THE PLESIOSAURUS. 



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world, but particularly in England, is deposited a fine sandy and 

 marly stratum, consisting- of distinct layers with occasional lime- 

 stones, and exceedingly abundant in remarkable fossil remains. 

 To this the name Lias has been given, and the reptilian remains 

 imbedded in it are the most magnificent objects of the Creator's 

 hand. During the deposit of these muddy beds which were un- 

 favorable to the growth of corals, we find but few traces of these 

 animals, but on the contrary the crinoidea, already alluded to, 

 were developed in singular and beautiful forms, and also very 

 peculiar forms of the cephalapodic group. Among the marine 

 reptiles of the epoch we are now considering, two are particular- 

 ly noticeable. The Pl&siosaurus, or almost lizard, and the Ichthy- 

 osaurus, or fish lizard. Below we represent the plesiosarus, which 

 possesses a head small, and lizard-like, with teeth like a croco- 



dile, a neck of enormous length like the body of a serpent, and a 

 back and tail having the proportions of an ordinary quadruped. 

 It is furnished with four paddles, and is supposed to have inhabi- 

 ted the shallow waters; darting by means of its long neck, sud- 

 denly at the fish which came near it. The largest complete spe- 

 cimen of the plesiosarus yet discovered is about eighteen feet in 

 length. Fierce and voracious as this animal undoubtedly was, ' 

 yet it had an enemy in the ichthyosarus represented in the follow- 

 i ng wood cut. This formidable marine reptile sometimes attain- 



ed to a length or thirty or forty feet, and like the whale possessed 

 a smooth and naked skin. The eyes were enormously large and 

 provided with bony plates, or divisions arranged around the pupil- 

 There are instances where the diameter of the orbit is eighteen 





