Usage:
Isabel Sandstone Member of Carbondale Formation (IL-local)
Geologic age:
Middle Pennsylvanian (Desmoinesian)
Type section, locality, area and/or origin of name:
Type locality: high bank on southeast side of ravine, in NW/4 NE/4 sec. 16, T. 4 N., R. 3 E., [approx. Lat. 40 deg. 19 min. 50 sec. N., Long. 90 deg. 10 min. 10 sec. W.], Havana quadrangle, Fulton Co., western IL. Named from Isabel Twp. (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 ([ ]).