compiled by Tom Simkin ... [and others] ; U.S. Department of the Interior, U.S. Geological Survey ; prepared in cooperation with the Smithsonian Institution
prepared from surveys by the Wisconsin Geological and Natural History Survey ; hydrography in charge of L.S. Smith ; field work by L.S. Smith and H.M. Trippe
prepared from surveys by the Wisconsin Geological and Natural History Survey ; hydrography in charge of L.S. Smith ; field work by L.S. Smith and H.M. Trippe