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National Geologic Map Database

Geologic Unit: Fall River

Usage:

Fall River Sandstone (MT*,ND*)
Fall River Sandstone of Inyan Kara Group (SD*)
Fall River Sandstone of Dakota Group (NE)
Fall River Formation (ND*)
Fall River Formation of Inyan Kara Group (MT, SD*, WY*)
Fall River Formation of Dakota Group (ND)
Fall River Sandstone Member of Colorado Shale (MT*, WY*)
Fall River Member of Omadi Sandstone of Dakota Group (NE) [From GNC files]
[?] Fall River Formation of Cloverly Group (MT)


Subunits:

FORMATION STATUS (alphabetical): Coyote Creek Member (MT,SD,WY), Keyhole Sandstone Member (SD*,WY*), Liscom Creek Member (MT,SD,WY), /Morton Member (MT,SD,WY).


Geologic age:

late Early Cretaceous (Albian)*


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

Not stated (Russell, 1927).
Type locality: Evans quarry on Fall River, below Hot Springs, Fall River Co., SD (Russell, 1928).
Type section: measured in Fall River Canyon, in N/2 sec. 33, T. 7 S., R. 6 E., Hot Springs quadrangle, Fall River Co., SD (Waage, 1959).


AAPG geologic province:

Chadron arch*
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 ([ ]).