U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database

Geologic Unit: Sinsinawa

Usage:

Sinsinawa Member of Wise Lake Formation of Galena Group (IL,IA,MN)
Sinsinawa Member of Galena Dolomite of Sinnipee Group (WI)
Sinsinawa Member of Stewartville Formation of Galena Group (MN)


Subunits:

Dygerts Bentonite Bed (IL,IA,MN).


Geologic age:

Late Ordovician (Cincinnatian; Edenian)


Type section, locality, area and/or origin of name:

Type section: roadcut along U.S. Highway 20 on east side of Galena River at Galena, in SW/4 SE/4 NE/4 sec. 20, T. 28 N., R. 1 E., [approx. Lat. 42 deg. 24 min. 34 sec. N., Long. 90 deg. 25 min. 18 sec. W., Galena 7.5-min quadrangle], Jo Daviess Co., northwestern IL (Templeton and Willman, 1963, Illinois Geol. Survey Bull., no. 89, p. 126; Willman and Buschbach, 1975, Illinois Geol. Survey Bull., no. 95, p. 47-87)
Named from Sinsinawa River, [Galena 7.5-min quadrangle, Jo Daviess Co., northwestern IL, about 3 mi northwest of type section] (Templeton and Willman, 1963, p. 123; Willman and Buschbach, 1975).
Notable exposures in Dixon-Oregon area, northern IL (Templeton and Willman, 1952).


AAPG geologic province:

Iowa shelf
Wisconsin arch


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).