346 ARRAN. GEOLOGY. GRANITE. 



stratification of the granite of Arran, to point out its 

 connexion with the superincumbent schists. This has 

 been brought to light at Loch Ransa in a most distinct 

 manner, by the removal of the soil where the junction 

 of these substances takes place. In numerous other 

 situations in Scotland, it can be seen already exposed 

 to view ; insomuch that no rational doubt can be enter- 

 tained respecting the true nature of a phenomenon so 

 very palpable and so frequent. As a fact proved, it 

 may also be considered a rule, not an exception. The 

 ramifications which proceed from the mass of granite 

 into the schist at the place above mentioned, are numerous 

 and intricate, and they diminish as they recede from 

 the main body ; while their mineral character undergoes 

 a change ; the granular structure becoming more minute, 

 almost in proportion to the minuteness of the vein, 

 until the true character of granite entirely disappears. 

 It is superfluous to repeat the conclusions which have 

 been drawn from these appearances, relative to the 

 origin of granite, since they must be familiar to every one. 



The prismatic forms visible in Goatfell and in many 

 of the neighbouring summits, are by no means an 

 universal feature of the granite of Arran. In many 

 places it presents solid and continuous faces of rock ; 

 while, in others, it offers a sort of irregularly laminated 

 structure, very much resembling that which occurs in 

 certain rocks of the trap family, including the syenites, 

 and porphyries. But there is a modification of this 

 structure in some of these granites which is deserving 

 of more particular notice ; as well from its rarity as from 

 the resemblance it possesses to that of some of the por- 

 phyries of the same island. It will also tend in some 

 measure to illustrate the views already held out respect- 

 ing the occasional pseudo-stratified appearance of this 

 rock. 



The fine grained granite found on the western side of 

 the granitic district, forms the entire mass of Ben huish, 

 Ben vearan, and some other hills, occupying, in conse- 



