CSUN Loc. 374, Las Llajas Canyon (Eocene of the United States)

Also known as LACMIP loc. 7242; LACMIP loc. 40374

Where: Ventura County, California (34.3° N, 118.7° W: paleocoordinates 35.1° N, 104.6° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Llajas Formation, Lutetian (47.8 - 41.3 Ma)

• The Stewart bed is a 1 m thick sandstone unit in the middle of the Llajas formation. Lutetian, chron 21r according to Squires (2001).

• bed-level stratigraphic resolution

Environment/lithology: transition zone or lower shoreface; lithified, bioturbated sandstone

• 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."
• sandstone.

Size class: macrofossils

Reposited in the LACM

Collection methods: bulk,

• Repository: formerly CSUN (California State University Northridge)

Primary reference: R. L. Squires. 1983. New Mollusks from the Lower Middle Eocene Llajas Formation, Southern California. Journal of Paleontology 57(2):354-362 [L. Ivany/E. Kowalski/J. Marcot]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 8012: authorized by Linda Ivany, entered by Elizabeth Kowalski on 12.06.2000, edited by Austin Hendy, Matthew Clapham and Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

Foraminifera
 Nummulitacea - Asterocyclinidae
"Pseudophragmina (Proporocyclina) clarki" = Pseudophragmina clarki3
"Pseudophragmina (Proporocyclina) clarki" = Pseudophragmina clarki3 Cushman 1920
Anthozoa
 Scleractinia - Acrosmiliidae
"? Trochocyathus striatus" = Trochosmilia (Acrosmilia) striata3
"? Trochocyathus striatus" = Trochosmilia (Acrosmilia) striata3 Gabb 1864 stony coral
 Scleractinia - Oculinidae
"Archohelia clarki" = Petrophyllia clarki4
"Archohelia clarki" = Petrophyllia clarki4 Vaughan 1927 stony coral
Cephalopoda
 Nautilida - Aturiidae
Aturia myrlae3 Hanna 1927 nautiloid
 Nautilida - Nautilidae
Kummelonautilus sp.4 Matsumoto 1984 nautiloid
Gastropoda
 Epitonioidea - Epitoniidae
Cirsotrema sp.3 Mörch 1852 wentletrap
 Cerithioidea - Brachytrematidae
Benoistia umpquaensis3 Turner 1938 snail
 Cerithioidea - Turritellidae
Turritella uvasana3 Conrad 1855 turret shell
as Turritella uvasana applinae
Turritella andersoni3 Dickerson 1916 turret shell
as Turritella andersoni lawsoni
 Architaenioglossa - Ampullinidae
Eocernina hannibali3 Dickerson 1914 snail
Pachycrommium clarki3 Stewart 1927 snail
 Sorbeoconcha - Strombidae
"Ectinochilus (Macilentos) macilentus" = Rimella macilenta3
"Ectinochilus (Macilentos) macilentus" = Rimella macilenta3 White 1889 true conch
 Neogastropoda - Buccinidae
Ancistrolepis carolineae n. sp.3 Squires 1984 true whelk
 Neogastropoda - Fasciolariidae
Clavilithes "n. sp. B"3 Swainson 1840 snail
Clavilithes tabulatus3 Dickerson 1913 snail
Fusinus teglandae3 Hanna 1927 snail
 Neogastropoda - Melongenidae
"Ficopsis cooperiana" = Fusus (Hemifusus) cooperii3
"Ficopsis cooperiana" = Fusus (Hemifusus) cooperii3 Gabb 1864 snail
 Neogastropoda - Clavatulidae
"Fusiturricula (Crenaturricula) crenatospira" = Crenaturricula crenatospira3
"Fusiturricula (Crenaturricula) crenatospira" = Crenaturricula crenatospira3 Cooper 1894 snail
also as Fusiturricula (Crenaturricula) crenatospira domenginica
 Neogastropoda - Conidae
Conus hornii3 Gabb 1864 cone shell
as Conus hornii umpquaensis
 Neogastropoda - Turridae
Surculites mathewsonii3 Gabb 1864 turrid
? Cochlespiropsis jenkinsi n. sp.4 Squires 2001 turrid
 Neogastropoda - Muricidae
Pseudoperissolax blakei3 Conrad 1855 murex snail
as Pseudoperissolax blakei praeblakei
 Neogastropoda - Volutidae
Lapparia eomagna4 Vokes 1939 volute
Lyrischapa lajollaensis3 Hanna 1927 volute
 Neogastropoda - Harpidae
"Eocithara mutica" = Harpa mutica3
"Eocithara mutica" = Harpa mutica3 Lamarck 1803 snail
as Eocithara mutica californiensis
 Sorbeoconcha - Ficidae
Ficopsis remondii3 Gabb 1864 fig shell
as Ficopsis remondii crescentensis
 Sorbeoconcha - Cymatiidae
"Olequahia domenginica" = Ranella domenginica3, Ranella katherineae n. sp.
"Olequahia domenginica" = Ranella domenginica3 Vokes 1939 snail
Ranella katherineae n. sp. Squires 1983 snail
 Sorbeoconcha - Cassidae
"Galeodea (Caliagaleodea) californica" = Galeodea californica3, "Phalium (Semicassis) tuberculiformis" = Coalingodea tuberculiformis3
"Galeodea (Caliagaleodea) californica" = Galeodea californica3 Clark 1942 snail
"Phalium (Semicassis) tuberculiformis" = Coalingodea tuberculiformis3 Gabb 1864 snail
 Sorbeoconcha - Ranellidae
Cymatium janetae n. sp. Squires 1983 triton shell
Cymatium (Septa) janetae3 Squires 1983 triton shell
 Sorbeoconcha - Cypraeidae
Bernaya kaylinae n. sp.2 Groves and Squires 2023 cowry
Subepona leahae n. sp.2 Groves and Squires 2023 cowry
 Sorbeoconcha - Xenophoridae
Xenophora stocki3 Dickerson 1916 carrier shell
 Sorbeoconcha - Naticidae
Polinices (Euspira) nuciformis3 Gabb 1864 moon snail
 Heterostropha - Architectonicidae
 Opisthobranchia - Philinidae
Megistostoma gabbianum3 Stoliczka 1868 snail
 Opisthobranchia - Retusidae
Cylichnina tantilla3 Anderson and Hanna 1925 snail
 Tectibranchia - Akeridae
Akera maga4 Vokes 1939 snail
Bivalvia
 Arcida - Glycymerididae
 Pectinida - Pectinoidae
Spondylus carlosensis3 Anderson 1905 scallop
 Ostreida - Malleidae
 Ostreida - Pinnidae
Pinna llajasensis n. sp. Squires 1983 oyster
 Ostreida - Gryphaeidae
"Pycnodonte (Phygraea) cf. pacifica" = Phygraea pacifica4
"Pycnodonte (Phygraea) cf. pacifica" = Phygraea pacifica4 Squires and Demetrion 1990 oyster
 Ostreida - Ostreidae
"Ostrea idriaensis" = Acutostrea idriaensis3
"Ostrea idriaensis" = Acutostrea idriaensis3 Gabb 1869 oyster
 Mytilida - Mytilidae
Brachidontes (Brachidontes) cowlitzensis3 Weaver and Palmer 1922 mussel
 Lucinida - Lucinidae
"Claibornites diegoensis" = Claibornites (Claibornites) diegoensis3
"Claibornites diegoensis" = Claibornites (Claibornites) diegoensis3 Dickerson 1916 clam
 Pholadida - Teredinidae
? Teredo sp.3 Linnaeus 1758 clam
 Cardiida - Veneridae
"Pitar uvasana" = Pitar uvasana4, "Pitar (Calpitaria) uvasanus" = Pitar uvasana3, Marcia (Mercimonia) bunkeri3
"Pitar uvasana" = Pitar uvasana4 Conrad 1855 venus clam
Subspecies: Pitar uvasana coquillensis
"Pitar (Calpitaria) uvasanus" = Pitar uvasana3 Conrad 1855 venus clam
Marcia (Mercimonia) bunkeri3 Hanna 1927 venus clam
 Cardiida - Cardiidae
"Nemocardium linteum" = Nemocardium (Nemocardium) linteum3, "Acanthocardia (Agnocardia) sorrentoensis" = Agnocardia sorrentoensis4, "Acanthocardia (Schedocardia) brewerii" = Schedocardia brewerii3
"Nemocardium linteum" = Nemocardium (Nemocardium) linteum3 Conrad 1855 cockle
"Acanthocardia (Agnocardia) sorrentoensis" = Agnocardia sorrentoensis4 Hanna 1927 cockle
"Acanthocardia (Schedocardia) brewerii" = Schedocardia brewerii3 Gabb 1864 cockle
 Cardiida - Psammobiidae
"Gari cf. eoundulata" = Gari (Gobraeus) eoundulata3, "Gari texta" = Gari (Gobraeus) texta4
"Gari cf. eoundulata" = Gari (Gobraeus) eoundulata3 Vokes 1939 clam
"Gari texta" = Gari (Gobraeus) texta4 Gabb 1864 clam
 Solenida - Solenidae
"Solena (Eosolen) navacularis" = Solena (Eosolen) novacularis3
"Solena (Eosolen) navacularis" = Solena (Eosolen) novacularis3 Anderson and Hanna 1925 clam
 Carditida - Carditidae
Venericardia (Pacificor) hornii3 Gabb 1864 clam
as Venericardia (Pacificor) hornii calafia
 Carditida - Crassatellidae
Crassatella uvasana3 Conrad 1855 clam
Scaphopoda
 Dentaliida - Dentaliidae
Dentalium stentor3 Anderson and Hanna 1925 tusk shell
Rhynchonellata
 Terebratulida - Terebrataliidae
Terebratalia aff. batequia4 Sandy et al. 1995
Polychaeta
 Sabellida - Serpulidae
Echinoidea
 Spatangoida - Brissidae
Eupatagus stevensi n. sp.1 Grant and Hertlein 1938 heart urchin
 Spatangoida - Schizasteridae
Schizaster diabloensis3 Kew 1920 heart urchin
Chondrichthyes
 Lamniformes - Odontaspididae
Odontaspis sp.3 Agassiz 1838 sand tiger shark
 Lamniformes - Mitsukurinidae
Striatolamia macrota4 Agassiz 1838 goblin shark