Usage:
Thorn Ranch Tuff (CO*)
Geologic age:
Tertiary*
Oligocene*
Type section, locality, area and/or origin of name:
Along mesa near Thorn Ranch, in S/2 sec. 23 and N/2 sec. 26, T. 17 S., R. 73 W., Fremont Co., CO (Epis and Chapin, 1974).
AAPG geologic province:
Denver 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 ([ ]).