CHAPTER III. 



LIFE DURING THE GEOLOGICAL AGES. 



THE fossils of the stratified rocks are believed to 

 give a history more or less complete of the life of 

 the world during past ages. Here it is, therefore, 

 that we should expect the most complete evidence 

 toward settling the question of the origin of species. 

 If existing organisms have been slowly evolved from 

 others, and if paleontology gives us a history of the 

 past, we might here expect something like proof. 

 The necessity of appealing to paleontology has 

 been seen by all scientists, and one of Darwin's 

 most difficult tasks was in endeavoring to reconcile 

 the known facts of this science with his views of 

 evolution. For it is safe to state that paleontology 

 has offered to Darwin and his followers greater dif- 

 ficulties than any other branch of science. Here, 

 where it would seem the strongest evidence might be 

 expected, have been found the most serious obsta- 

 cles, and the evidence has been the weakest. At 

 least this was true at the time of the appearance of 

 the " Origin of Species," and Darwin with his usual 

 candor acknowledged the great difficulties thus 

 arising. Since that time there have been great addi- 

 tions to our collections and knowlege of fossils, and 

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