U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database

Geologic Unit: Allan Mountain

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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).