Usage:
No current usage.
(†Brereton cyclothem (informal) (IL) considered obsolete.)
Geologic age:
Pennsylvanian
Type section, locality, area and/or origin of name:
Type section: along Middle Branch of Copperas Creek, 2 mi northeast of Brereton, in NE/4 SE/4 NE/4 sec. 1, T. 7 N., R. 4 E., Glasford 15-min quadrangle, Fulton Co., central western IL (Wanless, 1957).
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 ([ ]).