San Nicholas Island (21649): Middle Eocene - Late/Upper Eocene, California
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Scaphopoda
- Dentaliida
- Dentaliidae
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Dentalium cooperi
(Gabb 1864)
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Gastropoda
- Heterostropha
- Architectonicidae
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Architectonica cf. cognata
Gabb 1864
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| recombined as Architectonica (Stellaxis) cognata | ||||||||||
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Architectonica cf. ullreyana
Dickerson 1916
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Gastropoda
- Potamididae
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Potamides cf. carbonica
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Gastropoda
- Turritellidae
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Turritella cf. buwaldana
Dickerson 1916
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Turritella lawsoni
Dickerson 1916
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| recombined as Turritella andersoni lawsoni | ||||||||||
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Turritella uvasana
Conrad 1855
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| Subspecies: Turritella uvasana etheringtoni | ||||||||||
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Turritella cf. uvasana
Conrad 1855
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| Subspecies: Turritella uvasana hendoni | ||||||||||
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Gastropoda
- Melanopsidae
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Loxotrema turritum
(Gabb 1869)
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Gastropoda
- Ampullinidae
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Amaurellina clarki
(Stewart 1927)
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| recombined as Pachycrommium clarki | ||||||||||
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? Globularia cf. hannabali
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Gastropoda
- Neogastropoda
- Volutidae
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"Volutocristata" cf. lajollaensis
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| synonym of Lyrischapa | ||||||||||
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Lyria aff. andersoni
Waring 1917
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Gastropoda
- Neogastropoda
- Olivellidae
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"Agaronia" cf. mathewsoni
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Gastropoda
- Neogastropoda
- Buccinidae
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"Phos" cf. blakianus
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Gastropoda
- Neogastropoda
- Fasciolariidae
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Fusinus aff. merriami
Dickerson 1916
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Latirus cf. nightingalei
Hanna 1927
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Gastropoda
- Neogastropoda
- Turridae
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Pleurofusia aff. lindavistaensis
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Surculites cf. mathewsoni
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"Surcula" cf. praeattenuata
Gabb 1869
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| recombined as Eosurcula praeattenuata | ||||||||||
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Gastropoda
- Neogastropoda
- Clavatulidae
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? Cryptoconus cf. cooperi
(Dickerson 1916)
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| recombined as Turricula cooperi | ||||||||||
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Gastropoda
- Naticidae
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Amaurellina moragai
Stewart 1927
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Neverita cf. secta
Gabb 1864
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| synonym of Glossaulax reclusiana | ||||||||||
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Euspira cf. nuciformis
(Gabb 1864)
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| recombined as Polinices (Euspira) nuciformis | ||||||||||
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Bivalvia
- Ostreida
- Gryphaeidae
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Ostrea aff. stewarti
Hanna 1927
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| recombined as Phygraea stewarti | ||||||||||
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unclassified
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"Tubulostium" tejonensis
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| see common names | ||||||||||
Geography
| Country: | United States | State/province: | California | County: | Ventura |
| Coordinates: | 33.2° North, 119.5° West (view map) | ||||
| Paleocoordinates: | 33.0° North, 107.1° West | ||||
| Basis of coordinate: | stated in text | ||||
| Geographic resolution: | outcrop |
Time
| Period: | Paleogene | Epoch: | Eocene |
| Key time interval: | Middle Eocene - Late/Upper Eocene | ||
| Age range of interval: | 47.80000 - 33.90000 m.y. ago |
Stratigraphy
| Formation: | Unnamed | ||||
| Local section: | Dutch Harbor | ||||
| Regional section: | Ventura | ||||
| Stratigraphic resolution: | bed | ||||
| Stratigraphy comments: 3,500 feet of alternating marine sandstone and siltstone beds that contain minor amounts of interbedded conglomerate and pebbly mudstone. Is divided into 35 mapping units in Vedder and Norris (1963) but thestratigraphic location of the fossil collections are not indicated. Small andesite dikes of Miocene age intrude the Eocene strata. Dune sand and fossiliferous marine terrace deposits of Quaternary age overlie most of the Eocene strata. Bulk of the specific identifications suggest a middle to late Eocene age based on forms conspecific with those found in the Domengine Formation, the upper part of the Llajas Formation, the Rose Canyon shale member of the La Jolla Formation, and the Tejon Formation, all of whihc are considered to be in the upper half of the Eocene in Calfornia | |||||
Lithology and environment
| Primary lithology: | gray conglomeratic mudstone |
| Secondary lithology: | medium,gray conglomeratic sandstone |
| Includes fossils? | Y |
| Includes fossils? | Y |
| Lithology description: Conglomeratic mudstone and sandstone sequence. Matrix ranges from mudstone to poorly sorted medium-grained sandstone that is olive-gray in fresh exposures and locally contains large angular fragments of sandstone and siltstone. | |
| Environment: | coastal indet. |
| Geology comments: Structurally, San Nicholas Island is a broad, complexly faulted anticline that roughly parallels the long dimension of the island. Age of the main faulting is assumed to be pre-middle Miocene with continuing movement through Pleistocene time. | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection excludes: | some macrofossils |
| Collection methods: | selective quarrying,field collection |
| Reason for describing collection: | taxonomic analysis |
| Museum repositories: | USGS |
| Collection method comments: Collected by Vedder et al. (1955, 1956). Earlier collections by Bowers (1890), Harbor and Reed (1933). | |
| Taxonomic list comments:Representative for mollusca, coral mentioned in text, but not listed. | |
Metadata
| Also known as: | USGS 21649 | ||
| Database number: | 37928 | ||
| Authorizer: | A. Hendy | Enterer: | A. Hendy |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 2004-03-27 11:39:44 | Last modified: | 2013-11-25 13:37:23 |
| Access level: | the public | Released: | 2004-03-27 11:39:44 |
| Creative Commons license: | CC BY | ||
Reference information
Primary reference:
| 10107. | 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] |