- Geological Survey (U.S.)
- University of Illinois at Urbana-Champaign, University Library
Relief shown by contours and spot heights.; "Illinos culture and drainage in part compiled from aerial photographs taken by Air Corps, U.S. Army"; "Surveyed in 1926"; "Contour interval 20 feet. 45 x 36 cm.; 1 map, colored. 1:62,500. Geological Survey (U.S.); Kentucky Geological Survey (Lexington, Ky.); Geological Survey Division (Urbana, Ill.).