SOUTH UIST. GEOLOGY. 95 



The mountainous district is not highly productive of 

 pasture, and is principally, perhaps not most profitably, 

 applied to the rearing of black cattle. This appropriation 

 of the mountain pastures of the Long Island is however 

 to a certain extent unavoidable, as the difficulty of trans- 

 porting sheep to the main land is, from the length of the 

 voyage, so considerable as materially to discourage that 

 branch of pasturage. 



The want of roads is a serious obstacle to the improve- 

 ment of this island, which is peculiarly difficult to traverse 

 in any direction. The introduction of these would form 

 the first step to improvement. A few feeble attempts 

 to plant trees have been made, but they have been 

 attended with little success : the whole appears a naked 

 and dreary waste. 



THE reader is doubtless prepared to find that the rocks 

 of this island consist of gneiss : such is the fact, while 

 they afford scarcely any varieties to interest him after 

 what has already been remarked of the southern islands. 



Still, there is a change of character, the gneiss being 

 here almost uniformly of a granitic aspect, or this variety 

 being at least predominant. The external forms are 

 indeed so like those of granite, as, at first sight, almost 

 to mislead an observer. In the internal structure it also 

 approaches very near to that rock, although there is 

 always to be observed somewhere an indication of the 

 foliated tendency. I must here remark, for the sake of 

 those who may be little conversant with rocks in their 

 natural positions, that specimens may frequently be ob- 

 tained from beds of gneiss, undistinguishable from genuine 

 granite. It is true that they may sometimes be portions 

 of granite veins, but in other cases they constitute real 

 integrant parts of the gneiss beds. However proper 

 therefore it may be to consider them as granite when 

 viewed as cabinet specimens, it is still necessary that they 

 should be arranged as parts of a gneiss series. The views 



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