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National Geologic Map Database

Geologic Unit: Dunleith

Usage:

Dunleith Formation of Galena Group (IL,IA,WI)
Dunleith Member of Galena Dolomite of Sinnipee Group (WI)


Subunits:

FORMATION STATUS (alphabetical): Beecher Member (IL,IA,WI), Buckhorn Member (IL,IA,WI), Eagle Point Member (IL,IA,WI), Fairplay Member (IL,IA,WI), Loves Park Member (IL), Moredock Member (IL), Mortimer Member (IL,IA), New London Member (IL), Rivoli Member (IL,IA), Sherwood Member (IL,IA), St. James Member (IL,IA,WI), Wall Member (IL,IA), Wyota Member (IL,IA).
MEMBER STATUS: Fairplay Bed (WI), Ion submember (informal) (WI).


Geologic age:

Late Ordovician (Mohawkian; Chatfieldian)


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

Type section: exposure in Mississippi River bluffs on north side of East Dubuque, in SE/4 sec. 19, T. 29 N., R. 2 W., [approx. Lat. 42 deg. 29 min. 42 sec. N., Long. 90 deg. 38 min. 52 sec. W., Dubuque South 7.5-min quadrangle], Jo Daviess Co., northwestern IL (Templeton and Willman, 1963, Illinois Geol. Survey Bull., no. 89, p. 114; Willman and Buschbach, 1975, Illinois Geol. Survey Bull., no. 95, p. 47-87).
Named from Dunleith Twp., Jo Daviess Co., northwestern IL (Templeton and Willman, 1963, p. 114; Willman and Buschbach, 1975).
Type area: in extreme northwestern IL (Templeton and Willman, 1952).


AAPG geologic province:

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