Usage:
Clear Creek Chert (IL*,KY*,MO)
Clear Creek Chert of New Harmony Group (IL,IN)
Clear Creek Formation (IL*,MO)
Clear Creek Limestone (IL*,KY*,MO*)
Geologic age:
Early Devonian*
Type section, locality, area and/or origin of name:
Named from exposures on Clear Creek, Union Co., southwestern IL (Worthen, 1866).
AAPG geologic province:
Illinois 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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).