114 GEOLOGY OF THE ISLE OF WIGHT. 



Helen's, a locality we shall hereafter notice, and 

 was sold to a dealer, who afterwards disposed of 

 it to a casual visitor. It consists of the entire 

 carapace or Luckier of a turtle, apparently of an 



-T. 



lign. /. — tortios ok the buckler of a fossil turtle, from 

 st. Helen's. 



(Size of the original carajiace sixteen inches long, and nine wide.) 



adult Triowjx. It is sixteen inches in length, 

 and about nine inches in its greatest width ; and 

 is formed of eight pairs of ribs, united by a 

 dorsal series of eight plates. The ribs are of 

 nearly equal breadth throughout their entire 

 length, and have their dermal surface cancellated 

 somewhat after the pattern of the meso-sternal 

 plate figured in lign. 6. The buckler is as convex 

 ;i~- in some of the land tortoises, and therefore 

 differs greatly from the usual form of the carapace 

 in thi' recent Trionyx, which is depressed, and has 



