Devils Pocket Formation of Amsden Group (MT*)
Middle Pennsylvanian (Atokan to Desmoinesian)*
Type section: in Road Canyon, in sec. 31, T. 11 N., R. 21 E., about 0.5 mi west of Stonehouse Ranch. Named from Devils Pocket, and anticlinal valley on a long anticlinal nose breached by erosion in southeastern Big Snowy Mountains (T. 10 N., R. 21 E.), where formation is 141 feet thick (Gardner, 1959).
Sweetgrass arch*
Powder River basin*
Williston basin*
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 ([ ]).