Alisitos Fm. (UCB A-8332) (Cretaceous of Mexico)

Where: Baja California, Mexico (31.5° N, 116.7° W)

• small collection-level geographic resolution

When: lower Member (Alisitos Formation), Late/Upper Aptian (122.5 - 113.0 Ma)

• Age: "Aptian to middle Albian." Squires and Saul (2004) confirming and following Allison (1974) place this collection in the Late Aptian.

• bed-level stratigraphic resolution

Environment/lithology: shallow subtidal; volcaniclastic, brown, gray, green siltstone and shale

• "Gray-green to brown interbedded tuffaceous siltstone and silty shale exposed to about 10 m strat above base of mid cret section exposed along S side of Punta China."
• "Gray-green to brown interbedded tuffaceous siltstone and silty shale exposed to about 10 m strat above base of mid cret section exposed along S side of Punta China."

Collection methods: mechanical,

Primary reference: E. C. Allison. 1955. Middle Cretaceous gastropoda from Punta China, Baja California, Mexico. Journal of Paleontology 29(3):400-432 [J. Alroy/M. Sommers/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 1891: authorized by John Alroy, entered by Mike Sommers on 10.06.1999

Creative Commons license: CC0 (CC0)

Taxonomic list

• Abundances: A = 20+, C = 6-20, F = 3-5, R = 1-2. "A spectacular feature of the middle Albian deposits at Punta China is the fine preservation exhibited by many of the fossils. Despite the coarseness of some of the volcanic breccias, fragile tests of Forams, echinoids, and small molluscs are almost perfectly preserved. Pelecypods almost always occur with both valves intact. Some gastropods retain original pigmentation."
Show authors, comments, and common names
Nodosariata
 Vaginulinida - Vaginulinidae
Saracenaria bononiensis striatolipa
Gastropoda
 Heterostropha - Tubiferidae
Pseudonerinea stirtoni n. sp.
Pseudonerinea stirtoni n. sp. Allison 1955 snail
 Cerithioidea - Turritellidae
Turritella aff. seriatimgranulata
Turritella aff. seriatimgranulata Roemer 1849 turret shell
(Haustator) - originally entered as "Turritella aff. seriatimgranulata"
Stenolaemata
 Tubuliporata - Heteroporidae
Reptomulticava sp.
Ostracoda
 Platycopida - Cytherellidae
Cytherella sp.
Cytherella sp. Jones 1849 ostracod
 Podocopida - Candonidae
Paracypris sp.
Paracypris sp. Sars 1866 ostracod
 Podocopida - Loxoconchidae
? Loxoconcha sp.
? Loxoconcha sp. Sars 1866 ostracod
originally entered as "? Loxoconcha sp."
 Podocopida - Cytherideidae
? Haplocytheridea sp.
? Haplocytheridea sp. ostracod
originally entered as "? Haplocytheridea sp."
 Podocopida - Cytheruridae
Cytheropteron ? trinitiensis
Cytheropteron ? trinitiensis ostracod
originally entered as "Cytheropteron ? trinitiensis"
 Podocopida - Bairdiidae
Bairdia sp.
Bairdia sp. M'Coy 1844 ostracod
Foraminifera
 Lituolida - Lituolidae
Textularia ? chapmani
Textularia ? chapmani
"Textularia chapmani Lalicker (?) Nubecularia depressa Chapman" - originally entered as "Textularia ? chapmani"
Globothalamea
 Rotaliida - Discorbidae
Valvulineria sp., ? Discorbis sp.
Valvulineria sp. Cushman 1926
? Discorbis sp. Lamarck 1804
originally entered as "? Discorbis sp."
 Rotaliida - Cibicididae
? Cibicides sp.
? Cibicides sp. Monfort 1808
originally entered as "? Cibicides sp."
Foraminifera
 Rotaliacea - Rotaliidae
Hoeglundina carpenteri
Hoeglundina carpenteri
originally entered as "Hoglundina carpenteri"
Nodosariata
 Vaginulinida - Lagenidae
? Darbyella sp.
? Darbyella sp. Howe and Wallace 1932
 Vaginulinida - Vaginulinidae
Vaginulinopsis sp., Saracenaria sp., Lenticulina cf. subalta, Lenticulina sp.
Saracenaria sp. Defrance 1824
Lenticulina cf. subalta
originally entered as "Lenticulina cf. subalta"
Lenticulina sp. Lamarck 1804
 Nodosariida - Nodosariidae
Astacolus nuda, Dentalina sp., Tristix acutangulum, Nodosaria orthopleura, Nodosaria sceptrum, Nodosaria sp., Vaginulina debilis, Vaginulina kochii
Astacolus nuda
originally entered as "Astracolus nuda"
Dentalina sp. d'Orbigny 1826
Nodosaria sp. Lamarck 1812
 Polymorphinida - Polymorphinidae
Guttulina exepolita, Globulina exserta
 Robertinida - Ceratobuliminidae
Ceratobulimina woodi
 Robertinida - Epistominidae
? Epistomina cretosa
? Epistomina cretosa
originally entered as "? Epistomina cretosa"
Foraminifera
 Ammodiscoidea - Ammodiscidae
Ammodiscus incertus
Ammodiscus incertus d'Orbigny 1839