Region
California
10
Alaska
3
Arizona
3
Idaho
2
Mohave County
2
North Carolina
2
Salinas River Valley
2
Virginia
2
Washington (State)
2
Yellowstone National Park
2
Almería (Province)
1
Arctic regions
1
Baja California (Peninsula)
1
Beaufort Sea Region
1
Black Canyon (Ariz. and Nev.)
1
Chesapeake Group
1
Colorado
1
Colorado Plateau
1
Coso Range
1
Elk Hills
1
Enewetak Atoll
1
Fish Creek Watershed (North Slope Borough)
1
Florida
1
Great Plains
1
Iceland
1
Italy
1
Japan
1
Kansas
1
Kittitas County
1
Knox County
1
Las Animas County
1
Malheur County
1
Marshall Islands
1
Meighen Island
1
Mexico
1
Middle Atlantic States
1
Nebraska
1
New Mexico
1
Nunavut
1
Okinawa Island
1
Oregon
1
San Diego
1
Santa Maria Basin
1
Santa Maria Basin (Calif.)
1
Sisquoc Formation (Calif.)
1
Spain
1
Tjörnes Peninsula
1
Tulelake Region
1
Weiser Region
1
West (U.S.)
1