Region
Kentucky
5
Nevada
5
Utah
4
Idaho
3
Alaska
2
Anadarko Basin
2
East (U.S.)
2
Illinois
2
New England
2
Québec (Province)
2
Simpson Group
2
Tennessee
2
Trenton Group
2
Vermont
2
Wisconsin
2
Appalachian Basin
1
Argentina
1
Bristol Region
1
California
1
Champlain Valley
1
Connecticut
1
Custer County
1
Georgia
1
Grady County
1
Iowa
1
Kansas
1
Maryland
1
Maysville Region
1
Meiklejohn Peak
1
Mendoza (Province)
1
New Jersey
1
North America
1
North Dakota
1
Oklahoma
1
Paxton Group
1
Pennsylvania
1
Pioneer Mountains
1
Southern States
1
Tellico-Sevier Belt
1
Terra Cotta Mountains
1
Texas
1
Washington County
1