SKY. GEOLOGY. TRAP VEINS. 395 



sandstone at Loch Eishort, where they are of considerable 

 size. Here they are readily traced through all the beds as 

 far as the most distant surface of the limestone. 



The second set traverse not only the mountain trap but the 

 veins last named, and are therefore of a posterior date to 

 both. They are much smaller, often indeed not exceeding 

 half an inch in breadth, and are composed of an extremely 

 fine and hard black basalt. Even where they exist, they are 

 less abundant than the first, nor are they found in nearly so 

 many situations. They are frequently to be observed pass- 

 ing through the rock at Coruisk, and through the larger 

 veins of Garsven, in the neighbourhood of which latter 

 in particular, they abound. Their compactness and lustre 

 are frequently so great that they approach in appearance 

 to that pitchstone which forms the basis of the beautiful 

 columnar porphyry of Egg. In addition to this feature 

 they are strongly distinguished from the trap veins that 

 traverse the sandstone, by their intimate and almost inse- 

 parable union with the body of the rocks in which they 

 lie; whereas the latter are separated with the greatest 

 ease. 



The veins which are found in the stratified trap are not 

 very abundant, but may be seen distinctly among other 

 places on the western shore ; traversing the lofty cliffs 

 in various, but generally perpendicular directions, of a very 

 large size, and frequently of a stratified structure. They 

 do not resemble in composition those of the second rank, 

 just mentioned. 



As no useful purpose could be served by describing 

 all the individual examples that abound in this island, I 

 shall pass over many which offer no interesting features 

 in themselves, and are of no value in geological science ; 

 limiting mysejf to a few which present appearances the 

 most worthy of note. 



Those of Strathaird are among the first that deserve 

 notice, on account of their extraordinary number, and of 

 some particular appearances by which they are distin- 



