No current usage.
(†Clear Creek Gneiss (CO) replaced with Idaho Springs Formation. See Idaho Springs.)
Paleoproterozoic
Not stated. Occurs along Clear Creek, Jefferson and Clear Creek Cos., CO (Underhill, 1906).
Southern 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 ([ ]).