USGS 13958 - Tamaulipas, Mexico (upper Laredo Formation): Middle Eocene, Mexico
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Bivalvia
- Cardiida
- Anatinellidae
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Pteropsis lapidosa
(Conrad 1846)
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unclassified
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Gastropoda
- Neogastropoda
- Buccinidae
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Gastropoda
- Ampullinidae
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| see common names | |||||||
Geography
| Country: | Mexico | State/province: | Tamaulipas |
| Coordinates: | 26.4° North, 99.2° West (view map) | ||
| Paleocoordinates: | 32.2° North, 82.0° West (Wright 2013) | ||
| Basis of coordinate: | based on nearby landmark | ||
| Geographic resolution: | outcrop |
Time
| Period: | Paleogene | Epoch: | Eocene |
| 10 m.y. bin: | Cenozoic 2-3 | ||
| Key time interval: | Middle Eocene | ||
| Age range of interval: | 48.07 - 37.71 m.y. ago |
Stratigraphy
| Geological group: | Claiborne | Formation: | Laredo | Member: | Upper |
| Local section: | Ejidos | ||||
| Regional section: | Tamaulipas | ||||
| Stratigraphic resolution: | bed | ||||
| Stratigraphy comments: The succession of Claiborne Group in northeastern Mexico is exceptionally thick and well correlated to those units of the same name in Texas on the basis of faunal similarity. The name Laredo Formation replaces the "Cook Mountain Formation" in the Rio Grande embayment. The Laredo Formation is divided into three members: lower, middle and upper. The collection is from the upper member, which is overlain by the Yegua Formation. | |||||
Lithology and environment
| Primary lithology: | glauconitic,gray calcareous sandstone |
| Secondary lithology: | gray,white calcareous "limestone" |
| Includes fossils? | Y |
| Includes fossils? | Y |
| Lithology description: Gray, calcareous concretionary sandstone or chalky limestone weathering grayish white. | |
| Environment: | marine indet. |
| Geology comments: Siliciclastic. No paleoenvironmental data reported. | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection methods: | selective quarrying,field collection |
| Reason for describing collection: | taxonomic analysis |
| Museum repositories: | USNM |
| Collection method comments: Collections reposited in USGS and USNM collections. | |
| Taxonomic list comments:Exhaustive for mollusca. | |
Metadata
| Also known as: | USGS 13958 | ||
| Database number: | 42997 | ||
| Authorizer: | A. Hendy | Enterer: | A. Hendy |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 2004-08-07 21:18:55 | Last modified: | 2025-02-22 15:12:02 |
| Access level: | the public | Released: | 2004-08-07 21:18:55 |
| Creative Commons license: | CC0 | ||
Reference information
Primary reference:
| 7474. | J. Gardner. 1945. Mollusca of the Tertiary formations of Northeastern Mexico. Geological Society of American Memoir 11 [M. Kosnik/M. Kosnik/M. Kosnik] |