IS THIRD REPORT — 1833. 



few supporters among writers upon the subject, has yet claims to 

 be considered, and particularly as it has of late been urged upon 

 our notice, and by some whose observations have been made in 

 districts where veins of vai'ious order are abundant. 



This theory is, in short. That veins were formed at the same 

 time with the rocks themselves ; that the whole was a contem- 

 poraneous creation ; and that there have been neither fissures 

 subsequent to the consolidation of the mass, nor filling up from 

 above or below, or disturbances to produce the heaves or shifts 

 which we see. 



When this hypothesis was first proposed I do not know, but 

 that it was long since we may infer, as Agricola regards the 

 opinion which supposes veins such as we now see them to have 

 been formed at the same time with our globe, to be at variance 

 with fact, and he calls it the opinion of the vulgar. The same 

 hypothesis was indeed supported by Stahl ; but he seems to 

 have adopted it rather on account of the difficulties attendant 

 on any other explanation that had been proposed, than for any 

 good reason that he had to give. 



Such are, however, but assertions, to be received with doubt 

 by any one who inquires freely and without prejudice. Partial 

 evidence may appear for some such formations ; but it is another 

 affair to attribute all veins to such an origin, and thus to sweep 

 away at once the difficulty of explaining many complicated ap- 

 pearances. 



The doctrine of a contemporaneous formation of veins has 

 lately found an advocate in Dr. Boase, in his paper on the 

 geology of Cornwall. After commenting on the division into 

 different orders, which Mr. Carne had indicated as to veins, 

 according to certain appearances in their direction and the 

 character of the substances with which they are filled, he says 

 he cannot detect any characters which are not common to all 

 the Cornish veins ; and since some of them are generally ac- 

 knowledged to be contemporaneous with the rock, he concludes 

 that they have all the same origin. 



Dr. Boase, however, candidly sets out by stating that he had 

 purposely refrained from making inquiries at the mines con- 

 cerning the phasnomena of veins, and that bis experience is 

 therefore principally confined to jhose which occur in cliffs, 

 quarries, and natural sections that are exposed to open view. 



Lest this admission should create surprise, he remarks that 

 such sources of information are invaluable as the only ones 

 easily available to exercise the senses on the nature of veins ; 

 for, unless to those much accustomed to descend into mines, 

 they may as well be visited blindfold. 



