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Subject
- Geology6
- Geology, Stratigraphic6
- Paleontology5
- Jasperoid4
- Powell, John Wesley, 1834-19024
- Mines and mineral resources3
- Ammonoidea2
- Beryllium ores2
- Floods2
- Natural gas2
- Storms2
- Tungsten ores2
- Ammonoidea, Fossil1
- BASIC (Computer program language)1
- Basalt1
- Electric logging1
- Energy development1
- Explorers1
- Geology, Economic1
- Gold mines and mining1