EXCURSION I. 63 



stone, and ranges N. 29 W. The others have various 

 ranges between west and north. Many small shining flakes 

 of crystalline oxide of iron occur in the trap of these dikes. 

 The ridge of the Ceims is composed of the coarse-grained 

 granite; but the path at its west base, along which we have 

 come, is partly on the fine-grained variety. This appears 

 generally at the height of about 1600 feet on the cols, and on 

 the west side of the ridge, but is not seen in Glen Eosa nor 

 on Goatfell. It disappears on the ascent of Cior-Mhor, and is 

 succeeded by the coarse-grained variety. The contrast is 

 remarkable. The rock has quite a different aspect, a dif- 

 ferent feel under the hammer, and a peculiar style of disin- 

 tegration, giving smooth outlines, and an entire absence of 

 the aiguille-like highly picturesque forms, into which the 

 coarse variety is resolved by the action of the atmosphere. 

 The decomposition of both rocks conceals the contact, and 

 we were not so fortunate as to discover anywhere here the 

 actual junction of the two varieties. But the day is waning, 

 and we have yet to scale the lofty peak of Cior-Mhor, shoot- 

 ing grandly up 900 feet above the ridge on which we stand. 

 Thoxigh right to the summit " we might press, and not a sigh 

 our toil confess," we must pause now and again to mark the 

 ever-changing features of the magnificent scene gradually 

 opening towards the west and north, and the new aspects in 

 which the rugged crest of the Ben-Ghnuis range now appears. 

 We must note, too, the change in the rocky floor over which 

 we are passing. We leave the fine-grained granite on gain- 

 ing the foot of the steep ascent; thence to the summit the 

 mountain is composed wholly of the coarser kind. It is dis- 

 posed in irregular tabular masses, split up into rhombic or 

 cuboidal forms by fissures, independent of disintegration, and 

 coeval with the solidification of the rock. The thinner 

 masses we have called sheets; in both, the divisional planes 

 separating mass from mass, and the fissures perpendicular to 

 them, are alike the result of crystallization on the large scale, 

 and bear no analogy to stratification, which is the result of 



