Subject
Geology
155
Geology, Stratigraphic
16
South Dakota
11
Uranium ores
9
Geology, Structural
8
Pegmatites
6
National parks and reserves
5
Environmental monitoring
4
Hydrology
4
Moraines
4
Paleontology
4
Gold ores
3
Groundwater
3
Sediments (Geology)
3
Badlands National Park (S.D.) Environmental conditions
2
Black Hills (S.D. and Wyo.)
2
Carnotite
2
Faults (Geology)
2
Glacial epoch
2
Homestake Mine (S.D.)
2
Iron ores
2
Middle West Discovery and exploration
2
Natural history
2
Nebraska Description and travel
2
Petroleum Geology
2
Sandstone
2
Sedimentary rocks
2
Shale
2
South Dakota Description and travel
2
Water-supply
2
Wind Cave National Park (S.D.) Management
2
Argon-argon dating
1
Badlands National Park (S.D.)
1
Biotic communities
1
Boring
1
Clay
1
Cryptoexplosion structures
1
Custer County (S.D.)
1
Dakota Aquifer
1
Ecology
1
Igneous rocks
1
Jewel Cave National Monument (S.D.) Management
1
Lake sediments
1
Lignite
1
Meteorite craters
1
Mineralogy
1
Missouri River Valley
1
Mount Rushmore National Memorial (S.D.) Environmental conditions
1
National monuments
1
Natural resources
1
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