Saint Peter Sandstone  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Paleozoic
 ...Ordovician
 ....Middle Ordovician
 .....Saint Peter Sandstone
RTIowa
 Kentucky
 Missouri
 Oklahoma
 Illinois
 Indiana
 Ohio
 Wisconsin
 Minnesota
 Kansas
 Michigan
 Arkansas
SNOverlies Prairie du Chien Group and underlies Glenwood Shale Member of Platteville Formation.