Alisitos Fm. (UCB A-8326): Aptian, Mexico
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Echinoidea
- Holectypoida
- Holectypidae
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Holectypus planatus
Roemer 1852
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r category | |||||||||
| synonym of Coenholectypus neocomiensis | ||||||||||
| (Coenholectypus) | ||||||||||
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Bivalvia
- Pectinida
- Neitheidae
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Neithea aff. wrighti
(Shumard 1860)
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r category | |||||||||
| originally entered as "Neithea aff. wrighti" | ||||||||||
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Bivalvia
- Pectinida
- Plicatulidae
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Plicatula sp.
Lamarck 1801
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a category | |||||||||
| see common names | ||||||||||
Geography
| Country: | Mexico | State/province: | Baja California |
| Coordinates: | 31.5° North, 116.7° West (view map) | ||
| Paleocoordinates: | 30.0° North, 67.3° West | ||
| Geographic resolution: | small collection |
Time
| Period: | Cretaceous | Epoch: | Early/Lower Cretaceous |
| Stage: | Aptian | 10 m.y. bin: | Cretaceous 3 |
| *International age/stage: | Aptian - Albian | ||
| Key time interval: | Aptian | ||
| Age range of interval: | 121.40000 - 113.00000 m.y. ago | ||
| * legacy (obsolete) database fields | |||
Stratigraphy
Lithology and environment
| Primary lithology: | gray sandstone |
| Secondary lithology: | conglomerate |
| Environment: | shallow subtidal indet. |
| Geology comments: "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." | |
Taphonomy
| Modes of preservation: | body |
Collection methods and comments
| Collection methods: | mechanical,field collection |
| Reason for describing collection: | taxonomic analysis |
| Taxonomic list comments: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." | |
Metadata
| Database number: | 1885 | ||
| Authorizer: | J. Alroy | Enterer: | M. Sommers |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 1999-06-10 16:51:46 | Last modified: | 2006-09-08 17:40:04 |
| Access level: | the public | Released: | 1999-06-10 16:51:46 |
| 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] |