San Nicholas Island (SN-7) (Quaternary of the United States)

Also known as Vedder & Norris (1963) SN-7

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 37943: 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
 Pectinida - Pectinoidae
"Hinnites giganteus" = Crassadoma gigantea
"Hinnites giganteus" = Crassadoma gigantea Gray 1825 scallop
 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, "Petricola carditoides" = Petricola (Petricola) carditoides
"Transennella tantilla" = Nutricola tantilla Gould 1853 venus clam
"Petricola carditoides" = Petricola (Petricola) carditoides Conrad 1837 venus clam
 Cardiida - Semelidae
Cumingia californica Conrad 1837 clam
 Cardiida - Neoleptonidae
Bernardina bakeri Dall 1910 clam
 Cardiida - Lasaeidae
"Lasaea cf. cistula" = Lasaea adansoni
"Lasaea cf. cistula" = Lasaea adansoni Gmelin 1791 clam
 Lucinida - Lucinidae
Epilucina californica Conrad 1837 clam
Gastropoda
 Ptenoglossa - Epitoniidae
Epitonium cf. indianorum Carpenter 1864 wentletrap
Opalia cf. evicta wentletrap
 Patellogastropoda - Lottiidae
Lottia gigantea Sowerby 1834 limpet
Acmaea digitalis Eschscholtz 1833 limpet
Acmaea scutum Eschscholtz 1833 limpet
Acmaea mitra Eschscholtz 1833 limpet
Acmaea pelta Eschscholtz 1833 limpet
  - Siphonaliidae
Calicantharus cf. fortis Carpenter 1866 snail
 Neogastropoda - Columbellidae
Mitrella tuberosa Carpenter 1864 snail
Amphissa versicolor Dall 1871 snail
 Neogastropoda - Buccinidae
 Neogastropoda - Pseudolividae
 Littorinoidea - Littorinidae
Littorina scutulata Gould 1849 periwinkle
 Vanikoroidea - Hipponicidae
Hipponix antiquatus Linnaeus 1767 hoof shell
 Vermetoidea - Vermetidae
 Calyptraeoidea - Calyptraeidae
Crucibulum spinosum Conrad 1855 slipper shell
Crepidula adunca Sowerby 1824 slipper shell
Crepidula onyx Sowerby 1824 slipper shell
"Crepidula aculeata" = Bostrycapulus aculeatus Gmelin 1791 slipper shell
 Rissooidea - Barleeidae
 Rissooidea - Rissoidae
 Rissooidea - Vitrinellidae
 Truncatelloidea - Caecidae
 Sorbeoconcha - Cerithiidae
Bittium armillatum cerith snail
 Pulmonata - Trimusculidae
 Haliotoidea - Haliotidae
 Turbinoidea - Turbinidae
 Turbinoidea - Phasianellidae
 Fissurelloidea - Fissurellidae
 Trochoidea - Tegulidae
Polyplacophora
 Neoloricata - Acanthochitonidae
"Cryptochiton" stelleri Middendorf 1847 chiton
Echinoidea
 Camarodonta - Strongylocentrotidae
Strongylocentrotus cf. franciscanus Agassiz 1863 sea urchin
Anthozoa
 Scleractinia - Dendrophylliidae
Balanophyllia elegans Verrill 1864 stony coral