Region
Utah
44
Colorado
28
Wyoming
20
San Juan County
17
New Mexico
14
United States
14
Colorado Plateau
13
Arizona
11
South Dakota
10
California
8
Idaho
7
Montana
6
Nevada
6
Alaska
5
Emery County
5
Jefferson County
5
Kern County
4
Sweetwater County
4
Fall River County
3
Front Range (Colo. and Wyo.)
3
Gila County
3
Harding County
3
Johnson County
3
Juab County
3
Kansas
3
Marysvale
3
McKinley County
3
Nebraska
3
San Miguel County
3
Texas
3
West (U.S.)
3
Black Hills (S.D. and Wyo.)
2
Boulder County
2
Campbell County
2
Carbon County
2
Grand County
2
Great Plains
2
Karnes County
2
Larimer County
2
Lincoln County
2
Mohave County
2
Montrose County
2
Morrison Formation
2
Piute County
2
Powder River Basin (Wyo. and Mont.)
2
San Bernardino County
2
Silver Bow County
2
Sweetwater County (Wyo.)
2
Alabama
1
Apache County
1
more ...