San Nicholas Island (SN-8) (Quaternary of the United States)

Also known as Vedder & Norris (1963) SN-8

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 37942: authorized by Austin Hendy, entered by Austin Hendy on 27.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Comprehensive for invertebrates
Bivalvia
 Carditida - Carditidae
"Glans subquadrata" = Glans carpenteri
"Glans subquadrata" = Glans carpenteri Lamy 1922 clam
 Lucinida - Lucinidae
Epilucina californica Conrad 1837 clam
Gastropoda
 Patellogastropoda - Lottiidae
Acmaea sp. n. sp. Eschscholtz 1830 limpet
 Neogastropoda - Columbellidae
 Vanikoroidea - Hipponicidae
 Haliotoidea - Haliotidae
 Turbinoidea - Turbinidae
Astraea gibberosa Dillwyn 1817 red turban
 Trochoidea - Tegulidae
Echinoidea
 Camarodonta - Strongylocentrotidae