VEINSTONES. 



669 



others are divided from the rock by the salband, 

 or by the besteg of clay. The ore passing into 

 the chinks of the rock, sometimes for a few inches, 

 never more than a yard, is always in a leafy or 

 superficial form. In different mining districts of 

 Germany, several silver ores are wrought in the 

 decomposed gneiss of the rock adjacent to the 

 salbands of the mine ; and at Kongsberg in Nor- 

 way, native silver appears in gneiss, mica-slate, 

 and hornblende. Copper, galena, and even tin, 

 sometimes assume the same appearance. 



Sometimes fragments of the rock have dropped 

 into the vein, and been enveloped in its substance. 

 But Werner seems to elude a great difficulty, the 

 similar appearance of masses of mineral, by the 

 French called poches or pockets, which have been 

 accidentally discovered at detached and wide in- 

 tervals, in the solid body of the rock. 



It must not be conceived that all veins are me- stoi 

 talliferous. Many, on the contrary, disappoint 

 the hopes of the miner, and are found to consist 

 entirely of stone. Werner mentions veins of gra- 

 nite, porphyry, limestone, basalt, wacken, and 

 grunstein. He adds, that in some parts of Saxony 

 veins are found of small-grained granite, in a rock 

 of mica-slate, and these veins are traversed and 

 deranged by veins of silver, which proves that the 

 granitic veins are more ancient. In other districts 



