39S 



ILLUSTRATIONS OF THE 



motion, merely by their own weight. It is in, 

 deed remarkable, that fome of the largeft of thefe 

 ilones reft on very narrow bafes. Thofe at the 

 foot of Saleve touch the ground only in a few 

 points : The Boulder-ftone of Borrowdale is 

 fupported on a narrow ridge like the keel of a 

 fhip, and is prevented from tumbling by a ftone 

 or two, that ferve as a kind of fliores to prop it 

 tip. Very unexpected accidents foraetimes hap- 

 pen to difturb the reft of fuch fragments of 

 rock as have once migrated from their own 

 place. Sauftlire mentions a great mafs of lapis 

 qllaris *, that lies detached on the fide of a de- 

 clivity in the valley of IJrfercn, in the canton of 



J 



Pri. The people ufe this ftone as a quarry, and 

 are working it away on the upper fide, in 

 confequence of which it will probably be foon 

 overfet, and will roll to the bottom of the val- 



ley. 



356. In many indances it cannot be doubted, 



that ftones of the kind here referred to arc 



the remains of mafles or veins of whinftone or 



granite, now worn away, and that they have 



travelled but a very fliort way, or perhaps not 



at all, from their original place. Many of the 



large blocks of whinftone which we find in this 



country, fometimes fingle, and fometimes fcat- 



tered 



* Voyages aux AlpeSj tom.iv. § 1851 



O 



