Washakie Formation

The Washakie Formation in northern Colorado and southern Wyoming is a major record of Eocene life, preserving fossils from the Lutetian stage and sediments spanning the Bridgerian and Uintan ages. It has produced a diverse fossil assemblage including mammals, birds, turtles, crocodilians, and other reptiles, among them Heliosus apophis and several rodents. Study of its biostratigraphy, magnetostratigraphy, and sedimentology has helped place these faunas within the wider sequence of Eocene life in the Rocky Mountain region. As part of a group of classic western fossil-bearing formations, it is especially important for tracing changing middle Eocene terrestrial ecosystems in the Washakie and Sand Wash basins.

Wyoming · United States