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
Echinoidea
 Camarodonta - Strongylocentrotidae
Strongylocentrotus cf. franciscanus Agassiz 1863 sea urchin
Gastropoda
 Heterostropha - Pyramidellidae
 Trochoidea - Trochidae
"Tegula cf. brunnea" = Chlorostoma brunnea, "Tegula cf. funebralis" = Chlorostoma funebrale
"Tegula cf. brunnea" = Chlorostoma brunnea Philippi 1849 top snail
"Tegula cf. funebralis" = Chlorostoma funebrale Adams 1855 top snail
 Trochoidea - Turbinidae
"Homalopoma carpenteri" = Homalopoma (Homalopoma) luridum, "Astraea gibberosa" = Pomaulax gibberosa
"Homalopoma carpenteri" = Homalopoma (Homalopoma) luridum Dall 1885 snail
"Astraea gibberosa" = Pomaulax gibberosa Dillwyn 1817 red turban
 Patellida - Lottiidae
Acmaea mitra, "Acmaea ? pelta" = Lottia pelta, "Acmaea cf. scabra" = Lottia scabra
Acmaea mitra Eschscholtz 1833 limpet
"Acmaea ? pelta" = Lottia pelta Eschscholtz 1833 limpet
"Acmaea cf. scabra" = Lottia scabra Gould 1846 limpet
 Cerithioidea - Cerithiidae
"Bittium eschrichtii" = Neostylidium eschrichtii
"Bittium eschrichtii" = Neostylidium eschrichtii Middendorff 1849 cerith snail
Subspecies: Bittium eschrichtii montereyense
 Neotaenioglossa - Calyptraeidae
Crepidula ? adunca Sowerby 1824 slipper shell
 Sorbeoconcha - Procerithiidae
"Bittium ? armillatum" = Lirobittium armillatum
"Bittium ? armillatum" = Lirobittium armillatum Carpenter 1864 snail
 Sorbeoconcha - Hipponicidae
Antisabia panamensis2 Adams 1852 hoof shell
 Sorbeoconcha - Littorinidae
"Lacuna ? unifasciata" = Lacuna (Epheria) unifasciata
"Lacuna ? unifasciata" = Lacuna (Epheria) unifasciata Carpenter 1857 periwinkle
 Sorbeoconcha - Rissoidae
"Alvania cf. purpurea" = Alvinia purpurea
"Alvania cf. purpurea" = Alvinia purpurea Dall 1871 snail
 Sorbeoconcha - Barleeiidae
Barleeia cf. oldroydi Bartsch 1920 snail
 Neogastropoda - Columbellidae
Amphissa cf. versicolor, "Mitrella carinata" = Alia carinata
Amphissa cf. versicolor Dall 1871 snail
"Mitrella carinata" = Alia carinata Hinds 1844 dovesnail
 Neogastropoda - Buccinidae
"Searlesia" cf. dira Reeve 1846 true whelk
 Neogastropoda - Siphonaliidae
Calicantharus cf. fortis Carpenter 1866 snail
 Neogastropoda - Pseudomelatomidae
Pseudomelatoma ? torosa Gabb 1864 snail
 Neogastropoda - Olividae
"Olivella biplicata" = Callianax biplicata
"Olivella biplicata" = Callianax biplicata Sowerby 1825 olive snail
 Sorbeoconcha - Vermetidae
"Spiroglyphus cf. lituellus" = Dendropoma lituella
"Spiroglyphus cf. lituellus" = Dendropoma lituella Morch 1861 worm shell
 Vanikoroidea - Eulimidae
"Balcis cf. prefalcata" = Vitreolina macra
"Balcis cf. prefalcata" = Vitreolina macra Bartsch 1917 snail
Bivalvia
 Mytilida - Mytilidae
Mytilus cf. californianus Conrad 1837 mussel
 Cardiida - Semelidae
Cumingia ? californica Conrad 1837 clam
 Cardiida - Chamidae
Chama arcana1 Bernard 1976 jewel box
 Cardiida - Veneridae
"Transennella tantilla" = Nutricola tantilla
"Transennella tantilla" = Nutricola tantilla Gould 1853 venus clam
 Hiatellida - Hiatellidae
Hiatella ? arctica Linnaeus 1767 clam
 Lucinida - Lucinidae
Parvilucina tenuisculpta Carpenter 1864 clam
Epilucina californica Conrad 1837 clam
Thecostraca
 Balanomorpha - Tetraclitidae
Tetraclita squamosa barnacle
Subspecies: Tetraclita squamosa rubescens