Usage:
No current usage?
(†Black Hill Rhyolite (CO-local) considered obsolete? Uncertain if used by the CO Geol. Survey. Not used by the USGS.)
Geologic age:
Tertiary
Type section, locality, area and/or origin of name:
Forms Black Hill, about 18 mi southeast of Leadville, Lake Co., CO (Cross, 1886).
AAPG geologic province:
Eagle basin
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 ([ ]).