54 Sketch of the Mine of Pascd. 



heights of TuUuranca, in the chain of Alconoculpan, lake of Huisque 

 and Huarochiri. In all the rugged land which surrounds the ledge^ 

 as in the pampas of Bombou, the highlands of Pargas, Vinchos, 

 Cuypan, Vruda, Sic. this formation is visible and extensive ; the gi'es 

 is red, with yellow and white spots ; its grain is fine, rough to the 

 touch, and passes insensibly to the white, and argillaceous earth alter- 

 nating with strata of compact, white and blue limestone, and red and 

 green porphyry. In this sandstone or red gres, has been found in 

 small quantities, the cinnabar, near the tenements of St. Lovergo, 

 which is not strange, because the soil is just like that of Cuypan, and 

 lies in the same direction. This gres is varied by a darkish esquito, 

 in the strata, of small bulk, with limestone full of shells, (height of la 

 Vinda,) and with a cuarzolidio or touchstone, (chain of Colquijuca.) 

 From the center of the mine, some promontories of a quartzose rock, 

 full of cavities, rise up, of a yellowish color, like the ochre of iron ; 

 within it is of a dirty white, with a conchoidal fracture ; it passes in 

 some pieces to flint, but its qualities indicate it to be a quartzose por- 

 phyry, (hornslein.) Many fragments, and other pieces extracted 

 from one of the sky lights of the excavation, show the pudinga, (pud- 

 dingstone or conglomerate,) distinguished by iron pyrites and white 

 quartz. This composes all the hill of St. Catalina, hills of Yaua- 

 chancha, Chaupimarca, Caya, St. Rosa, Fraguarmachay, and ex- 

 tends to Ayapota, &;c. Li the interior of the mines, it passes to a 

 decomposed gres, as in the mines of St. Augustin, Descubridora, the 

 great mine of the Ijarras, of Tingo, he. the grain of which is loose, 

 is not as hard as that of the former, and is more mixed witli the ox- 

 ide of iron. This rock is the gangue of metals kno^vn by the name 

 of paces, which compose all the soil of St. Rosa. Here no stratifi- 

 cation is perceptible on the surface, nor m the interior ; it is nothing 

 more than a shapeless mass of metals extracted in abundance, with- 

 out the necessity of gunpowder. Thousands of loads are here found, 

 about five or six marks in value, which do not defray the expenses, 

 when the quicksilver is dear. The metals exploded in the mines 

 which have been mentioned, are extracted from a very distinct stra- 

 tum, which is found decomposed in this rock, and anotlier of pyrites. 

 There is a dispute whether it is really a stratum or a vein ; tlie miners 

 commonly call it a vein, and Trevithich, a miner and engineer of 

 Cornwall, who was some years in the mine, has fallen into the same 

 mistake. No quality or sign favors tliis supposition. 



