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National Geologic Map Database

Geologic Unit: Fox Hills

Usage:

Fox Hills Sandstone (CO*,MT*,ND*,SD*,WY*)
Fox Hills Formation (ND*,SD*,WY*)
Fox Hills Formation of Montana Group (MT*,ND)


Subunits:

(alphabetical): Bullhead Member (ND,SD), Colgate Member (MT*,ND*,SD,WY), Fairpoint Member (SD), Iron Lightning Member (ND*,SD*), Linton Member (ND,SD), Milliken Member (CO*), Stoneville Member (SD), Trail City Member (ND,SD*), Timber Lake Member (ND,SD*), White Owl Creek Member (SD).


Geologic age:

Late Cretaceous (Maastrichtian)*


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

Named from exposures in Fox Ridge, northwestern Armstrong and southwestern Dewey Cos., SD (shown on pl. 1 of USGS Bull. 575; see US geologic names lexicon, USGS Bull. 896).
Type area: in Corson, Dewey, and Ziebach Cos., SD (Waage, 1968).
Historical type locality delimited as south of Moreau River, south of Highway 212 on Cheyenne-Moreau divide, southwest Dewey Co. and northeast Ziebach Co., SD (Waage, 1968).
Reference section: in SW/4 SW/4 sec. 13 and SE/4 SE/4 sec. 14, T. 22 N., R. 89 W., Carbon Co., southern WY (Gill and others, 1970).


AAPG geologic province:

Denver basin*
Green River basin*
Powder River basin*
Williston basin*


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 ([ ]).