1. Illinois (Greene County), Roodhouse quadrangle. University Of Illinois Urbana Champaign Public content 1926. Geological Survey (U.S.). Contour interval 20 feet.;"Surveyed in 1924";Relief shown by contours and spot heights.;1 map, colored;45 x 35 cm.;1:62,500. Geological Survey (U.S.)|Geological Survey Division (Urbana, Ill.).