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

Geologic Unit: Greyson

Usage:

Greyson Shale of Missoula Group of Belt Supergroup (MT*)
Greyson Formation of Missoula Group of Belt Supergroup (MT*)
Greyson Formation of Belt Supergroup (MT)
(Restricted from Glacier National Park and adjacent areas, Glacier Co., MT, where Appekunny is exposed.)


Geologic age:

Middle Proterozoic*


Type section, locality, area and/or origin of name:

Type locality: on side of ridge between Deep and Greyson Creeks, southeast of Townsend, [Teton Co.], Belt Mountains, western central MT (Walcott, 1899).


AAPG geologic province:

Northern Rocky Mountain region*


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 ([ ]).