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Volume XIII

REVIOUS to the discovery of the Pleistocene beds at Rancho La Brea only three localities on the Pacific Coast of North America had yielded any information regarding fossil birds. Of these three localities two were rep resented by but a single bone each.

Since the exploration of the Rancho La Brea deposits brought out the importance of the subject, avian fossils from four other localities have been studied, making thus a total of eight different horizons which now contribute to our knowledge of the birds of previous geological time.

In 1894 Cope (1) described the new pelecanid form Cyphornis magnus from a single bone taken in the Eocene of Vancouver. This specimen probably represents the largest known bird of flight.

Lucas (2) in 1901 described from the upper Miocene of Los Angeles the flightless diver Mancalla californicus, represented by the major part of a humerus.

All the other known specimens are from the Pleistocene of Oregon and California. Fossil Lake in Oregon is a lacustrine deposit. The Rodeo formation on San Francisco Bay is littoral marine, three localities in middle and northern California furnish cavern deposits, while the great mass of material from Rancho La Brea represents animals entrapped in soft asphalt.

The Fossil Lake beds yielded to Cope (3), to Shufeldt (4) and to Miller (5) fifty-two species of birds, the large majority of which were recorded by Shufeldt. Of these species 67.3 per cent are still living. All except one belong to recent genera.

The results thus far published on the Rancho La Brea collections by Miller