The Hawthorn Group is a

stratigraphic unit A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it ...

that includes several

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

s of

Late Oligocene The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58North Florida North Florida is a region of the U.S. state of Florida comprising the northernmost part of the state. Along with South Florida and Central Florida, it is one of Florida's three most common "directional" regions. It includes Jacksonville and near ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It is known for its

phosphate rock Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxi ...

resources, and for its rich assemblages of

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s. It was originally called the Waldo Formation by L.C. Johnson of the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

in 1887, and later became the Hawthorne Group named for

Hawthorne, Florida Hawthorne () is a city in Alachua County, Florida, United States, incorporated in 1881. Indigenous peoples of the Americas had been living in the area since around 100 CE; Hawthorne grew around their trading trails. Throughout its history, Hawth ...

, where its phosphate-rich rock was quarried and processed for use as fertilizer.

Age

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

Epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

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 recen ...

Faunal stage In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by conventi ...

Chattian The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ...

through early

Blancan The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years Before Present, BP, a period of .

~28.4 to ~2.588 mya, a period of

Location

The Hawthorn Group extends from

Suwannee County Suwannee County is a county located in the north central portion of the state of Florida. As of the 2020 census, the population was 43,474, up from 41,551 in 2010. Its county seat is Live Oak. Suwannee County was a dry county until August 201 ...

in the north and southward to

Hernando County Hernando County is a county located on the west central coast of the U.S. state of Florida. As of the 2020 census, the population was 194,515. Its county seat is Brooksville, and its largest community is Spring Hill. Hernando County is incl ...

. It encompasses in part the counties of Gilchrist,

Levy Levy, Lévy or Levies may refer to: People * Levy (surname), people with the surname Levy or Lévy * Levy Adcock (born 1988), American football player * Levy Barent Cohen (1747–1808), Dutch-born British financier and community worker * Levy Fi ...

Dixie Dixie, also known as Dixieland or Dixie's Land, is a nickname for all or part of the Southern United States. While there is no official definition of this region (and the included areas shift over the years), or the extent of the area it cover ...

Citrus ''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as Orange (fruit), oranges, Lemon, lemons, grapefruits, pomelos, and lim ...

Sumter Sumter may refer to: People Given name * Sumter S. Arnim (1904–1990), American dentist * Sumter de Leon Lowry Jr. (1893–1985), United States Army general Surname * Rowendy Sumter (born 1988), Curaçaoan footballer * Shavonda E. Sumter ( ...

, Alachua and Marion County. The Hawthorn is also present below undifferentiated sediments (TQu) as well as the

Tamiami Formation The Tamiami Formation is a Late Miocene to Pliocene geologic formation in the southwest Florida peninsula. Age Period: Neogene Epoch: Late Miocene to Pliocene Faunal stage: Clarendonian through Blancan ~13.06–2.588 mya, calculates to a ...

from

Polk County Polk County is the name of twelve counties in the United States, all except two named after president of the United States James Knox Polk: * Polk County, Arkansas * Polk County, Florida * Polk County, Georgia * Polk County, Iowa * Polk Count ...

south through

Highlands Highland is a broad term for areas of higher elevation, such as a mountain range or mountainous plateau. Highland, Highlands, or The Highlands, may also refer to: Places Albania * Dukagjin Highlands Armenia * Armenian Highlands Australia *Sou ...

, Glades, Hendry, Dade, Collier, and

Monroe County Monroe County may refer to seventeen counties in the United States, all named for James Monroe: * Monroe County, Alabama *Monroe County, Arkansas * Monroe County, Florida * Monroe County, Georgia *Monroe County, Illinois *Monroe County, Indian ...

at depths ranging from

mean sea level There are several kinds of mean in mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. ...

near Polk to below 600 meters in Monroe Co. The Hawthorn overlies

Ocala Limestone The Ocala Limestone is a late Eocene geologic formation of exposed limestones near Ocala, Marion County, Florida. Age Period: Paleogene Epoch: Late Eocene Faunal stage: Late Clarkforkian through early Orellan Absolute Age: ~55.8 to ~33.9 mya, ...

Glen L. Faulkner, Geological Survey (U.S.), United States. Army. Corps of Engineers, Geohydrology of the Cross-Florida Barge Canal area, Tallahassee, 1973.

Sub-units

Arcadia Formation The Arcadia Formation and its sub-unit, the Tampa Member, are Late Oligocene geologic formations in North Florida, United States. It is part of the Hawthorn Group. Age Period: Paleogene to Neogene Epoch: Early Late Oligocene through Pliocene F ...

Coosawhatchie Formation The Coosawhatchie Formation is a Miocene geologic formation with an outcrop in North Florida. It is within the Hawthorn Group. Age Period: Neogene Epoch: Miocene ~23.03 to 5.33 mya, calculates to a period of {{Mya, 23.03-5.33, million years Fa ...

(Miocene-Pliocene) *

Peace River Formation The Peace River Formation is a stratigraphical unit of middle Albian age in the Western Canadian Sedimentary Basin. It takes the name from the Peace River, and was first described on the banks of the river, downstream from the Smoky River conflue ...

(Miocene-Pliocene) *

Statenville Formation The Statenville Formation is a geological formation of northern Florida, USA. Age Period: Neogene Epoch: Miocene Faunal stage: Chattian through early Blancan ~28.4 to ~2.588 mya, calculates to a period of Location The Statenville Formation is ...

(Miocene) *

Torreya Formation The Torreya Formation is a Miocene geologic formation with an outcrop in North Florida. It is within the Hawthorn Group. Age Period: Neogene Epoch: Early Miocene Faunal stage: Aquitanian through early Messinian ~19–15.3 mya, calculates to a ...

(Miocene)

Paleofauna

Reptiles *''

Apalone ferox The Florida softshell turtle (''Apalone ferox'') is a species of softshell turtle native to the Southeastern United States.Rafinesque, Constantine S. "12. Description of two new genera of Soft Shell Turtles of North America." Atlantic Journal, a ...

'' (Florida Softshell Turtle) *''

Pseudemys ''Pseudemys'' is a genus of large, herbivorous, freshwater turtles of the eastern United States and adjacent northeast Mexico. They are often referred to as cooters, which stems from ''kuta'', the word for turtle in the Bambara and Malinké lang ...

caelata'' (Pond Turtle) *'' Terrapene'' (Box Turtle) *''

Deirochelys ''Deirochelys'' is a genus of freshwater turtle in the family Emydidae, the pond and marsh turtles. It contains one extant species, the chicken turtle (''Deirochelys reticularia''), which is native to the southeastern United States. A second exti ...

'' (Chicken Turtle) *''

Geochelone ''Geochelone'' is a genus of tortoises. ''Geochelone'' tortoises, which are also known as typical tortoises or terrestrial turtles, can be found in southern Asia. They primarily eat plants. Species The genus consists of two extant species: A n ...

'' (Tortoise) *''

Alligator mississippiensis The American alligator (''Alligator mississippiensis''), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile native to the Southeastern United States. It is one of the two extant species in the gen ...

'' (American Alligator) *†''

Gavialosuchus ''Gavialosuchus'' is an extinct genus of gavialid crocodylian from the early Miocene of Europe. Currently only one species is recognized, as a few other species of ''Gavialosuchus'' have since been reclassified to other genera. Taxonomy The typ ...

americanus'' or '' Thecachampsa antiqua'' (American Crocodile) *''

Typhlops ''Typhlops'' is a genus of blind snakes in the family Typhlopidae. The genus is endemic to the West Indies. Some species which were formerly placed in the genus ''Typhlops'' have been moved to the genera '' Afrotyphlops, Amerotyphlops, Anilios, ...

'' (Blind snake) *''

Xenodontinae Xenodontinae is a subfamily of snakes in the family Colubridae. The subfamily Xenodontinae encompasses a number of rear-fanged (opisthoglyphous), mildly venomous snake genera found in South America and the Caribbean. Members of the subfamily ...

'' (Mud Snake) *''

Heterodon ''Heterodon'' is a genus of harmless colubrid snakes endemic to North America.Platt, Dwight R. 1983. Heterodon'. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles, 351: 1-2. They are stout with up ...

'' (Hognose Snake) *''

Elaphe ''Elaphe'' is a genus of snakes in the family Colubridae. ''Elaphe'' is one of the main genera of the rat snakes, which are found in many regions of the northern hemisphere. ''Elaphe'' species are medium to large constrictors by nature. Althoug ...

'' (Rat Snake) *'' Lampropeltis getulus'' (Kingsnake) *''

Nerodia ''Nerodia'' is a genus of nonvenomous colubrid snakes commonly referred to as water snakes due to their aquatic behavior. The genus includes nine species, all native to North America. Description ''Nerodia'' species vary greatly, but all are ...

'' (Water snake) *'' Thamnophis'' (Garter Snake) *''

Crotalinae The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . crotaline snakes (from grc, κρόταλον ''krotalon'' castanet), or pit adders, are a subfa ...

'' (Lancehead, Rattlesnake) *''

Sistrurus :''Common names: ground rattlesnakes, pygmy rattlesnakes, massasaugas'' Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates, a Division of Cornell University Press ...

'' (Rattlesnake) Birds *''

Anserinae The Anserinae are a subfamily in the waterfowl family Anatidae. It includes the swans and true geese. Under alternative systematical concepts (see e.g., Terres & NAS, 1991), it is split into two subfamilies, the Anserinae contain the geese and ...

'' (Swan) *'' Podicipedidae'' (Grebe) *''

Phalacrocoracidae Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven gen ...

'' (Cormorant) *''

Anhinga The anhinga (; ''Anhinga anhinga''), sometimes called snakebird, darter, American darter, or water turkey, is a water bird of the warmer parts of the Americas. The word ''anhinga'' comes from ''a'ñinga'' in the Brazilian Tupi language and means ...

grandis'' (Snakebird) *'' Ciconiidae'' (Stork) *''

Phoenicopteridae Flamingos or flamingoes are a type of wading bird in the family Phoenicopteridae, which is the only extant family in the order Phoenicopteriformes. There are four flamingo species distributed throughout the Americas (including the Caribbean) ...

'' (Flamingo) *'' Ardea'' (Heron) *''

Egretta ''Egretta'' is a genus of medium-sized herons, mostly breeding in warmer climates. Representatives of this genus are found in most of the world, and the little egret, as well as being widespread throughout much of the Old World, has now started ...

'' (Egret) *''

Ardeola Pond herons (''Ardeola'') are herons, typically long with an wingspan. Most breed in the tropical Old World, but the migratory squacco heron occurs in southern Europe and the Middle East and winters in Africa. The scientific name comes from L ...

'' (Heron) *''

Aramidae Aramidae is a bird family in the order Gruiformes. The limpkin The limpkin (''Aramus guarauna''), also called carrao, courlan, and crying bird, is a large wading bird related to rails and cranes, and the only extant species in the family Ara ...

'' (Limpkin) *'' Gruidae'' (Crane-like) *''

Rallidae The rails, or Rallidae, are a large cosmopolitan family of small- to medium-sized, ground-living birds. The family exhibits considerable diversity and includes the crakes, coots, and gallinules. Many species are associated with wetlands, althoug ...

'' (Crakes & Coots) *''

Cathartidae The New World vulture or condor family, Cathartidae, contains seven extant species in five genera. It includes five extant vultures and two extant condors found in warm and temperate areas of the Americas. The "New World" vultures were widespread ...

'' (New World Vulture) *''

Pandionidae ''Pandion'' is a genus of birds of prey, known as ospreys, the only genus of family Pandionidae. Most taxonomic treatments have regarded this genus as describing a single extant species, separated to subspecies or races, while some treatments rec ...

'' (Osprey) *''

Accipitridae The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-s ...

'' (Eagle) *''

Passeriformes A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by t ...

'' (Songbird) Mammals *†''

Metaxytherium ''Metaxytherium'' is an extinct genus of dugong that lived from the Oligocene until the end of the Pliocene. Fossil remains have been found in Africa, Europe, North America and South America. Generally marine seagrass specialists, they inhabit ...

floridanum'' (Sea Cow) *†''

Gomphotherium ''Gomphotherium'' (; "welded beast") is an extinct genus of proboscids from the Neogene and early Pleistocene of Eurasia, Africa, North America and Asia. As of 2021, two species, ''G. annectens'' and possibly ''G. subtapiroideum'', are also kno ...

'' (Elephant) *†''

Tapirus ''Tapirus'' is a genus of tapir which contains the three living American tapir species. The Malayan tapir is usually included in ''Tapirus'' as well, although some authorities have moved it into its own genus, ''Acrocodia''. Extant species The ...

simpsoni'' (Tapir) *†''

Teleoceras ''Teleoceras'' (Greek: "perfect" (teleos), "horn" (keratos)) is an extinct genus of grazing rhinoceros. It lived in North America during the Miocene and Pliocene epochs during the Hemingfordian to the end of Hemphillian from around 17.5 to 4.9 mi ...

proterum'' (Rhinoceros) *†''

Aphelops ''Aphelops'' (Greek: "smooth" (apheles), "face" (ops), in a reference of lacking a horn) is an extinct genus of hornless rhinoceros endemic to North America. It lived from the Middle Miocene to the early Pliocene, during which it was a common com ...

malacorhinus'' (Rhinoceros) *†''

Pseudhipparion ''Pseudhipparion'' is an extinct genus of three-toed horse endemic to North America during the Miocene. They were herding animals whose diet consisted of C3 plants. Fossils found in Georgia and Florida Florida is a state located in the ...

skinneri'' (Horse) *†''

Hipparion ''Hipparion'' (Greek, "pony") is an extinct genus of horse that lived in North America, Asia, Europe, and Africa during the Miocene through Pleistocene ~23 Mya—781,000 years ago. It lived in non-forested, grassy plains, shortgrass prairie or st ...

tehonense'' (Horse) *†''

Neohipparion ''Neohipparion'' (Greek: "new" (neos), "pony" (hipparion)) is an extinct genus of equid, from the Neogene (Miocene to Pliocene) of North America and Central America Central America ( es, América Central or ) is a subregion of the Ameri ...

trampasense'' (Horse) *†''

Nannippus ''Nannippus'' is an extinct genus of three-toed horse endemic to North America during the Miocene through Pleistoceneabout 13.3—1.8 million years ago (Mya), living around 11.5 million years. This ancient species of three-toed horse grew up to 3 ...

westoni'' (Horse) *†''

Hippotherium ''Hippotherium'' is an extinct genus of horse that lived in during the Miocene through Pliocene ~13.65—3.3 Mya, existing for . Species The type species, ''H. primigenius'', is known from Miocene deposits in Europe and the Middle East ...

ingenuum'' and ''H. plicatile'' (Horse) *†'' Calippus cerasinus'' and ''C. elachistus'' (Horse) *†''

Protohippus ''Protohippus'' is an extinct three-toed genus of horse. It was roughly the size of a modern donkey. Fossil evidence suggests that it lived during the Late Miocene (Clarendonian to Hemphillian), from about 13.6 Ma to 5.3 Ma. Analysis of ''Proto ...

gidleyi'' (Horse) *'' Microchiroptera'' (Microbat) *†'' Leptarctus'' (Mustelidae) *†'' Hoplictis'' (Mustelidae) *†'' Plionictis'' (Mustelidae) *†''

Sthenictis ''Sthenictis'' is an extinct genus in the weasel family (mustelids) endemic to North America and Asia during the Miocene epoch living from ~15.97—5.33 Ma ( AEO) existing for approximately . Fossil distribution The oldest specimen was uncovere ...

lacota'' (Mustelidae) *†'' Arctonasua floridana'' (Raccoon) *†'' Paranasua biradica'' *†''

Leptocyon The genus ''Leptocyon'' (Greek: ''leptos'' slender + ''cyon'' dog) includes 11 species and was the first canine. They were small and weighed around . They first appeared in North America around 34 million years ago in the Oligocene at the same ...

'' *†''

Epicyon ''Epicyon'' ("more than a dog") is a large, extinct, canid genus of the subfamily Borophaginae ("bone-crushing dogs"), native to North America. ''Epicyon'' existed for about from the Hemingfordian age of the Early Miocene, to the Hemphillian of ...

haydeni'' and ''E. saevus'' (Proto-dog) *†''

Nimravides ''Nimravides'' is a genus of extinct saber-toothed cats that lived in North America during the Late Miocene, between 10.3 and 5.332 Ma. Despite its scientific name, ''Nimravides'' does not belong to the Nimravidae, but is a true cat, belonging ...

galiani'' (False Saber-tooth cat) *†''

Barbourofelis ''Barbourofelis'' is an extinct genus of large, predatory, feliform carnivoran mammals of the family Barbourofelidae (false saber-tooth cats). The genus was endemic to North America and Eurasia during the Miocene until its extinction during t ...

loveorum'' (False Saber-tooth cat) *†'' Antilocaprinae'' (Antilope) *†'' Pseudoceras'' (Early horse-type ungulate) *†'' Yumaceras hamiltoni'' (Camel-like) *†''

Cetacea Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

'' (Whale) *†''

Aepycamelus ''Aepycamelus'' is an extinct genus of camelids that lived during the Miocene 20.6–4.9 million years ago, existing for about . Its name is derived from the Homeric Greek , "high and steep" and κάμηλος – "camel"; thus, "high camel"; ''a ...

major'' (Camel) *†''

Procamelus ''Procamelus'' is an extinct genus of camel endemic to North America. It lived from the Middle to Late Miocene 16.0—5.3 mya, existing for approximately . The name is derived from the Greek πρό, meaning "before" or denoting priority of ord ...

grandis'' (Camel) *†''

Hemiauchenia ''Hemiauchenia'' is a genus of laminoid camelids that evolved in North America in the Miocene period about 10 million years ago. This genus diversified and moved to South America in the Early Pleistocene, as part of the Great American Biotic In ...

minima'' (Camel) *''

Talpidae The family Talpidae () includes the moles (some of whom are called shrew moles and desmans) who are small insectivorous mammals of the order Eulipotyphla. Talpids are all digging animals to various degrees: moles are completely subterranean a ...

'' (Mole) *'' Soricidae'' (Shrew) *†'' Archaeolaginae (Rabbit) *''

Sciuridae Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

'' (Squirrel) *†''

Eucastor ''Eucastor'' is an extinct genus (biology), genus of beaver-grouped rodents. Based on the available evidence of the Foramen, foramina, ''Eucastor'' most likely is closely related to Beaver, ''Castor'', but not in its direct lineage. References ...

planus'' (Beaver) *'' Abelmoschomys simpsoni'' (Vole) *†''

Mylagaulus ''Mylagaulus'' is an extinct genus of rodents in the family Mylagaulidae. ''Mylagaulus'' lived in the Americas during the middle to late Miocene. The genus contains the following species: *''M. cambridgensis'' *''M. cornusaulax'' Czaplewski, 20 ...

elassos'' (Horned gopher)

References

{{reflist *USGS: Florida Geology
/small> *Paleobiology database: Love Bone Bed Collection
/small> Geologic groups of Florida Neogene Florida Paleogene Florida Oligocene Series of North America Miocene Series of North America Paleontology in Florida Miocene United States