Usage:
No current usage.
(Rocks of †Pitchfork Formation of Sunlight Group of Absaroka Volcanic Supergroup (WY) reallocated to Aycross Formation and Tepee Trail Formation. See Aycross and Tepee Trail.)
Geologic age:
early Tertiary (Eocene)*
Type section, locality, area and/or origin of name:
Not designated, although exposures on east side of Francs Fork, on south side of Greybull Valley, in sec. 4 and center sec. 9, T. 47 N., R. 103 W., nearly approaches a type section. Named from Pitchfork Post Office, Park Co., WY (Hay, 1956).
AAPG geologic province:
Bighorn 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 ([ ]).