Muddy Sandstone  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Mesozoic
 ...Cretaceous
 ....Lower Cretaceous
 .....Muddy Sandstone
RTWyoming
 Montana
 J Sandstone
SNOf Thermopolis Shale. Overlies a lower black shale member and underlies a black shale member. Surface and subsurface in central N Wyoming and subsurface in central S Montana.