USGS #15544 - Pittsburg Bluff Formation (Oligocene of the United States)

Where: Washington County, Oregon (45.7° N, 123.2° W: paleocoordinates 45.4° N, 114.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Pittsburg Bluff Formation, Chattian (28.1 - 23.0 Ma)

• Upper part of Pittsburg Fm. The Pittsburg Bluff Formation conformably overlies the Keasey Formation (late Eocene and early Oligocene) and is conformably overlain by the Scappoose Formation (late Oligocene and early Miocene). Parts of the formation are lithologically similar and therefore the stratigraphic position of exposures are sometimes uncertain. The estimated thickness for the entire formation is 200 ml the thickest continuous section of the formation is 100 m thick.

• bed-level stratigraphic resolution

Environment/lithology: offshore; poorly lithified, fine-grained, concretionary, gray sandstone

• Massive olive-gray fine-grained sandstone, with concretions, trough shaped prisms, silstone rip-up clasts.

Size class: macrofossils

Reposited in the USGS

Collection methods: quarrying,

• Material housed in the USGS, Menlo Park. Also collections from UCMP, CAS, Stanford University (SU), University of Washington (UW), University of Oregon (UO), and the Academy of Natural Sciences of Philadelphia (ANSP)

Primary reference: E. J. Moore. 1976. Oligocene marine mollusks from the Pittsburg Bluff Formation in Oregon. United States Geological Survey Professional Paper 922:1-66 [A. Miller/A. Hendy/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 37689: authorized by Austin Hendy, entered by Austin Hendy on 20.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Very complete for mollusca.
Bivalvia
 Cardiida - Mactridae
"Spisula (? Mactromeris) veneriformis" = Mactromeris
"Spisula (? Mactromeris) veneriformis" = Mactromeris clam
 Cardiida - Ungulinidae
 Cardiida - Tellinidae
"Tellina (Eurytellina) aduncanasa" = Eurytellina
"Tellina (Eurytellina) aduncanasa" = Eurytellina tellin clam
 Solenida - Solenidae
Gastropoda
 Neogastropoda - Buccinidae
Molopophorus gabbi Dall 1909 true whelk