HOBACK FORMATION--Interbedded drab and gray sandstone and claystone.  Locally con-
     tains thick red and gray conglomerate.  Th
DEVILS BASIN FORMATION--Light-gray sandstone interbedded with green and gray
     claystone; sparse coal and carbonaceous shale.  Tdb
HANNA FORMATION--Brown and gray sandstone, shale, conglomerate, and coal; giant
     quartzite boulders near Medicine Bow Mountains.  Tha
FORT UNION FORMATION
  Northwest, southwest, and central Wyoming--Brown to gray sandstone, gray to black shale,
     and thin coal beds.  Tfu
  East Wyoming--Light-colored massive sandstone, drab shale, and thick coal beds.  Tfu
    Tongue River Member--Thick beds of yellow sandstone interbedded with gray and black
     shale and many coal beds.  Tftr, Tftl
    Lebo Member--Dark-gray clay shale and concretionary sandstone.  Tfl, Tftl, Tflt
    Tullock Member--Soft gray sandstone, gray and brown carbonaceous shale, and thin coal
     beds.  Tft, Tflt