productive within a very little distance from the surface (usually from ten to fifteen yards); whereas the Veta Madre of Guănăjūātŏ yields little or nothing until the depth of eighty yards is attained. The metals seem to increase in richness as you approach the North; insomuch that in the Real, or District, of Jesus Maria, in that great branch of the Sierra Madre, which separates the States of Durango and Chihuahua, from those of Sonora and Sinaloa, to the North and West,—the ores of the mine of Santa Juliana (which does not exceed seventy yards in depth) appear, by a certified Report from the Diputacion de Mineria, now before me, to average seven and eight marcs of silver per carga, of (300 lbs.,) which is the average produce often cargas of good ore in Guănăjūātŏ; while ores of the best quality yield as much as from four to ten marcs per Arroba, (of 251bs.) or forty marcs per carga.
At Bătŏpīlăs, (in the State of Chĭhūāhuă,) where the matrix is, in general, quartz, the pure malleable silver intermixed with it often exceeds in proportion one half; and masses of this description, of the weight of eleven Arrobas, (270 lbs.,) have been raised. One of five Arrobas in weight, (125 lbs.,) was in existence at Chĭhūāhuă during my visit to the North, and I was even solicited to purchase it for the British Museum.
Only three Districts in the North have been, hitherto, worked with any sort of regularity, Santa Eŭlālĭă, Bătŏpīlăs, and Guārĭsămĕy.
