prepared from surveys by the Wisconsin Geological and Natural History Survey, E.A. Birge, Director ; survey in charge of C. Dwight Marsh ; survey by C. Dwight Marsh and E.F. Chandler
Also shows roads and hotels.
Depths shown by hypsometric tints, bathymetric isolines and soundings.
"Contour interval = 20 ft."
Includes 5 cross sections.
At head of cover title: no. 7.
Explanation of map on inside of front cover.
Imprint from cover.