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tain. This wealth is displayed, and the fact is very remarkable, not in the ravins, and where the veins run along the gentle slope of the mountains, but most frequently on the most elevated summits, on points where the surface appears to have been tumultuously torn, in the antient revolutions of the globe. The mines of Zacatecas produce yearly at an average, from 2500 to 3000 bars of silver, at 134 marcs each*.
The mass of the veins of this districtt con: tains a great variety of metals, viz: quartz, splintery hornstone, calcareous spar, a little of the sulfate of baryte and brown spar; prismatic black silver called in the country uzul acerado; sulfuretted silver, (azul plomilloso) mixed with native silver; fuligenous silver (the silberschwärtze of the Germans, polvorilla of the Mexicans); pearl grey, blue, violet, and leek green muriated silver, (plata parda azul y verde) at very inconsiderable depths, a little red silver (petlangue or rosicler); and native gold, parti
* From 219,866 to 263,839 lib. Troy. Trans.
+ Sonneschmidt, p. 185. The minerals called by the inhabitants of Zacatecas copalillo, metal cenizo, and metal azul de plata, appear to this mineralogist mixtures of galena, sulfuretted silver, and native silver. I have thought proper to insert these synonimes of the Mexican minerals, because their knowledge is very important to the mineralogical traveller. See Garces, Nueva Theoria del beneficio de los metales, p. 87, 124, and 138.
cularly to the south west of the town of Zao catecas; argentiferous sulfuretted lead (soroche plomosa reluciente y tescatete); carbonated lead; black, brown, and yellow sulfuretted zinc, (estoraque and ojo de vivora); pyrite of copper and iron (bronze nochistle, or dorado, and bronze chino); magnetical oxyduloted iron; blue and green carbonated copper, and sulfuretted antimony. The most abundant metals of the celebrated vein called the veta grande, are prismatic black silver (sprödglaserz), sulfuretted ro vitreous silver, mixed with native silver and silberschwärze.
The Intendancy of Zacatecas contains the mines of Fresnillo, and those of Sombrerete. The former are very feebly wrought, and are situated in an insulated group of mountains, which rise above the plains of the central table land. These plains are covered with porphyritic formations; but the metalliferous group itself is composed of grauwakke. According to the observation of M. Sonneschmidt, the rock is traversed there by an innumerable quantity of veins, rich in grey and green muriated silver. · The mines of Sombrerete have become celebrated, from the immense riches of the vein of the veta negra, which in the space of a few months left to the family of Fagoaga, (Marques del Apartado) a net profit of more than
20 millions of livres tournois*. The most part of these veins are found in a compact limestone, which contains like that of the Sauceda kiesel slate, and lydian stone. The dull red silver particularly abounds in this district of mines; and it has been seen to form the whole mass of the veins which have more than a metre in extentt (puissance). Near Sombrerete the mountains of secondary calcareous formation, rise much above the porphyritic mountains. The Cerro de Papanton appears to be more than 3400 metrest, above the level of the sea.
The mineral depository of Catorce, holds at present the second or third rank among the mines of New Spain, classing them according to the quantity of silver which they produce. It was only discovered in the year 1778. This discovery, and that of the veins of Gualgayoc, in Peru, vulgarly called the veins of Chota, are the most interesting in the history of the mines of Spanish America, for the last twocenturies. The small town of Catorce, the true name of which is la Purissima Concepcion de Alamos de Catorce; is situated on the calcareous table land, which declines towards the nuevo reyno de Leon, and towards the
* £ 833,400 Sterling. Trans.
I 11,184 feet. Trans.: *
province of New Santander. From the bosom of these mountains * of secondary compact limestone, masses of basalt, and porous amygdaloid rise up as in the Vicentin, which resemble voleanic productions, and which contain olivine, zeolite, and obsidian. A great number of veins of small extent, and very variable in their breadth and direction, traverse the limestone, which itself covers a transition clay state ; and the latter perhaps is superimposed to the syenitic rock of the Buffa del Fraile. The greatest number of these veins are western (spathgänge); and their inclination is from 25° to 30° towards the north east.f The minerals which form the gangue are generally found in a state of decomposition. They are wrought with the mattock, the pickaxe, and with the bore, (pointrole.) The consumption of powder is much less than at Guanaxuato, and at Zacatecas. These mines possess also the great advantage of being almost entirely dry, so that they have no need of costly machines to draw off the water.
In 1773, Sebastian Coronado, and Antonio, · Llanas, two very poor individuals, discovered veins in a situation now called Cerro de Catorce Viejo, on the western slope of the Pi
* Near the mine del Padre Flores, and on the road from San Ramon to Catorce, ( Sonneschmidt, p. 279.)
+ Descripcion del Real de Catorce, por Don Jose Monuel Gonzales Cueto, 1800 (Manuscript).
chaco de la Variga de Plata. They began to work these veins, which were poor and inconstant in their produce. In 1778, Don Barnabé : Antonio de Zepeda, a miner of the Ojo del Agua de Matchuala, went over during three months, this group of arid and calcareous mountains. After attentively examining the ravins, he was fortunate enough to find the crest or surface of the veta grande, on which he immediately dug the pit of Guada. lupe. He drew from it an immense quantity of muriated silver, and colorados mixed with native gold; and he gained in a short time more than half a million of piastres*. From that period, the mines of Catorce were wrought with the greatest activity. That of Padre Flores alone produced in the first year 1,600,000 piastrest; but the vein only displayed great riches from 50 to 150 metrest of perpendicular depth. The famous mine of Purissima belonging to Colonel Obregon, has scarcely ever ceased since 1788, to yield annually a net profit of 200,000 piastresg; and its produce in 1796 amounted to 1,200,000 piastres, while the ex- pences of working did not amount to more than 80,000. The vein of Purissima, which is not
* € 109,383 sterling. Trans. + Upwards of 350,000 sterling. Transa † From 164 to 328 feet. Trans. $ $ 43,752 sterling. Trans.