San Nicholas Island (SN-4) (Quaternary of the United States)

Also known as Vedder & Norris (1963) SN-4

Where: Ventura County, California (33.2° N, 119.6° 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 37946: authorized by Austin Hendy, entered by Austin Hendy on 27.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Comprehensive for invertebrates
Anthozoa
 Scleractinia - Dendrophylliidae
Balanophyllia elegans Verrill 1864 stony coral
Polyplacophora
 Neoloricata - Acanthochitonidae
"Cryptochiton" stelleri Middendorf 1847 chiton
Bivalvia
 Mytilida - Mytilidae
Mytilus californianus Conrad 1837 mussel
 Pectinida - Pectinoidae
"Hinnites giganteus" = Crassadoma gigantea
"Hinnites giganteus" = Crassadoma gigantea Gray 1825 scallop
 Carditida - Carditidae
"Glans subquadrata" = Glans carpenteri
"Glans subquadrata" = Glans carpenteri Lamy 1922 clam
 Lucinida - Lucinidae
Epilucina californica Conrad 1837 clam
 Cardiida - Semelidae
Cumingia californica Conrad 1837 clam
Gastropoda
 Lepetellida - Fissurellidae
Fissurella volcano Reeve 1849 snail
Diodora ? aspera Rathke 1833 snail
 Lepetellida - Haliotidae
Haliotis cf. cracherodii Leach 1814 abalone
 Patellida - Lottiidae
"Acmaea scabra" = Lottia scabra Gould 1846 limpet
Lottia gigantea Sowerby 1834 limpet
Acmaea mitra Eschscholtz 1833 limpet
 Sorbeoconcha - Procerithiidae
"Bittium ? armillatum" = Lirobittium armillatum
"Bittium ? armillatum" = Lirobittium armillatum Carpenter 1864 snail
 Sorbeoconcha - Littorinidae
"Littorina cf. scutulata" = Littorina (Littorina) scutulata, "Lacuna unifasciata" = Lacuna (Epheria) unifasciata, "Littorina cf. planaxis" = Littorina (Neritrema) keenae
"Littorina cf. scutulata" = Littorina (Littorina) scutulata Gould 1849 periwinkle
"Lacuna unifasciata" = Lacuna (Epheria) unifasciata Carpenter 1857 periwinkle
"Littorina cf. planaxis" = Littorina (Neritrema) keenae Rosewater 1978 periwinkle
 Sorbeoconcha - Hipponicidae
Antisabia panamensis Adams 1852 hoof shell
 Sorbeoconcha - Barleeiidae
Barleeia cf. subtenuis Carpenter 1864 snail
 Sorbeoconcha - Caecidae
"Fartulum ? occidentale" = Fartulum dextroversum, Caecum cf. californicum
"Fartulum ? occidentale" = Fartulum dextroversum Carpenter 1857 snail
Caecum cf. californicum Dall 1885 snail
 Neogastropoda - Mitridae
"Mitra idae" = Mitra (Atrimitra) idae
"Mitra idae" = Mitra (Atrimitra) idae Melville 1893 mitre shell
 Neogastropoda - Columbellidae
Amphissa cf. versicolor Dall 1871 snail
 Neogastropoda - Olividae
"Olivella biplicata" = Callianax biplicata
"Olivella biplicata" = Callianax biplicata Sowerby 1825 olive snail
 Neogastropoda - Conidae
"Conus californicus" = Californiconus californicus
"Conus californicus" = Californiconus californicus Reeve 1844 cone shell
 Neogastropoda - Muricidae
? Maxwellia cf. gemma Sowerby 1879 murex snail
"Ocenebra cf. lurida" = Paciocinebrina lurida Middendorff 1848 murex snail
 Sorbeoconcha - Triphoridae
"Triphora cf. pedroana" = Monophorus pedroanus
"Triphora cf. pedroana" = Monophorus pedroanus Bartsch 1907 snail
 Sorbeoconcha - Cerithiopsidae
Seila montereyensis Bartsch 1907 snail
 Neotaenioglossa - Calyptraeidae
Crepipatella lingulata Gould 1846 slipper shell