580 E. C. CASE 



the North Dwina, carries a fauna typical of the South African region. 



As is well known, the genus Naosaurus occurs in the Permian of 

 Bohemia. 



The resemblance between the Poliosauridae and the Proterosau- 

 ridae is in just such primitive and generalized characters as would 

 persist from one formation to another. 



The evidence for the Permian character of the beds rests then on 

 the presence of a single genus, Naosaurus, common to the Permian of 

 North America and Europe and on the community of many very 

 primitive characters and numerous more speciaHzed ones, which, 

 however, reach either down into the Carboniferous below or up into 

 the Triassic above. 



CONCLUSION 



1. The evidence from vertebrates is not sufficient to demonstrate 

 the Permian Age of the beds in Illinois and Texas, they may reach 

 down into the Carboniferous or they may extend upward into the 

 Triassic. 



2. There is no unlikelihood that reptihan life began in the Carbo- 

 niferous. The evidence is rather affirmative than otherwise. 



It is becoming more and more evident from the vertebrate paleon- 

 tology that the Red Beds of North America and their eastern equiva- 

 lents represent an enormous interval of emergence which may well 

 have begun while Carboniferous (Pennsylvanian) forms still lingered 

 in the waters and have continued until Triassic types were well 

 established. 



