Potrerillos Formation, Mexico

The Potrerillos Formation is a geologic formation in Mexico. It preserves fossils dating back to the Early Paleocene period.

Description
The Potrerillos Formation was subdivided into five members by McBride (1974), with the second highest, the Upper Mudstone Member. Foraminifera in the lower members indicate a Maastrichtian age, while fossils in the upper members indicate a Paleocene age. Fossil remains are abundant and include transported remains of corals, gastropods, bivalves, shark teeth, and bone fragments.

Fossil content
The following fossils have been reported from the formation:
 * Bivalves
 * Venericardia (Baluchicardia) francescae
 * Venericardia sp.
 * Cephalopods
 * Cimomia haltomi
 * Elimia cf. trigemmata