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78 former locality, as well as at Tasco and Catorce, are poor in gold; while those of the latter town, and also at Guadalupe y Calvo, are rich in their percentage of the same metal.

Perhaps the two most remarkable mineral veins of North America, excepting the famous Comstock lode of Nevada, are the veta madre of Guanajuato and the veta grande of Zacatecas. These veins have been worked for about three hundred years. (Vide section on the Mexican Central Railroad, for description.) The region adjoining these mining towns is an elevated desert, similar to the environs of Virginia City in Nevada.

Next to argentiferous deposits in importance are the immense beds of iron, which consist principally of the oxides called magnetite and hematite. The well-known Cerro del Mercado, in the State of Durango, has been calculated to contain sixty million cubic yards of iron-ore, having a specific weight of five billion quintals. An analysis of this ore by Mr. M. H. Borje, of Philadelphia, Pennsylvania, gave 66 per cent of pure metal. There are other vast hills of iron in Sonora, near Coalcoman, in Michoacan, and in the central part of the State of Oaxaca.

Lead-ores, usually in the form of galena and oftentimes argentiferous, are abundant throughout the country.

Copper, either native or as oxide, carbonate, or sulphide, is mined at various localities in Chihuahua and Oaxaca, at the towns of Mazapil and Jalapa, and near the volcano of Jorullo.

The oxide of tin is found in veins and alluvial beds at Durango.

Mercury occurs combined with sulphur, i. e., cinnabar, in the States of Querétaro, San Luis Potosí, Michoacan, Oaxaca, Chihuahua, and Guanajuato. Zinc-ores are met with in Chihuahua; and platinum, antimony, cobalt, and nickel come from the same State. These last-named metals, however, are not found in large quantities.