Cuchullin Hills in Skye. 95 



masses," bespeak, even from a distance, what a close examina- 

 tion entirely confirms, that the tendency to fracture is in 

 forms peculiarly angular, and the reverse of spheroidal. The 

 most rugged mountain-outlines are almost invariably accom- 

 panied by a more or less slaty structure ; and the examples of 

 the granites of Arran and the Alps, far from being excep- 

 tions, establish the analogy. 



The surfaces at Coruisk, are therefore of a description en- 

 tirely opposite to the natural forms of the rock which they 

 bound. The evidences which prove them to be the result of 

 abrasion, are so numerous and conclusive, that the fact may 

 be said to be certain rather than probable. These are too 

 numerous to detail here, and, besides, cannot be appreciated 

 without examination. It may be observed, however, that 

 here, as in the Alps, we may in vain seek for any one of 

 these smooth surfaces disappearing beneath a superincumbent 

 bed of rock, or placed in such an angle, that an abrading 

 agent could not reach it. But the most positive and catego- 

 rical proof is derived from the occurrence of the numerous 

 claystone and other veins already mentioned, which are in- 

 variably shaven over with the greatest nicety parallel to the 

 general surface to which they belong. Such an invariable 

 coincidence amounts to as strong a proof of the posteriority 

 of the moulding of the surface to the formation of the rock, 

 and injection of the veins, as any physical truth can admit of. 



The occurrence of angular transported blocks being found 

 isolated in the most curious and seemingly unnatural posi- 

 tions upon the worn and furrowed rocky knolls, has been al- 

 luded to, as affording a probability of their transport by glaciers. 

 It is curious to see that this fact also has not escaped Dr 

 MacCulloch, and his description is equally true and strik- 

 ing : — " The appearance presented by the fallen fragments 

 is very remarkable, and cannot fail to strike a visitor on his 

 first entrance into the valley of Coruisk. The interval be- 

 tween the borders of the lake, and the side of Garsven, is 

 strewed with them ; the whole, of whateveT size, lying on the 

 surface in a state of uniform freshness and integrity, unat- 

 tended by a single plant or atom of soil, as if they had all 



