USGS M4051 (Oligocene of the United States)

Also known as Slip Point

Where: Clallam County, Washington (48.3° N, 122.3° W: paleocoordinates 48.0° N, 113.3° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

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

• SPECIFIC STRATIGRAPHY: From Macoma arctata beds about 10 m thick. GENERAL STRATIGRAPHY: 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].

• group of beds-level stratigraphic resolution

Environment/lithology: offshore; lithified 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 Addicott in 1968; reposited in the USGS

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

• REPOSITORY: USGS (Menlo Park).

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 37585: 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
 Pectinida - Pectinoidae
 Mytilida - Crenellidae
 Mytilida - Mytilidae
"Mytilus aff. tichanovitchi" = Mytilus (Tumidimytilus) tichanovitchi
"Mytilus aff. tichanovitchi" = Mytilus (Tumidimytilus) tichanovitchi Makiyama 1934 mussel
 Cardiida - Mactridae
"Spisula albaria" = Mactromeris albaria
"Spisula albaria" = Mactromeris albaria Conrad 1848 clam
 Cardiida - Veneridae
 Cardiida - Tellinidae
Tellina emacerata Conrad 1849 tellin clam
"Macoma arctata" = Macoma (Psammacoma) arctata Conrad 1849 tellin clam
 Solenida - Solenidae
"Solen conradi" = Solena (Plectosolen) conradi
"Solen conradi" = Solena (Plectosolen) conradi Dall 1900 clam
 Thraciida - Thraciidae
Thracia cf. schencki Teglund 1933 clam
"Thracia trapezoides" = Thracia (Homoeodesma) trapezoides Conrad 1849 clam
 Nuculida - Nuculidae
"Acila conradi" = Acila (Truncacila) conradi
"Acila conradi" = Acila (Truncacila) conradi Meek 1864 divaricate nutclam
Gastropoda
 Neogastropoda - Turridae
Ophiodermella olympicensis Addicott 1976 turrid
 Ficoidea - Ficidae
Ficus ? modesta, "Trophosycon clallamensis" = Ficus (Trophosycon)
Ficus ? modesta fig shell
"Trophosycon clallamensis" = Ficus (Trophosycon) fig shell
 Naticoidea - Naticidae
Natica vokesi Addicott 1966 moon snail
Polinices victorianus Clark and Arnold 1923 moon snail
 Calyptraeoidea - Calyptraeidae
Crepidula rostralis slipper shell
Crepidula praerupta Conrad 1849 slipper shell
  - Neptuneidae
Scaphopoda
 Dentaliida - Dentaliidae
Dentalium schencki Moore 1963 tusk shell