CONTORTIONS OF ROCKS. 127 



rendered the strata flexible enough to yield to the 

 power which it exerted. 



That force has been exerted in the flexure of strata, 

 is further rendered probable by the circumstance, al- 

 ready mentioned, respecting the greater frequency 

 and more violent nature of the curvatures that occur 

 in the more antient strata, which, from causes suffi- 

 ciently apparent, have undergone those greater 

 changes of position that mark the extent and magni- 

 tude of the motions which have been impressed on 

 them. Facts, elsewhere noticed, respecting the com- 

 position, nature, and origin of these rocks, seem also 

 to justify the notion, that in these cases also, the 

 flexibility and the curvature have been, both, equally 

 the consequences of the action of heat. The argu- 

 ment, in this case, rests precisely on the same basis 

 as it does in those where curvatures of the adjoining 

 strata attend the intrusion of masses or veins of trap ; 

 and, in both cases, the force exerted, and the capacity 

 to suffer from it, are equally the effects of a common 

 cause. It is here of course concluded, as is fully 

 argued and, I trust, proved elsewhere, that whatever 

 is received respecting the nature and origin of the trap 

 rocks, cannot be denied to those of granite. 



The gneiss which forms Cape Rath, elsewhere 

 noticed, is traversed by innumerable granite veins ; 

 by the interference of which the beds of that rock 

 and of the accompanying hornblende schist, are bro- 

 ken into fragments and entangled among a mass of 

 veins of different dates, so considerable as far to ex- 

 ceed in quantity the rocks which these have invaded. 

 In many parts of this compound mass, the detached 

 portions of the hornblende schist, rendered peculiarly 

 visible by their colour, are bent in various ways ; pro- 



