586 SUPPLEMENT. 



called gneiss by the Saxon miners, before the 

 term was transferred to the entire rock now so 

 denominated. 



Daubuisson, in his able translation of Werner's 

 work on Veins, has given two remarkable exam- 

 ples of the decomposition of granite, which may 

 best be explained in his own words*. 



" Near Bautzen, in Lusatia, in a hollow way, 

 there is a cut made into a granitic soil, which is a 

 mere assemblage of balls of granite, mostly a 

 fathom in diameter ; while the interstices are of a 

 granite, decomposed to such a degree that the 

 spot resembles a gravel-pit. The balls are cover- 

 ed with envelopes, consisting of many layers of 

 granite, also falling into decay. I observed one 

 ball which had thirteen of these envelopes, each 

 nearly an inch in thickness, and the more decom- 

 posed as they were distant from the kernel. A 

 ball detached from the mountain, having split in 

 the middle, afforded me an opportunity of observ- 

 ing the nature and structure of that kernel, which 

 consists of a fair solid granite, of a hardness and 

 freshness of colour, demonstrating that it has suf- 

 fered no alteration ; nor does it present any fis- 

 sure, nor any lineament of a structure in concen- 



* Theorie, 148. 



