Usage:
Pearl Formation (IL)
Subunits:
(alphabetical) --all in IL: Berry Clay Member, Hagarstown Member.
Geologic age:
Quaternary
Pleistocene, middle
Illinoian
Sangamonian
Type section, locality, area and/or origin of name:
Type section: exposure in box canyon 1 mi southwest of Pearl, in SE/4 SW/4 NE/4 sec. 16, T. 7 S., R. 2 W., Pike Co., IL. Named from Pearl, Pike Co., 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 ([ ]).