Upper Ordovician

Limestone, shaley limestone, and dolostone; includes the Maquoketa Formation, and the Stewartville, Prosser, and Cummingsville Formations of the Galena Group. Also includes limestone and dolostone of the Red River Formation, and sandstone and shale of the Winnipeg Formation in northwest Minnesota.
State Minnesota
Name Upper Ordovician
Geologic age Upper Ordovician
Lithologic constituents
Major
Sedimentary > Carbonate > Dolostone (Bed)
Sedimentary > Carbonate > Limestone (Bed)limestone and shaly limestone.
References

Jirsa, Mark A., Boerboom, Terrence J., Chandler, Val W., Mossler, John H., Runkel, Anthony C., and Setterholm, Dale R., 2011, S-21 Geologic Map of Minnesota-Bedrock Geology; Minnesota Geological Survey, State Map Series S-21. Scale 1:500,000.

NGMDB product
Counties Dodge - Faribault - Fillmore - Freeborn - Goodhue - Houston - Kittson - Marshall - Martin - Mower - Olmsted - Polk - Rice - Steele - Waseca - Winona