Usage:
Chugwater Group (CO*,WY*)
Chugwater Formation (CO*,WY*,MT*)
Subunits:
GROUP STATUS (alphabetical): Alcova Limestone (WY*), Crow Mountain Sandstone (WY*), Jelm Formation (CO*,WY*), Popo Agie Formation (WY*), Red Peak Formation (CO*,WY*).
FORMATION STATUS (alphabetical): Alcova Limestone (WY*), Crow Mountain Sandstone Member (WY), Popo Agie Member (WY*), Red Peak Member (CO*,WY*).
Geologic age:
Triassic*
Type section, locality, area and/or origin of name:
Named from Chugwater Creek near Iron Mountain, [Platte Co.], WY (Darton, 1904).
AAPG geologic province:
Bighorn basin*
Denver basin*
Green River basin*
Powder River basin*
Wind River basin*
Yellowstone province*
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 ([ ]).