San Nicholas Island (SN-9) (Quaternary of the United States)

Also known as Vedder & Norris (1963) SN-9

Where: Ventura County, California (33.2° N, 119.5° W: paleocoordinates 33.2° N, 119.2° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Unnamed Formation, Quaternary (2.6 - 0.0 Ma)

• Dune sand and fossiliferous marine terrace deposits of Quaternary age. These overlie Eocene strata. Fossils come from seven well-developed wave-cut platforms at altitudes of 25 to 990 feet. Several submerged terraces are present on the shelf adjacent to the island., the lowest being 400 ft below sea-level. Presumably all the terrace platforms on San Nicholas Island were cut later than the middle Pleistocene diastrophism recognized elsewhere in southern California. Terrace platforms are covered with a variety of sediments of marine and non-marine origin and range in thickness from a few inches to many feet.

• bed-level stratigraphic resolution

Environment/lithology: coastal; pebbly, shelly/skeletal, conglomeratic, calcareous sandstone

• Higher emergent terraces may represent wave-abraded platforms that were eroded during eustatic changes in sea level combined with tectonic uplift. The lowest emergent terrace may have been cut during eustatic sea-level changes followed by very slight regional seaward warping. Presumably all the terrace platforms on San Nicholas Island were cut later than the middle Pleistocene diastrophism recognized elsewhere in southern California
• Generally comprise poorly sorted calcareous sand and gravel composed primarily of mollusc shell fragments, echinoid plates and spines, calcareous algae, and bryozoans.

Size class: macrofossils

Collection methods: quarrying,

• Collections made by Vedder et al (1955-1956). Earlier collections by Cooper (1894), and Howard (1955)

Primary reference: J. G. Vedder and R. M. Norris. 1963. Geology of San Nicolas Island, California. United States Geological Survey Professional Paper 369:1-65 [A. Miller/A. Hendy/P. Wagner]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 37941: authorized by Austin Hendy, entered by Austin Hendy on 27.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Comprehensive for invertebrates
Maxillopoda
 Sessilia - Tetraclitidae
Tetraclita squamosa barnacle
Subspecies: Tetraclita squamosa rubescens
Polychaeta
  -
Bivalvia
 Mytilida - Mytilidae
Mytilus cf. californianus Conrad 1837 mussel
 Cardiida - Chamidae
Chama arcana Bernard 1976 jewel box
 Cardiida - Veneridae
"Transennella tantilla" = Nutricola tantilla
"Transennella tantilla" = Nutricola tantilla Gould 1853 venus clam
 Cardiida - Semelidae
Cumingia ? californica Conrad 1837 clam
 Hiatellida - Hiatellidae
"Hiatella ? arctica" = Hiatella (Hiatella) arctica
"Hiatella ? arctica" = Hiatella (Hiatella) arctica Linnaeus 1767 clam
 Lucinida - Lucinidae
Parvilucina tenuisculpta Carpenter 1864 clam
Epilucina californica Conrad 1837 clam
Gastropoda
 Patellogastropoda - Lottiidae
Acmaea mitra Eschscholtz 1833 limpet
Acmaea ? pelta Eschscholtz 1833 limpet
 Neogastropoda - Olividae
"Olivella biplicata" = Olivella (Callianax) biplicata
"Olivella biplicata" = Olivella (Callianax) biplicata Sowerby 1825 olive snail
 Neogastropoda - Columbellidae
 Neogastropoda - Buccinidae
Calicantharus cf. fortis Carpenter 1866 true whelk
 Neogastropoda - Pseudomelatomidae
 Littorinoidea - Littorinidae
 Vanikoroidea - Hipponicidae
Hipponix antiquatus Linnaeus 1767 hoof shell
 Vanikoroidea - Eulimidae
 Calyptraeoidea - Calyptraeidae
Crepidula ? adunca Sowerby 1824 slipper shell
 Rissooidea - Barleeidae
 Rissooidea - Rissoidae
 Sorbeoconcha - Cerithiidae
Bittium eschrichtii cerith snail
Subspecies: Bittium eschrichtii montereyense
Bittium ? armillatum cerith snail
 Pyramidelloidea - Pyramidellidae
 Turbinoidea - Turbinidae
Astraea gibberosa Dillwyn 1817 red turban
 Trochoidea - Tegulidae
Echinoidea
 Camarodonta - Strongylocentrotidae