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20 millions of livres tournois.*

The most part of these veins are found in a compact limestone, which contains like that of the Sauceda flint-slate, and lydian stone.

The deepred 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 width † (puissance). Near Sombrerete the mountains of secondary calcareous formation, rise much above the porphy. ritic mountains. The Cerro de Papanton appears to be more than 3400 metres f, above the level of the sea.

The mineral repository of Catorce, holds ac 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 two centuries. 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.
+ More than 3 feet 3 inches. Trans.

# 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 volcanic productions, and contain olivine, zeo. lite, 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 slate ; and the latter perhaps is superimposed on the sye. nitic rock of the Buffa del Fraile. The greatest number of these veins are western (spathgänge); and their inclination is from 250 to 30° towards the north-east. The minerals which form the gangue are generally found in a state of decomposition. They are wrought with the mat. tock, 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 Caronado, and Antonio Llanas, two very poor individuals, discovered veins in a situation now called Cerro de Ca. torce 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 Manuel 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, Dan Barnabé Antonio de Zepeda, a miner of the Ojo del Agua de Matchuala, investigated during three months this group of arid and calcareous mountains. After attentively examining the ravins, he was fortunate enough to find the crest or

or surface of the veta grande, on which he immediately dug the pit of Guadalupe. He drew from it an immense quantity of muriate of silver, and colorados mixed with native gold; and gained in a short time more thon 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 piastres t; 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 piastres ; and its produce in 1796 amounted to 1,200,000 piastres, while the expences 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. Trans.

From 164 to 328 feet. Trans.
$ £ 43,752 sterling. Trans.

the same with that of Padre Flores, sometimes reaches the extraordinary extent of 40 metres* ; and it was worked in 1802 to the depth of 480 metres. Since 1798, the value of the minerals of Catorce has singularly diminished ; the native silver is now . rarely to be seen ; and the metales colorados, which are an intimate mixture of muriate of silver, earthy carbonate of lead, and red ocre, begin to give place to pyritous and coppery minerals. The actual produce of these mines is nearly 400,000 marcs of silver annually. I

The mines of Pachuca, Real del Monte, and Moran, are highly celebrated for their antiquity, their wealth, and their proximity to the capital. Since the beginning of the eighteenth century, the vein of la Biscaina, or Real del Monte, has alone been wrought with activity. The working of the mines of Moran was only resumed within these few years; and the mineral depository of Pachuca, one of the richest of all America, has been wholly abandoned since the terrible fire which took place in the famous mine del Encino, which alone furnished more than 30,000 marcs of silver annually.S The wooden work which supported the roof

* 131 feet. Trans.
t 1574 feet. Trans.
| 262,526 lb. Troy. Trans.
$ 19,689 lb. Troy. Trans.


of the galleries was consumed by fire, and the greatest number of the miners were suffocated before being able to reach the shafts. A similar conflagration in 1787, put a stop to the working of the mines of Bolaños, which were only again begun to be cleared out in 1792.

The valley of Mexico is separated from the basin of Totonilco el Grande, by a chain of porphyritic mountains, of which the highest summit* is the peak of the Jacal, elevated according to my measurement with the assistance of the barometer, 3124 metrest above the level of the

This porphyry serves for base to the porous amygdaloid, which surrounds the lakes of Tezcuco, Zumpango, and San Christobal. It seems to be of the same formation with that, which in the road from Mexico to Acapulco, immediately covers the granite between Sopilote and Chilpansingo, near the village of Acaguisotla, and l’Alto de los Caxones. To the north-east of the district of Real del Monte, the porphyry is at first concealed under the columnar basalt of the farm of Regla, and farther on in the valley of Totonilco, under beds of secondary formation. The Alpine limestone of a greyish blue, in which is the famous cavern of Danto, called also the pierced moun

* See my Nivellement Barometrique, p. 40–42 n. 290—-312. † 10,248 feet. Trans.

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