Platteville Formation  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Paleozoic
 ...Ordovician
 ....Middle Ordovician
 .....Platteville Formation
RTIowa
 Illinois
 Wisconsin
 Minnesota
 Glenwood Shale
SNIncludes Mifflin Limestone Member, Quimbys Mill Member, Pecatonica Member, McGregor Member, and Carimona Member, Hidden Falls Member, Magnolia Member, Glenwood Shale. E Iowa, NW Illinois, S Minnesota, and SW Wisconsin.