1. Illinois (Marion County) Salem quadrangle University Of Illinois Urbana Champaign Public content 1960. Geological Survey (U.S.). Relief shown by contours and spot heights.;"Surveyed in 1921, 1926, 1928, and 1934";Contour interval 10 feet.;1 map, colored;45 x 35 cm.;1:62,500. Geological Survey (U.S.)|Geological Survey Division (Urbana, Ill.).