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