Usage:
Allan Mountain Limestone of Madison Group (MT*)
Geologic age:
Early Mississippian (Tournaisian; Kinderhookian to early Osagean)*
Type section, locality, area and/or origin of name:
Type section: exposure along north shore of Gibson Reservoir, in SE/4 sec. 36, T. 22 N., R. 10 W., Patricks Basin quadrangle, [southwestern] Teton Co., Lewis and Clark National Forest, northwestern MT. Named from exposures on Allan Mountain [Lat. 47 deg. 33 min. 42 sec. N., Long. 112 deg. 48 min. 07 sec. W., Patricks Basin quadrangle, Lewis and Clark Co., Lewis and Clark National Forest, MT] (Mudge and others, 1962).
AAPG geologic province:
Montana folded belt*
Sweetgrass arch*
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 ([ ]).