Region
California
23
Colorado
16
Alaska
15
Nevada
10
Wyoming
10
Utah
9
North America
6
Puerto Rico
6
Canal Zone
5
Panama
5
Piceance Creek Basin
5
Baja California (Peninsula)
4
Mexico
4
New Mexico
4
Oregon
4
Southern States
4
Washington (State)
4
Florida
3
Maryland
3
Mississippi Embayment
3
Montana
3
San Juan Basin (N.M. and Colo.)
3
South Carolina
3
United States
3
West (U.S.)
3
Arizona
2
Atlantic States
2
Coast Ranges
2
Cook Inlet
2
Fremont County
2
Georgia
2
Green River Formation
2
Inyo County
2
Japan
2
Kootznahoo Formation (Alaska)
2
Natrona County
2
New Jersey
2
North Carolina
2
Okinawa-ken
2
Olympic Peninsula
2
Piceance Creek Basin (Colo.)
2
San Joaquin Valley
2
Texas
2
Uinta Basin (Utah and Colo.)
2
Virginia
2
Aegean Islands (Greece and Turkey)
1
Alabama
1
Alaska, Southeast
1
Astoria
1
Blanco, Cape
1
more ...