Washakie Formation

The Washakie Formation is a geologic formation in northern Colorado and southern Wyoming. It preserves many mammal, bird, reptile and other fossils dating back to the Lutetian stage of the Eocene within the Paleogene period. The sediments fall in the Bridgerian and Uintan stages of the NALMA classification.

Fossil content
The Washakie Formation has provided many fossil mammals, turtles and other reptiles, birds and other fossils.

The artiodactyl Heliosus apophis was described from the formation by Burger and Jolley, and the rodents Pareumys flynni, Pauromys turnbulli and Thisbemys intermedius by Korth in 2020.