LOCH-KATTERIN. 287 



penetrated with innumerable veins of quartz, 

 which are sometimes straight, oftener undulating, 

 and indeed infinitely diversified in their shapes 

 and appearances. These veins, in most instances, 

 are seen entire, that is, completely included or 

 terminated in the mass of the rock ; and lead ir- 

 resistibly to the idea of cotemporaneous veins, 

 forming an apposite illustration of what has been 

 described and figured by Professor Jameson, in his 

 paper on that subject, formerly read to this Society *. 



The rock to which I now refer, is fine slaty, 

 bordering on clay-slate. We then observe, as we 

 proceed, a species of mica- slate, in which the 

 quartz predominates to such a degree as renders 

 it peculiarly tenacious and indestructible. It has 

 a brecciated aspect, and contains small crystals or 

 particles of a matter belonging to to the calcare- 

 ous tribe, which, when of a brownish colour (pro- 

 bably rhomb-spar) seems to have been mistaken 

 for felspar.. From the appearance which this lat- 

 ter substance gives it, the rock has usually been 

 considered as granite, by the people of the neigh- 

 bourhood ; but that mineral, so far as my obser- 

 vation extends, does not occur in the vicinity of 

 Loch-Katterin,- — In other beds, the slaty struc- 

 ture is very minute, and the rock is intimately 

 mixed with hornblende of a greyish-green colour, 

 which gives it a distant resemblance to horn- 

 blende-slate. We also find beds in which the 



Antea> p. 1, &c. 



