Middle Miocene Pholadid Borings at the Base of the Isidro Formation, Arroyo Mezquital, Baja California Sur, Mexico
Abxxnddinl sediment-infilled clavate (club-shaped) borings, assignable to ichnogenus Gastrochaenolites, are reported from the base of the Miocene Isidro Formation, Baja California Sur, Mexico. The infilled borings were made by pho- ladid bivalves that lived in a nearshore-marine environment on a semi-consoli- dated substrate ("'Glossifungites'' ichnofacies). Some borings are connected by horizontal burrows that are sculptured (Spongeliomorpha) or unsculptured (Tha- lassinoides). The localized pholadid community was short lived and abruptly terminated by an influx of sediment.
Demetrion, Robert A. and Squires, Richard L.
"Middle Miocene Pholadid Borings at the Base of the Isidro Formation, Arroyo Mezquital, Baja California Sur, Mexico,"
Bulletin of the Southern California Academy of Sciences:
Available at: http://scholar.oxy.edu/scas/vol93/iss2/1