OOLITIC ERA. 



137 



merous generic forms (pachytormus, pycnodus, echmodus, 

 lepidotus, &c.), the majority of which, are peculiar to the 

 mesozoic period, and many of them even restricted to the 

 time of the lias and oolite. It is now, too, the high noon 

 of reptilian development " the Age of Eeptiles" when 

 marine genera (ichthyosaurus and irtesiosaurus) were the 



IcliLhyubaurus ; Loug-uecked Plesiosaurus ; aud Pterodactyle. 



whale-like monarchs of the ocean ; when crocodilians (teleo- 

 saurus and cetiosaurus) thronged the rivers and estuaries ; 

 turtles (chclone and platemys) traversed the muddy shores ; 

 gigantic land-saurians (meyalosaurus, hylffiosaurus, and igu- 

 anodon) roamed, elephant -like, over the river -plains, or 



