00991cam a22002531  4500001001300000003000400013005001700017008004100034010001700075035001900092040004200111042001200153050001500165100003900180245014900219260002500368300004100393410007100434500012000505504003200625650004000657650002300697999001700720gs 26000138 DLC20260227111330.0760625s1926    xx            000 0 eng c  ags 26000138   a(OCoLC)2281936  aU.S. Geol. Survey. LibrarycTxEUdDLC  apremarc00aQE662b.B41 aBevan, Arthur Charles,d1888-1968.14aThe Glenwood beds as a horizon marker at the base of the Platteville formation,cby Arthur Bevan. Printed by authority of the state of Illinois.  aUrbana, Ill.,c1926.  a13 p.billus., map., tables.c25 cm.20aIllinois State Geological SurveytReport of investigations,vno. 9  aAt head of title: State of Illinois. Department of registration and education. Division of state geological survey.  aBibliographical foot-notes. 0aGeology, StratigraphicyOrdovician. 0aGeologyzIllinois.  c26451d26451