Region
Texas
5
Arizona
4
New Mexico
3
Utah
3
Bighorn Basin (Mont. and Wyo.)
2
Montana
2
North America
2
Oregon
2
West (U.S.)
2
Wyoming
2
Africa
1
Arionza
1
Atlantic Coast (U.S.)
1
Baja California (Peninsula)
1
Bering Sea Region
1
California
1
California, Southern
1
Catron County
1
Chiricahua Mountains
1
Chiricahua Mountains Region
1
Colorado
1
Colorado Plateau
1
Dakota Territory
1
Elkhead Mountains (Colo. and Wyo.)
1
Europe
1
Grant County
1
Greenlee County
1
Gualala Formation
1
Hidalgo County
1
Japan
1
Jeff Davis County
1
Kansas
1
Mexico
1
Mongolia
1
Monterey Formation (Calif.)
1
Nebraska
1
Needle Range
1
Niobrara River Valley (Wyo. and Neb.)
1
Powder River Basin (Wyo. and Mont.)
1
Presidio County
1
Rocky Mountains Region
1
Scotland
1
Shikoku Region
1
Socorro County
1
Texas, West
1
Washington (State)
1
White River Group
1