Texas 35
Idaho 27
New Mexico 27
Phosphoria Formation 26
Montana 19
Utah 19
Wyoming 18
Colorado 16
Kansas 10
Alaska 9
California 8
Oklahoma 8
Cutler Formation 5
United States 5
Antarctica 4
Arizona 4
Brown County 4
Coleman County 4
Manzano Mountains 4
Baylor County 3
China 3
Maroon Formation (Colo.) 3
Nevada 3
Pakistan 3
Pennsylvania 3
Powder River Basin (Wyo. and Mont.) 3
Powder River Watershed (Wyo. and Mont.) 3
West (U.S.) 3
White Rim Sandstone (Utah) 3
Afton Region 2
Alaska Range 2
Argus Range Region 2
Bernalillo County 2
Brazos River Valley 2
Butte County 2
Canyonlands National Park 2
Caribou County 2
Central Oklahoma Aquifer (Okla.) 2
Chinle Formation 2
Cutler Group 2
Eagle County 2
East Tintic Mountains 2
Glass Mountains 2
Great Basin 2
Greece 2
Guadalupe Mountains National Park 2
Guadalupe Mountains National Park (Tex.) 2
Hydra Island 2
Inyo Mountains 2
Kent County 2
Lisbon Valley 2
Mesaverde Group 2
Permian Basin (Tex. and N.M.) 2
Piceance Creek Basin 2
Piceance Creek Basin (Colo.) 2
Pitkin County 2
Prehistoric Trackways National Monument 2
Prehistoric Trackways National Monument (N.M.) 2
Rocky Mountains 2
San Juan Basin (N.M. and Colo.) 2
San Miguel County 2
Sandoval County 2
Santa Fe County 2
Scurry County 2
Seven Devils Mountains 2
Snake River Valley (Wyo.-Wash.) 2
Snowdrift Mountain 2
Torrance County 2
Uinta Basin (Utah and Colo.) 2
Valencia County 2
Washington Region 2
Weber County 2
Wrangell Mountains 2
Yeso Formation (N.M. and Tex.) 2
Afghanistan 1
Alaska, Southeast 1
Amador County 1
Belden Formation (Colo.) 1
Brown County (Tex.) 1
Calaveras County 1
California, Southern 1
Central Oklahoma Aquifer 1
Central Oklahoma Aquifer Region 1
Chaves County 1
Coleman County (Tex.) 1
Cowley County 1
Denver Basin 1
Eagle Mountains region 1
Eagle River Watershed 1
Eagle Valley Formation (Colo.) 1
Eddy County 1
Elk County 1
Glass Mountains (Tex.) 1
Gondwana (Continent) 1
Grand Canyon 1
Grand Canyon Region 1
Greer County 1
Guadalupe Mountains (N.M. and Tex.) 1
Hardin County 1
Idaho, South Central 1