ammonites
south side of the Quebrada La Pola, Eastern flank of Sierra de Villicum (Ordovician of Argentina)

Where: San Juan, Argentina (31.3° S, 68.5° W: paleocoordinates 33.8° S, 134.5° W)

• outcrop-level geographic resolution

When: Climacograptus bicornis zone, Caradocian (460.9 - 449.5 Ma)

Environment/lithology: marine; pebbly conglomerate

• "Fossils described in this paper come from pebbles of the upper part of the lower diamictite member of the Don Braulio Fm. Clasts consist of sandstones, limestones, quatzites, quartz, and volcanic rocks, some of them being striated and facetted. This succession is interpretted as glacimarine in origin and is synchronous with the Late Ashgillian world-wide glaciation event."
• Fossils described come from the upper part of the lower member of the Don Braulio Fm. The lower member (8-12 m) is composed of pebbly mudstones capped by channelized conglomerates. This succession is interpretted as a diamictite. Studied fossils have come from coquinites in the diamictite.

Size classes: macrofossils, mesofossils

Preservation: cast

Collection methods: chemical,

• "In order to enhance exposure of teeth and muscle scars, shells were dissolved with hydrochloric acid (10%).

Primary reference: T. M. Sanchez. 1999. New late Ordovician (Early Caradoc)Bivalves from the Sierra De Villicum (Argentine Precordillera). Journal of Paleontology 73(1):66-76 [A. Miller/R. Krause/R. Krause] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 13513: authorized by Arnold Miller, entered by Rich Krause on 10.04.2002, edited by Pete Wagner