CSUN Loc. 548, Simi Arroyo: Lutetian, California

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
unclassified
Palaeopinnixa aff. rathburnae
Asterocyclinidae
Pseudophragmina (Proporocyclina) clarki (Cushman 1920)
Squires 1984
recombined as Pseudophragmina clarki
Anthozoa - Scleractinia - Caryophylliidae
Trochocyathus stantoni Vaughan 1900
Cephalopoda - Nautilida - Nautilidae
Kummelonautilus sp. Matsumoto 1984
Gastropoda - Neotaenioglossa - Calyptraeidae
Calyptraea diegoana (Conrad 1855)
Squires 1984
Gastropoda - Turritellidae
Turritella buwaldana Dickerson 1916
Squires 1984
Turritella uvasana Conrad 1855
Squires 1984
as Turritella uvasana applinae
Turritella andersoni Dickerson 1916
Squires 1984
as Turritella andersoni lawsoni
Gastropoda - Strombidae
Platyoptera pacifica Squires and Demetrion 1990
Gastropoda - Neogastropoda - Clavatulidae
Fusiturricula (Crenaturricula) crenatospira (Cooper 1894)
Squires 1984
recombined as Crenaturricula crenatospira
as Fusiturricula (Crenaturricula) crenatospira domenginica
Gastropoda - Neogastropoda - Clathurellidae
Domenginella claytonensis (Gabb 1864)
Squires 1984
Bivalvia - Ostreida - Pteriidae
Pteria pellucida (Gabb 1864)
original and current combination Avicula pellucida
Bivalvia - Ostreida - Pinnidae
Pinna lewisi Waring 1914
Squires 1984
recombined as Pinna (Pinna) lewisi
Bivalvia - Ostreida - Ostreidae
Ostrea idriaensis Gabb 1869
Squires 1984
recombined as Acutostrea idriaensis
Bivalvia - Cardiida - Cardiidae
Nemocardium linteum (Conrad 1855)
Squires 1984
recombined as Nemocardium (Nemocardium) linteum
Acanthocardia (Schedocardia) brewerii (Gabb 1864)
Squires 1984
recombined as Schedocardia brewerii
Bivalvia - Cardiida - Psammobiidae
Gari texta Gabb 1864
recombined as Gari (Gobraeus) texta
Bivalvia - Cardiida - Gastrochaenidae
Gastrochaena ? dubitata Hanna 1927
Bivalvia - Carditida - Carditidae
Venericardia (Pacificor) hornii (Gabb 1864)
Squires 1984
as Venericardia (Pacificor) hornii calafia
Scaphopoda - Dentaliida - Dentaliidae
Dentalium (Laevidentalium) calafium Vokes 1939
Squires 1984
Rhynchonellata - Terebratulida - Terebrataliidae
Terebratalia aff. batequia Sandy et al. 1995
Malacostraca - Decapoda - Scyllaridae
Parribacus caesius n. sp. Squires 2001
recombined as Llajassus caesius
Malacostraca - Decapoda - Cymonomidae
Eonomus californianus n. gen., n. sp. Nyborg et al. 2017
Nyborg et al. 2017
Malacostraca - Decapoda - Euryplacidae
Glyphithyreus weaveri (Rathbun 1926)
Squires 1984
recombined as Orbitoplax weaveri
Malacostraca - Decapoda - Macropipidae
Portunites insculpta Rathbun 1926
Malacostraca - Decapoda - Raninidae
Raninoides slaki n. sp. Squires 2001
Echinoidea - Camarodonta - Temnopleuridae
? Brochopleurus sp.
Chondrichthyes - Myliobatiformes - Myliobatidae
? Myliobatis sp. Cuvier 1816
see common names

Geography
Country:United States State/province:California County:Ventura
Coordinates: 34.3° North, 118.7° West (view map)
Paleocoordinates:35.0° North, 104.7° West
Basis of coordinate:estimated from map
Altitude:288 meters
Geographic resolution:outcrop
Time
Period:Paleogene Epoch:Eocene
Stage:Lutetian 10 m.y. bin:Cenozoic 2
Key time interval:Lutetian
Age range of interval:47.80000 - 41.30000 m.y. ago
Stratigraphy
Formation:Llajas
Stratigraphic resolution:bed
Stratigraphy comments: Immediately below the "Stewart Bed", middle of the Llajas Formation, "Domengine" stage, top of CP12a calcareous nannoplankton zone, lower Lutetian stage, Middle Eocene, C21r chron.
Lithology and environment
Primary lithology: lithified argillaceous siltstone
Secondary lithology:planar lamination,bioturbation sandstone
Includes fossils?Y
Includes fossils?Y
Lithology description: Alternating laminated and bioturbated sandstones grading into muddy siltstone.
Environment:transition zone/lower shoreface
Glacial or sequence phase:transgressive
Geology comments: The "Stewart bed" is located in a section of transition from shallow-marine to outer slope and shelf facies. A nearshore environment is interpreted for that portion of the shallow-marine (transgressive) facies which consists of laminated beds alternating with bioturbated beds. In such cases, the finely laminated sand represents storm-influenced stratification, and the biogenic reworking is the inter-storm activity. Shell fragments commonly are concentrated as channel lags in surge channels. Fossils were apparently subjected to wave action because the apices of elongate shells such as Turritella are bimodally oriented in opposite directions. The deeper the water, the less amount of laminated sandstone and the more amount of bioturbated sandstone. Such areas, which were farther below effective wave base, existed 1) where the shallow-marine (transgressive) facies grades into the outer shelf to slope facies and 2) in the shallow-marine (regressive) facies. One of the deepest-water shallow-marine beds was the "Stewart bed."
Taphonomy
Modes of preservation:body,mold/impression
Size of fossils:macrofossils
Preservation of anatomical detail:medium
Collection methods and comments
Collection methods:field collection,survey of museum collection
Reason for describing collection:taxonomic analysis
Museum repositories:LACM
Collection method comments: Collected by R.L. Squires, (1978) and CSUN paleontology classes in the 1980's-1990's and G. Slak (1997-1998)
Taxonomic list comments:Exhaustive for mollusca, corals, arthropoda, and includes other groups where obvserved; list compiled from meticulous search of the invert collections at the LACM, private collections and fieldwork.
Metadata
Database number:51922
Authorizer:A. Hendy, P. Holroyd, J. Marcot Enterer:A. Hendy, J. Marcot, P. Holroyd
Modifier:M. Clapham Research group:marine invertebrate
Created:2005-07-04 09:28:41 Last modified:2019-08-18 20:03:25
Access level:the public Released:2005-07-04 09:28:41
Creative Commons license:CC BY
Reference information

Primary reference:

13852. R. L. Squires. 2001. Additions to the Eocene megafossil fauna of the Llajas Formation, Simi Valley, southern California. Contributions in Science (Natural History Museum of Los Angeles County) 489:1-40 [A. Miller/A. Hendy/A. Hendy]

Secondary references:

69206 T. Nyborg, A. Garassino, and G. Slak. 2017. Eonomus californianus n. gen., n. sp. (Crustacea, Brachyura, Cymonomidae) from the Eocene Llajas Formation, California (USA). Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 286(2):189-193 [P. Holroyd/P. Holroyd]
59877 R. L. Squires. 1984. Megapaleontology of the Eocene Llajas Formation, Simi Valley, California. Contributions in Science, Natural History Museum of Los Angeles County 350:1-76 [M. Clapham/M. Clapham]