Region
Colorado
15
California
14
Florida
7
Nevada
7
Utah
7
Kansas
6
Missouri
6
North Atlantic Ocean
6
Oregon
5
San Juan County
5
Klamath County
4
Minnesota
4
North Carolina
4
Oklahoma
4
South Carolina
4
Alaska
3
Louisiana
3
New Mexico
3
Pacific Coast
3
Virginia
3
West (U.S.)
3
Wyoming
3
Arctic Ocean
2
Bertie County
2
Cajon Pass
2
Charleston County
2
Chesapeake Bay (Md. and Va.)
2
Creede Formation
2
Creede Formation (Colo.)
2
Green River Formation
2
Hawaii
2
Idaho
2
Kilauea Volcano
2
Maryland
2
Mexico, Gulf of
2
Monmouth County
2
Montana
2
New Jersey
2
Nye County
2
Piceance Creek Basin
2
Rifle
2
San Francisco Bay
2
United States
2
Washington (State)
2
Albuquerque
1
Apalachicola Bay
1
Arkansas
1
Australia
1
Bladen County
1
Broward County
1
more ...