EXTINCT ANIMALS 



Mesozoic period and abruptly died out; at any 

 rate their remains disappear from the rocks at 

 the close of the Chalk or Cretaceous period (see 

 the table of strata, p. 60). These extinct 

 orders of reptiles are the Dinosaurs, the Thero- 

 morphs, the Ichthyosaurs, the Plesiosaurs and 

 the Pterodactyles. They are a prominent 

 example of that kind of extinct animal which is 

 not the forefather, so to speak, of living ani- 

 mals, but of which the whole race, the whole 

 order, has passed away, leaving no descendants 

 either changed or unchanged. 



To begin with the Dinosaurs. They are a 

 very varied group and mostly were of great size. 

 They seem to have occupied in many ways the 

 same sort of place on the earth's surface which 

 was filled at a later period by the great mam- 

 mals, such as elephants, rhinoceroses, giraffes, 

 giant kangaroos, etc. Preying on the vege- 

 table-feeding kinds there were huge carnivorous 

 dinosaurs, representing the lions and tigers of 

 to-day. Yet the mammals I have mentioned 

 are in no way descended from these great 

 reptiles. They came from another stock, and 

 only superseded them on the face of the earth 

 by a slow process of development, in which the 



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