MINES AND MINING. 



MINERAL REGIONS OF MEXICO. 



33 



"Mex'co," says Lyell, "originally consisted of granitic ranges, with intervening 

 valleys, subsequently filled up to the level of the plateaus by subterranean erup- 

 tions, as igneous rocks of every geologic epoch to a large extent form the super- 

 structure of the central plateau. The most elevated regions are composed, espe- 

 cially the high ranges, of plutonic and volcanic rocks, although a great portion 

 of the plateau is metamorphic, and contains the greatest variety of ores." Says 

 another authority: "A line drawn from the capital to Guanajuato, and thence 

 northward to the southwestern point of Chihuahua, and southward to Oaxaca, thus 

 cutting the main axis of upheaval at an angle of 45°, will intersect probably the 

 richest known argentiferous region in the wliole world ! " 



In a genera] way it may be said that a metalliferous vein runs through the entire 

 Cordillera of Mexico, extending from the mines of the Sierra Madre in Sonora, — 

 in the far northwest, — to the gold-deposits of Oa.xaca, in the extreme south. The 

 mineral districts most distinguished for their productions of silver and gold are 

 those of Guanajuato, Zacatecas, Fresnillo, Real del Monte, Pachuca, Catorce, Tasco, 

 and Oaxaca. 



As the relative importance of mines is largely due to their proximity to great 

 centres of population, the mines of Pachuca, — including those of Real del Monte, 

 Chico, Capula, Santa Rosa, etc., — should fi!-st claim attention, being distant from 

 the capital less than seventy miles. This group, in the State of Hidalgo, covers an 

 area of twenty-five kilometres from north to south, and thirty-three from east to 

 west. A second cluster is that of the district of Tasco, and those of Zacualpan, 

 Sultepec, Angangeo, Tlalpujahua, and Zimapan. These groups, with those of 

 Oaxaca, describe a circuit round about the City of Mexico, though open towards 

 the east with a radius of about two hundred kilometres. 



The districts of Guanajuato and Zacatecas form two groups, important for 

 their numerous and industrious population. An offshoot from the main cordillera is 

 the district of Catorce, north of San Luis Potosi. The states of Sonora, Oaxaca, 

 Michoacan, Chihuahua, and Guerrero, abound not only in the precious metals, but 

 in copper, iron, lead, zinc, etc. The most notable of these are the hills of iron in 

 Durango and Oaxaca, and the copper found in Michoacan, and Chihuahua. 

 Humboldt divided the Mexican mines into eight groups : the first, and most 

 considerable, includes the almost contiguous districts of Guanajuato, San Luis 

 Potosi, Catorce, Fresnillo, and Sombrerete ; those to the west of Durango and 

 Sinaloa form the second; the third group comprehends the mines of Chihuahua, 

 and is the most northern ; northwest of Mexico City lies the Real del Monte or 

 Pachuca; those of Zimapan or el Doctor, the fifth; Boianos, in Guadelajara, 

 is the central point of the sixth ; Tasco, of the seventh, and the mines of Oaxaca 

 the eighth. 



That part of the Mexican mountains containing the greatest quantity of silver 

 lies between the parallels of 21° and 24° 30' north latitude. 



" It is remarkable," says Humboldt, (then, of course, being ignorant of the vast 

 deposits of Nevada and Arizona), " that the metallic wealth of Mexico and Peru 

 should be placed at an almost equal distance, in either hemisphere, from the 

 equator." 



