AMSDEN FORMATION
  Thrust belt--Red and gray cherty limestone and shale, sandstone, and conglomerate.  P&Ma,
     P&M
  Northern Yellowstone area--Red and green dolomitic shale, siltstone, and sandstone.  P&Ma
  North Wyoming--Red and green shale and dolomite; at base is brown sandstone.  P&Ma,
     PM, MzPz
  South Wyoming--Red and green shale and dolomite; at base is persistent red to brown sand-
     stone.  PM, MzPz