Region
United States
42
West Virginia
36
Virginie-Occidentale
33
Kentucky
19
Montana
17
Nevada
17
Alaska
16
Utah
12
Pennsylvania
11
Ohio
10
Missouri
9
Virginia
8
Brooks Range
7
Madison Group
7
Indiana
6
Williston Basin
6
Wyoming
6
Arizona
5
Brooks, Chaîne de
5
North America
5
Pennsylvanie
5
West (U.S.)
5
West United States
5
États-Unis
4
Idaho
4
Illinois Basin
4
Llano Region
4
Maryland
4
Michigan
4
Oklahoma
4
Texas
4
Williston, Bassin de
4
Antelope Range (Eureka County and Nye County)
3
Appalachian Basin
3
Bakken Formation
3
Colorado
3
Fayette
3
Fayette County
3
Illinois
3
Monongalia
3
Monongalia County
3
New Mexico
3
North Dakota
3
Weber County
3
Appalaches, Bassin des
2
Appalachian Region
2
Aux Vases Formation
2
Bakken, Formation de
2
Big Stone Gap
2
Cache County
2
more ...