Monterey Formation : Vertebrates

Though precise correlations between terrestrial and marine deposits have not been made yet, the deposits of the Monterey Formation correlate with the Late-Middle and Upper Miocene, and with the Barstovian, Clarendonian, and early Hemphillian North American Land Mammal Ages (NALMA).

In addition to the representative fossils shown below, workers have found fossils of desmostylians, dugongs, pinnipeds, and baleen whales.

Aves (birds)

Morus cf. vagabundus - a gannet

This is the right humerus (upper arm) of a large bird, identified as a species of gannet. Bird fossils are actually more common in aquatic deposits than terrestrial ones. This is most likely a reflection of the delicacy of the hollow bones, rather than a preference of extinct birds for swimming.

Cetacea (whales and porpoises)

Loxolithax stocktoni - a toothed cetacean.

A toothed cetacean known only from the Middle Miocene of North America. This specimen was found near Los Angeles in the Valmonte Diatomite; it is a UCMP type specimen, and includes the skull and portions of the skeleton.

Phocoenid - a porpoise.

An unidentified porpoise skull from Duxbury Reef in Marin County. Part of the Al Trombla collection now housed at UCMP.

Phocoenid - a porpoise.

Another view of the same skull shown above, with a vertebra from the collection. The collection includes several dozen bones from cetaceans.

Chondrichthyes (sharks)

Isurus - teeth from two species.

This genus has existed since the Cretaceous, and is considered closely related to the massive Carcharodon. Fossils have been found almost globally. The curved teeth are I. planus, the straight ones I. hastalis.


Lampanyctus sp. - a holostean fish.

This genus has been found in the Miocene of Europe, North America, and New Zealand, as well as from the Pliocene of Europe. Three Lampanyctus are circled on the rock at left. The fish at right is unidentified.

Ganolytes sp. - a Miocene holostean.

Ganolytes is known only from North American Miocene deposits. This particular fossil preserves the skeleton...

Ganolytes sp. - scales.

...while this fossil preserves scales of the genus shown above.