- Geological Survey (U.S.)
- University of Illinois at Urbana-Champaign, University Library
Relief shown by contours and spot heights.; "Culture and drainage in part compiled from aerial photographs taken by Air Corps, U.S. Army."; "Surveyed in 1927."; "Contour interval 20 feet. 45 x 35 cm.; 1 map, colored. 1:62,500. Geological Survey (U.S.); Geological Survey Division (Urbana, Ill.).