GEOLOGICAL SUEVEY OF THE TEREITOEIES. db7 



now in existence ; that is to say, the great land-tortoise ol the Gallipagos 

 Islands. The species was named in honor of its discoverer. 



Emys. 

 Emys wyomingenHs. 



The most abundant remains of turtles of the Bridger Tertiary forma- 

 tion which have come under the notice of the writer are those of a 

 species of Umys to which the above name was originally given. Many 

 specimens of shells, some of them nearly perfect, have been submitted 

 to my examination by Dr. Carter, Dr. Corson, and Prof. Hayden 

 IFragments of shells of this species, sent to me by Dr. Carter in 1868, 

 were among the first fossils I had seen from the Tertiary formatioli of 

 Wyoming. 



The first specimens examined exhibited sufficient variation to lead me 

 to refer them to several different species under the additional names of 

 Umys Stevensonianus, E. Haydeni, and E. Jeanesi. Additional specimens, 

 of different ages, from a young one about the size of the palm of the 

 hand, to those which had reached maturity and are a foot long, and are 

 three-fourths of a foot broad, led me to view all as pertaining to a sin- 

 gle species. Every specimen exhibits some variation, so that following 

 the original plan, they would indicate a dozen species. 



The form and constitution of the shell of Emys icyoiningensis, as well 

 as the impressions of the horny scales, are the same as in living species 

 of terrapenes. 



Emys Carteri. 



Dr. J. Van A. Carter, who has pursued the investigation of the Bridger 

 Tertiary formation with untiring industry and zeal, the last summer, 

 sent to the Academy of E"atural Sciences of Philadelphia the remains 

 of one of the largest known species of terrapenes ; the specimen con- 

 sisting of the greater portion of the i^lastron or under shell, and the 

 fore part of the carapace or upper shell. Dr. Carter discovered it imbed- 

 ded in a green, friable sandstone in the vicinity of Fort Bridger. In its 

 complete condition this turtle has measured about two and a half feet 

 in length. The plastron is 2 feet long. The first vertebral plate is 

 clavate in outline, and 4 inches in length. The first vertebral scute 

 is vase-like in its form, and is 5^ inches in its fore and aft diameter. 

 The species has been named in honor of its discoverer. 



Baptemys. 



Baptemys tvyomingensis. 



A peculiar and interesting extinct genus of turtles, pertaining to the 

 Bridger Tertiary formation and named as above, appears to be inter- 

 mediate in character to the living genera Dermatemys and Staurotypus. 

 It was one of the earlier described animals from the Tertiary formation 

 of Wyoming, and was first indicated by a well-preserved and nearly 

 complete shell discovered in the vicinity of Fort Bridger by Mr. O. C. 

 Smith. A second less complete specimen was obtained at Grizzly Buttes 

 during Prof. Hayden's exploration of 1870. 



