1. Hydrogeology of the basal confining unit of the carbonate aquifer system in the midwestern basins and arches region of Indiana, Ohio, Michigan, and Illinois [microform] Yale Public content 1992. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Casey, George D. The Survey : For sale by Books and Open-File Reports Section [distributor]. English. Public. Middle West.