3^2 ON THE HIGHLANDS. 



vered, and decompose in such a manner, that it is 

 difficult to ascertain whether or no they are dis- 

 posed in beds, and if they are so, to determine 

 precisely their dip and direction. Splitting, in- 

 deed, in rhomboidal masses, they appear in one 

 view to consist of layers or strata, which main- 

 tain a pretty regular bearing, east of north, with 

 an inclination of 75 0 \ dip north of west. But an- 

 other view presents uniform lines of separation 

 in the mass, which suggest the idea of a dip and 

 direction entirely different ; a circumstance, which 

 is probably owing to the structure of the stone, 

 as occurring in tabular distinct concretions. 



It then struck me, that the junction I had 

 sought in vain, might perhaps be found laid open 

 on the opposite side of the mountain, along the 

 front of the precipice. With this hope, which it 

 will afterwards appear was not unfounded, I con- 

 soled myself for the disappointment now suffered, 

 and resumed the ascent, along which, the dark 

 coloured rock soon begins, by the addition of em- 

 bedded crystals, or concretions, of reddish fel- 

 spar, to exhibit a porphyritic aspect. These 

 crystals or nodules, are of great size in some 

 places, particularly near the summit, where we ob- 

 serve them as large as a common brick, or even 

 larger, and of a similar appearance and shape. 

 When they are of an ordinary size, and uniform- 

 ly disseminated through the mass of the rock, as 

 it occurs at different places of the ascent, we 

 have a regular and excellent porphyry, of which the 



