BEN-NEVIS. 337 



place, while the motion continues, and a sort of 

 medium density may be the result. 



STONE-BUllN* 



The common ascent, and the summit, of Ben-* 

 Nevis, being thus examined, my next object, 

 when I resumed the investigation, was to survey 

 the mountain, on the opposite or precipice-side. 

 This is done by following upwards the course of 

 the two streams, called the Mill-Burn, and the 

 Stone-Burn. For it is only in the channels of 

 these rivulets, that we find the rocks on this side ? 

 laid bare for examination. These channels were 

 traced with great attention ; and I trust that no- 

 thing of importance in their contents escaped my 

 notice. 



In ascending, then, from the bottom of these 

 streams, a succession of characters in the appear- 

 ance of the rocks, similar to that which has been 

 described on the way to the summit, is found to 

 take place. Having observed the mica-slate con- 

 taining small disseminated shorl, and the beds of 

 gneiss, w hich running as 1 usual with an inclina- 

 tion of 70°, appear to form the base of the country 

 on the west and north ; we meet at first with a 

 species of sienite, in which the prevalence of the 

 hornblende intermixed with mica, and the grey- 

 ish-white colour of the felspar, give the rock the 

 aspect of grey, and sometimes a tendency in its 



y 



