The Clarkforkian North American Stage, on the

geologic timescale The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ...

, is the North American

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 conven ...

according to the

North American Land Mammal Ages The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when ref ...

chronology (NALMA), typically set from 56,800,000 to 55,400,000 years BP lasting . Considered to be within the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

, more specifically the

Late Paleocene The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Serie ...

, the Clarkforkian shares its upper boundary with the

Thanetian The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Serie ...

. The Clarkforkian is preceded by the

Tiffanian The Tiffanian 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 60,200,000 to 56,800,000 years BP lasting . It is usually co ...

and followed by the

Wasatchian The Wasatchian 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 55,400,000 to 50,300,000 years Before Present, BP lasting . I ...

NALMA stages.

Substages

It is considered to contain the following substages: *Cf3: (shares the upper boundary) and lower boundary source of the base of Clarkforkian (approximate) and upper boundary source of the base of the

Ypresian In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

(approximate). *Cf2: Is the lower boundary source of the base of the Clarkforkian (approximate) *Cf1: Upper boundary source of the base of the Ypresian (approximate)

Fauna

Notable mammals

Multituberculata Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct Order (biology), order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the M ...

- non-therian mammals * ''

Ectypodus ''Ectypodus'' is an extinct genus of mammals, containing the species ''E. aphronorus, E. childei, E. musculus, E. lovei, E. powelli, E. szalayi'', and ''E. tardus''. ''Ectypodus'' was an arboreal omnivore, living in the Paleocene to Eocene of N ...

'', neoplagiaulacid multituberculate

Metatheria Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as wel ...

- marsupials * ''

Peradectes ''Peradectes'' is an extinct genus of small metatherian mammals known from the latest CretaceousKorth, W. W. (2008). Marsupialia. In C. M. Janis, G. F. Gunnell, & M. D. Uhen (Eds.)Evolution of Tertiary Mammals of North America: Volume 2, Small Mam ...

'', peradectid marsupial

Carnivora Carnivora ( ) is an order of placental mammals specialized primarily in eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the sixth largest order of mammals, comprising at least 279 species. Carnivor ...

- carnivores, including living carnivorous mammals * '' Didymictis'', viverravid carnivoran Condylarthra - archaic ungulates * '' Apheliscus'', hyopsodontid condylarth * '' Ectocion'', phenacodontid condylarth * '' Phenacodus'', phenacodontid condylarth * '' Thryptacodon'',

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...

-like arctocyonid condylarth

Creodonta Creodonta ("meat teeth") is a former order of extinct carnivorous placental mammals that lived from the early Paleocene to the late Miocene epochs in North America, Europe, Asia and Africa. Originally thought to be a single group of animals ance ...

- extinct group of carnivorous mammals * '' Oxyaena'', semi-

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

creodont

Dinocerata Dinocerata, from Ancient Greek (), "terrible", and (), "horn", or Uintatheria, is an extinct order of large herbivorous hoofed mammals with horns and protuberant canine teeth, known from the Paleocene and Eocene of Asia and North America. With ...

- large, tusked herbivores * '' Probathyopsis'', early North American uintathere

Eulipotyphla Eulipotyphla (, from '' eu-'' + '' Lipotyphla'', meaning truly lacking blind gut; sometimes called true insectivores) is an order of mammals comprising the Erinaceidae ( hedgehogs and gymnures); Solenodontidae (solenodons); Talpidae ( mole ...

- insectivorous mammals * '' Plagioctenodon'', nyctitheriid insectivore * ''

Wyonycteris ''Wyonycteris'' is a genus of small mammals that existed in the late Paleocene and early Eocene Epoch (geology), epochs. The type species is ''Wyonycteris chalix'', which lived in Wyoming during the Clarkforkian North American land mammal age, No ...

'', nyctitheriid insectivore

Mesonychia Mesonychia ("middle claws") is an extinct taxon of small to large-sized carnivorous ungulates related to artiodactyls. Mesonychians first appeared in the early Paleocene, went into a sharp decline at the end of the Eocene, and died out entirely w ...

- carnivorous hoofed mammals * '' Dissacus'', dog-sized mesonychid

Pantodonta Pantodonta is an extinct suborder (or, according to some, an Order (biology), order) of eutherian mammals. These herbivorous mammals were one of the first groups of large mammals to evolve (around 66 million years ago) after the K-T boundary, en ...

- large herbivorous mammals * ''

Coryphodon ''Coryphodon'' (from Greek , "point", and , "tooth", meaning ''peaked tooth'', referring to "the development of the angles of the ridges into points n the molars") is an extinct genus of pantodonts of the family Coryphodontidae. ''Coryphodo ...

'',

semi-aquatic In biology, being semi-aquatic refers to various macroorganisms that live regularly in both aquatic and terrestrial environments. When referring to animals, the term describes those that actively spend part of their daily time in water (in ...

hippo The hippopotamus (''Hippopotamus amphibius;'' ; : hippopotamuses), often shortened to hippo (: hippos), further qualified as the common hippopotamus, Nile hippopotamus and river hippopotamus, is a large semiaquatic Mammal, mammal native to su ...

-like pantodont * '' Titanoides'', large pantodont Primatomopha - primates and relatives * ''

Carpolestes ''Carpolestes'' is a genus of extinct primate-like mammals from the late Paleocene of North America. It first existed around 58 million years ago. The three species of ''Carpolestes'' appear to form a Lineage (evolution), lineage, with the earli ...

'', carpolestid plesiadapiform * '' Chiromyoides'', small plesiadapid * '' Phenacolemur'', paromomyid plesiadapiform * ''

Plesiadapis ''Plesiadapis'' is one of the oldest known primate-like mammal genera which existed about 58–55 million years ago in North America and Europe. ''Plesiadapis'' means "near-Adapis", which is a reference to the Adapiformes, adapiform primate of th ...

'', plesiadapid plesiadapiform

Rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

ia - rodents * '' Alagomys'', alagomyid rodent * '' Paramys'', ischyromyid rodent Tillodontia - medium sized, digging herbivores * '' Esthonyx'', esthonychid tillodont

References

Paleocene life {{geochronology-stub