Baadsgaard, HalfdanGoldich, Samuel S., 1909-Hoffman, J. H. (John H.)Krueger, Harold W.Nier, Alfred O. (Alfred Otto), 1911-1994Map of the Minnesota-Ontario border region, showing location of dated samples, scale 1 inch = about 20 miles.PDFengMinnesota Geological SurveyPublicPrecambrian geology and geochronology of Minnesota, Bulletin 41, Plate 3MapsMinnesota1961University of Minnesota