1922. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1919-1920.";"Surveyed in cooperation with the States of Wisconsin and Illinois.";Relief shown by contours an... Geological Survey (U.S.), Geological Survey Division (Urbana, Ill.), and Geological and Natural History Survey (Madison, Wis.).
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1950. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1921.";Relief shown in contours.;1 map, colored;45 x 34 cm.;1:62,500. Geological Survey (U.S.), Geological Survey Division (Urbana, Ill.), and Geological and Natural History Survey (Madison, Wis.).
1954. Geological Survey (U.S.). Contour interval 10 feet.;"Culture and drainage in part compiled from aerial photographs taken 1938 and 1949. Topography by plane-table surveys 195... Geological Survey (U.S.) and Geological Survey Division (Urbana, Ill.).