Mount Simon Sandstone  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Paleozoic
 ...Cambrian
 ....Upper Cambrian
 .....Mount Simon Sandstone
RTIowa
 Illinois
 Indiana
 Ohio
 Wisconsin
 Minnesota
 Michigan
SNUnconformably overlies Precambrian basement; underlies Eau Claire Formation. Added to Thesaurus in 1989.