Region
Colorado
5
Wyoming
4
Emery County
2
Montana
2
Utah
2
Arizona
1
Blackleaf Formation (Mont.)
1
Carbon County
1
Charleston Region
1
Denver Basin
1
La Plata County
1
La Plata County (Colo.)
1
Mexico, Gulf of
1
Pioneer Mountains
1
Powder River Watershed (Wyo. and Mont.)
1
San Juan Basin (N.M. and Colo.)
1
Sanpete County
1
South Carolina
1
West (U.S.)
1