San Nicholas Island (SN-6) (Quaternary of the United States)

Also known as Vedder & Norris (1963) SN-6

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 37944: authorized by Austin Hendy, entered by Austin Hendy on 27.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Comprehensive for invertebrates
unclassified
  -
Maxillopoda
 Sessilia - Tetraclitidae
Tetraclita ? squamosa barnacle
Subspecies: Tetraclita squamosa rubescens
Bivalvia
 Mytilida - Mytilidae
Mytilus californianus Conrad 1837 mussel
 Carditida - Carditidae
"Glans subquadrata" = Glans carpenteri
"Glans subquadrata" = Glans carpenteri Lamy 1922 clam
 Cardiida - Veneridae
"Transennella tantilla" = Nutricola tantilla
"Transennella tantilla" = Nutricola tantilla Gould 1853 venus clam
 Cardiida - Semelidae
Cumingia cf. californica Conrad 1837 clam
 Cardiida - Neoleptonidae
Bernardina ? bakeri Dall 1910 clam
 Lucinida - Lucinidae
Epilucina californica Conrad 1837 clam
Gastropoda
 Patellogastropoda - Lottiidae
Acmaea sp. n. sp. Eschscholtz 1830 limpet
Acmaea digitalis Eschscholtz 1833 limpet
Acmaea mitra Eschscholtz 1833 limpet
 Neogastropoda - Olividae
"Olivella biplicata" = Olivella (Callianax) biplicata
"Olivella biplicata" = Olivella (Callianax) biplicata Sowerby 1825 olive snail
 Neogastropoda - Nassariidae
 Neogastropoda - Fasciolariidae
Barbarofusus cf. arnoldi Cossmann 1903 snail
 Neogastropoda - Mitridae
"Mitra cf. idae" = Mitra (Atrimitra) idae
"Mitra cf. idae" = Mitra (Atrimitra) idae Melville 1893 mitre shell
 Neogastropoda - Mangeliidae
"Mangelia cf. nitens" = Cythara (Mangelia), Mangelia variegata
"Mangelia cf. nitens" = Cythara (Mangelia) snail
Mangelia variegata Carpenter 1864 snail
 Neogastropoda - Raphitomidae
 Neogastropoda - Conidae
"Conus californicus" = Californiconus californicus
"Conus californicus" = Californiconus californicus Reeve 1844 cone shell
 Neogastropoda - Pseudomelatomidae
 Littorinoidea - Littorinidae
Littorina cf. scutulata Gould 1849 periwinkle
 Vanikoroidea - Hipponicidae
Hipponix tumens hoof shell
Hipponix antiquatus Linnaeus 1767 hoof shell
 Vermetoidea - Vermetidae
 Calyptraeoidea - Calyptraeidae
Crepidula adunca Sowerby 1824 slipper shell
Crepidula onyx Sowerby 1824 slipper shell
 Rissooidea - Barleeidae
 Rissooidea - Rissoidae
 Sorbeoconcha - Cerithiidae
Bittium eschrichtii cerith snail
Subspecies: Bittium eschrichtii montereyense
 Pyramidelloidea - Pyramidellidae
 Turbinoidea - Turbinidae
Astraea gibberosa Dillwyn 1817 red turban
 Turbinoidea - Phasianellidae
 Fissurelloidea - Fissurellidae
Diodora aspera Rathke 1833 snail
 Trochoidea - Trochidae
Pupillaria cf. optabilis Carpenter 1864 top snail
Calliostoma cf. ligatum Gould 1849 top snail
 Trochoidea - Tegulidae
Polyplacophora
 Neoloricata - Mopaliidae
Echinoidea
 Camarodonta - Strongylocentrotidae