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| First Page | Document Content | |
|---|---|---|
 Date: 2006-12-31 17:00:13Igneous petrology Petrology Tuff Ignimbrite John Day River John Day Formation Volcanic rocks Volcanology Tephra |
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| First Page | Document Content | |
|---|---|---|
Date: 2006-12-31 17:00:13Igneous petrology Petrology Tuff Ignimbrite John Day River John Day Formation Volcanic rocks Volcanology Tephra |
Add to Reading List |
Composite Section Upper John Day Beds John Day River Valley Picture Gorge