Precambrian geology and geochronology of Minnesota, Bulletin 41, Plate 4
Description:
Map of western part of the Lake Superior region, Minnesota, showing location of samples that were age-dated by radioactive isotope methods, scale 1 inch = about 40 miles.
Creator:
Baadsgaard, Halfdan, Goldich, Samuel S., 1909-, Hoffman, J. H. (John H.), Krueger, Harold W., and Nier, Alfred O. (Alfred Otto), 1911-1994