340 ON THE APPARENT DISLOCATIONS [Ch. XV. 



pendicular joints of the granite : and all the large veins 

 which traverse this rock generally run in a serpentine course. 

 These appearances are beautifully displayed near Mousehole 

 at the Logan Rock, and in other parts of the granitic districts 

 of CornwalL 



No advocate of the Plutonic theory would offer to explain 

 all these phenomena by a mechanical agency : but they ap- 

 pear to be so nearly allied to each other, that it would be 

 no easy task to distinguish those that have been violently 

 formed from those which could not have had such an origin. 

 Take, however, the most favourable of these examples, the 

 primary slates, and, even admitting that granite has been pro- 

 truded, how and when were their convolutions effected? 

 These are generally referred to the elevation of the granite. 

 Sir James Hall advocated this opinion, though he candidly 

 confesses, that he " has not been able to discover any case in 

 which it has performed this function, all the junctions bear- 

 ing marks of an infusion of the liquid granite into hard and 

 brittle strata." " The scenes in Galloway," he adds, " prove 

 that the granite has been more recently formed than the 

 contorted slate; but they prove over-much in one respect, 

 since they show the arrival of the granite at its present place 

 to have been posterior, not only to the formation of the 

 strata, but also to their convolutions when in a state of soft- 

 ness, and to their subsequent consolidation." He therefore 

 concludes, that the existing granite has not produced this 

 mechanical effect, but some unknown mass of granite, acting 

 at some unknown time antecedent to the elevation of the 

 strata.* 



By such arguments as these the violent formation of con- 

 voluted strata is still maintained : their fallacy, however, is 

 too obvious to need farther comment. 



The curvature of the layers of the unstratified rocks, both 

 on the large and small scale, appears to be intimately con- 



* Royal Trans, of Edinburgh, vol. vii. p. 98. 



