tag:digital.library.illinois.edu,2005:/items/a6181bc0-994e-0134-2096-0050569601ca-5Illinois, Piper City quadrangle : 15-minute series2022-09-15T18:31:55Ztag:digital.library.illinois.edu,2005:Item/700712016-11-30T19:20:10Z2022-09-15T18:31:55ZIllinois, Piper City quadrangle : 15-minute seriesMapped by the Geological Survey, 1944.University of Illinois at Urbana-Champaign Library