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National Geologic Map Database

Geologic Unit: Crab Orchard

Usage:

Crab Orchard Formation (KY*,OH)
Crab Orchard Shale (KY*)
Crab Orchard Group (KY*,OH*)


Subunits:

GROUP STATUS (alphabetical): Alger Shale (KY*-local), Drowning Creek Formation (KY*), Estill Shale (KY*,OH*), Noland Formation (KY,OH).


Geologic age:

early Early Silurian (Llandovery)*


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

Vicinity of Crab Orchard village, Crab Orchard quadrangle, Lincoln Co., central KY (Linney, 1882).
Reference section (Crab Orchard Group): along U.S. Highway 150 just east of Cedar Creek, 2.5 mi west of Crab Orchard village, Crab Orchard quadrangle, Lincoln Co., central KY (McDowell, 1983).


AAPG geologic province:

Cincinnati arch*


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 ([ ]).