Geography
California
359 results
Texas
355 results
United States
327 results
Colorado
266 results
Utah
217 results
Wyoming
215 results
Montana
202 results
Nevada
200 results
New Mexico
181 results
Alaska
178 results
Arizona
141 results
Illinois
120 results
Kansas
109 results
Idaho
106 results
Oklahoma
87 results
Michigan
83 results
Powder River Basin (Wyo. and Mont.)
73 results
Kentucky
71 results
North America
70 results
Washington (State)
69 results
Pennsylvania
64 results
Virginia
63 results
West (U.S.)
60 results
Alabama
55 results
Missouri
55 results
Australia
53 results
Mexico
53 results
Oregon
51 results
Indiana
50 results
New York (State)
47 results
Wisconsin
43 results
Mexico, Gulf of
42 results
South Dakota
42 results
Mississippi
41 results
Middle West
40 results
Florida
37 results
Georgia
37 results
North Dakota
36 results
Antarctica
35 results
Appalachian Basin
35 results
Europe
34 results
Canada
33 results
Great Britain
33 results
Minnesota
33 results
China
32 results
New Jersey
32 results
Arkansas
31 results
South Carolina
30 results
San Juan Basin (N.M. and Colo.)
29 results
Uinta Basin (Utah and Colo.)
29 results
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