Usage:
Logan Gulch Member of Three Forks Formation (MT*,WY*)
Geologic age:
Late Devonian*
Type section, locality, area and/or origin of name:
Type section: included in type section of Three Forks, as given by Sandberg (1962), in gulch and on bluffs at north side of Gallatin River, northeast of Logan, in S/2 S/4 sec. 25, T. 2 N., R. 2 E., Gallatin Co., MT. Named from exposures in Logan Gulch, near Logan (Sandberg, 1965).
AAPG geologic province:
Williston basin*
Montana folded belt*
Bighorn basin*
Sweetgrass arch*
Yellowstone province*
Central Montana uplift*
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 ([ ]).