582 SUPPLEMENT. 



and alleged by Werner, among his arguments, 

 that the veins were filled from above. Such is a 

 bricia, consisting of little fragments of barytes in 

 a cement of bluish grey fluor. But he particular- 

 ly instances the celebrated bricia of agate, found 

 at Schlotwitz near KunersdorfF. This singular 

 Agate bricia. and beautiful stone consists of large and small 

 fragments of a fine ribon agate, which forms a 

 powerful vein in that spot ; the fragments being 

 joined by a cement of amethyst and quartz. In 

 the polished specimens there are fragments, of 

 which the parts correspond so exactly, that it is 

 evident that they must have dropped from the 

 same portion of the vein. 



Among singular veinstones may also be classed 

 pebbles, pebbles. Werner mentions that a vein of pebbles 

 of gneiss, fourteen inches in thickness, was found 

 at the depth of 180 fathoms. In Hessia, a vein 

 of cobalt, almost vertical, was traversed by an- 

 other vein consisting almost entirely of sand and 

 gravel. At Chalanches in Dauphiny, several 

 veins are entirely filled with rolled pebbles. But 

 one of the most remarkable examples is reported 

 by M. Duhamel, in his Subterranean Geometry. 

 The principal vein of the mine of lead containing 

 silver, at Huelgoat in Lower Brittany, is accom- 

 panied, as well on the roof as on the sole, with 

 ten or twelve feet in thickness of rolled stones or 



