Jansen Creek Mbr, Makah Fm - Jansen Creek (Eocene to of the United States)

Where: Clallam County, Washington (48.3° N, 124.5° W: paleocoordinates 48.1° N, 113.3° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Jansen Creek Member (Makah Formation), Bartonian to Bartonian (41.3 - 23.0 Ma)

• STRATIGRAPHIC RELATIONS: The Makah Fm is in the upper part of a middle Eocene to lower Miocene sequence of marine sedimentary sequence that is more than 6000 m thick. The Makah Fm overlies the upper Eocene Hoko River Fm. The Makah Fm underlies the upper Oligocene and lower Miocene Pysht Fm. The Jansen Mbr occurs about 1600 m through the 2800 m thick Makah Fm, between the Third Beach and Falls Creek Mbrs. AGE: Addicott (written communs., 1973-1977) assigns a late Eocene age (Lincoln Stage of Weaver 1937) to this collection. Foraminiferal assemblages indicate a Refugian (Late Eocene) age, a Lincoln equivalent. More recent workers (e.g. Goedert et al. 1995) assign an Oligocene (Rupelian-Chattian) age for the unit. An older (more conservative) Rupelian age is assigned here. STRATIGRAPHIC POSITION: From Jansen Creek Mbr is approximately 200 m thick, but it is not clear where in this succession the collection is derived from.

• member-level stratigraphic resolution

Environment/lithology: deep-water; poorly lithified, volcaniclastic, shelly/skeletal sandstone and volcaniclastic, shelly/skeletal conglomerate

• ENVIRONMENT: Addicott (written communs., 1973-1977) suggested a middle-outer sublittoral environment of deposition. Foraminiferal assemblages indicate a shallow-water depositional environment. This unit is underlain and overlain by lower to middle bathyal sediments, supporting the interpretation that the shallow-marine sediments are allocthonous deposits derived from uplifted older strata along an ancient narrow shelf that borded the deep marginal basin of the Makah. These shallow-water deposits were transported into the deep marginal basin by a large submarine slide.
• SPECIFIC LITHOLOGY: Olistostromal blocks of shallow-water basaltic sandstone and conglomerate; interbedded fossiliferous basaltic sandstone and pebble conglomerate. LITHIFICATION: Assumed to be poorly lithified-lithified based on photographic plates of outcrop exposures.

Size class: macrofossils

Reposited in the USNM

• COLLECTOR: W. Addicott (1973-1977). REPOSITORY: Presumed to be USGS, and USNM.

Primary reference: P. D. Snavely, Jr, A. R. Niem, N. S. Macleod, J. E. Pearl, and W. W. Rau. 1980. Makah Formation - A deep-marginal-basin sequence of Late Eocene and Oligocene age in the Northwestern Olympic Peninsula, Washington. United States Geological Survey Professional Paper 1162(B):1-28 [A. Miller/A. Hendy/M. Uhen]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 62246: authorized by Austin Hendy, entered by Austin Hendy on 16.07.2006, edited by Mark Uhen and Mihaela Krause

Creative Commons license: CC BY (attribution)

Taxonomic list

• COMPLETENESS: Probably not exhaustive, but representative. NOMENCLATURE: Not an authoritative publication, although list is cited to have been identified by Addicott and is reliable. Nomenclature is reasonably modern and carries species-level assignments.
 Carditida - Carditidae
Cyclocardia hannibali Clark 1925 clam
 Cardiida - Cardiidae
"Nemocardium cf. weaveri" = Anechinocardium weaveri
"Nemocardium cf. weaveri" = Anechinocardium weaveri Anderson and Martin 1914 cockle
 Lucinida - Lucinidae
Lucinoma cf. columbiana Clark and Arnold 1923 clam
 Lucinida - Thyasiridae
"Conchocele cf. disjuncta" = Conchocele bisecta
"Conchocele cf. disjuncta" = Conchocele bisecta Conrad 1849 clam
 Mytilida - Mytilidae
? Crenella sp. Brown 1827 mussel
 Ostreida - Ostreidae
Ostrea sp. Linnaeus 1758 oyster
 Sorbeoconcha - Turritellidae
Turritella cf. porterensis Weaver 1912 turret shell
 Sorbeoconcha - Naticidae
Naticidae indet. Guilding 1834 moon snail
 Sorbeoconcha - Epitoniidae
Acrilla aff. olympicensis Durham 1937 wentletrap
Listed as "Acrilla n. sp. ? aff. A. olympicensis
 Neogastropoda - Fasciolariidae
? Perse sp. Clark 1918 snail
 Neoloricata - Ischnochitonidae
Stenoplax "sp. A"1 Carpenter 1879 chiton
 Dentaliida - Dentaliidae
Dentalium porterensis Weaver 1912 tusk shell
 Pelecaniformes -
 Suliformes - Plotopteridae
? Tonsala sp.3 Olson 1980 bird
precise locality information not listed for this occurrence
Tonsala buchanani2 Dyke et al. 2011 bird
Tonsala cf. hildegardae3 Olson 1980 bird
precise locality information not listed for this occurrence
Klallamornis clarki n. sp.3 Mayr and Goedert 2016 bird
precise locality information not listed for this occurrence