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National Geologic Map Database

Geologic Unit: Grassy Creek

Usage:

Grassy Creek Shale (MO*)
Grassy Creek Member of Maple Mill Formation of Yellow Spring Group (IA)
Grassy Creek Shale Member of New Albany Shale of Knobs Group (IL)
Grassy Creek Member of New Albany Shale (KY)
[?] Grassy Creek Shale of New Albany Group (IL*)


Geologic age:

Late Devonian (Famennian)*


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

Type locality: Mississippi River bluff in Pike Co., northeastern MO, some distance above Champ Clark Bridge, in approx. SW/4 NW/4 NE/4 sec. 18, T. 54 N., R. 1 W. (Mehl, 1960).
Notable exposures on Grassy Creek in sec. 19 (Weller, 1935).


AAPG geologic province:

Illinois basin*
Iowa shelf
Lincoln anticline*
Ozark uplift*


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 ([ ]).