on the "Mountain Cruachan. 121 



of Loch Ranza, yet in many places they are intermingled with it in 

 a very remarkable manner. Crystals of the hornblende may be 

 observed shooting far into the body of the schist, so as to render it 

 often difficult to assign the limits of each rock. In a less degree the 

 quartz and felspar exhibit the same appearance. Together with this, 

 the schist is singularly contorted, being bent, broken, and inter- 

 mingled in a most confused manner with the rock that traverses it, 

 while distinct detached fragments are often involved in the mass of 

 granite. In many instances these fragments either exhibit at their 

 edges a change into a substance resembling basalt, or are actually 

 converted into a black matter which has at first sight the aspect of 

 a fine grained hornblende rock or a basalt of the blackest hue, and 

 which only an accurate inspection discovers to be modified fragments 

 of schistus. The schistus in general which lies in the immediate 

 vicinity of the granite vein is highly indurated and gives fire readily 

 with steel : in other respects it retains its general character, a lami- 

 nated structure and alternating stripes of colour. 



Independently of the peculiarities now described which charac- 

 terize the junction of the granite with the schist at this place, the 

 passage of the porphyry veins may be observed in great perfection, 

 and as they form an important feature of the character of Cruachan 

 and occur in all parts of it, I shall here describe them at some 

 length. 



These veins are of different sizes as w r ell as aspects, varying from 

 the breadth of three or four feet to that of fifty, or more : they are 

 all very erect, and in a general view appear perpendicular. They 

 traverse both the schist and the granite, and are to be observed in 

 this part of the hill, cutting the vein equally with the schist in all 

 directions, as may be seen in the accompanying sketches. They are 

 uniformly well defined, neither intermixing in any respect with the 



