Region
Alaska
8
Alaska Range
2
Appalachian Basin
1
Appalachian Region
3
Argus Range Region
2
Arizona
3
Arkansas
5
Bannock Peak Limestone (Idaho)
1
Belden Formation (Colo.)
1
Bernalillo County
3
Big Hatchet Peak Region
1
Black Warrior Basin (Ala. and Miss.)
1
Brazos River Valley
1
Breathitt Formation (Ky. and Tenn.)
2
Brooks Range
4
Brown County
7
Brown County (Tex.)
2
Burnet County
1
California
4
California, Southern
1
Clark County
2
Coleman County
6
Coleman County (Tex.)
2
Colorado
25
Colorado Plateau
1
Crawford County
1
Custer County
1
Cutler Group
2
Denver Basin
2
Eagle County
4
Eagle River Watershed
1
Eagle Valley Formation (Colo.)
2
East Tintic Mountains
2
Fort Smith Region
1
Franklin Mountains (Tex. and N.M.)
1
Geauga County
2
Grand Canyon
1
Grand Canyon Region
1
Grant County
1
Hermosa Mountain (Colo.)
1
Honaker Trail Formation
2
Idaho
4
Illinois
2
Illinois Basin
1
Inyo Mountains
2
Iowa
1
Kansas
26
Kent County
2
Kent County (Tex.)
1
Kentucky
9
more ...