Region
California
9
Colorado
5
Idaho
5
Washington (State)
4
Wyoming
4
Alaska
3
Kansas
3
Montana
3
Snake River Plain (Idaho and Or.)
3
South Dakota
3
Amchitka Island
2
Chesapeake Bay Region (Md. and Va.)
2
Deep Springs Valley
2
Glacier National Park Region
2
Glenns Ferry Formation (Idaho)
2
Great Basin
2
Great Plains
2
Gros Ventre River Valley
2
Illinois
2
Inyo County
2
Long Island
2
Louisiana
2
New Jersey
2
New York (State)
2
North Carolina
2
North Dakota
2
Northeastern States
2
Saint Helens, Mount
2
Utah
2
West (U.S.)
2
Arizona
1
Boulder County
1
Chowan River Watershed
1
Denver
1
Denver Region
1
England
1
Front Range (Colo. and Wyo.)
1
Graham County
1
Great Lakes (North America)
1
Great Salt Lake
1
Hawaii
1
Hungary
1
Indiana
1
Jefferson County
1
Kittitas County
1
Kittitas Valley
1
Lake County
1
Lee Creek Mine Region
1
Leidy Formation
1
Leidy Formation (Wyo.)
1
more ...