299 



include distinctive parts, this specimen would have been regarded as be- 

 longing to B. variolosa. A species not certainly identified occurs in the 

 Hell Creek beds. During the past season an undescribed, closely related 

 species was discovered in the Lance Creek deposits in Converse County, 

 Wyoming, by a member of the IT. S. Geological Survey. Nothing re- 

 sembling these turtles has ever been found in beds above those equivalent 

 to the Lance Creek deposits. Indeed, all those turtles of the Upper Cre- 

 taceous which had the carapace and plastron sculptured in various ways, 

 appear to have become extinct before the beginning of the Tertiary. Not 

 long after the opeuing of the Tertiary, in the Wasatch, there came in the 

 Emydidae and the Testudinidse, and these developed other styles of orna- 

 mentation of the shell. 



Figures of all the species of turtles named above are to be found in the 

 present writer's "Fossil Turtles of North America." 



Dinosaurs. — Both in the Judith River beds and in those of the Lance 

 Creek epoch the most abundant and the most conspicuous reptiles are the 

 dinosaurs. Five families of these, belonging to four superfamilies and to 

 two suborders, are represented in the Judith River epoch, and each of these 

 families reappears in the Lance Creek epoch. Furthermore, many of the 

 genera are common to the two formations and it is believed that the same 

 is true of a considerable number of species. From the Judith River beds 

 Cope described eight species of carnivorous dinosaurs that seem to come 

 under the genus Dryptosaurus. Mr. Hatcher (Bull. U. S. Geol. Surv., 

 257, p. 86) mentions the occurrence of two of these, called by him Deinodon 

 explanatus and D. hazcnianus, in the Lance Creek beds. Another car- 

 nivorous dinosaur, Deinodon Jiorridus, was originally described from the 

 Judith River beds. Hatcher (loc. cit., p. 83, Aublysodon mirandus) be- 

 lieved that it was found likewise in the Lance Creek beds. Another. 

 Zapsalis abradens, is thought (p. 84) to occur in both formations. The 

 great carnivorous dinosaur described by Osborn, Ti/rannosaurus rex, may 

 be a descendant of Marsh's Ornithomimus grandis, of the Eagle formation, 

 older still than the Judith beds. 



In the herbivorous order Orthopoda are placed the remarkable rep- 

 tiles called the Stegosauria. Two species, Troodon formosus and Palwo- 

 scincm costatus, are mentioned by Hatcher (loc. cit., pp. 83, 88) as being 

 represented in the Lance Creek deposits by numerous teeth of size and 

 pattern similar to the types, which were described from the Judith River 



