Permian Phosphoria 150-250 Dolomite, gray, North and west Formation cherty, sandy, flanks of Teton black shale and Range, north phosphate beds; flank of Gros marine. Ventre Mountains, southern Jackson Hole. Pennsylvanian Tensleep 600-1,500 Tensleep Sandstone, North and west and Amsden light-gray, hard, flanks of Teton Formations underlain by Range, north Amsden Formation, flank of Gros a domolite and red Ventre Mountains, shale with a basal southern Jackson red sandstone; Hole. marine. Mississippian Madison 1,000-1,200 Limestone, North and west Limestone blue-gray, hard, flanks of Teton fossiliferous; Range, north thin red shale in flank of Gros places near top; Ventre Mountains, marine. southern Jackson Hole. Devonian Darby 200-500 Dolomite, dark-gray North and west Formation to brown, fetid, flanks of Teton hard, and brown, Range, north black, and yellow flank of Gros shale; marine. Ventre Mountains, southern Jackson Hole. Ordovician Bighorn 300-500 Dolomite, North and west Dolomite light-gray, flanks of Teton siliceous, very Range, north and hard; white dense west flanks of very fine-grained Gros Ventre dolomite at top; Mountains, marine. southern Jackson Hole. Cambrian Gallatin 180-300 Limestone, blue North and west Limestone gray, hard, flanks of Teton