tag:digital.library.illinois.edu,2005:/items/9f959750-994e-0134-2096-0050569601ca-aIllinois, Newton quadrangle : 15-minute series2022-09-15T18:31:49Ztag:digital.library.illinois.edu,2005:Item/699502016-11-30T19:19:28Z2022-09-15T18:31:49ZIllinois, Newton quadrangle : 15-minute seriesContour interval 10 feet.University of Illinois at Urbana-Champaign Library