East Gulch Tuff (CO*)
Tertiary*
Oligocene*
In East Gulch, from which unit is named, in secs. 2, 3, and 11, T. 49 N., R. 12 E., south-central part of Black Mountain quadrangle, Fremont Co., CO (Epis and Chapin, 1974).
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 ([ ]).