The Duchesnean 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 42,000,000 to 38,000,000 years BP. It is usually considered to fall within the Eocene epoch. The Duchesnean is preceded by the Uintan and followed by the Chadronian NALMA stages. The Duchesnean is considered to be contained within the Bartonian sharing the upper boundary.