Cope. I 1o2i [Nov. 2, 



Descriptions of Extinct Vertebrata from the Permian and Triassic Forma- 

 mations of the United States. 



By E. D. Cope. 



{Meeting of the American Philosophical Society, November 2d, 1877.) 



The Triassic formation of North America has yielded many of the rep- 

 tilian types which characterize the horizon in other parts of the world. A 

 Lahyrinthodont has been recognized in North Carolina, and I have deter- 

 mined .the existence of the genus Belodon in the formation in both that 

 State and Pennsylvania. Of Dinosauria three types occur in both Europe 

 and North America. The Palceosaurus of the former country is represented 

 by the American Olepsysaurus, and Zanclodon is somewhat similar in den- 

 tal characters to the Zatomus of North Carolina. Of genera with com- 

 pressed teeth which have a lenticular section, and both edges denticulate, 

 Bathygnathus has been found in North America, and Cladiodon and Ter- 

 atosaurus in Europe. This type has, however, been wanting heretofore 

 from the extinct Triassic fauna of Pennsylvania and North Carolina. The 

 present communication introduces it for the first time from the Tormer 

 State, under a form generically different from any of the preceding, and 

 with the name 



PAL^OCTONUS APPALACHIANS. 



The specimens on which this determination rests, were found by my 

 friend Charles M. Wheatley, A. M., in one of bis copper pyrites mines. 

 The most characteristic are two teeth which differ somewhat from each 

 other in form. One of them has a greater transverse, and less anteroposte- 

 rior diameter, indicating an anterior position in the series. The other is 

 more compressed, and presents a greater anteroposterior width. Judging 

 by the analogy of the genus Lcelaps, this tooth occupied a position poste- 

 rior to the first one. The two were found in close proximity, though not 

 in actual contact, . in a fragile, argillaceous portion of the copper-bearing 

 rock . 



The profile of the anterior tooth is regularly conic with a slight recurva- 

 ture, which is not seen in the apex, but in the basal portion of the crown, 

 and in the root. The section is almost semicircular at all points, but the 

 inner and flatter face is slightly convex ; rather strongly so at the apex. 

 The denticulation of the edges is minute, measuring M. .00033. It con- 

 tinues to the base of the crown both fore and aft. At this point the edges 

 are as elsewhere, at one side of the anterior and posterior aspects. There 

 are no ridges nor facets on the crown, and the enamel possesses an obsolete 

 minute rugosity of short linear ridges. 



The crown of the second tooth is not only flatter and wider than that of 

 the first, but is lit :le more than half as long. Both edges are crenate -to 

 the base. The marked peculiarity of the tooth is seen in the division of 

 the crown into facets by angular ridges. The convex face is divided into . 

 two, an anterior-looking and a posterior-looking, the former half as wide 



