SILVER ORKS. 329 



wacke. In Sombrerete they occur in limestone ; and there are exten* 

 sive veins of the antinioni.il .sulpliuret, one of which ga\e in six months 

 700,000 marcs, (418,000 lbs. troy) ot silver. The Pachtca, Real del 

 Monte, and Moran districts, are near one another. Four great parallel 

 veins transverse these districts, through a decomposed porphyry. From 

 the vein Biscaina, in Real del Monte, $5,000,000 were realized by the 

 Count de Regla, in twelve years. 



In South America the Chilian mines are on the western slope of the 

 Cordilleras, and are connected mostly with stratified deposits, of a shaly, 

 sandstone, or conglomerate, character, or with their intersections with 

 porphyries. The chlorids and native amalgams are found in regions 

 more towards the coast, while the sulphurets and antimonial ores 

 abound nearer the Cordilleras. The mountains north of the valley of 

 Huasco contain the richest silver mines of Chili. The mines of Mt. 

 Chanarcillo produces at the present time more than 80,000 marcs of 

 silver per year. The veins abound in horn silver, and begin to yield 

 arsenio-sulphurets at a depth of about 500 feet. The mines of Punta 

 Brava, in Copiapo, which are nearer the Cordilleras, afford the arseni- 

 uretted ores. 



In Peru, the principal mines are in the districts of Pasco, Chota, and 

 Huantaya. Those of Pasco are 15.700 feet above the sea, while those 

 of Huantaya are in a low desert plain, near the port of Yquique, in the 

 southern part of Peru. The ores afforded are the same as in Chili. 

 The mines of Huantaya are noted for the large masses of native silver 

 they have afforded. 



The Potosi mines in Buenos Ayres, occur in a mountain of argilla- 

 ceous shale, whose summit is covered by a bed of argillaceous porphyry. 

 The ore is the red silver, the vitreous ore along with native silver. It has 

 been estimated that they have afforded since their discovery $1,300,- 

 000,000. These mines have diminished in value, though they still rank 

 next to those of Guanaxuato. 



In Europe the principal mines are those of Spain, of Kongsberg in 

 Norway, of Saxony, the Hartz, Austria, and Russia. The mines of 

 Kongsberg occur in gneiss and hornblende slate, in a gangue of calc 

 spar. They were especially rich in native silver, but are now nearly 

 exhausted. The silver of Spain is obtained mostly from galena, and 

 principally in the Sierra Almagrera in Grenada. 



The mines of Saxony occur mostly in gneiss, in the vicinity of Frey- 

 berg, Ehrenfriedem doif, Johangeorgenstadt, Annaberg and Schneebe-rg. 

 The ores of the Hartz aie mostly argentiferous copper pyrites and 

 galena, yet the red silver, vitreous silver ore, brittle silver ore, and ar- 

 senical silver, occur, especially at Andreaskreutz, and the mines of that 

 vicinity. The rock intersected by the deposits is mostly an argillace- 

 ous shale. Carbonate of lime is the usual gangue, though it is some- 

 times quartz 



In the Tyiol, Austria, sulphuret of silver, argentiferous gray copper, 

 and mispickel occur in a gangue of quartz, in argillaceous schist. The 

 Hungarian mines at Schemmitz and Kremnitz, occur in syenite and 

 hornblende porphyry, in a gangue of quartz, often with calc spar or 

 heavy spar, and sometimes iluor. The ores are sulphuret of silver 



Where are the principal mines in Europe ? 

 28 



