00846nam a22002171 4500 gs 17000080 DLC 20260227111320.0 880107s1916 iluab s00010 eng c gs 17000080 //r88 U.S. Geol. Survey Libr./ICU ICU n-us-il QE105 .A16 Sauer, Carl Ortwin, 1889- Geography of the upper Illinois Valley and history of development, by Carl Ortwin Sauer. Printed by authority of the state of Illinois. Urbana, Illinois state geological survey, University of Illinois, 1916. 208 p. fold. front., illus., fold. map, diagrs. 26 cm. Illinois. State geological survey. Bulletin no. 27 Geology Illinois. Bulletin (Illinois State Geological Survey) ; no. 27. 25737 25737