Ch. III.] COMPARED WITH THOSE OF CORNWALL. 31 



range parallel to each other in a north and south direction ; 

 while these are frequently crossed under various angles by 

 others, which sometimes produce a heave or throw in the tra- 

 versed veins. They sometimes occur so numerously in a 

 narrow compass as almost to resemble a kind of net- work : the 

 position of these veins is generally vertical." * 



The granitic rocks of Saxony cannot fail to interest the 

 geologist, as the field in which Werner obtained no incon- 

 siderable portion of his knowledge on this subject ; but these 

 rocks cannot be satisfactorily described independent of the 

 primary schists with which they are associated. Indeed, this 

 is the case with all the patches of granite, not only in the 

 north of Europe, but in every other country. In conformity, 

 however, with the plan of this work, and with the general 

 opinion that the granitic and schistose rocks are of a very 

 different nature, a brief description of the granite of the 

 Erzgebirge will be attempted. 



In this mountain chain the granite is not of great extent, 

 only occurring in small patches near Freyberg and Altenberg, 

 on the eastern side ; and on the west, near Schwartzenberg, 

 it forms small hills, the summits of which are rounded, and of 

 little elevation. 



At Freyberg this rock is fine-grained, and composed of 

 grey or yellowish felspar, greyish quartz, and brown mica, in 

 nearly equal proportions, and without the admixture of any 

 other mineral. Near Altenberg the granite is similar, but, 

 in some parts, contains large crystals of felspar. In the 

 district of Schneeberg the granite is large-grained, and 

 assumes various appearances, according to the size of the 

 felspar crystals, which oftentimes impart a porphyritic cha- 

 racter ; in some places it decomposes very readily into por- 

 celain-clay, and in others it contains much black shorl, 

 crystallised or in nodules, and is traversed by granite veins, 

 which are fine-grained, and, near Schorlau, are metalliferous, 

 containing arsenical pyrites and sulphuret of molybdena. At 



* Geol. Trans., vol. v. p. 136. 



