288 A VISIT TO THE PROVINCES 



Through the first fifteen or sixteen feet to which the vein was explored, the only metals found 

 were ioduret of silver and native silver, the latter in very small proportion and in extremely 

 attenuated particles. The ioduret is in very narrow and wholly irregular filets, and is perfectly 

 pure, having no admixture of iodine or chlorine. Its gangue consists partly of carbonate of 

 lime, and partly of an extremely fine argil of a dark brick-red color. To this earthy substance 

 the small amorphous particles and veinules of ioduret seem to have given preference. An 

 analogous material also exists in the fissures at Arqueros, where Prof. Domeyko succeeded 

 in detecting traces of this rare silver ore of a fine citron color. Specimens of considerable size 

 and purity have since been found in the mines of Chanarcillo, and form part of the collec- 

 tion brought home by the expedition. An analysis and description by Prof. Smith will be found 

 in the Appendix. 



About a ton and a half of ore containing ioduret were extracted from Los Algodones above 

 the level mentioned ; and then, although the gangue remained the same, the product changed 

 to greenish chloro-bromide ores, similar to those of Chanarcillo. In its turn, this also disap- 

 peared, and was succeeded by chlorite of silver, the ore in the last case becoming cupriferous 

 and siliceous. 



Six hundred feet from the preceding vein, and parallel with it, a second has been found ; but 

 it contains no ioduret, and only a cupreous mineral with sulphuret and chlorite of silver in a 

 green silicated gangue, mixed with carbonate of lime. 



Between the valley of the river Barrasa and that of the Aconcagua, the granite formation 

 extends much farther to the eastward ; "the stratified formation is pushed towards the Cordilleras. 

 The calcareous and siliceous rocks of Chanarcillo and Agua Amarga are entirely wanting ; 

 only fossiliferous strata near the line of separation and stratified porphyries preponderate."* 

 Auriferous deposits have been found in a multitude of places in the granite section; and though 

 the most valuable ore is farthest removed from the ocean, there are more veins and washings 

 along the coast. Near Illapel, Petorca, and Andacollo, the deposits have been the most produc- 

 tive. Those near the contacts of granite and stratified rock have not ^infrequently copper veins 

 among them. Many of the ores from these, situated in the valley of Barrasa, are smelted on 

 the spot, and the rest are sent to Tongoy, whence they are shipped to Coquimbo or Valparaiso. 



Of the actual wealth of the mines in Aconcagua much less is known, and it is only by infer- 

 ence that we can arrive at an approximate result. Nature has interposed obstacles to their 

 transportation, even when liberated from the worthless earthy portions. There is no stream in 

 the province navigable by boats even for a short distance ; the whole face of the country is 

 broken by hills, across which there are only mule paths ; and unless the mines be found in the 

 vicinity of towns or supplies of fuel, none but the most valuable ores repay exploration. In 

 times past the province was famed for its gold washings, of which those of La Ligua, on a 

 hill just to the northward of Quillota, and of Catemo, twelve leagues nearer to the source of the 

 river, were among the most noted. The gold, disseminated in minute particles through sienite, 

 was extracted by amalgamation at establishments erected on the river, both at San Felipe and 

 Quillota. Dr. Darwin mentions valuable copper mines at Jajuel, a ravine east of San Felipe, 

 on the flank of the great Cordilleras. Its ores were all sent to England to be smelted. Speci- 

 mens have been brought from mines in the hill of San Lorenzo, and an account of them is given 

 in Prof. Smith's report. As Valparaiso exported in copper and its ores to the value of 

 $1,086,000 during the year 1850, and received from Atacama, Coquimbo, and the furnaces at 

 Talcahuano, only the value of $205,000 within the same period, there being no mines known in 

 the province of which it is the capital, it follows that Aconcagua. Santiago, and Colchagua have 

 furnished about $881,000. It is most probable that the greater portion was brought from 

 Aconcagua. 



As far back as 1803, a committee appointed under the captain generalcy of Guzman reported 



*Prof. Domeyko: Annales des Mines. 



