WAYAN FORMATION--Variegated mudstone, siltstone, and sandstone.  Kws
SAGE JUNCTION FORMATION--Gray and tan siltstone and sandstone.  Kss
QUEALY FORMATION--Variegated mudstone and tan sandstone.  Kss
COKEVILLE FORMATION--Tan sandstone, claystone, limestone, bentonite, and coal.  Kss
THOMAS FORK FORMATION--Variegated mudstone and gray sandstone.  Kss
SMITHS FORMATION--Ferruginous black shale and tan to brown sandstone.  Kss, Kws
ASPEN SHALE--Light- to dark-gray siliceous tuffaceous shale and siltstone, thin bentonite beds,
     and quartzitic sandstone.  Ka
BEAR RIVER FORMATION--Black shale, fine-grained brown sandstone, thin limestone, and
     bentonite beds.  Kbr
MOWRY SHALE (AGE 94 TO 98 Ma)--Silvery-gray hard siliceous shale containing abundant
     fish scales and bentonite beds.  Kmt, Knt, Kgbm, Kft, Kmr
THERMOPOLIS SHALE--Black soft fissile shale; Muddy Sandstone Member at top.  Kmt, Kft,
     Knt
NEWCASTLE SANDSTONE--Gray sandstone and sandy shale containing some bentonite
     and coal.  Kns
SKULL CREEK SHALE--Black soft fissile shale.  Kns