No current usage.
(†Needle Mountains Group (CO) abandoned.)
Proterozoic
Not designated. Origin of name not stated by authors, but probably named from Needle Mountains, La Plata and San Juan Cos., CO (Cross and Howe, 1905).
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 ([ ]).