§ 30. TURTLES OF THE WEALDEN, 411 



to an Emys, or freshwater turtle, described by Cuvier,* 

 as occurring in the Jura limestone at Soleure. It is a very 

 flat species, and probably attained two feet in length. 



Many ribs and other parts of the carapace of a Tri- 

 onyx have been discovered in the shale of Pounceford, 

 and grit of Tilgate Forest ; the external surface of the 

 dorsal plates is shagreened all over, as is usual in these 

 chelonians, which have no shelly covering, but only a 

 thick, tough skin, or integument ; the recent species 

 inhabit the Nile and Euphrates. 



Trionyx BakewellL Among these remains of fresh-water 

 turtles are costal and dorsal plates, and other bones of a 

 chelonian reptile, which, in its essential characters, is closely 

 allied to the Trionyces, but differs from all known recent 

 species, in having possessed a horny dermal integument 

 formed of plates of tortoise-shell. This is indicated by the 

 fossil ribs, which not only have a shagreen or punctated 

 surface, like those of the recent species, but also imprints of 

 the horny scutes or scales. t Except in having a defensive 

 coating of tortoise-shell, this turtle must have closely re- 

 sembled the existing predaceous, soft, fresh-water chelo- 

 nians ; and doubtless, like those reptiles, inhabited the 

 muddy beds of rivers and lakes ; preying upon the eggs 

 and young of the larger reptiles, and on the mussels and 

 other fluviatile mollusca, whose shells are commonly associ- 

 ated with its remains. J 



Chelonia Bellii. A considerable portion of the carapace 



* Oss. Foss. torn. v. p. 232. 



t See Medals of Creation, vol. ii. p. 777. 



% I discovered remains of this species, and pointed out their pecu- 

 liar characters, more than twenty-five years since. The specific name 

 is to commemorate the important services rendered to British Geology 

 by my late respected friend, Eobert Bakewell, Esq., author of the best 

 " Introduction to Geology," in this or any other language. See my 

 Fossils of Tilgate Forest, p. 60, PI. VI. fig. 1 ; and Geology of the 

 South-East of England, p. 225. 



