PBDB Collection

Alisitos Fm. (UCB A-8322) (Cretaceous of Mexico)

Where: Baja California, Mexico (31.5° N, 116.7° W: paleocoordinates 29.9° N, 68.2° W)

• small collection-level geographic resolution

When: upper 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 siltstone

• "Brown weathered tuffaceous siltstone ~1 m wide immediately overlying A-8323 on south 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 1882: authorized by John Alroy, entered by Mike Sommers on 10.06.1999

Creative Commons license: CC BY (attribution)

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

Malacostraca
Decapoda -	Decapoda indet. Decapoda indet. Latreille 1802 decapod crab fragments
Gastropoda
Heterostropha - Nerinellidae	"Aptyxiella parallela" = Nerinella parallela "Aptyxiella parallela" = Nerinella parallela Anderson and Hanna 1935 snail (Endiatrachelus)
Bivalvia
Ostreida - Gryphaeidae	Gryphaea mucronata Gryphaea mucronata Gabb 1869 oyster
Polychaeta
Sabellida - Serpulidae	Serpula aff. socialis Serpula aff. socialis originally entered as "Serpula aff. socialis"