PRIMARY GEOLOGY. 



CHAPTER I. 



Introduction : reasons for undertaking this work the nature of its contents 

 its objects twofold. The study of the primary rocks long neglected 

 beginning to attract more attention. The proposed order of arrangement. 



THE discussion of geological opinions, which are professedly 

 hypothetical, and which can only be expected to enjoy an 

 ephemeral existence, in consequence of the rapidly progres- 

 sive state of the science, may appear to many to be an unpro- 

 fitable occupation of time, which might be better employed in 

 the examination and description of the phenomena of nature. 

 But it will, perhaps, be more generally admitted that such 

 speculations are conducive to the welfare of the science, by 

 promoting and directing various investigations, and by ex- 

 citing the geologist to greater exertions during his toilsome 

 excursions. 



By such an admission, however, it is not intended to advo- 

 cate the labours of the mere theorist, whose knowledge has 

 been entirely derived from books ; but, to contend for the 

 utility of such theoretical views as have been deduced from 

 practical experience. 



Having, therefore, observed, during a geological survey of 

 Cornwall, many facts which appeared to.be incompatible with 

 the prevailing theory, I was induced to publish them in the 

 " Cornish Transactions," and to attempt their solution by an- 

 other explanation. 



B 



