1912] Miller: Pacific Coast Avian Palaeontology 



111 



shows a greater degree of robustness, both absolute and relative. 

 The humerus-is slightly longer and stouter, but whether the wing 

 expanse is increased to a degree commensurate with the in- 

 creased body weight is questionable. We seem, then, to be deal- 

 ing with a vulture that was of a heavier body and shorter 

 limb than the persistent Catharista urubu. The difference be- 

 comes more significant when it is noted that the character separ- 

 ating the extinct from the persistent species of Catharista is 

 identical with one of those separating the more restricted Cathar- 

 ista urubu from the wider ranging Cathartes aura. It should 

 also be noted that the extinct form Catharista shastensis from 

 the caves is separable from the Rancho La Brea species, C. occi- 

 dentalis, by a greater robustness of the tarsometatarsus and 

 by a greater body size as indicated by its stouter coracoid. The 

 cave form, the asphalt form, and the Recent form of Catharista 

 thus fall with the Recent Cathartes into a series of progressively 

 lighter-bodied and possibly more strongly flying vultures, which 

 display, in the cases of the last three at least, a progressively 

 greater ability to cope with their environment. 



That the cavern and the asphalt deposits are not of the same 

 age is evidenced by the occurrence therein of distinct but closely 

 related species of cathartids belonging to two genera, i.e. Gym- 

 nogyps and Catharista. The localities are separated by approx- 

 imately seven degrees of latitude and a difference in elevation 

 of fourteen hundred feet. Both lie at present in approximately 

 the same faunal zone. Species possessed of the excellent volant 

 powers shown by the large vultures when present in the con- 

 siderable numbers indicated by their remains in the two deposits 

 would scarcely feel the restrictions of such slight barriers as 

 could have existed at that time. 



The existing species of Gymnogyps, before its numbers were 

 depleted by the influence of man, ranged from Lower California 

 to British Columbia and from sea-level to the summits of the 

 Coast Range, while the existing Cathartes is almost ubiquitous. 

 Furthermore our knowledge of the Recent vultures as a group 

 would lead us to discard as incongruous the conception of a 

 vulture so strictly boreal as to come southward in considerable 

 numbers as far as the Shasta region and not reach the more 



