__________________________________________ Introduction _____________________________________ Purpose of the investigation____________________ Location and geographic setting__________________ Field work.____________________________________ Acknowledgments. ______________________________ Regional geology and stratigraphicrelations_____ ________ Structure ______________________________________ Regional stratigraphic summary __________________ Stratigraphic principles._________________________ Stratigraphic problems. _________________________ Platteville-Decorah boundary _ _______________ Beloit dolomite.____________________________ Unnamed limestone member, Decorah formation. _ Subdivisions of Galena dolomite ______________ Origin and application of the names.______________ Madison sandstone-________________________ Pecatonica dolomite member.________________ McGregor limestone member_________________ Quimbys Mill member _______________________ Stratigraphy of the mining district.___________________ Pre-Platteville rocks_ ___________________________ Pre-Cambrian rocks_________________________ Cambrian rocks_ ___________________________ Ordovician rocks____________________________ Prairie du Chien group __________________ St. Peter sandstone_ ____________________ Platteville formation____________________________ General features____________________________ Glenwood shale member.____________________ Lithologic description and stratigraphic relations _______________________________ Distribution.. __________________________ Fauna and correlation.__________________ Economic products______________________ Pecatonica dolomite member.________________ Lithologic description and stratigraphic re-lations_ ______________________________ Distribution, ___________________________ Fauna and correlation.__________________ Economic products______________________ McGregor limestone member.________________ Lithologic description and stratigraphic relations. ______________________________ Distribution. _ __________________________ Fauna and correlation.__________________ Economic products._____________________