- Geological Survey (U.S.)
- University of Illinois at Urbana-Champaign, University Library
Relief shown by contours and spot heights.; "Control in part by Illinois River Commission and Corps of Engineers U.S. Army."; "Surveyed in 1922-1923."; "Contour interval 20 feet." Coordinates: (W 90⁰15ʹ00ʺ--W 90⁰00ʹ00ʺ/N 40⁰30ʹ00ʺ--N 40⁰15ʹ00ʺ). 45 x 34 cm.; 1 map, colored. 1:62,500. Geological Survey (U.S.); Geological Survey Division (Urbana, Ill.).