Usage:
Dygerts Bentonite Bed of Sinsinawa Member of Wise Lake Formation of Galena Group (IL,IA,MN)
Geologic age:
Middle Ordovician
Type section, locality, area and/or origin of name:
Type section: Galena roadcut section, on U.S. Highway 20 along east side of Galena River, in SW/4 SE/4 NE/4 sec. 20, T. 28 N., R. 1 E., in Galena, Jo Daviess Co., northwest IL. Named from Dygerts Mound, 2.4 km southeast of type section (Willman and Kolata, 1978).
AAPG geologic province:
Wisconsin arch
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 ([ ]).