Alisitos Fm. (UCB A-8325): Late/Upper Aptian, Mexico
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Bivalvia
- Ostreida
- Gryphaeidae
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Gryphaea wardi
Hill and Vaughan 1898
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a category | |||||||||
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Exogyra cf. quitmanensis
(Cragin 1893)
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c category | |||||||||
| originally entered as "Exogyra cf. quitmanensis" | ||||||||||
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Exogyra yabei
Nagao 1934
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r category | |||||||||
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Bivalvia
- Pectinida
- Limidae
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Lima wacoensis
Roemer 1849
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f category | |||||||||
| see common names | ||||||||||
Geography
| Country: | Mexico | State/province: | Baja California |
| Coordinates: | 31.5° North, 116.7° West (view map) | ||
| Paleocoordinates: | 29.9° North, 68.2° West | ||
| Geographic resolution: | small collection |
Time
| Period: | Cretaceous | Epoch: | Early/Lower Cretaceous |
| 10 m.y. bin: | Cretaceous 2-3 | ||
| *International age/stage: | Aptian - Albian | ||
| Key time interval: | Late/Upper Aptian | ||
| Age range of interval: | 119.50000 - 113.00000 m.y. ago | ||
| * legacy (obsolete) database fields | |||
Stratigraphy
Lithology and environment
| Primary lithology: | conglomerate |
| Environment: | shallow subtidal indet. |
| Geology comments: "Dark pyroclastics consisting of rounded andesitic cobbles in matrix of volcanic breccia, 6-8 m strat below A-8323." | |
Taphonomy
| Modes of preservation: | body |
Collection methods and comments
| Collection methods: | mechanical,field collection |
| Reason for describing collection: | taxonomic analysis |
| Taxonomic list comments: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." | |
Metadata
| Database number: | 1884 | ||
| Authorizer: | J. Alroy | Enterer: | M. Sommers |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 1999-06-10 16:46:55 | Last modified: | 2006-09-08 17:34:45 |
| Access level: | the public | Released: | 1999-06-10 16:46:55 |
| Creative Commons license: | CC BY |
Reference information
Primary reference:
| 51. | 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] |
Secondary references:
| 18606 | R. L. Squires and L. R. Saul. 2004. Uncommon Cretaceous naticiform gastropods from the Pacific Slope of North America. The Velliger 47(1-2):21-37 [A. Miller/A. Hendy] |