| 3. ||Tuscola quadrangle, Illinois : 15 minute series (topographic) ||Maps; Topographic maps; Topography; Illinois; Tuscola (Ill.); Douglas County (Ill.) ||Relief shown by contours and spot heights.; "Culture and drainage in part compiled from aerial photographs taken 1948. Topography by plane-table methods 1935 and 1950."; "Contour interval 10 feet."