MINERALOGY. ^5 



inclining to blue. They yield a greater proportion of silver 

 than any others which have hitherto been discovered in Peru. 



The mountainous and mineral territory which is under 

 consideration, being taken in its whole extent, consists of 

 the above-mentioned mines of Santa Rosa and Lauri-Cocha, 

 together with those of Yanacancha, Caya, Cheupimarca, 

 and Pariajilca. That of Cheupimarca, although replete with 

 rich ores, has been but little worked, in consequence of the 

 water having gained on it at the commencement. The ores 

 extradled from these mines are of a yellow colour with red- 

 dish spots, and commonly yield from six to twelve marks 

 per caxon*. A bank, commonly denominated the royal 

 mantle^ stretches over a territory of upwards of a league and 

 a half in circumference ; and it therefore happens that the 

 mines are not limited to the direction of the veins. In the 

 year 1789, from fifteen to sixteen thousand caxons of ore 

 were extracted ; and about a hundred and twenty thousand 

 marks of silver refined in the royal foundery of Pasco. 



To the west of the mineral territory, at the distance of 

 two leagues and a half, lies the mountain of Raco, having 

 the form of a cylinder truncated at the point. It is entirely 

 composed of white granite, which, on being thrown into 

 water, changes its colour to a dusky blue. It is of a very 

 firm texture, is named ala-de-mosca, and is of great utility 

 in the constru6lion of buildings. 



The river which runs through the above territory, and 

 which extends from six to seven leagues, branches off into 



* The mark weighs half a pound, and the caxon contains two tons and a 

 half. 



K several, 



