1. Geologic structure and altitude of the top of the Minnelusa Formation and orientation of mapped cave passages in the Madison Limestone, southern Black Hills, South Dakota Yale Public content 1991. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; Books and Open-file Reports [distributor]. English. Public. Black Hills (S.D. and Wyo.).