CH. XLI. SUCCESSION OF ANIMALS. 461 



crocodiles and lizards, but much larger, have left their 

 bones in the rocks. Next come reptiles with wings, which 

 measure sixteen feet across from tip to tip, and we must 

 picture these huge flying lizards, with wings like bats, roam- 

 ing over the globe with no higher animals to persecute 

 them. 



But they were only to have their turn, for in rocks formed 

 a little later there appear two skeletons, one of a small 

 creature half reptile half bird, about the size of a pigeon, and 

 the other of a real bird with some of its feathers still remain- 

 ing ; and in beds of about the same age there occurs the 

 jaw of a small insect-eating animal something like an ant- 

 eater. Birds and quadrupeds therefore had now begun to 

 exist, and soon the bones of pouched animals are found, and 

 then of mammalia, like our moles and shrews ; and from 

 this time the reptiles become smaller, as if they were kept 

 down and gradually destroyed by the higher animals, and the 

 quadrupeds become larger and more powerful ; till, in those 

 beds which Cuvier studied near Paris, we find the gigantic 

 elephant and rhinoceros-like animals we spoke of before ; 

 while in beds of about the same age occur the first bones of 

 monkeys. 



This is a very rough sketch of the order in which ani- 

 mals are found in the earth's crust. The lower kinds first, 

 and then gradually higher and higher forms as they come 

 near to our own time ; and if we could study them more 

 closely you would see that in rocks nearly of the same age 

 the forms are always very like each other, while the farthei 

 apart the formations are, the more different are the animals. 

 It is true that there are very few close links to be found 

 between fossil animals ; but when we remember that nearly 

 all the rocks in the earth's crust are made out of others which 

 have been destroyed, it is scarcely wonderful that so few 



