ON THE VICINITY OF LOCH-LOMOND. 397 



the side of Loch-Katterin ; and it is probably of 

 the same formation, as this substance may be 

 traced for many miles in the general direction of 

 the strata along the intermediate country. 



On the west side of Loch-Lomond, between 

 Tarbet and Luss, mica-slate, talcky, and talc-slate, 

 with beds of greenstone and felspar-porphyry, are 

 found occurring in the same order of relative po- 

 sition, and with the same oryctognostic characters, 

 as the beds and strata already noticed in the struc- 

 ture of the mountain and its base : so that, com- 

 paring the distances and positions of the corres- 

 ponding rocks on each side, in the general line or 

 bearing of the strata, we perceive that they are 

 parts of one formation. 



Southward of Row Ardennan, the mica-slate 

 approaches to, and passes into clay-slate, and also 

 alternates with it. Clay-slate is found in the bed 

 of a stream called Cullimore, which forms the 

 southern extremity of the base of Ben-Lomond. 

 Amongst the rocks in this direction, the most re- 

 markable are two beds of felspar-porphyry, about 

 half a mile from Row Ardennan, which may be 

 traced to a great length, running from the water 

 into the high ground parallel to each other, and 

 separated only by a narrow stratum of mica-slate. 

 This stratum appears to maintain the same breadth, 

 so far as it is possible to follow the rocks ; and 

 along with the two beds, by which it is inclosed, 

 lies conformably with the other strata in its vici^ 



