196 PICTURESQUE SKETCHES. 



corresponding parts of the former, but the animal 

 resembling the latter in the absence of apparent neck. 

 For these reasons the genus has been named PUosaurus.* 

 One of the most remarkable of the numerous 

 crocodilian reptiles, a natural group, which, though 

 not first introduced into the earth in the middle se- 

 condary period, yet seems then to have attained in 

 all respects its chief development, was the Cetio- 

 saurus, already alluded to. This animal, rivalling the 

 largest whales in bulk, seems to have been of strictly 

 aquatic, and most probably of marine habits, and 

 was indeed closely allied to the group of true marine 

 reptiles. In this genus, too, was combined a broad 

 vertical tail and extremities developed into webbed 

 feet, the toes of which were terminated by strong 

 claws, probably assisting the animal in taking its prey. 

 Nothing is known of the teeth or skull, but there is 

 no doubt that the habits of the genus must have 

 been strictly predaceous. 



About the middle, or perhaps before the middle of 

 the secondary period, there existed a considerable 

 tract of dry land, so near what is now England that 

 the remains of the animals dwelling there could be de- 

 posited at the bottom of the sea, and this in a condition 

 admitting of their being almost instantly embedded 

 and preserved. One bed in particular of the oolitic 

 series, occurring at Stonesfield, near Oxford, has 

 received remains of this kind in comparative abun- 

 dance; and we find in it, associated with marine 

 shells, several fruits, leaves, and other fragments of 

 vegetable origin, several wing-cases and other parts 



* IlXawv (pleion\ more ; aavpog (sauros), a saurian : having greater 

 analogy with reptiles than the plesiosaurg. 



