Station 49 Alazan-Moyutla Road, Alazan (Oligocene of Mexico)

Where: Mexico (23.7° N, 102.8° W: paleocoordinates 24.6° N, 96.8° W)

• coordinate based on political unit

• local area-level geographic resolution

When: Palma Real Formation (Alazan Group), Early/Lower Oligocene (33.9 - 28.4 Ma)

• Underlain by shales and overlain by yellowish clay. Thickness of 70-80 feet are exposed. Lowest part of the formation. Woodring (1966): this is the Palma Real Formation.

• formation-level stratigraphic resolution

Environment/lithology: marine; lithified, blue shale

• Shales end abruptly as though faulted.
• Fossiliferous beds are eroded in places into potholes 8-10m in diameter. In some places fossiliferous beds seem broken and piled together in every direction.

Size class: macrofossils

Primary reference: C. W. Cooke. 1928. New Vicksburg (Oligocene) Mollusks From Mexico. Proceedings from the United States National Museum 73(10):1-11 [A. Miller/K. Bulinski]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 61206: authorized by Arnold Miller, entered by Kate Bulinski on 30.05.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• the species named here include only a small part of the total number of mollusks in the Alaxan clay.
Bivalvia
 Pectinida - Pectinoidae
Amussium alazanum Cooke 1928 scallop
new species
Gastropoda
 Architaenioglossa - Ampullinidae
Ampullina vaughani Cooke 1928 snail
new species
 Neogastropoda - Olividae
Ancilla (Ancillina) alazana Cooke 1928 olive snail
new species
 Neogastropoda - Turridae
Gemmula mexa Cooke 1928 turrid
new species
Gemmula alazana Cooke 1928 turrid
new species
 Neogastropoda - Borsoniidae
Borsonia aguilae Cooke 1928 snail
new species
 Neogastropoda - Conidae
Glyptotoma rhombica Cooke 1928 cone shell
new species
 Vanikoroidea - Eulimidae
Protonema bartschi Cooke 1928 snail
new species
 Naticoidea - Naticidae
"Polynices (Lunatia) lacrimans" = Lunatia, Natica alazana, "Polynices (Euspira) byramensis" = Polinices
"Polynices (Lunatia) lacrimans" = Lunatia moon snail
new species
Natica alazana Cooke 1928 moon snail
new species
"Polynices (Euspira) byramensis" = Polinices moon snail
new species
Scaphopoda
 Dentaliida - Dentaliidae
Dentalium (Dentalium) alazanum Cooke 1928 tusk shell
new species
Dentalium ovale Cooke 1928 tusk shell
new species