Usage:
Markham Member of Roxana Silt of Mason Group (IL*)
Geologic age:
Pleistocene (Wisconsinan Age)*
Type section, locality, area and/or origin of name:
Type section: Chapin section, in roadcuts along IL Highway 104, 2.4 km northwest of Markham on west side of Mauvaise Terre Creek, in SW/4 NE/4 NW/4 sec. 8, T. 15 N., R. 11 W., Morgan Co., west-central IL. Named from village of Markham, 4 mi west of Jacksonville, Morgan Co., west-central IL (Willman and Frye, 1970).
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 ([ ]).