VERTEBRATE FOSSILS ^11 



it is characteristic of the most primitive type of reptiles and persists 

 even to the present {S phenodon) . 



The humerus mentioned by Cope was that of an amphibian or 

 one of the Diadectidae and the French form was probably Euchiro- 

 saurus. 



3. With regard to the amphibians the evidence is scarcely better. 

 Cope emphasizes the rhachitomous character of the vertebrae and 

 compares the condition of Eryops and Trimerorhachis with similar 

 rhachitomous forms from the French Permian, the genus is not men- 

 tioned but it is evident that he had Euchirosaurus in mind. This 

 character of the vertebrae comes nearer to being a determinant char- 

 acter than anything mentioned by Cope, but it is open to question 

 because the same form of vertebrae occurs in the Carboniferous 

 amphibian, Dendrerpeton. 



4. The fishes mentioned by Cope have the distribution shown 

 below : 



Sagenodus — Carboniferous and Lower Permian. 



Janassa — Carboniferous to Triassic. 



Strigilina — A petalodont selachian of Carboniferous affinities. 



Diplodus (Orthocanthus) — Carboniferous and Permian. 



Evidently the fishes are of little more value than the amphibians 

 and the reptiles. 



5. The Cotylosauria common to North America and South Africa. 

 The similarity of Pariotichus and Procolophon was suggested by 

 Cope; this has been shown to be impossible, but Williston has very 

 recently (Journal of Geology, Vol. XVI, No. 2, 1908, p. 148) attempted 

 to show that Labidosaurus, a form very closely related to Pariotichus, 

 is also very closely related to Procolophon. 



However, even if this should be accepted, the presence of two 

 distinct genera of this extremely primitive order could not prove the 

 contemporaneity of two beds in such distant regions. 



The evidence adduced by Cope is not sufficient to prove the 

 Permian Age of the Illinois and Texas beds as against a possible 

 Carboniferous Age. 



It now remains to examine the evidence discovered since 1877. 

 Undoubtedly Cope regarded much of this as directly confirmatory of 

 his ideas. 



