THE AGE OF REPTILES 



was at first very like what would happen at the pre- 

 sent day if the coast of Palestine were depressed, so 

 that the waters of the Mediterranean flowed into the Dead 

 Sea. The few fish of the salt lakes were killed ; and as 

 the land continued to sink, the sea at last flowed all 

 over Central and West England, bringing with it an 

 abundance of marine life. But the reptiles were far 

 from being finished with; and the progress of the small 

 mammals was extremely slow. 



First, as to the reptiles. The whale-shaped Ichthyo- 

 saurs continued to develop in the seas, and grew 

 larger and larger till some of which we have found traces 

 reached a length of forty feet. The long-necked Plesio- 

 saurs also advanced from strength to strength, and 

 some types grew larger. But by this time new breeds 

 were developing, with shorter necks and larger heads 

 (and consequently larger brain-power), which had a 

 better chance of surviving in the struggle for existence 

 than the unwieldy and slow-witted reptiles which pre- 

 ceded them. The Ichthyosaurs became more and more 

 fish-like, and some of them developed the habit of breed- 

 ing at sea instead of having to return to the land to 

 deposit their eggs, as do the sea-going turtles and cro- 

 codiles. Descended from quite a different stock, the 

 Plesiosaurs adapted themselves to sea life in their own 

 fashion. Instead of adopting the flowing lines of a fish, 

 the body took on a form more like that of a turtle, 

 while the lengthened neck gave rise to the description 

 applied to him since that they had the " body of a 

 turtle strung on a snake." At their longest their necks 



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