Usage:
St. Regis Formation of Ravalli Group of Belt Supergroup (ID*,MT*,WA*)
Geologic age:
Mesoproterozoic*
Type section, locality, area and/or origin of name:
Not designated. Best exposed in vicinity of St. Regis Pass, and about 3 mi northeast of Mullan, T. 47 N., R. 5 E., Shoshone Co., ID. Named from St. Regis Pass (Ransome, 1905).
AAPG geologic province:
Northern Rocky Mountain region*
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 ([ ]).