prepared from surveys by the Wisconsin Geological and Natural History Survey, E. A. Birge, PH.D., director ; Survey in charge of C. Dwight Marsh ; Survey by C. Dwight Marsh and E. F. Chandler ..
prepared from surveys by the Wisconsin Geological and Natural History Survey, E. A. Birge, PH.D., director ; Hydrography in charge of L.S. Smith, C.E. ..
prepared from surveys by the Wisconsin Geological and Natural History Survey ; E.A. Birge, PH.D., director ; hydrography in charge of L.S. Smith ; field work by L.S. Smith and H.M. Trippe