Sierra del Alamo, Unit 3 (Jurassic of Mexico)

Where: Sonora, Mexico (30.6° N, 112.6° W: paleocoordinates 15.4° N, 55.8° W)

• coordinate estimated from map

When: Canadensis ammonoid zone, Antimonio Formation, Hettangian (201.3 - 199.3 Ma)

• ~8 m from the basis of the section

Environment/lithology: marine; siliciclastic sediments

Size class: macrofossils

Preservation: cast

Primary reference: D. Taylor, J. Guex, and M. Rakus. 2001. Hettangian and Sinemurian ammonoid zonation for the western Cordillera of North America. Bulletin de la Société Vaudoise des Sciences Naturelles 87(4):381-421 [J. Pálfy/E. Kovács]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 201178: authorized by József Pálfy, entered by Emma Kovács on 02.05.2019

Creative Commons license: CC BY (attribution)

Taxonomic list

Cephalopoda
 Ammonitida - Psiloceratidae
 Ammonitida - Arietitidae
"Paracaloceras sp." = Vermiceras (Paracaloceras)
"Paracaloceras sp." = Vermiceras (Paracaloceras) Spath 1923 ammonite