00991cam a22002531 4500 gs 26000138 DLC 20260227111330.0 760625s1926 xx 000 0 eng c gs 26000138 (OCoLC)2281936 U.S. Geol. Survey. Library TxEU DLC premarc QE662 .B4 Bevan, Arthur Charles, 1888-1968. The Glenwood beds as a horizon marker at the base of the Platteville formation, by Arthur Bevan. Printed by authority of the state of Illinois. Urbana, Ill., 1926. 13 p. illus., map., tables. 25 cm. Illinois State Geological Survey Report of investigations, no. 9 At head of title: State of Illinois. Department of registration and education. Division of state geological survey. Bibliographical foot-notes. Geology, Stratigraphic Ordovician. Geology Illinois. 26451 26451