92 THE ADVANCE OF SCIENCE 



proved to have occurred, in the course of 

 the secular changes which have taken 

 place during the deposition of the strati- 

 fied rocks. The publication of ' The Prin- 

 ciples of Geology,' in 1830, constituted 

 an epoch in geological science. But it 

 also constituted an epoch in the modern 

 history of the doctrines of evolution, by 

 raising in the mind of every intelligent 

 reader this question : If natural causation 

 is competent to account for the not-living 

 part of our globe, why should it not ac- 

 count for the living part? 



By keeping this question before the 

 public for some thirty years, Lyell, 

 though the keenest and most formidable 

 of the opponents of the transmutation 

 theory, as it was formulated by Lamarck, 

 was of the greatest possible service in 

 facilitating the reception of the sounder 

 doctrines of a later day. And, in like 

 fashion, another vehement opponent of 

 the transmutation of species, the elder 



