CHAPTER XX 



THE AGE OF REPTILES 



(Continued.) 



THE Triassic period in its later stages was very like the 

 earlier period of the era which followed it, and the 

 reptiles which were characteristic of the close of the 

 first were continued in some cases with only slight differ- 

 entiation in the second. The Plesiosaurs and Ichthyosaurs 

 are associated with the Trias, and we may therefore 

 describe them now. Though some of these large aquatic 

 creatures must have measured thirty feet from snout to 

 tail, they do not equal in size the great aquatic mammals 

 of to-day the whales. In life the Plesiosaur had a body 

 like the hull of a submarine with four great paddles 

 attached the fore and the hind legs. It had a long 

 neck like a gigantic swan, and an elongated head provided 

 with powerful jaws armed with numerous pointed teeth. 

 It probably could swim under water as well as on the 

 surface, and when floating could snap small lizards from 

 the land. The paddles have a definite structure like 

 legs, with five toes, wrist or ankle, forearm or foreleg, and 

 upper arm or thigh. A great number of these Plesiosaurs 

 have been found in the Lias formation of the south of 

 England; and slabs containing whole skeletons have 



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