USGS 13503 - Tamaulipas, Mexico (Jackson Formation) (Eocene of Mexico)

Also known as USGS 13503

Where: Tamaulipas, Mexico (26.3° N, 98.8° W: paleocoordinates 27.4° N, 91.5° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Middle Member (Jackson Formation), Late/Upper Eocene (37.2 - 33.9 Ma)

• The Jackson Group of Mexico and the Gulf Coastal Plain is here considered as a formation. The Jackson Formation can be subdivided into three members, the basal "Roma Sandstone" and middle and upper members (no lithostratigraphic name). No comments are made on relations to Gulf Coastal Plain units, but the enterer considers that the Jackson Formation of this collection is equivalent in age (late Eocene) as the Jackson Group (Gulf Coastal Plain). Collection is from a 10-15 ft lens of fine-grained sandstone or limestone, overlain and underlain by gypsiferous clays and sandy clays.

• bed-level stratigraphic resolution

Environment/lithology: coastal; fine-grained, calcareous sandstone and fine-grained, sandy limestone

• Siliciclastic. Enterer considers the fauna to be an inner shelf assemblage. No paleoenvironmental data reported.
• Fine-grained calcareous sandstone or sandy limestone.

Size class: macrofossils

Reposited in the USNM

Collection methods: quarrying,

• Collections reposited in USGS and USNM collections.

Primary reference: J. Gardner. 1945. Mollusca of the Tertiary formations of Northeastern Mexico. Geological Society of American Memoir 11 [M. Kosnik/M. Kosnik/M. Kosnik]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 43056: authorized by Austin Hendy, entered by Austin Hendy on 09.08.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for mollusca.
Gastropoda
 Opisthobranchia - Cylichnidae
Acteocina melinoides barrel-bubble
 Opisthobranchia - Retusidae
Bivalvia
 Ostreida - Pteriidae
Pteria limula Conrad 1833 pearl oyster
Scaphopoda
 Gadilida - Gadilidae
"Cadulus (Polyschides) ? jacksonensis" = Cadulus jacksonensis
"Cadulus (Polyschides) ? jacksonensis" = Cadulus jacksonensis Harris and Palmer 1947 tusk shell
 Dentaliida - Dentaliidae