%0 Map %0 U.S. Federal Government Document %0 Print %A Hansen, R. E. %E Geological Survey (U.S.) %E Iowa Geological Survey %I U.S. Geological Survey %D 1972 %C Washington, D.C. %G English %B Miscellaneous investigations series (Geological Survey (U.S.)) ; %T Bedrock topography of east-central Iowa