DESERTED MINES. 



75 



commonly, in spite of their industry, they do not in a week 

 find particles of gold of the value of two piastres. Here, 

 however, as in every place where native gold and auriferous 

 pyrites are disseminated in the rock, or by the destruction 

 of the rocks, are deposited in alluvial lands, the people con- 

 ceive the most exaggerated ideas of the metallic riches of 

 the soil. But the success of the workings, which depends 

 less on the abundance of the ore in a vast space of land 

 than on its accumulation in one point, has not justified 

 these favourable prepossessions. The mountain of Chacao, 

 bordered by the ravine of Tucutunemo, rises seven hundred 

 feet above the village of San Juan. It is formed of gneiss, 

 which, especially in the superior strata, passes into mica- 

 slate. AVe saw the remains of an ancient mine, known by 

 the name of Real de Santa Barbara. The works were 

 directed to a stratum of cellular quartz,* full of polyhedric 

 cavities, mixed with iron-ore, containing auriferous pyrites 

 and small grains of gold, sometimes, it is said, visible to 

 the naked eye. It appears that the gneiss of the Cerro de 

 Chacao also furnishes another metallic deposit, a mixture of 

 copper and silver-ores. This deposit has been the object of 

 works attempted with great ignorance by some Mexican 

 miners under the superintendance of M. Avalo. The gal- 

 leryf directed to the north-east, is only twenty-five toises 

 long. We there found some fine specimens of blue carbo- 

 nated copper mingled with sulphate of barytes and quartz ; 

 but we could not ourselves judge whether the ore contained 

 any argentiferous fahlerz, and whether it occurred in a 

 stratum, or, as the apothecary who was our guide asserted, 

 in real veins. This much is certain, that the attempt at 

 working the mine cost more than twelve thousand piastres 

 two years. It would no doubt have been more prudent 

 have resumed the works on the auriferous stratum of the 

 Real de Santa Barbara. 



* This stratum of quartz, and the gneiss in which it is contained, lie 

 hor. 8 of the Freyberg compass, and dip 70 to the south-west. At a 

 hundred toises distance from the auriferous quartz, the gneiss resumes its 

 ordinary situation, hor. 3-4, with 60 dip to the north-west. A few 

 strata of gneiss abound in silvery mica, and contain, instead of garnets, 

 an immense quantity of small octahedrons of pyrites. This silvery gneisi 

 tesembles that of the famous mine of Himmelsftlrst, in Saxony, 

 f La Cueva de los Mexicanos. 



