OF A FORMER WORLD. 27 



CHAPTER HI. 



" To discover order and intelligence, in scenes of apparent wildness and 

 confusion, is the pleasing task of the geological inquirer. Dr. Paris. 



THE next formation is the oolite,* consisting also of lime- 

 stone and shales, and like the lias formation, teeming with 

 the evidence of a very different animal economy existing 

 in the ancient from the modern ocean. Among these are 

 the remains of the Ichthyosaurus! and the Plesiosaurus, J an- 

 imals combining the structure of a fish with that of the 

 crocodile, and furnished with paddles like those of the whale. 

 The character of these and the other animals will now be 

 described, and from which the reader will perceive that time 

 must have been required for their production and growth, 

 and that any condition of the ocean, by which deposition 

 would be more hastily precipitated than now } would have 

 been incompatible with the duration of their existence in 

 the ancient seas. 



The periods of secondary deposition were those in which 

 the Saurian tribe seemed to have attained the most extraor- 

 dinary development, and many of them were formed after 

 types which have wo analogy among existing forms ; such 

 are the flying Saurians, the Pterodactyles (fig. 4), the Ich- 

 thyosaurians (fig. 1), and the Plesiosaurians (fig. 2). The 

 highest of all the Iguanoden (fig. 6) has its representative 

 in the recent Iguana ; the megalosaurus combined the struc- 



* Oolite, from oon, an egg, and lithos, a stone, given to this formatiolf .' 

 from some of its limestones, containing little round particles like the roe 

 of a fish. 



t Ichthyosaurus ichthys, a fish, and saurus, a lizard. (See fig. I.) 

 t Plesiosaurus, from plesios nearly allied, and saurus, a lizard. (See 



