BUTE. GEOLOGY. 469 



Contain them if they existed as distinct veins. Future 

 geologists may try to ascertain this fact, although it cannot 

 be considered of much importance. 



Similar veins are very abundant. They are seen in 

 several places traversing the sandstone between Kilchattan 

 bay and Rothsay, and a very conspicuous one occurs at 

 Scalspie point. They vary much in size, being sometimes 

 very minute, and occasionally attaining, as in other places, 

 a considerable dimension. They are at times erect, at 

 others inclined, and more rarely they are curved in their 

 courses. In one or two places they may be observed 

 to ramify ; a feature by no means common in them, al- 

 though extremely remarkable in Airdnamurchan. * As 

 far as I have observed, they consist of the same substances 

 as the overlying masses described above. In some places 

 they are also to be seen traversing the schistose rocks, 

 appearing to have very extensive courses ; but they are, 

 from the want of contrast, less obvious in these rocks than 

 in the sandstone ; and on this account perhaps, appear less 

 numerous. It is not uncommon to find the larger veins 

 with a laminated structure, which is further cross fractured 

 into imperfectly columnar divisions. It would serve no 

 useful purpose to enter into the details of these several 

 veins ; but I shall conclude this account of them by a 

 particular description of two, which seem to claim it from 

 the peculiarities of structure which they exhibit. 



It has on former occasions been seen, that several 

 varieties of trap, tufaceous, columnar, simple, and amygda- 



* As the ramification of trap veins is a very important feature in their 

 history, and no very distinct example of it has occurred in this survey of 

 the Western islands, I have subjoined a sketch of part of the shore of 

 that promontory, where this phenomenon occurs throughout a large 

 space. The stratified rock is the limestone common to Mull and 

 Morven. The specimen selected is one of the most simple, as the 

 intermixture, multiplicity, and minuteness of the veins, are such as gene- 

 rally to defy the powers of the pencil ; particularly as no point of view 

 can be obtained but from a boat, in a sea which is never at rest, 

 Plate XXXIII. fig. i. 



