Geological Survey (U.S.)Contour interval 10 feet;"Culture and drainage in part compiled from aerial photographs taken 1938-1941. Topography by plane-table methods, 1947.";Relief shown by contours and spot heights.;1 map, colored;45 x 35 cm.;1:62,500JPEG2000https://digital.library.illinois.edu/items/9b4eb0a0-82d4-0134-1f08-0050569601ca-dengGeological Survey (U.S.)Geological Survey Division (Urbana, Ill.)PublicOlney quadrangle, Illinois : 15 minute series (topographic).MapsIllinois1949University of Illinois Urbana-Champaign