Usage:
Colchester (No. 2) Coal Member of Carbondale Formation (IL)
Colchester (No. 2) Coal Member of Linton Formation of Carbondale Group (IN)
Geologic age:
Middle Pennsylvanian (Desmoinesian)
Type section, locality, area and/or origin of name:
Type locality: in secs. 12 and 13, T. 5 N., R. 4 W., Colchester quadrangle, McDonough Co., western IL (Kosanke and others, 1960; coal named by Worthen, 1868, IN Geology and Paleontology, v. 3, Illinois Geol. Survey).
Reference section (subsurface): Indiana Geol. Survey drillhole SDH 306, in SW/4 NE/4 sec. 2, T. 2 S., R. 7 W., Pike Co., southern IN (Hasenmueller and Ault, 1991).
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 ([ ]).