NP163 (Oligocene of the United States)

Where: Clallam County, Washington (48.3° N, 124.3° W: paleocoordinates 47.9° N, 115.3° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Clallam Formation, Chattian (28.1 - 23.0 Ma)

• The Clallam Formation is a predominantly marine sandstone with minor conglomerate and siltstone exposed along the Strait of Juan de Fuca in northwestern Washington. Marine molluscs occur throughout the 600 to 800 m thick formation but are especially abundant in the lowermost 240 m. Pillarian Stage age, a provincial time stratigraphic unit of late early Miocene age. Revised to Chattian following more recent work [Hendy, 7/2016].

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, silty sandstone

• All Clallam Formation assemblages represent inner sublittoral depths (less than about 100 m). Qualitative analysis of these assemblages indicates a gradual shallowing during deposition of the formation. The highest strata in the formation contain coal and are presumably non-marine.
• Sandstone with minor conglomerate and siltstone.

Size class: macrofossils

Preservation: mold/impression

Collected by Hannibal in 1912; reposited in the CAS

Collection methods: surface (float), surface (in situ),

• REPOSITORY: California Academy of Science.

Primary reference: W.O. Addicott. 1976. Molluscan paleontology of the lower Miocene Clallam Formation, northwestern Washington. United States Geological Survey Professional Paper 976:1-44 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 37595: authorized by Austin Hendy, entered by Austin Hendy on 17.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Only molluscan taxa listed
Bivalvia
 Cardiida - Veneridae
 Cardiida - Tellinidae
Tellina emacerata Conrad 1849 tellin clam
"Macoma arctata" = Macoma (Psammacoma) arctata Conrad 1849 tellin clam
 Hiatellida - Hiatellidae
Panopea ? abrupta Conrad 1849 clam
 Thraciida - Thraciidae
"Thracia trapezoides" = Thracia (Homoeodesma) trapezoides
"Thracia trapezoides" = Thracia (Homoeodesma) trapezoides Conrad 1849 clam
 Lucinida - Lucinidae
Lucinoma acutilineata Conrad 1849 clam
 Nuculida - Nuculidae
"Acila conradi" = Acila (Truncacila) conradi
"Acila conradi" = Acila (Truncacila) conradi Meek 1864 divaricate nutclam
 Protobranchia - Nuculanidae
Nuculana chehalisensis pointed nut clam
Cephalopoda
 Nautilida - Aturiidae
Aturia angustata Conrad 1849 nautiloid