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 BP lasting 5.1 million years.

It is usually considered to be within the Eocene, more specifically the Early Eocene.

The Wasatchian is preceded by the Clarkforkian and followed by the Bridgerian NALMA stages.