Belle Fourche Shale  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Mesozoic
 ...Cretaceous
 ....Upper Cretaceous
 .....Belle Fourche Shale
RTCody Shale
 Colorado Group
 Graneros Shale
SNIn Colorado Group or Cody Shale. In Wyoming, Montana, North Dakota, and South Dakota. Added to Thesaurus in 1995.