Lithology
The Bushnell Rock Member is a basal conglomerate with sandstone beds occurring on a rarity. It was deposited by an onlapping sea that started during the Paleocene but the bulk of the formation was deposited during the early Eocene. The conglomerate is composed of 70% rock fragments (60% sedimentary, 30% metamorphic, 10% volcanic) 1 to 2 inches in diameter and a 30% percent matrix of medium to coarsegrained sands(66% quartz, 33% feldspar). Because the member is not well exposed other than a few limited areas, measurement for the overall stratigraphic thickness has not been achieved. It was determined in one measured section to be at least 5 meters thick but there is indication where it contacts the Olalla Creek Member of up to 100 meters.Fossils
Conglomerate rocks can produce fossils, but they are usually contained in a portion of a rock type within the fragment mix. The Bushnell Rock Member is not known for producing fossils.See also
* List of fossiliferous stratigraphic units in Oregon *References
Bibliography
* * Formations Paleogene geology of Oregon Geologic members of the United States Stratigraphy of Oregon {{Paleogene-stub