Mr Mantell on the Geological Age of' Reptiles. 18^ 



fitted for progressive motion on the land ; it is therefore pro- 

 bable that it swam on or near the surface of the water, carrying 

 its neck like a swan, and darting on its prey, its food consisting 

 of fishes, cuttle-fish, &c. Contemporary with the animals above 

 mentioned, were several herbivorous reptiles, whose remains have 

 been found in the lias at Boll, in Wurtemburg, also a species of 

 crocodile; and at Guildorf, a salamander of enormous size. The 

 remains of tortoises and turtles occur also, but very sparingly, 

 although, from the foot-marks observable in the red sandstone 

 at Corn Cockle Muir, in Dumfriesshire, this family of reptiles 

 must have existed at a still earlier period. In this bed also, se- 

 veral species of the Pterodactylus, or flying reptile, first make 

 their appearance ; animals which, with the wings of a bat, and 

 the structure of a reptile, had jaws furnished with sharp teeth, 

 and claws with long hooked nails. 



The entire series of deposites composing the oolite formation, 

 of which the lias is the inferior, or lower member, abounds 

 with the remains of the animals of this order, and these are as- 

 sociated with vast quantities of marine shells, principally belong- 

 ing to the ancient multilocular genera, namely Ammonites, Nau- 

 tilites, Belemnites, &c. the whole formation having manifestly 

 been deposited by an ocean. The only apparent exceptions to 

 this conclusion are the Stonesfield beds, composed of thin strata 

 of calcareous sandy slate, which occur in the lower division of 

 the oolite, and contain not only marine plants, shells, and bones 

 of reptiles, but also the outer cases or elytra of winged insects, 

 and jaws of animals allied to the opossum ( DldelpMs J . The 

 occurrence of terrestrial mammalia in beds of this ancient epoch 

 has not been satisfactorily explained, and it would be foreign to 

 our present purpose to enter into any discussion upon the sub- 

 ject ; the intermixture of terrestrial remains with those of marine 

 origin, may of course have been effected by the agency of a 

 river or current. In the Stonesfield slate we first meet with the 

 remains of that gigantic reptile the Megalosaurus (Great Lizard). 

 This monster, which, from the form of its teeth and skeleton, 

 is evidently allied to the Monitor, must have been nearly forty 

 feet in length, and seven or eight in height, and was probably a 

 terrestrial animal. The crocodiles of this ancient epoch appear 

 to have been exceedingly numerous, and belonged to species dis- 



