224 Granite not an Jgefit of Elevation. 



Solid granite has no inherent principle of motion ; if it «iove, it 

 can only be by virtue of the impulsion it has received from some 

 other body, not in consequence of its igneous origin or its want 

 of stratification. The disturbances of strata that adjoin granite 

 are not more constant, nor more striking, nor more extensive, 

 than those of strata far remote from it, as for instance the lime- 

 stone shales of Derbyshire or the coal-beds of Liege. Granite 

 veins are too small to raise mountains, and the changes or ano- 

 malies that take place at the junction of granite with other rocks, 

 whatever else they may prove, appear to me to have no bearing 

 on the question of elevation. On the other hand, the arguments 

 adduced against the doctrine that granite while fluid has been 

 forcibly injected from beneath into its present position, are, to 

 my mind, conclusive, especially that which is founded on the 

 frequent transition which takes place from granite to the rocks 

 that adjoin it. We find a continuous series from granite through 

 gneiss and mica-slate to clay-slates and the fossiliferous slates ; 

 and it is not possible to stop at any point of this progress, and 

 to say in which direction the tendency is strongest. If the gra- 

 dation were single, the difficulty would be great, but what shall 

 we say to a repetition of such gradations ? In Mr Weaver's pa- 

 per on the East of Ireland, two detailed sections are given, in 

 one of which, more than six layers of granite alternate with as 

 many of mica-slate, and in the other five alternations of the same 

 kind occur, the rocks in each instance forming bands from three 

 to seventy fathoms in thickness. 



The reliance which some authors place on granite and other 

 unstratified rocks, as agents of' elevation, is to me very extraor- 

 dinary ; let one instance suffice. At Castrogiovanni in Sicily, 

 the Pleiocene beds attain an altitude of 3000 feet ; hence it has 

 been inferred, that si7ice these beds were deposited, there has been 

 formed and introduced into the beds .subjacent, a body of granite, 

 sienite, porphyry, or other crystalline and unstratified rocJcs, 

 SOOO Jeet in thickness. This supposition is said to be necessary, 

 but since I do not see the necessity, I will venture another sup- 

 position, viz. that Etna has not risen to the height of 10,000 feet, 

 without occasioning large cavities in its neighbourhood, some of 

 them submarine; that Castrogiovanni is situate over one of 

 these ; that the Pleiocene strata have closed the cavity and ren- 



