MESOZOIC ERA. AGE OF REPTILES. 359 



Tertiary. Yet, doubtless, marsupials did exist throughout 

 the Cretaceous, because they existed in the Jurassic, and 

 again in the Tertiary, and even now ; and it is a law in 

 paleontology that a form, once become extinct, is never 

 revived. Nature never repeats herself. Doubtless, mar- 

 supials existed in some part of the earth, and their 

 remains will yet be discovered. 



General Observations on the Mesozoic. 



That this was, in a most wonderful degree, an age of 

 reptiles, is easily shown. In the world, at the present 

 time, there are about six great reptiles one crocodile in 

 Africa, two gavials in India, three alligators in America, 

 North and South all of them in tropical and sub-tropical 

 regions, and none more than twenty to twenty-five feet 

 long. Now, take a single epoch, the Wealden compar- 

 able, therefore, with the present and only the small 

 area of England. There were in England, in Wealden 

 times, five or six dinosaurs, twenty to sixty feet long ; 

 ten or twelve marine saurians and crocodilians, ten to 

 fifty feet long, besides pterodactyls, turtles, etc. Again, 

 in America, in Cretaceous times, leaving out the turtles, 

 there were more than one hundred species of land, marine, 

 and flying reptiles, the larger number of which were 

 greater than any living crocodile. In the epoch of the 

 Atlantosaur beds, reptiles were probably as numerous, 

 and certainly of still greater size. These are the known ; 

 but, of course, the findings are but a small fraction of 

 the actual fauna. The fact is, reptiles were rulers in 

 every realm of Nature. They stood in place of beasts, 

 as rulers of the land ; of whales and sharks, as rulers of 

 the sea ; and in place of birds, as rulers of the air. They 

 impressed their reptilian character the fashion of the 

 court on till other higher classes ; the mammals were 

 reptilian, and so were the birds. 



