Usage:
No current usage.
(†Bear Formation (MT) not used since its introduction, considered invalid. Rocks now included in Fort Union Formation. See Fort Union.)
Geologic age:
early Tertiary (Paleocene)
Type section, locality, area and/or origin of name:
Typically developed around Bear Butte [local name; in T. 5 and 6 N., R. 16 E., approx. Lat. 46 deg. 12.5 min. N., Long. 109 deg. 44 min. W., Jim Creek 7.5-min quadrangle], Sweetgrass and Wheatland Cos., central MT (Simpson, 1937).
AAPG geologic province:
Central Montana uplift
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 ([ ]).