No current usage.
(Rocks of †Monument Creek Group (CO) reallocated to Castle Rock Conglomerate and Dawson Arkose. See Castle Rock and Dawson.)
early Tertiary (Oligocene)
Notable exposures along Monument Creek, [Castle Rock and Colorado Springs quadrangles], El Paso Co., eastern central CO (Hayden, 1869).
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 ([ ]).