FOR UNDERTAKING THIS WORK. [Ch, I. 



It has been advanced, in reply, that the granitic formation 

 of Cornwall may not be analogous to that of other countries : 

 it has also been suggested, that I have greatly erred in sup- 

 posing the circumstances of this narrow peninsula to be appli- 

 cable to all granitic districts ; and that a more extended 

 knowledge would lead me to confess, with the peasant Tityrus, 



" Urbem, quam dicunt Romam, Melibcee, putavi 

 Stultus ego huic nostrae similem." 



This censure, however, has been expressed in the most court- 

 eous terms ; and certainly the position into which I ventured, 

 as an opponent of generally received principles, fairly exposed 

 me to such reproof: but this would not have been so strongly 

 called for, if the limits of the channel through which my dis- 

 sent was made public had permitted me to enter more fully 

 on the subject. Now, however, no such restraint can operate, 

 and, by freely quoting the works of those geologists who have 

 most carefully examined the primary rocks, I shall endeavour 

 to show that the geological structure of Cornwall is similar to 

 that of other granitic districts. 



Having failed in my first attempt to induce geologists to 

 enquire into the validity of these objections, which indeed 

 bear on the fundamental principles of the science, I, in the 

 next place, invited the geological section of the British Asso- 

 ciation at Cambridge to discuss this subject, being prepared 

 to maintain my position, not only by reference to Cornwall, 

 but also by arguments derived from the published descrip- 

 tions of other countries. Circumstances, which need not be 

 here mentioned, prevented this proposition from being then 

 entertained ; but it was appointed that the matter should be 

 fully discussed at the succeeding annual meeting, which is to 

 be held at Edinburgh during the present year. 



In consequence of this resolution, I now publish an ex- 

 position of my objections to the Plutonic theory, with the 

 intent that the members of the Association may clearly under- 

 stand the grounds of dissent, and come prepared to examine 



