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National Geologic Map Database

Geologic Unit: Claggett

Usage:

Claggett Formation of Montana Group (MT*)
Claggett Shale of Montana Group (MT*)
Claggett Member of Cody Shale (MT*)


Subunits:

FORMATION STATUS (alphabetical) --all in MT*: Ardmore Bentonite Beds, Parkman Sandstone Member.


Geologic age:

Late Cretaceous (Campanian)*


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

Not designated. Named from Fort Claggett, Fergus Co., MT (Hatcher and Stanton, 1903).


AAPG geologic province:

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