320 THE REVOLUTIONS OF THE CRUST OF THE EARTH. 



in the Chalk, the gigantic Mosasaurns, the Iguanodon, and the Hyleo- 

 saurus ; all these animals after a period of great importance gradually 

 diminish and disappear in the Chalk. Up to that time the saurians 

 ruled as sovereigns over land and sea to the sixty-fifth degree of lati- 

 tude. Even the air was invaded by fantastic pterodactyles, with 

 wings, claws, and crocodile's head, and lacking only the proportions 

 of the dragons with which the imagination of poets peopled the grot- 

 toes and caverns in times past. Everywhere hideous creatures crawled 

 or slept in the sunlight, and preyed upon each other when, after a 

 long season of repose, hunger or other needs forced them to activity. 

 Their voracity was such that they did not spare even the individ- 

 uals of their own species. This fact is proved by the analysis of the 

 coprolites, whose discovery is due to Miss Mary Anning. The rivers, 

 lakes, marshes, and shores all were filled with monsters, whose scale- 

 covered bodies glistened in the sun's rays, while in the damp forests, 

 hidden among the branches of the virginal crowns of the palms, other 

 reptiles lay in wait for their prey. The appearance of the crocodile is 

 the last act of this exuberant creation, whose forms cannot fail to 

 astonish us when in thought we compare them with the creatures of 

 the present world ; and this is our only link with this class of animals, 

 which, within a time relatively limited, had very extended ramifications. 



The Chelonians, the Batrachians, and even the Ophidians, were, accord- 

 ing to Owen, very numerous and well developed in the Jurassic and 

 Cretaceous periods, although Cuvier concluded from the few fossil re- 

 mains of serpents found that they were rare at the times mentioned.* 



The fossil remains of Birds are found particularly in the red sandstone 

 of Massachusetts, which corresponds very nearly with the mixed sand- 

 stone of Central Europe. Foot-prints especially are frequently discov- 

 ered. In later deposits new species appear, and fossil remains become 

 more frequent. 



The Mammals commence with the marsupials. In the schists of Stone- 

 field, belonging to the Jurassic formation of England, we find incon- 

 testable remains of these animals, which, by their organization, form the 

 intermediate link between the oviparous and viviparous animals. The 

 Cetaceans were developed at the same time, and attained colossal propor- 

 tions. Among the animals of dry land were the Pachyderms, begin- 

 ning with the herbivorous, which first attained great development. 

 These animals were the initial efforts of nature, which by these inert 

 forms prepared the way for other animals, whose light and graceful 

 structure was better suited for pursuit or flight, for attack, and for de- 

 fense. The Paleotheria, the Anoplotheria, the Chccropotami, the Adapides, 

 the Xyphodonts, were the principal animals living at this time. The im- 

 mense forests and vast plains furnished them with an abundant supply 

 of food. 



* Cuvier, Ilecherches sur les Ossemcnts Fossiles, t. v, 2d part, p. 520. 



