1912] Miller: Pacific Coast Avian Palaeontology 87 



Other members of the group range as follows: The Andean 

 condor (Sarcorhamphus) occurs along the Cordillera from 

 equatorial Peru to the extremity of Patagonia and from sea- 

 level to the highest summits of the Andes; Catharista urubu 

 inhabits the whole of tropical America, southward to Argentina 

 and northward as a straggler to the Canadian border ; the two 

 remaining genera, Gyparclms and Gymnogyps, occupy succes- 

 sively more circumscribed areas. Not, however, till the latter 

 was so nearly exterminated by human agency, was either form 

 of restricted range. Gymnogyps is confined entirely to the 

 Nearctic realm, Sarcorhampkus is entirely Neogaeic, but the three 

 remaining forms are distributed without regard to realm and 

 all are independent of the generally recognized life-zones. That 

 a group thus distributed, many of whose members are so in- 

 dependent of climatic and of minor geographic barriers, should 

 be limited to the western hemisphere seems indeed strange. 



The influence of a virile and aggressive species is not infre- 

 quently effective as a barrier to the distribution of a less active 

 one and it may be urged that the slightly more rapacious vul- 

 turines of the Old World have served as a check upon any ten- 

 dency of the cathartids to diffuse into Eurasia. Such a view is 

 controverted by the fact that the latter birds prove themselves 

 perfectly able to maintain their existence in competition with 

 the polyborine scavengers which, in a .way, represent the Old 

 World vultures in their habits. 



With the geographical limitations of the group before us, the 

 question of ancestry and the geological record assume a very 

 important aspect. 



Concerning the antiquity of the group there is unfortunately 

 but little known. Previous to the opening up of the Rancho La 

 Brea deposits in California, fossil cathartids of unquestionable 

 identity were unknown to North America. Cope's Palaeoborus 

 umbrosus^ from the Pliocene of New Mexico, which he orig- 

 inally placed in the genus Cathartes, he later transfers to the 

 genus Vultur. The new genus Palaeoborus was established by 

 Coues for its reception since " .... the description and figures 



21 Cope, E. D., U. S. G. Surv. W. of 100th MericL, vol. 4, pt. 2, p. 287, 

 1876. 



