282 



A VISIT TO THE PROVINCES 



been found at an elevation of 7,000 feet. An interesting account of them is given by Dr. 

 Darwin, in the narrative of his journey over the Uspallata Pass. 



Generally, veins of gold and copper are found in the formation of which a detailed account 

 has been given ; those of silver, argentiferous copper, sulpho-arseniates and sulpho-antimoniates 

 of silver, in rocks of the secondary formation. Subdividing the former into ancient and rocks of 

 sublevation, gold veins are found in the midst of the ancient granitic masses, and copper veins 

 (non-argentiferous and without antimony or arsenic) among diorites, dioritic porphyries, sien- 

 ites, &c. } composing the strata in the vicinity of the upheaved formation. Examining in like 

 manner the distribution of silver, we find chlorides and native amalgams near the principal line 

 of contact of the primary and secondary groups in the vicinity of the sea; arseniates and 

 sulpho-arseniates, cupriferous and argentiferous, farther east ; and argentiferous sulphurets of 

 copper, sulphuret of lead, argentiferous blendes, and pyrites, still nearer to the Andes. When 

 all of these silver ores are encountered in the same lode, they are arranged in nearly the same 

 order, those first named being nearest to the surface. Quicksilver is found in both formations : 

 sometimes associated with gold and copper, sometimes with silver. In the first case it appears 

 only as a sulphuret or chloride, and in the second as native amalgam. This general law is 

 exact only as applied to the principal mines of the country ; such as are remarkable either for 

 the abundance or richness of their ores, and whose veins have been called by miners vetasreales 

 (royal or veritable veins). As they are invariably of considerable extent, the name is really due 

 to them; and in this respect they differ from others called guias (literally, guides), which often 

 depart from the law, and present to us inexplicable anomalies. 



A review of the principal mines will properly commence with Atacama. The portion of Chile 

 which lies north of the valley of Huasco is undoubtedly the richest in mineral products, but is 

 more especially so in silver, whose veins have seduced most of the gold and copper miners from 

 their old pursuits. At the close of 1842, the number of mines worked in the department of 

 Copiapo one of the three forming the province were, 100 of silver, 4 of gold, and 40 of cop- 

 per. Eight years afterwards the number had increased to 290 of the first, and 6 of the second' 

 whilst the number of the last had diminished to 30. No wonder copper mines should be 

 deserted, when ores yielding twenty-five per cent, of pure metal could be purchased in the city of 

 Copiap6 at $39 per ton of 2,240 pounds as late as 1851. Late and definite information as might 

 be wished from the other two departments is not obtainable, the Intendente whose report has 

 been referred to having been prevented from personally inspecting them by want of time and ill 

 health. The account published by Prof. Domeyko in the Annales des Mines, Vol. IX, for 1846 

 is the latest I have seen ; and from this are extracted such facts as relate to the mines south of 

 27^, except the statistics embraced in the subjoined table, which is compiled from the Inten- 

 dente' s memoir : 



