The Torreya Formation is a

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

geologic formation with an outcrop in North Florida. It is within the Hawthorn Group.

Age

Period: Neogene
Epoch: Early

Faunal stage: Aquitanian through early Messinian ~19–15.3

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, calculates to a period of

Composition

The Torreya Formation is exposed or near the surface from Gadsden County, Florida on the west. Its eastern extent is westernmost Hamilton County, Florida. It includes the counties of

Liberty Liberty is the ability to do as one pleases, or a right or immunity enjoyed by prescription or by grant (i.e. privilege). It is a synonym for the word freedom. In modern politics, liberty is understood as the state of being free within society fr ...

, Leon, Jefferson, Madison, and Wakulla. It is informally subdivided into a lower

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonat ...

unit and an upper siliciclastic unit. The majority of Torreya Formation outcrops expose the siliciclastic part of the unit.

Lithology

The siliciclastics are

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

and vary in color from white to light olive gray. They are unconsolidated to poorly indurated (hard), slightly clayey sands with minor phosphate to light gray to bluish gray, poorly consolidated, variably silty clay (Dogtown Member). The siliciclastics are sporadically fossiliferous and often contain

oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not a ...

shells as found in the

Seaboard Air Line Railroad site The Leon County paleontological sites are assemblages of Early Miocene invertebrates and vertebrates of Leon County, Florida, United States. Age Era: Neogene. Period: Early Miocene. Faunal stage: Arikareean, ~23.1–21.9 Ma, calculates to ...

. The carbonate sediments contain phosphate and are white to light olive gray. They are generally not hard but variably sandy with clay. This unit is also fossiliferous with both molds and casts and includes limestone ( mudstone and wackestone). The limestones often grade into

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an a ...

-cemented sands. The Dogtown Member is time transgressive with older aged material at ~15.9–15.3 Ma. and found in the south while the younger material is in the north.Improved chronologic resolution of the Hawthorn and the Alum Bluff Groups in northern Florida: Implications for Miocene chronostratigraphy by J. Daniel Bryant, Bruce J. MacFadden, and Paul A. Mueller, Geological Society of America, February 1992
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Overlay

The Torreya Formation overlies the Floridan aquifer and forms part of the intermediate confining unit/aquifer system. (USGS)

Paleofauna

Barstovian land-mammal fauna found in northern Gadsden County dated 14.7–16.6 Ma. Paleofauna based on the fossils from: Gadsden County paleontological sites, Leon County paleontological sites, Jefferson County paleontological sites, and Hamilton County paleontological sites. Bivalve *'' Ostrea normalis'' Fish *'' Myliobatis'' (Rays) *'' Carcharhinidae'' (Sharks) *'' Pristis'' (Sawfish) *'' Pogonias cromis'' Reptiles *'' Alligatoridae'' (Alligator) *'' Boidae'' (Boa) *'' Ciconiidae'' (Turtle) *†'' Crocodylidae'' (Crocodile) *'' Geochelone'' (Turtle) *'' Pseudemys'' (Turtle) Birds * Gruidae (Crane) Mammals *†''

Aletomeryx ''Aletomeryx'' is an extinct genus of Artiodactyla, of the family Dromomerycidae, endemic to North America from the early Miocene epoch (Hemingfordian stage) 20.6—16.3 Annum, Ma, existing for approximately . Taxonomy ''Aletomeryx'' was nam ...

'' and ''A. gracilis'' *†'' Amphicyon'' and ''A. pontoni'' (dog-like carnivore) *†'' Anchitherium'' and ''A. clarencei'' (Horse) *†'' Archaeohippus'' and ''A. blackbergi'' (Horse) *†'' Borophaginae'' (Bone-crushing dog) *†'' Camelidae'' (Camel) *†''

Canidae Canidae (; from Latin, ''canis'', "dog") is a family (biology), biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid (). There are three subfamily, ...

'' (Canine unknown) *†''

Equidae Equidae (sometimes known as the horse family) is the taxonomic family of horses and related animals, including the extant horses, asses, and zebras, and many other species known only from fossils. All extant species are in the genus ''Equus'' ...

'' (Horse) *†''

Floridatragulus ''Floridatragulus'' is an extinct genus of camelids. It lived in North America during the Early to Middle Miocene, about 20.6—15.9 mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created b ...

'' (Camel) *†'' Harrymys magnus'' (Mouse) *†'' Merychippus'' and ''M. gunteri'' (Horse) *†''

Nanosiren ''Nanosiren garciae'' is an extinct sirenian dugong that lived in warm shallow seas in what is now Venezuela, approximately 11.610—3.6 Ma during the Miocene and Pliocene. The species is listed in the Paleobiology Database, funded by the Austra ...

'' (Sea Cow) *†'' Nothokemas'' and ''N. floridanus'' (Camel) *†'' Osbornodon iamonensis'' (Proto-dog) *†'' Parahippus leonensis'' (Horse) *†'' Proheteromys'' and ''P. floridanus'' (Rodent) *†''

Prosynthetoceras ''Prosynthetoceras'' is an extinct genus of Artiodactyla, of the family Protoceratidae, endemic to North America. It lived from the Early to Middle Miocene 20.6—13.6 Ma, existing for approximately . In appearance, ''Prosynthetoceras'' looked m ...

'' and ''P. texanus'' (Deer-like ungulate) *†'' Procyoninae'' (Mustelid) *†'' Merycoidodontidae'' (Hog) *†'' Mesogaulus'' (Horned gopher) *†'' Rhinocerotidae'' (Rhinoceros) *†''

Ruminantia Ruminants ( suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. Th ...

'' (Ruminant basal) *†'' Squalodon'' (shark toothed dolphin)

References

{{reflist *Paleobiology database: Seaboard Air Line Railroad Company collection, S. J. Olsen, R. Cantwell, C. Cox.
/small> Neogene Florida Miocene United States Miocene Series of North America Geologic formations of Florida