00873cam a22002291  4500001001300000003000400013005001700017008004100034010001700075035001900092040005500111050002000166100002500186245006700211260007700278300005300355410006600408500008400474504002600558650004200584999001700626gs 29000068 DLC20260227111333.0820714s1929    ilu           000 0 eng c  ags 29000068   a(OCoLC)8599483  aU. S. Geol. Survey. Libr.cGStGdIDeKNdOCoLCdDLC00aQE105b.A3 no.21 aRolfe, Deette, 1879-14aThe Rock River country of northern Illinois,cby Deette Rolfe.  aUrbana, Ill.a[SpringfieldbJeffersons Printing & Stationery Co.]c1929.  a[58], [1] p. incl. front.billus., maps.c20 cm.20aIllinois State Geological Survey.tEducational series,vno. 2  aAt head of title: State of Illinois.  Department of Registration and Education.  aBibliography: p. [59] 0aGeologyzIllinoiszRock River Valley.  c26701d26701