Map 96 Water Mesozoic Era: Jurassic/Early Cretaceous periods Physical Resources Cloverly and Morrison formations Cenozoic Era: Pleistocene and Holocene Epochs Cloverly, Morrison, Sundance, and Gypsum Spring formations Geology Alluvium and Colluvium Cloverly, Morrison, and Sundance formations All Alternatives Glacial Deposits Sundance Formation Legend Landslide Deposits Sundance and Gypsum Spring formations Terrace, Pediment, and Fan Deposits Gypsum Spring Formation, Nugget Sandstone Undivided Surficial Deposits Mesozoic Era: Triassic Period Cenozoic Era: Eocene - Oligocene Epochs Chugwater Formation or Group White River Formation Chugwater and Goose Egg formations Intrusive Igneous Rocks: Thorofare Creek Group: Wiggins Formation Chugwater and Dinwoody formations Intrusive Igneous Rocks: Washburn Group: includes Sepulcher, Lamar River, and Cathedral Cliffs formations Goose Egg Formation Intrusive Igneous Rocks: Thorofare Creek Group: Tepee Trail Formation Mesozoic and Paleozoic Rocks Undivided Intrusive Igneous Rocks: Sunlight Group: includes Trout Peak Trachyandesite, Wapiti Formation, Crescent Hill Basalt, and Mt. Wallace Formation Intrusive Igneous Rocks: Sunlight Group: Wapiti Formation Paleozoic Era: Permian Phosphoria Formation and Related Rocks Intrusive Igneous Rocks: Thorofare Creek Group: Aycross Formation Goose Egg Formation Tat ma n F orm at ion Wagon Bed Formation Paleozoic Era: Pennsylvanian Tensleep Sandstone and Amsden Formation Willwood Formation Paleozoic Era: Mississippian Madison Limestone Group Cenozoic Era: Paleocene Epoch Fort Union Formation Madison Limestone and Darby Formation Madison Limestone, Darby or Three Forks, Jefferson, and Beartooth formations Mesozoic Era: Cretaceous Period Lance Formation Paleozoic Era: Ordovician Bighorn Dolomite, Three Forks, Jefferson, and Beartooth Butte formations Lance Formation, Meeteetse Formation Meeteetse Formation Paleozoic Era: Cambrian Gallatin Limestone, Gros Ventre Formation, and Flathead Mesaverde Group Sandstone Gallatin Limestone, Gros Ventre Formation, and Flathead Cody Shale Sandstone Frontier Formation Precambrian Eon Frontier Formation, Mowry and Thermopolis shales Plutonic Rocks Mowry and Thermopolis shales Granitic Rocks Oldest Gneiss Complex.