Geological Survey (U.S.)Marginal legend and cross sections. "Base map compiled by the U. S. Geological Survey from U. S. Geological Survey atlas sheets, Land Office records, compilations by State Geological Surveys, official maps of Canada and other data."58 x 89 centimetersJPEGUMN_ALMA:9965784510001701engU.S. Geological Survey (Washington, D.C.?)PublicGeologic map of the Lake Superior region, with sectionsMapsUnited States--Lake Superior1910University of Minnesota