates
43.3, 105.4, P) LM, mid-focus, UF18049-043596, PY01A, coordinates 45,
95), Q) LM, high focus, UF18049-043596, PY01A, coordinates 33.2, 99.8,
R) same specimen as "Q" at mid-focus, S) SEM, UF18049-043596, PYO1,
SEM-B, T) SEM, UF18049-043596, PY01, SEM-B, U) closeup of "S"
showing clavate sculpturing.
V-X. Liquidambar. V) LM, high focus, UF18049-043592, PY02C,
coordinates 48.4, 103), W) SEM, UF18049-043591, PY01, SEM-B, X)
SEM, UF18049-043594, PY01, SEM-B.
Y-Z. Myrica. Y) LM, UF18049-043596, PY01A, coordinates 43, 104.5, Z)
SEM, UF18049-043591, PY01, SEM-C
Figure 24. Fagaceae and Ulmaceae pollen from Alum Bluff. Scale bar=15p.
LM=Light micrograph, SEM=Scanning electron micrograph.
A-F. Fagaceae. A) SEM, equatorial view, UF18049-043591, PY01, SEM-
C, B) closeup of A showing sculpturing, C) LM, polar view, UF18049-
043592, PY02C, coordinates 50.5, 97.5, D) LM, polar view, UF18049-
043592, PY02B, no coordinates available), E) SEM, polar view, UF18049-
043591, PY01, SEM-C, F) SEM, polar view, UF18049-043594, PYO1,
G-L. Ulmaceae. G) LM, polar view, UF18049-043592, PY02A, no
coordinates available, H) SEM, polar view, UF18049-043596, PY01, SEM-
C, I) LM, oblique view, UF18049-043592, PY02C, coordinates 48.2, 113,
J) SEM, oblique view, UF18049-043596, PY01, SEM-C, K) LM, polar
view, UF18049-043592, PY02B, no coordinates available, L) SEM,
oblique view, UF18049-043596, PY01, SEM-C.
Figure 25. Miscellaneous dicotyledonous pollen from Alum Bluff. Scale
bar=15p. LM=Light micrograph, SEM=Scanning electron micrograph.
A-E. Asteraceae/Malvaceae type. A) possible helianthid type, LM,
UF18049-043592, PY02B, no coordinates available, B) possible helianthid
type, LM, UF18049-043592, PY02C, coordinates 40,99, C) Malvaceae?,
SEM, UF18049-043592, PY04, SEM-B, D) Malvaceae?, LM, UF18049-
043592, PY02C, coordinates 43.6, 112.9, E) Malvaceae?, LM, UF18049-
043592, PY02F, coordinates 33.8, 94.8).
F. Betulaceae ? type, LM, UF18049-043596, PY01A, coordinates 43.4,
G-H. Euphorbiaceae ? type. G) SEM, UF18049-043591, PY01, SEM-C,
H) closeup showing sculpturing of "H."
I. Fabaceae ? type, possible Vigna ? type, SEM, UF18049-043594, PYO1,
J-P. Gleditsia (Fabaceae), J) LM, UF18049-043596, PY01A, coordinates
34.4, 110.8), K) SEM, UF18049-043594, PY01, SEM-B, L) SEM,
UF18049-043596, PY01, SEM-B, M) closeup of"L", N) SEM, UF18049-
043596, PY01, SEM-A, O) closeup of "N," P) SEM, UF18049-043596,
Q-R. Rhamnaceae/Rubiaceae ? type. Q) LM, UF18049-043592, PY02C,
coordinates 43.5, 111, R) LM, UF18049-043592, PY02C, coordinates
S-T. Rosaceae ? type. S) SEM, UF18049-043591, PY01, SEM-C (minor
grain), T) closeup of "S."
U-X. Vitaceae. U) LM, polar view, UF18049-043592, PY02C,
coordinates 47.1, 107.4, V) SEM, polar view, UF18049-043591, PYO1,
SEM-B, W) closeup of colpus and sculpturing of "W," X) SEM, equatorial
view, UF18049-043591, PY01, SEM-B.
B i 251 25n
5n 0 25s
-^^^^- -rig 6a
Figure 26. Unknown palynomorphs and dinoflagellate cyst from Alum Bluff.
Scale bar=15p. LM=Light micrograph, SEM=Scanning electron micrograph.
A. Unknown large monosulcate pollen grain, LM, UF18049-043596,
PY02A, coordinates 45.9, 106.
B-D. Unknown triporate pollen grains. B) LM, UF18049-043592, PY02C,
coordinates 46, 107.1, C) LM, UF18049-043592, PY02B, no coordinates
available, D) SEM, UF18049-043596, PY01, SEM-B.
E-I. Unknown Tricolporate pollen grains. E) LM, UF18049-043592,
PY02B, no coordinates available, F)SEM UF18049-043591, PY01, SEM-
B, G) LM, UF18049-043592, PY02B, no coordinates available, H) LM,
UF18049-043592, no coordinates available, I) LM, UF18049-043592,
PY02B, no coordinates available, J) SEM, UF18049-043591, PY01, SEM-
K-L. Unknown tricolpate pollen grain. K) SEM, UF18049-043594, PYO1,
SEM-A, L) closeup of sculpturing of "J."
M-N. Unknown periporate pollen grains. M) LM, UF18049-043592,
PY02C coordinates 33, 107.5, N SEM, UF18049-043596, PY01, SEM-A.
O-P. Unknown apparently inaperturate pollen grains. 0) SEM, UF18049-
043591, PY01, SEM-A, P) SEM, UF18049-043591, PY01, SEM-B.
Q. Dinoflagellate cyst, LM, UF18049-043595, PY01A, coordinates 45.9,
Figure 27. Fungal sporomorphs from Alum Bluff. Scale bar in A applies to
A. Unknown obovate, dicellate fungal spore, SEM, UF18049-043596,
B. Unknown elliptic, tricellate fungal spore, SEM, UF18049-043596,
C. Unknown rounded rhombic, dicellate fungal spore, SEM, UF18049-
043592, PY04, SEM-B.
D. Unknown elliptic, monocellate fungal spore, LM, UF18049-043592,
PY01A, no coordinates available
E-F. Unknown obdeltate, monocellate fungal spores. E) LM, UF18049-
043592, PY02B, no coordinates available, F) LM, UF18049-043592,
PY02C, coordinates 47.1, 43.8.
G. Unknown scutate fungal fruit body, LM, UF18049-043596, PY01A,
coordinates 44.5, 101.
H. Unknown circular, dicellate fungal spore, SEM, UF18049-043594,
I. Unkown elliptic, monocellate fungal spore, LM, UF18049-043596,
PY01A, coordinates 32.2, 99.
J-K. Unknown circular, monocellate fungal spore clusters. J) SEM,
UF18049-043596, PY01, SEM-C, K) LM, UF18049-043592, PY02C,
coordinates 49, 104.5.
Comparison with Other Miocene Floras
To place the paleocology of the Alum Bluff deposits in context, it may be
useful to compare the flora to other known Miocene plant assemblages (Table 3).
As mentioned earlier in the text, there are several southeastern U.S. Miocene
pollen localities that are useful for comparison (Table 2, 3). In addition, Miocene
pollen records are known from western localities such as the Clarkia flora of
northern Idaho (Gray 1985). Leaf macrofossils have been identified from North
American Miocene localites such as the Miocene Brandon Lignite, Vermont,
(Tiffney 1993, 1994a, 1994b), the Brandywine deposits, Maryland (Late Miocene)
(McCartan et al. 1990), the Clarkia flora, northern Idaho (Smiley et al. 1975,
Smiley and Rember 1981, Rember 1991, Manchester et al. 1991, Kva6ek and
Rember 2000), and the Seldovia Point flora, Alaska (Miocene) (Wolfe 1972,
Wolfe and Tanai 1980). Fruits and seeds have been identified from Miocene
localities such as the Brandon Lignite, Vermont the Brandywine deposits of
Maryland (Late Miocene) (McCartan et al. 1990), and the Clarkia Flora of Idaho
(Smiley et al. 1975, Smiley and Rember 1981, Rember 1991, Manchester et al.
1991, Kvacek and Rember 2000).
Tiffney described the Early Miocene Brandon Lignite to be a mixed
evergreen-deciduous forest with a climate similar to that of the U.S. Gulf coast
(temperate to subtropical) (1994). The Middle Miocene Old Church flora of
Virginia was estimated to be similar to a modern temperate southern oak-
hickory type forest (Fredericksen 1984). The late Miocene Brandywine flora of
Maryland was thought to be deciduous with a warm-temperate climate (McCartan
et al. 1990). The Ohoopee River Dune Field paleoecology was interpreted as
being a myriad of habitats all similar to those of the southern coastal plain today,
including an oak-hickory forest, a shrub swamp dominated by Cyrilla, and a
Sphagnum-bog (Rich et al. 2002). The flora of the Calvert Formation of
Delaware was interpreted as being similar to the modern coastal plain flora of
Delaware, typified by a temperate to warm-temperate flora (Groot 1992). The
Legler Lignite of New Jersey was interpreted as being similar to that of the
modern southern coastal plain floras (Rachele 1976). The Miocene Catahoula
Formation in Louisiana was thought to be a subtropical to tropical mangrove type
environment (Wrenn et al. 2003), though the large presence of temperate taxa
shared with Alum Bluff (Table 3) may suggest other climatic conditions than
described by Wrenn et al (2003).
Turning to Miocene floras from Western North America, the Clarkia Flora
of northern Idaho, unlike most of the Miocene floras of eastern North America,
exhibits a larger number of taxa with Asian distributions today, such as
Cercidiphyllum, Trochodendron, and Paliurus among others. The Clarkia Flora
has been described as being a mixed-mesophytic forest (Smiley et al. 1975,
Smiley and Rember 1981, Rember 1991, Manchester et al. 1991, Kva6ek and
Rember 2000). Higher latitude floras such as the Seldovian Point flora of Alaska
also share some elements with Alum Bluff. The Seldovian Point flora is also
described as a mixed-mesophytic to broad-leaved deciduous assemblage (Wolfe
1969, 1972, Wolfe and Tanai 1980). This flora also possesses more taxa now
restricted to Asia, such as Zelkova and Cercidiphyllum, than the eastern North
America Miocene floras. In this respect, Alum Bluff is more like some western
North American floras than with its eastern counterparts due to the presence of
Paliurus, which is restricted to the Eurasian landmass today.
The European Miocene fossil flora of Hambach, near DCren, Germany
(which is also based on micro- and megafossils), was estimated to represent a
floodplain forest with some upland elements being co-dominant with a sedge
wetland (van der Burgh and Zetter 1998). The Miocene floras of Central Honshu,
Japan illustrate some of the shared components of Alum Bluff with Asian
Miocene localities (Ozaki 1991). These floras are thought to represent temperate
Though paleoecological and paleoclimatological work has been done
based on invertebrate assemblages from strata above and below the geological
formation where plant fossil are found at Alum Bluff (DuBar and Taylor 1962),
little such work has been done with the floristic assemblages of the region. Berry
(1916) made some climatological and ecological inferences about the Alum Bluff
flora in his original report. He inferred the significant presence of thermophillic
elements that he identified indicated the climate of the Miocene Alum Bluff region
was much warmer than the conditions occurring in that region of Florida today.
Table 3. Taxa shared between Alum Bluff and other Miocene localities.
Alum Bluff, X X X X X X X X X X X X X X X X X X
-X X X X X
Brandywine XX X X X X
Formation, X X X X X X X
Legler X X XX X X X X X
Formation, X X X X X X
River Dune X X X X X
Formation, X X X X X X X X X X X
Clarkia flora, X X X X X
Point flora, X X X X
flora, X X X X X X X X X X X X
floras, X X X X X X X XX
In other words, he interpreted the flora as being predominantly tropical and being
gradually invaded by temperate elements, rather than the modern condition
where the flora is predominantly temperate with some subtropical to tropical
elements (Berry 1916). Berry identified tropical genera such as Artocarpus,
Pisonia, Caesalpinia, Fagra (=Zanthoxylum), Rhamnus, Nectandra, and Bumelia
(=Sideroxylon). According to Dilcher (1973a), at least 60% of the material Berry
described for southeastern Eocene floras is incorrect. Though no attempt was
made to revise Berry's original descriptions of the Alum Bluff flora, the statistics
presented by Dilcher suggest that revision of Berry's 1916 Alum Bluff flora may
The description of the Alum Bluff flora presented here provides new data
and a different interpretation regarding paleoclimate than that of Berry (1916). Of
those morphotypes identified here, most are present in temperate areas. Taxa
representative of tropical environments from the present study include Cyathea
and Diospyros. Cyathea has been found in other Miocene temperate
palynofloras (Table 3), and there is one species of Diospyros (Diospyros
virginiana) in the extant flora of the region. The current author observed that the
common serrated leaf forms and small leaf sizes at Alum Bluff are more typical of
temperate floras. In addition, the presence of leaves identified as Carva, Ulmus,
and Paliurus, as well as the large number of temperate taxa represented in the
pollen, fruits, and seeds of Alum Bluff suggest that the climate of Alum Bluff was
warm-temperate and more similar to the other North American, European, and
eastern Asian Miocene communities discussed earlier. The community type
would have been similar to the modern northern Gulf Coast of Florida possessing
an elm-hickory-cabbage palm forest occurring adjacent to or near an oak and
pine dominated landscape. This differs somewhat from the modern flora at the
immediate area surrounding Alum Bluff, which is today influenced by the unique
environmental circumstances created by the Apalachicola River corridor.
Instead, the Miocene flora of Alum Bluff more closely resembles the area from
the northern Gulf Coast of peninsular Florida through northern central Florida to
the northern Atlantic coast of peninsular Florida extending up along the Georgia
and South Carolina coasts. This difference between the modern and fossil floras
of Alum Bluff is likely because the Apalachicola River Valley was in its infancy in
the Middle Miocene (Clewell 1977) and had not yet developed the unique set of
topographic (bluffs and ravines) and biogeographic (connection with Piedmont
and Appalachia) characteristics that exists in the region today.
As mentioned earlier, based on taphonomy and lithology of the site, the
undifferentiated beds of Alum Bluff Group are thought to represent deltaic or pro-
deltaic sediments deposited in a high energy depositional environment (pers.
comm. Dilcher 2004, Schmidt 1986). Thus, it can be interpreted that the warm-
temperate flora of Alum Bluff occurred as floodplain and upland forests flanking a
The presence of dinoflagellate cysts suggest marine influence, though the
infrequency of dinoflagellates (<0.1%) in the sediment indicates only a slight
marine input. This reiterates the deltaic environment described previously, but it
suggests that the coastline may have been near enough for some marine
sediments to reach from the Gulf up the pre-Apalachicola river delta to Alum
Bluff. However, it is not uncommon for sediment from other more ancient strata
to be re-worked with younger sediments (Traverse et al. 1988, Wrenn et al.
2003). This is especially common when the anomalous element is found with
extremely low frequency (Traverse 1988). Thus, the presence of dinoflagellates
at Alum Bluff may indicate re-working from older sediments rather than a marine
influence at the site.
Because both the overlying Jackson Bluff Formation and the underlying
Chipola Formation represent marine deposits (Schmidt 1986), it can further be
inferred that the Alum Bluff flora represents a forest encroachment during an
interval of sea level drop which was summarily displaced again as sea level rose.
Several important biogeographical conclusions are presented by this
analysis of the Alum Bluff Flora. The presence of Paliurus suggests affinities
with eastern Asian or southern European floras that are present in western North
American Miocene assemblages, but conspicuously lacking from other eastern
North American assemblages. This suggests that Paliurus at Alum Bluff was one
of the last remnants of Eurasian taxa in eastern North America by the Miocene.
The last record of Paliurus in North America was from the Miocene of
Washington, USA (Berry 1928). It is unclear why Paliurus at Alum Bluff is
disjunct from its contemporaneous western counterparts, or why Paliurus
persisted at this more southern latitude while remaining absent in Miocene
assemblages from the northeastern United States. Manchester (1999)
commented that the Paliurus likely made its way to the North American continent
via a Beringial crossing in the Eocene. The genus disappears from North
America after the Miocene (Manchester 1999). Thus, Paliurus may have arrived
at Alum Bluff after being dispersed across the North American continental interior
from the west. This cannot be confirmed, however, due to a lack of Miocene age
deposits in the interior North America (Manchester pers. comm. 2004).
Alternatively, Paliurus may have arrived via a North Atlantic Land Bridge
crossing. The genus is present in Europe and Asia today, and has an extensive
fossil record on these continents, so it would be possible for Paliurus to arrive
from Europe (in the Eocene?), however no Miocene fossil record of Paliurus is
known from the northeastern U.S. (where it would have first arrived via an
The floral assemblage described here supports the concept of a warm
temperate climate existing in the region since the early Tertiary. Dilcher (1973a,
1973b) reported a warm temperate to cool subtropical climate for the Middle
Eocene Claiborne Formation in Tennessee. Prior to the author's investigations,
the Alum Bluff flora was thought to represent a Miocene tropical flora
intermediate between an Eocene warm temperate to cool subtropical flora
(Claiborne Formation) and a Pliocene temperate flora (Citronelle Formation)
(Dilcher 1973a, 1973b, Graham 1964). However, new data presented here show
that warm temperate conditions have continued in the southeastern United
States Gulf Coastal Plain region since the Eocene.
Of the taxa at Alum Bluff, two are positively confirmed in both the leaf and
pollen record (Carva, Ulmus), one is positively confirmed in the leaf, pollen, and
fruit record (Carva), and one is tentatively confirmed in the leaf and pollen
records while being positively confirmed in the fruit record (Paliurus). A summary
of these and other taxa occurring at Alum Bluff is presented in Table 4. Of the
North American Miocene paleofloras, there are only a handful known from pollen,
fruits, seeds, and leaves including the Clarkia flora of Idaho (Smiley et al. 1975,
Smiley and Rember 1981, Rember 1991, Manchester et al. 1991, Kva6ek and
Rember 2000), and the Brandywine flora of Maryland (McCartan et al. 1990). A
few sites are known to have fruits, seeds, and pollen such as the Brandon Lignite
flora (Traverse 1951, Traverse 1955, Traverse 1994, Tiffney 1993, 1994a,
1994b). According to Graham (1964), the best circumstance for reconstructing
paleoenvironments is a study of mega- and microfossils from a given locality. He
also reported that very few Tertiary localities of this type in the southeastern
United States were available. Review of the literature by the author also found
occurrence of such sites in the Atlantic coastal plain to be rare. The
compounding of data from both mega- and microfossils and the resulting
increase in floristic diversity makes the current analysis of the Alum Bluff flora a
paleobotanically important case. The examination of palynomorphs at Alum Bluff
has greatly increased the number of taxa known from the site. Examination of
fruit and seed material has helped to confirm identification of pollen and leaves
and increased the overall morphotype diversity at the site. The culmination of his
study has been the determination that the Alum Bluff flora is more diverse than
Berry originally described. Also, it was found that the Alum Bluff flora was likely
warm-temperate, and that these conditions have persisted since the early
Tertiary. In addition, the existence of Paliurus at Alum Bluff suggests
biogeographical affinities with Eurasia, which further demonstrates that floristic
elements limited to Eurasia today were once widely dispersed through both
western and eastern North America.
Table 4. Summary of taxa identified at Alum Bluff.
Taxon Pollen Leaf? Seed or Fruit?
SELECTED WOODY TAXA OCCURRING
IN AND AROUND THE APALACHICOLA BLUFFS AND
RAVINES AREA AND THEIR TYPICAL HABITATS
Taxa marked with an asterisk (*) are either rare to Florida or endemic species.
The list is compiled from taxa discussed for the region in Clewell (1977, 1985),
Harper (1914), Ward (1979), Wolfe et al. (1988), and Wunderlin and Hansen
Species Family Habitat
Bluffs, levees, hammocks
Bluffs, levees, hammocks
Pine-oak-hickory woods, calcarious
Hammocks, pine-oak-hickory woods
Floodplains, bluffs, hammocks,
Creek swamps, bluffs near
Bluffs, hammocks, bayheads
Bluffs, floodplains, hammocks,
Hammocks, bluffs, bayheads
Hammocks, bluffs, well-drained
Species Family Habitat
Pinus serotina Pinaceae Pinelands
Prunus caroliniana Rosaceae Bluffs, calcareous hammocks, scrub
Quercus alba Fagaceae Bluffs, hammocks, pine-oak-hickory
Quercus laevis Fagaceae Sandhills, scrub, pine-oak-hickory
Quercus michauxii Fagaceae Moist hammocks, floodplains, sinks
Quercus muhlenbergii Fagaceae Bluffs
Quercus nigra Fagaceae Floodplains, hammocks, secondary
Quercus shumardii Fagaceae Bluffs, calcareous hammocks
Taxodium ascendens Cupressaceae Swamps, ravines
Taxodium distichum Cupressaceae Swamps, ravines
Tilia americana Malvaceae Bluffs, hammocks, riverbanks
*Taxus floridana Taxaceae Hammocks and cedar swamps
*Torreya taxifolia Taxaceae Hammocks (Endemic)
Ulmus alata Ulmaceae Bluffs, floodplains, calcareaous river
Ulmus americana Ulmaceae Bluffs, floodplains, hammocks
Ulmus rubra Ulmaceae Bluffs, floodplains, hammocks
Bignonia capreolata Bignoniaceae Floodplains, hammocks
Campsis radicans Bignoniaceae Floodplains, ruderal
Decumaria barbara Hydrangeaceae Calcareous hammocks, margins of
Gelsemium sempervirens Gelsemiaceae Various habitats
*Schisandra coccinea Schisandraceae Bluffs
Smilax smallii Smilacaceae Hammocks, bluffs, dunes,
Vitis aestivalis Vitaceae Hammocks, riverbanks
Vitis rotundifolia Vitaceae Various habitats
Along creeks and branches
Hammocks, secondary woods
Flatwoods, scrub, bluffs, secondary
Species Family Habitat
Bluff, hammocks, floodplains, creek
Bluffs, calcareous hammocks,
Bluffs, hammocks, floodplains
Bluffs, stream banks
Bluffs, creek swamps
Wet ravines, bogs
Creek swamps, seepages on bluffs
Flatwoods, bogs, acid swamps,
Flatwoods, bogs, acid swamps,
Flatwoods, bogs, hammocks
Floodplains, bluffs, flatwoods,
Bluffs, calcareous hammocks
Bluffs, hammocks, floodplains
Bluffs, steepheads, bayheads
Hammocks, bluffs, floodplains,
Hammocks and swamps, flatwoods,
Dry bluffs, calcareous hammocks,
Sandhills, flatwoods, floodplains,
secondary woods, ruderal
Floodplains, bluffs, titi swamps,
EXPLANATION OF PALYNOMORPH TERMINOLOGY
The following is a brief description of terminology used to describe spores
and pollen grains from Alum Bluff. Not all of the terms below are used in the
thesis, but are provided as background and comparison for the palynomorph
terminology that was used.
The basic structure of a pollen grain consists of an outer exine. The exine
is made up of the sexine (which is composed of a tectum, column and foot
layer) and the nexine. An intine, a plasmalemma and the protoplast are the
innermost layers. In fossilized pollen, typically only the outer layers remain
(intine and exine). Some pollen grains belonging to conifers possess vesiculate
pollen, or pollen with attached bladders (as in Pinus). The sacci vesiclesles" or
"bladders") attach to the corpus, or body of the pollen grain. There are typically
two sacci present, however in some groups there is only one.
Pollen is described based on (1) the shape of the grain, (2) the
ornamentation of the exine, and (3) the number and arrangement of pores or
apertures over the surface of the grain.
(1) Grain Shape: The shape of a pollen grain is determined based on a
ratio of the polar and equatorial diameters of the grain. The pole of a grain is the
location of a single pore or the midpoint of a furrow of the grain OR where the
end of the grain where furrows converge (in tricolpate or tricolporate grains).
Grain shape, however, often varies between polar and equatorial views. Thus,
grain shape terminology is often omitted from descriptions unless both polar and
equatorial views are identified. The following terms describe the shape of a grain
based on the P/E ratio.
>2.0=perprolate (very elongated)
1.3-2.0=prolate (slightly elongated)
0.50-0.75=oblate (slightly flattend)
<0.5=peroblate (very flattened).
(2) Ornamentation of the exine: The following terms describe the
ornamentation of the exine. These features are often helpful in determining
generic or specific divisions.
Perforate-surface with small holes
Foveolate-with holes or depressions
Fossulate-sideways elongate holes
Scabrate-rough or flecked
Verrucate-warty or bumpy
Papillate-hollow, finger-like projections, longer than broad and >1 pm
Baculate-having rod-shaped sculptural elements
Gemmate-having "door knob" shaped elements less than 1 pm in height.
Clavate-having club-shaped sculptural elements
Pilate-similar to gemmate, but knob-shaped elements taler than 1 pm.
Striate-roughly parallel ridges
Reticulate-net like (ridges and gaps)
(3) Number and Arrangement of pores and apertures: Pollen with pores is
referred to as porate. Pollen may be mono-, di-, tri-, or periporate. When a
grain has more than four pores oriented along the equator of a grain, it is referred
to as stephanoporate. In addition to pores, furrows also known as colpi may be
present. Grains with furrows are referred to as colpate. Colpi range from being
very long and stretching the length of the grain to being short and unapparent.
When the colpi of a pollen grain fuse or meet (typically at the apex of the grain),
it is referred to as being syncolpate. When a pollen grain possesses both pore
and colpi, it is referred to as corporate. The pores in these grains are located
within the furrows. Sometimes, the exine around the pore is modified. When the
pore possesses a cap or plug, it is referred to as an operculum. The aspis is
the thickening of the exine around the pore. The annulus may be a ring around
the pore and may be a thickened or thinned area of the exine. The oncus is a
thickening of the intine that may occur under a pore, and the arcus may be a
band which arcs between pores and is actually thickened sexine.
The terminology for pteridophyte and lycopod spore morphology differs
somewhat from that of pollen. Spores that form tetrads during development may
or may not split apart upon maturity. When they do split apart, they form
monads with tetrad scars remaining on the surface where the spore once made
contact with the tetrad. There are two basic forms: a radiosymetrical trilete
form and a bilaterally symmetrical monolete form. Monolete and trilete refers
to the number of dehiscence fissures present, also known as laesura. A spore is
called anisopolar when there is a prominent tetrad scar on the proximal end (the
end that was connected to the tetrad). A spore is apolar when the two poles are
identical (occurs in globose and alete spores). When a swollen protrusion is
present surrounding the laesura, this is referred to as a margo. The margo may
be lip-like, flange-like, or line-like. When a margo is absent, the palynomorph is
said to have a laesura with a simple commissure. When present, the lasural
ridges may be ornamented. In addition, proximal ridges may be present near
the equator of the spore. These proximal ridges may assume several different
Regarding the surface ornamentation of spores, the same terminology that
was used for pollen in part II above may be used (as was done in this thesis).
Shape of spores is also an important characteristic. Spores may be
ellipsoidal (ratio of long axis/short axis falling between 1.25 to 2),
subellipsoidal (ratio of long axis/short axis above 2), globose (ratio of long axis
to short axis below 1.25), rounded triangular (convex sides), subtriangular
(sides straight and angle rounded), deltoid triangular (sides straight and angles
acute), triquete (sides slightly concave), or trilobate (sides deeply concave). In
some fern species, an equatorial ridge is evident. When the equatorial ridge is
the same width all the way around the spore, it is referred to as annulate. When
the equatorial ridge is wider on the interradial side than at the radial angles, it is
referred to as annulotrilete.