Subject
- Mineral industries -- Oregon13
- Natural gas -- Prospecting -- Oregon11
- Petroleum -- Prospecting -- Oregon11
- Earthquakes -- Oregon -- Portland3
- Geology -- Oregon -- Field work3
- Geothermal resources -- Oregon3
- Continental shelf -- Oregon2
- Geology -- Hells Canyon (Idaho and Or.)2
- Geology, Stratigraphic -- Tertiary2
- Gold -- Economic aspects2
- Metallurgical plants -- Oregon2
- Metallurgy -- Oregon2
- Agates -- Oregon1
- Asbestos -- Oregon1
- Asbestos mines and mining -- Oregon1
- Assaying -- Oregon1
- Astoria (Or.)1
- Astoria (Or.) -- History1
- Automobiles -- Scrapping1
- Basalt -- Oregon -- Lane County1