Usage:
Clarkforkian age*
A provincial North American land mammal age (NALMA). Between Tiffanian and Wasatchian.
Geologic age:
early Tertiary (late Paleocene)*
Type section, locality, area and/or origin of name:
Name based on Clark Fork Member (and faunal zone) of Polecat Bench Formation, Park Co., WY (Wood and others, 1941).
AAPG geologic province:
North America*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).