(1) Field mapping and biostratigraphic data indicate that the Yamhill Formation overlies and is younger than the Tyee Formation; interfingering of the two formations is not indicated. (2) Stewart's correlation of the Yamhill Formation with the Sacchi Beach member of the Tyee was based on incomplete knowledge of the range...
The purpose of this study of the Lyons flora is to determine the age and paleoecology of the flora through the examination and identification of the fossil plant species of the flora. The plant fossils comprising the Lyons flora were collected from a locality in the upper Thomas Creek area,...
Periodic violent eruptions from many different centers during Cenozoic time deposited vast quantities of pyroclastic material as ash-flow tuffs over most of Oregon, although the Coast Ranges and isolated patches elsewhere in the state appear to have been spared these recurring inundations. Eruptions occurred at different times throughout the Cenozoic,...