tag:digital.library.illinois.edu,2005:/itemsItems2022-09-15T18:31:26Ztag:digital.library.illinois.edu,2005:Item/668772016-11-15T17:24:37Z2022-09-15T18:31:26ZIllinois, Delavan quadrangle : 15-minute seriesRelief shown by contours and spot heights.University of Illinois at Urbana-Champaign Library