42 VERTEBRATA OF TDE TERTIARY. 



the Pampean formation of South America; such are twelve genera, of 

 which six are extinct genera, and four are pecuHar to that formation and 

 fauna. The genera found in the Pampean are marked (p), and those of 

 the Subapennine (s). In the list from the Oregon localities, Mylodon and 

 Auchenia were observed to be the only distinctively Pampean genera. As 

 a conclusion of the comparison of the American Equus beds in general 

 with those of Europe, it may be stated that the number of identical gen- 

 era is so large, that we may not hesitate to parallelize them as stratigraph- 

 ically the same. On the other hand, the agreement with the South Ameri- 

 can Pampean formation is so marked in some respects as to induce us to 

 believe that the distinction is geographic rather than stratigraphic. Believ- 

 ing that the Pampean formation contains too large a percentage of extinct 

 genera to be properly regarded, as it has been, as Post-Pliocene or Quater- 

 nary, its characters, both essentially and as a result of the comparison 

 which I have been able to make, refer it properly to the Pliocene. It 

 appears, then, that the term Pliocene or Subapennine is appHcable to the 

 horizon of this fauna in Europe and North and South America. 



RESUME OF COMPARISONS. 



The conclusions to be derived from the facts enumerated in the pre- 

 ceding pages are as follows: 



I. Portions of all the faunae of all the primary divisions of geologic 

 time have been recognized on both the European and North American con- 

 tinents. 



II. Parallels requiring general identification of principal divisions of 

 these faunaj may be detected. These are: the Coal Measures; the Per- 

 mian; the Laramie; the Maestri chtian; the Eocene; the Miocene. 



III. Exact identifications of restricted divisions maj' be made in a few 

 instances only; such are the Turonian and the Niobrara; the Snessonian 

 and the Wasatch; the Equus beds and the Pliocene. 



It is not impossible that some of the relations mentioned in II will be 

 by the accession of further information, referrible to the list of exact com- 

 parisons in III. In iill cases of identification it will be necessary to employ 

 the name first proposed with definition for the horizon, other names taking 



