Wyoming 43 Colorado 30 Green River Formation 27 California 16 Utah 15 'Eua Island 14 Tonga 14 Wasatch Formation 11 Pakistan 9 Washington (State) 9 Green River Watershed (Wyo.-Utah) 8 Mississippi 7 Piceance Creek Basin 7 Georgia 6 Southern States 6 Sweetwater County 6 Texas 6 Alabama 5 Balochistan Region 5 Uinta Basin (Utah and Colo.) 5 Duchesne County 4 Montana 4 Piceance Creek Watershed 4 South Carolina 4 West (U.S.) 4 Fresno County 3 Gulf Coast (U.S.) 3 Japan 3 King County 3 Nevada 3 Powder River Basin (Wyo. and Mont.) 3 Ryukyu Islands 3 United States 3 Virginia 3 Wilcox Group 3 Alaska 2 Alaska, Gulf of, Region 2 Balochistān 2 Bighorn Basin (Mont. and Wyo.) 2 Bighorn Mountains (Wyo. and Mont.) 2 Black Hills (S.D. and Wyo.) 2 British Columbia 2 Canal Zone 2 Chesapeake Bay (Md. and Va.) 2 Fiji 2 Florissant Fossil Beds National Monument (Colo.) 2 Ghazij Formation 2 Ghazij Formation (Pakistan) 2 Gulf States 2 Hinds County 2 Hot Springs County 2 Luzon 2 Marshall Islands 2 Mississippi Embayment 2 New Jersey 2 North Carolina 2 Olympic Peninsula 2 Oregon 2 Panama 2 Philippines 2 Piceance Creek Basin (Colo.) 2 Rattlesnake Hills 2 Republic Region 2 Santa Barbara County 2 Sindh 2 Sylvania Tablemount 2 Teton Range (Wyo. and Idaho) 2 Uintah County 2 Ventura County 2 Viti Levu 2 Wind River Basin 2 Yazoo County 2 Absaroka Range Region (Mont. and Wyo.) 1 Absaroka Volcanic Supergroup (Mont. and Wyo.) 1 Alpes-Maritimes 1 Amador County 1 Appalachian Basin 1 Badlands National Park 1 Badlands National Park (S.D.) 1 Bangladesh 1 Bighorn River (Wyo. and Mont.) 1 Bighorn River Watershed (Wyo. and Mont.) 1 Brazos River Valley 1 California, Northern 1 Central Valley 1 Chesapeake Bay Region (Md. and Va.) 1 Claiborne Group 1 Egypt 1 Elderberry Canyon 1 Europe 1 Fairfield 1 Fayyūm (Province) 1 Florida 1 Florissant Fossil Beds National Monument 1 Fossil Butte National Monument 1 Fossil Butte National Monument (Wyo.) 1 France 1 Fremont County 1 Great River Basin 1 Green River 1