The Bridgerian 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 50,300,000 to 46,200,000 years BP. It is usually considered to overlap the Ypresian and Lutetian within the Eocene epoch. The Bridgerian is preceded by the Wasatchian and followed by the Uintan NALMA stages. The Bridgerian is considered to contain the following substages: