1867. 1 Sir diaries Lyell and Modern Geology. 3 



which so eminent a geologist, who has seen the full effects of the 

 ' Principles/ holds that work and its author. 



Although Dr. Whewell, Mr. Conybeare, and others united in 

 recognizing the importance and merit of the ' Principles ' in a 

 general way, most of the geologists of five-and-thirty years ago 

 also joined with them in declaring that Sir Charles Lyell went too 

 far; that the doctrine of uniformity does not hold good when 

 applied to remote epochs ; but that, for instance, the metamorphic 

 rocks were altered by agencies of far greater intensity than any 

 that prevail at the present day. They contended that although the 

 forces which formerly produced changes on the surface of the globe 

 were in bygone times the same in kind as they are now, they were 

 different in degree. Sir Charles Lyell, on the other hand, has 

 persistently maintained that we have no evidence to warrant us in 

 assuming those forces to have possessed greater intensity than at 

 present during any geological period, and that until such evidence 

 is discovered we have no right to attempt to explain past events by 

 reference to causes of greater intensity than now operate at and 

 beneath the surface of the earth. In the first chapter of the ' Prin- 

 ciples,' Sir Charles Lyell quotes Hutton for the purpose of showing 

 that geology is not concerned " with questions as to the origin of 

 things," and is entirely distinct from cosmogony and cosmogonic 

 speculations. 



The science of Geology is, indeed, like every other science, a 

 knowledge of phenomena and their causes ; and no period can 

 therefore be considered geologic that is not represented by rock- 

 masses on some part of the present surface of the globe. No doubt 

 there were pre-Laurentian periods ; but at present we know nothing 

 of them, and they cannot yet be considered to come within the scope 

 of geological inquiry. The objection which has frequently been 

 made to the doctrine of uniformity, that it assumes the eternity of 

 the globe, is therefore of no value, for geologists do not attempt to 

 speculate on the causes of phenomena of which they have no kind 

 of knowledge. 



It is unnecessary to enter into any argument respecting the 

 doctrine of uniformity, as it is now practically acknowledged on all 

 hands ; but we would observe, that an examination of geological 

 literature will show that while the terms " convulsion," " cata- 

 strophe," and the like were in common use previous to the year 

 1830, since that time they have been used with a gradually decreas- 

 ing frequency ; and a careful study of the progress of geological 

 thought will likewise show that this result is almost entirely attri- 

 butable to the publication of Sir Charles Lyell's 'Principles of 

 Geology.' 



It has, however, been assumed by some geologists of the present 

 day, that the only claim on our respect which it could be pretended 



b2 



