FOSSIL MAMMALIA. 29 



merable fish, of a genus unknown at present, but which, from 

 its analogy with some existing genera, appears to have inha- 

 bited the fresh water. The monitors we know to be inhabi- 

 tants of the same element. 



A little higher is the Alpine limestone, and on it the coquil- 

 laceous limestone, abounding in entrochi and encrini, and form- 

 ing the basis of a great portion of Germany and Lorraine. It 

 contains the osseous remains of a very large sea-tortoise, and 

 another reptile of the lizard tribe, of very great length, and 

 pointed muzzle. 



Next come certaui sandstone strata, having only vegetable 

 impressions of the large reeds, bamboos, palms, &c.; and then 

 of Jurassic limestone, where the remains of the reptile class 

 exhibit a diversity of singular conformations, and a gigantic 

 degree of development. Its middle portion is composed of 

 oolites and lias, or the gray limestone, containing therecurvivalve 

 oysters ; and in it were found the debris of two most extraordi- 

 nary genera, uniting the characters of oviparous quadrupeds, 

 with locomotive organs, like those of the cetacea. Those are 

 the ichthyosaurus and plesiosaurus^ first discovered and deter- 

 mined here by our distinguished countrymen. Sir Everard 

 Home and Mr. Conybeare. These, with their species, shall be 

 described in the proper place. Their skeletons are in a state 

 of high perfection, and their remains have been found extended 

 through all the formations of lias. 



In the same deposition were also found two species of the 

 crocodile, amidst ammonites, terebratulae, and other shells of 

 the ancient sea. These are called by Cuvier the long-beaked 

 and short-beaked gavial. Another crocodile was discovered in 

 the oolite at Caen, and another in the same formation here. 



The megalosaurus, a fossil reptile of prodigious size, has 

 been discovered by Dr. Buckland in this country. Its remains 

 appear to have been contemporaneous with the concretion of 

 the lias, but are also dispersed abundantly in the oolite and 

 higher sands. From the magnitude of a femur and other 



