Fall River Formation  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Mesozoic
 ...Cretaceous
 ....Lower Cretaceous
 .....Fall River Formation
RTWyoming
 South Dakota
 Inyan Kara Group
SNIn Inyan Kara Group. Includes Keyhole Sandstone Member. W South Dakota and NE Wyoming.