sandstone at top; and southern part marine. of Jackson Hole. Cloverly and 650 Sandstone, light North end of Teton Morrison(?) gray, sparkly, Range and Gros Formations rusty near top, Ventre River Valley. underlain by variegated soft claystone; basal part is silty dully-variegated sandstone and claystone. JURASSIC Sundance 500-700 Sandstone, green, North end of Teton Formation underlain by soft Range, Blacktail gray shale and thin Butte, Gros Ventre highly River Valley. fossiliferous limestones; marine. Gypsum Spring 75-100 Gypsum, white, North end of Teton Formation interbedded with Range, Blacktail red shale and gray Butte, Gros Ventre dolomite; partly River Valley. marine. Nugget 0-350 Sandstone, North flank of Gros Sandstone salmon-red, hard. Ventre Mountains, southern Jackson Hole. TRIASSIC Chugwater 1,000-1,500 Siltstone and North flank of Gros Formation shale, red, Ventre Mountains, thin-bedded; one north end of Teton thin marine Range, southernmost limestone in upper Jackson Hole. third. Dinwoody 200-400 Siltstone, brown, North flank of Gros Formation hard, thin-bedded; Ventre Mountains, marine. north end of Teton Range, southernmost Jackson Hole. Drab Cretaceous strata