Bridgerian North American Stage
The Bridgerian North American Stage on the
North American Land Mammal Ages chronology (NALMA), typically set from 50,300,000 to 46,200,000 years BP lasting 4.1 million years.[1]
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.
Substages
The Bridgerian is considered to contain the following substages:
- Twinbuttean: Lower boundary source of the base of the Bridgerian (approximate).
- Lutetian which is contained within the Bortonian stage, and Heretaungan stage.[2]
References
 | This geochronology article is a stub. You can help Wikipedia by expanding it. |