Usage:
Piegan Group of Belt Supergroup (ID,MT)
Subunits:
(alphabetical) --all in ID,MT: Helena Formation, Wallace Formation.
Geologic age:
Mesoproterozoic
Type section, locality, area and/or origin of name:
Type locality: Piegan Mountain, Glacier National Park, [Glacier Co.], western MT (Fenton and Fenton, 1937).
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 ([ ]).