202 



LYELL'S ELEMENTS OF GEOLOGY. 



Wealden Group 



Fig. 184. 



Fig. 185. 



Fiff. 186. 



Cypris spiyii- 

 gera, Fitton. 



Cypris Valdemis, Fitton. {C.faba, 

 Min. Con. 485.) 



Cypris tuberculata, 

 Fitton. 



Fig. 187. 



Shells of the Cypris, an animal allied to the Crustacea, and 

 before mentioned (p. 47.) as abounding in lakes and ponds, are 

 also plentifully scattered through the clays 

 of the Wealden, sometimes producing like 

 plates of mica, a thin lamination (see Fig. 

 187.). Similar cypriferous marls are found 

 in the lacustrine tertiary beds of Auvergne, 

 and in recent deposits of shell marl. 



The fishes of the Wealden belong partly 

 to the genera Pyenodus and Hybodus, forms 

 common to the Wealden and Oolite (see Fig. 

 225.); but the teeth and scales of a species of Lepidotus are 

 most widely diffused (see Fig. 188.). The general form of these 

 fish was that of the carp tribe, although perfectly distinct in ana- 

 tomical character, and more allied to the pike. The whole body 

 was covered with large rhomboidal scales very thick, and having 

 the exposed part covered with enamel. Most of the species of 



Fig. 188. 



a. palate and teeth. 



Lepidotus Mantelli. Agass. Wealden. 



h. side view of teeth. 



c. scale. 



this genus are supposed to have been either river fish, or inhab- 

 itants of the coasts, having not sufficient powers of swimming to 

 advance into the deep sea. 



Among the remains of vertebrata, those of reptiles form the 

 most remarkable feature. Some of them belong to tortoises, 

 such as the Trionyx and Emys, genera now occurring in fresh' 



