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 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 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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).