646 



GEOLOGY. 



composed. Wherever I turned my eyes, the beds of rock in the chains of secondary 

 mountains, and even in the primary mountains of the second order, rise toward Mont 

 Blanc and the lofty summits in its neighbourhood. The escarpments of these beds of rock 

 were all facing Mont Blanc ; but beyond these chains were others, whose escarpments 

 were turned in a contrary direction. Notwithstanding the irregularity in the forms and 

 distribution of the great masses that surround Mont Blanc, and those which constitute 

 the mountain itself, I could trace some features of resemblance not less certain than im- 

 portant. All the masses that I could see were composed of vertical plates, and the 

 greater part of these plates were ranged in the same direction from north-east to south- 

 west. I had particular pleasure in observing the same structure in the lofty peak of 

 granite called the Col du Midi, which I had formerly endeavoured, but in vain, to 

 approach, being prevented by inaccessible walls of granite. After the second day's 

 ascent, this lofty pinnacle was beneath me ; and I fully convinced myself that it is 

 entirely composed of magnificent plates of granite, perpendicular to the horizon, and 

 ranging from east to west. I had' formerly been induced to believe that these plates 

 were folded round the peak, like the leaves of an artichoke ; but this was an optical illu- 

 sion, when seen imperfectly from below. Here, where the eye could as it were dart down 

 into the interior structure of the mountains, the plates of rock appeared regularly parallel 

 in a direct line. I was also particularly desirous of ascertaining, whether the vertical 

 beds were composed of the same substances at their summits as at their bases, where I 

 had so frequently inspected them; and I am perfectly satisfied, from actual examination, 

 that they preserve the same nature through their whole extent, and are the same at the 

 summit as below." The vertical position of the beds of granite composing the chief part 

 of Mont Blanc, and the Col du Midi, together with the same arrangement of adjoining 

 stratified formations, and their general direction towards the point of highest elevation, 

 profoundly impressed the mind of Saussure with the conviction, that this configuration 

 had been produced by forces acting from beneath. Viewing, however, the Alps in the mass, 

 we do not contemplate the effect of a single operation of nature, as was formerly imagined, 

 but the result of successive elevations taking place, after great and unequal intervals. 



Ben Lomond from the Lake. 



