View source for Earth:Torreya Formation

{{Infobox Rockunit
| name           = Torreya Formation
| image          =
| caption        =
| type           = [[Earth:Geological formation|Geological formation]]
| age            = Miocene
| prilithology   =
| otherlithology =
| namedfor       = [[Biology:Torreya taxifolia|Torreya tree]]
| namedby        = 
| region         = North Florida
| country        = {{flag|United States}}
| coordinates    =
| unitof         = Hawthorn Group
| subunits       = Dogtown, Sopchoppy
| underlies      = [[Earth:St. Marks Formation|St. Marks Formation]], Suwanee Limestone
| overlies       = 
| thickness      = 
| extent         =
| area           =
| map            =
| map_caption    =
}}
[[File:Torreya Formation map.png|thumb|right|190px|Location of the Torreya Formation in Florida in red.]]
The '''Torreya Formation''' is a Miocene geologic formation with an [[Earth:Outcrop|outcrop]] in North Florida. It is within the Hawthorn Group.

==Age==
'''Period''': [[Earth:Neogene|Neogene]]<br/>
'''[[Earth:Epoch (geology)|Epoch]]''': Early Miocene<br/>
'''Faunal stage''': [[Earth:Aquitanian (stage)|Aquitanian]] through early [[Biology:Messinian|Messinian]] ~19–15.3 [[Physics:Mya (unit)|mya]], calculates to a period of {{Mya|19.0-15.3|million years}}

==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, Leon, Jefferson, Madison, and Wakulla. It is informally subdivided into a lower [[Chemistry:Carbonate|carbonate]] unit and an upper [[Earth:Siliciclastic|siliciclastic]] unit. The majority of Torreya Formation outcrops expose the siliciclastic part of the unit.<ref>[https://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=FLMIht%3B0 United States Geological Survey: Hawthorne Group: Torreya Formation]</ref>

==Lithology==
The siliciclastics are [[Chemistry:Quartz|quartz]] 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 [[Biology:Oyster|oyster]] shells as found in the Seaboard Air Line Railroad site.

The carbonate sediments contain [[Chemistry:Phosphate|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 [[Earth:Calcareous|calcareous]]-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.<ref>[http://bulletin.geoscienceworld.org/cgi/content/abstract/104/2/208 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]</ref>

==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'''
*''[[Biology:Ostrea|Ostrea]] normalis''
'''Fish'''
*''[[Biology:Myliobatis|Myliobatis]]'' (Rays)
*''[[Biology:Carcharhinidae|Carcharhinidae]]'' (Sharks)
*''[[Biology:Pristis|Pristis]]'' (Sawfish)
*''Pogonias cromis''
'''Reptiles'''
*''[[Biology:Alligatoridae|Alligatoridae]]'' (Alligator)
*''[[Biology:Boidae|Boidae]]'' (Boa)
*''[[Biology:Ciconiidae|Ciconiidae]]'' (Turtle)
*†''[[Biology:Crocodylidae|Crocodylidae]]'' (Crocodile)
*''[[Biology:Geochelone|Geochelone]]'' (Turtle)
*''[[Biology:Pseudemys|Pseudemys]]'' (Turtle)
'''Birds'''
*Gruidae (Crane)
'''Mammals'''
*†''[[Biology:Aletomeryx|Aletomeryx]]'' and ''A. gracilis''
*†''[[Biology:Amphicyon|Amphicyon]]'' and ''A. pontoni'' (dog-like carnivore)
*†''[[Biology:Anchitherium|Anchitherium]]'' and ''A. clarencei'' (Horse)
*†''[[Biology:Archaeohippus|Archaeohippus]]'' and  ''A. blackbergi'' (Horse)
*†''[[Biology:Borophaginae|Borophaginae]]'' (Bone-crushing dog)
*†''[[Biology:Camelidae|Camelidae]]'' (Camel)
*†''[[Biology:Canidae|Canidae]]'' (Canine unknown)
*†''[[Biology:Equidae|Equidae]]'' (Horse)
*†''[[Biology:Floridatragulus|Floridatragulus]]'' (Camel)
*†''Harrymys magnus'' (Mouse)
*†''[[Biology:Merychippus|Merychippus]]'' and ''M. gunteri'' (Horse)
*†''[[Biology:Nanosiren|Nanosiren]]'' (Sea Cow)
*†''[[Biology:Nothokemas|Nothokemas]]'' and ''N. floridanus'' (Camel)
*†''[[Biology:Osbornodon iamonensis|Osbornodon iamonensis]]'' (Proto-dog)
*†''[[Biology:Parahippus leonensis|Parahippus leonensis]]'' (Horse)
*†''Proheteromys'' and ''P. floridanus'' (Rodent)
*†''[[Biology:Prosynthetoceras|Prosynthetoceras]]'' and ''P. texanus'' (Deer-like ungulate)
*†''Procyoninae'' (Mustelid)
*†''Merycoidodontidae'' (Hog)
*†''Mesogaulus'' (Horned gopher)
*†''[[Biology:Rhinocerotidae|Rhinocerotidae]]'' (Rhinoceros)
*†''[[Biology:Ruminantia|Ruminantia]]'' (Ruminant basal)
*†''[[Biology:Squalodon|Squalodon]]'' (shark toothed dolphin)

==References==
{{reflist}}
*<small>[http://paleodb.org/cgi-bin/bridge.pl?action=basicCollectionSearch&collection_no=18586 Paleobiology database: Seaboard Air Line Railroad Company collection, S. J. Olsen, R. Cantwell, C. Cox.]</small>

[[Category:Geologic formations of Florida]]

{{Sourceattribution|Torreya Formation}}