The Harrisonian 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 geochronol ...

is the North American faunal stage 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 24,800,000 to 20,600,000 years BP, a period of .Paleobiology Database, Harrisonian
/ref> It is usually considered to overlap the

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 ...

and

Aquitainian Aquitaine ( , , ; oc, Aquitània ; eu, Akitania; Poitevin-Saintongeais: ''Aguiéne''), archaic Guyenne or Guienne ( oc, Guiana), is a historical region of southwestern France and a former administrative region of the country. Since 1 January ...

stages within the late

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

. The Harrisonian is preceded by the Monroecreekian and followed by the Hemingfordian NALMA stage.

References

{{Paleogene Footer Oligocene Miocene Arikareean