Usage:
No current usage.
(†Hall cyclothem (informal) in McLeansboro Group (IL) or †Hall cyclothem (informal) in †/Modesto-Bond Formation [informal] in McLeansboro Group (IL) considered obsolete.)
Geologic age:
Pennsylvanian
Type section, locality, area and/or origin of name:
Type locality: in NW/4 SW/4 sec. 33, T. 16 N., R. 11 E., Bureau Co., northern IL (Wanless, 1956).
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 ([ ]).