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National Geologic Map Database

Geologic Unit: Stewartville

Usage:

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


Subunits:

Rifle Hill (top) and Sinsiniwa Members (MN)
[In IA and IL these members are assigned to Wise Lake Formation].


Geologic age:

Middle Ordovician*
Ordovician, Late


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

Typical exposure at Old quarry, north bank of Root River, one-half mile above dam at Stewartville, Olmstead Co., MN. Named from Stewartville (Ulrich, 1911).


AAPG geologic province:

Sioux uplift*
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 ([ ]).