tag:digital.library.illinois.edu,2005:/items/92f46420-82d4-0134-1f08-0050569601ca-fIllinois, Cave in Rock quadrangle2022-09-15T18:31:18Ztag:digital.library.illinois.edu,2005:Item/667512016-11-15T17:24:03Z2022-09-15T18:31:18ZIllinois, Cave in Rock quadrangleContour interval 20 feet.University of Illinois at Urbana-Champaign Library