Preliminary integrated geologic map databases for the United States; Minnesota, Wisconsin, Michigan, Illinois, and Indiana

Online link http://pubs.usgs.gov/of/2004/1355/
Description Digital geologic map information with a consistent set of attributes, part of a national compilation of similar maps. Available in formats compatible with GIS.
Originators Nicholson, Suzanne W.; Dicken, Connie L.; Foose, Michael P.; and Mueller, Julia A.L.
Publication U.S. Geological Survey Open-File Report 2004-1355

States or counties