Alisitos Fm. (UCB A-8326) (Cretaceous of Mexico)

Where: Baja California, Mexico (31.5° N, 116.7° W: paleocoordinates 30.0° N, 67.3° W)

• small collection-level geographic resolution

When: lower Member (Alisitos Formation), Aptian (125.0 - 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; gray sandstone and conglomerate

• "Several thin beds of dark gray tuffaceous sandstone interbedded with coarse pebbly pyroclastics. Exposed about half way b/w tip of Punta China and base of point on S side, 10-50 m below A-8323."

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 1885: authorized by John Alroy, entered by Mike Sommers on 10.06.1999

Creative Commons license: CC BY (attribution)

Taxonomic list

• FAUNA INCLUDES WORM TUBES. 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
Echinoidea
 Holectypoida - Holectypidae
"Holectypus planatus" = Coenholectypus neocomiensis
"Holectypus planatus" = Coenholectypus neocomiensis Gras 1848 sea urchin
(Coenholectypus)
Bivalvia
 Pectinida - Plicatulidae
Plicatula sp.
Plicatula sp. Lamarck 1801 scallop
 Pectinida - Neitheoidae
Neithea aff. wrighti
Neithea aff. wrighti Shumard 1860 scallop
originally entered as "Neithea aff. wrighti"