BEN-NEVIS. 



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the geognostic result of the investigation enables 

 me to say, that this enorrrious body of rock is an 

 overlying massive formation, in which felspar is 

 the leading ingredient ; that the particular rocks 

 of this species, which form the inferior mass of 

 Ben-Nevis, are (conformably to geognostic prin- 

 ciple in such a case) varieties of Sienite, passing 

 from the simple granular into the granular por- 

 phyritic, — also sienite-porphyry, and porphyritic 

 compact felspar, all of which have in general a 

 reddish aspect ; and that the upper part of the 

 mountain, comprehending the summit, with about 

 one-third of the whole ascent, and from icoo to 

 1500 feet of perpendicular height, is composed of 

 a substance allied to felspar, which is for the most 

 part porphyritic, and much tinged with the mat- 

 ter of hornblende, giving the mass a deep-green or 

 darkish colour. This rock, into which the com- 

 pact felspar evidently passes, by the addition of a 

 colouring substance, I must leave to further ex- 

 amination, without presuming to assign it a name 

 or place, in the Wernerian system of mineralogical 

 arrangement. 



The portion of the great deposition, which thus 

 assumes a darkish hue, has somewhat the shape of 

 a vast wedge sunk into the body of the mountain, 

 so that from a particular point in the hollow be- 

 neath, it may be traced up to the bottom of the 

 precipice, in the form of a fan widely spread. 

 This is perceived, by surveying attentively the 

 north-east front of the precipice, which, as Mr 

 Willi ams has observed, exhibits a magnificent 



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