158 ASSOCIATIONS OF [Ch. VIII. 



the granitic and schistose beds declines towards the north at 

 a gentle angle, whilst the laminae of the slate dip eastward. 

 The elvan appears to occupy the declining surface, as it dips 

 northward so as to cross the laminae of the slate: and it is 

 worthy of remark, that the strike of the slate gradually winds 

 round this granitic promontory ; so that, approaching St. Paul, 

 it becomes N., and at length N.W. ; which fact may account 

 for the deviation of the elvan from a course parallel with the 

 granite-veins. 



The excellent examples of Cornwall have led us into 

 lengthened details, but not greater than the importance of this 

 topic requires : it is time, however, to turn to the granite- 

 veins of other countries. 



On the shore beyond Bunawe, says Macculloch*, in his 

 account of the Mountain Cruachan, the junction of the granite 

 with the schist is clearly seen. Two distinct varieties of 

 granite appear in this place : the one, a granite according to 

 the strictest acceptation of the term, consisting of reddish 

 felspar, quartz, and mica ; the other a syenitic granite, or a 

 compound of white felspar, mica, and hornblende. " These 

 are co-existent in every respect, and seem to pass into each 

 other, while both of them ramify in a similar manner through 

 the schist ; a sufficient proof, if any were wanting, of the geo- 

 logical identity of these two rocks, which have so improperly 

 been distinguished by the accidental presence or absence of 

 the single ingredient, hornblende." 



The schist which lies in the immediate vicinity of the 

 granite is highly indurated, and gives fire readily with steel ; 

 in other respects, it retains its general character, a laminated 

 structure, and alternating stripes of colour. 



Large veins proceed from the great mass of the granite, 

 and ramify into innumerable small divisions, penetrating and 

 traversing the schist in every direction. Although these 

 veins sometimes run through the schist in a distinct form, 

 just as they do in the junction of Loch Ranza, yet in many 

 places they are intermingled with it in the most remarkable 



* Geol. Trans., vol. iv. p. 120. 



