*

shores and fall an easy prey to the hunter. On the gulf side the_pearl fisheries have been among the most famous in the world for more than a century. Ever since its commencement, the annual yield has averaged about $25,000 per year, and it is still carried op, but with diminished activity.

CONCLUSION.-By reading the foregoing imperfect sketch it will be seen that while Lower California is by no means the faultless country it might be; while by tar the greater portion can never be made available for either mining, agricultural, grazing or any other purposes; while its mines are few, its agricultural lands limited, and its supply of water small, still its position, its harbors, its climate, and its resources are sufficient to give it a real intrinsic value. From its position with relation to Upper California, it is much more an appendage to this State than to Mexico, out of sight across the "Sea of Cortez." It commands the mouth of the Colorado, and thus affects the trade of the great interior basin east of the Sierra Nevada. Its harbors are neither few nor small, and they have a direct value with reference to our trade and navy in the Central Pacific. Its agricultural products can be increased in quantity; its fisheries are, as yet, in their infancy, and its mines alone would be sufficient reason for its acquisition by the United States. Further, everywhere outside of the moral influence of La Paz, the seat of government, the people, are earnestly in favor of annexation, and I am by no means certain that a popular vote ou the question would not result in a decided majority in favor of such a measure.

MEXICO.

MINING IN MEXICO.-Mexico is peculiarly a mining country, and indeed it has no industry worthy of note save mining. The exportation of agricultural products and manufactured articles does not average 75 cents annually to the inhabitant, while in highly civilized states the average is from $10 to $50.

All the past and present importance of Mexico in the commercial world is due to its silver, which attracted the Spaniards to the country and fixed there and determined the location of their towns. With the exception of the capital, to which, of course, the wealthy men resorted to spend their money, Puebla and Guadalajara, manufacturing towns, and Vera Cruz and Mazatlan, seaports, all the largest towns were built in the immediate vicinity of the mines, or in the agricultural districts nearest the mines. Guanajuato was a place of minor note till its great mineral wealth was discovered in the middle of the last century, and then it suddenly rose to be the second city of the country, and the adjacent plains of Bajio at the same time grew rich by agriculture; and in the same way the mining town of Zacatecas and the agricultural district of Aguas Calientes grew up side by side. Durango, Chihuahua, San Luis Potosi, Alamos, and hundreds of others of less note are strictly mining

towns.

The total registered yield of the mines of Mexico from 1521 to 1803 is reported by Humboldt at $1,767,952,000, and he thinks that an allowance of one-seventh should be made for the unregistered yield, giving a total of $2,027,952,000. Ward estimates the quantity produced from 1810 to 1825 at $159,255,840. According to Whitney the yield of Mexico, previous to 1845, was $2,700,000,000; and if we allow an average of $20,000,000 for each of the 22 succeeding years, we have a total yield of $3,140,000,000 from 1521 to the end of 1866. The average annual yield of the mines of Mexico was as follows, at various periods: About 1700..

$5,400,000

About 1810..

$19,000,000 7,000,000 10,000,000

18,000,000

+1820...

1841...

The amount coined in 1825 was $8,000,000; in 1835, $11,000,000; in 1845, $15,000,000; in 1856, §$19,000,000; and from 1821 to 1856, $2,636,745,951.

The opening of all the ports of the country to commerce, the great reduction in the price of quicksilver caused by the large production of the New Almaden mines in California, and the gradual increase of educated engineers and of mining machinery, have brought up the production of the country to a higher figure than that reached at the beginning of the centurythat is, in years of comparative peace and order, such, for instance, as most of those from 1850 to 1860.

If Mexico had a government as good as that of Chili, and had railroad communication from Vera Cruz and Mazatlan to all the principal mining districts, and were protected against the Apaches, the production would at least double within ten years.

The argentiferous region of Mexico is a long triangle, 800 miles long from southeast to northwest, 350 miles wide at the base on the northern boundary, having the. city of Oajaca for its southern point.

Nearly all the mining districts of any note are from 4,000 to 9,000 feet above the sea. The great elevation counteracts the torrid influence of the latitude, and many of the mining towns have very cool climates.

*Duport, p. 193.

†Ib., 194.

‡Ib., p. 190.

Lempriere, p. 214.

In most of the districts porphyry is found with micaceous schists, and the conjunctions of those two rocks with quartz veins is considered an indication of silver.

The mode of mining generally is very rude. No mine is accessible by railroad, and few have wagon roads. Usually the reduction works are at a distance from the mines, and the ore is packed on mules. The ore is brought to the surface on the backs of men, up steep inclines, or even up perpendicular shafts, the carriers climbing up on notched poles. In some mines the ore is carried by men to the shaft and there hoisted by whim. There is no mention in Humboldt or Ward of tramways and cars to bring the ore from remote parts of the drift to the shaft. Water is hoisted in the same manner as the ore.

Steam was not used previous to the revolution, but it has been coming into use gradually, and now much of the hoisting, pumping, and pulverizing is done by it.

The general practice in Mexico as to pulverization has been to mash the ore to a coarse sand under the stamps, and then grind it fine in arrastras. The degree of fineness varies much in the different districts, partly because of differences in the ores and modes of reduction, and partly because of ignorance and prejudice. At Guanajuato the ore is ground to an impalpable powder; at Zacatecas, Catorce, and Fresnillo, in a coarse flour. In 1842, 82 per cent. of the silver yield of Mexico was obtained by the yard amalgamation; 8 per cent. by the Cazo or copper-pan amalgamation, and 10 per cent. by smelting.* In 1800 one-seventh was smelted.t

The proportion of smelted silver has been decreasing gradually, and will no doubt continue to decrease. A hundred years ago it was two-fifths of the total yield.

Since the opening of the Washoe mines and the successful introduction of the iron-pan amalgamation there, a number of mines have been purchased in Sonora, Sinaloa, Chihuahua, Durango, and Lower California, by Americans, who have introduced machinery and American modes of working, and they would probably have obtained some splendid results, at least in a few instances. before this time, if the civil war had not thrown everything into confusion.

The average loss of mercury in the yard amalgamation is a pound and a half to one pound of silver extracted.

The best writers on mining in Mexico agree that the country has great wealth as yet undeveloped, and that a time must come when the production of the precious metals will far surpass anything of the past. Humboldt said he was "tempted to believe Europeans have scarcely begun to profit by the inexhaustible fund of wealth contained in the New World. Europe would be inundated with the precious metals if the deposits of ore at Bolanos, Bato-. pilas, Sombrerete, Rosario, Pachuca, Moran, Zultepec, Chihuahua, and so many other places that enjoyed an ancient and just celebrity, were assailed at one and the same time with all the means offered by the perfection to which the art of the miner has attained."

The opinion of Ward is given in the following passages: "That the great mineral treasures of Mexico commence exactly at the point where Humboldt rightly states the labors of the Spaniards to have terminated, (above latitude 240,) is a fact now universally admitted by the native miners, although heretofore but little known in Europe. The states of Durango, Sonora, Chihuahua, and Sinaloa contain an infinity of mines hitherto but little known, but holding out, wherever they have been tried, a promise of riches superior to anything that Mexico has yet produced. In common I believe with all those who have had an opportunity of inqniring into the resources of New Spain, I do regard it so well ascertained a fact that her mineral riches are almost unexplored, that I am willing to rest upon it my whole calculation with regard to her future importance as a country." (Ward, vol. 1, pp. 127-160.)

*

*

*

Duport expresses himself thus: "After having visited only Tasco, Real del Monte, and Guanajuato, Humboldt said 40 years ago that there was enough silver in the Mexican mines to flood the world: what would he not have said if he had pushed his researches further north? More strongly convinced than he could possibly be of the abundance of the argentiferous veins, I am not so confident about the brevity of the time within which the progress of science in Europe, and the free intercourse of all nations with Mexico, can exert any considerable influence on the amount of the production of the precious metais."‡

And again he says: "The want of capital, of political quiet, of population, and of education in the northwest of the republic, and of wide-spread scientific knowledge, and finally the high price of mercury, are the obstacles which oppose the increase of the production of the precious metal in Mexico. These causes will exercise their fatal influence for some years yet, and will prevent the yield from passing the figure which it reached at the beginning of this century. But these obstacles are not permanent in their character; they are only temporary, and will after a time be neutralized, and then overcome, by the abundance of the ore and the progress of science, which gives a wider dominion every year to the power of man. The time will come, a century sooner or a century later, when the production of silver will have no limit save that imposed by the steady decrease of its value."§

NORTHERN STATES OF MEXICO.-The late Mr. A. Rémond, whose untimely decease is an irreparable loss to science, made a tour of exploration through the northwestern States of Mexico during the years 1863, 1864, and 1865, in the course of which he carefully examDuport, p. 369. † Humboldt, p. 141. § Duport, p. 426.

Duport, p. 380.

ined the geology of the country, and collected some valuable statistics on the subject of mines and mining. Professor J. D. Whitney, of the geological survey of California, in March, 1866, submitted to the Academy of Natural Sciences an interesting report from Mr. Rémond. The following extracts convey a clear idea of the geological formation and general characteristics of northern Mexico. The tables accompanying the report show the extent, character, and condition of the mines:

"The name of the Sierra Madre' is usually applied to the main range of mountains of this country, or the western border of the plateau which stretches north through the territories of the United States, forming what may be called the great orographical feature of the continent. In northwestern Mexico this crumpled border of the great plateau comprises an extensive mountainous region, by no means forming a continuous single chain, but rather several central ranges, with associated groups of parallel ridges, all having the same general course, which is approximately north-northwest and south-southeast. As the breadth of the chain widens as we go towards the north, so, too, that of the valleys increases in that direction, the whole system of mountains and valleys spreading out in something like a fan shape. "Going north, the chain appears to sink gradually, although determinations of altitude in northern Mexico are extremely few in number. It is certain that there is, in about latitude 320, a depression of the mountain ranges which extends entirely across the continent, and which would enable the traveller to cross from the Atlantic to the Pacific, without necessarily surmounting any elevation greater than 4,000 feet. The southeastern range is the highest, and the culminating point is said to be the Cerro de Cuiteco, 60 leagues northeast of Jesus Maria, on the western borders of Chihuahua. The approximate altitude of the Cumbre de Basascachic is 7,429 feet, and that of Guadalupe y Calvo 7,825 feet. To the north, the ranges east of Sahuaripa are also very high; but they have never been measured. No peaks or ridges, however, in this portion of Mexico attain anything like the elevation of the higher portion of the Sierra Nevada, few if any points exceeding 10,000 feet in altitude. "The direction of the sierra is nearly that of a line connecting some of the best mining districts in Mexico, which are situated on or very near the summit of the mountains. These districts are the following, enumerating them in their geographical order from the south towards the north: in Durango, San Antonio de las Ventanas, Guarisamey, and San Dimas, remarkable for their auriferous silver ores, and 62 Mexican leagues northeast of Mazatlan; in Chihuahua, Guadalupe y Calvo and San Pedro de Batopilas, yielding fine specimens of native silver; also, Jesus Maria, in the same State, and the Real del la Cieneguita, Sonora, with silver and gold mines.

"GENERAL GEOLOGY.-The geological structure of the occidental slope of the Sierra Madre, as well as that of other parts of this great chain, is exceedingly interesting, and, as yet but very little known, notwithstanding the valuable investigations of Humboldt and other eminent men; for, up to the present time, the age of the different formations has never been fixed with any degree of accuracy, from want of materials and of sufficient observations. In 1863, 1864, and 1865, however, I explored quite a number of localities in northwestern Mexico, and was thus enabled to obtain a pretty good general idea of the geology of that region; and, in Sonora, to which my attention was especially devoted, I succeeded in finding fossils in sufficient quantity to allow of the determination of the age of the principal formations of the northern Sierra Madre. By tracing the connection of these rocks with those of Central Mexico, additional light will be thrown on those districts of which, at present, but little is definitely known.

"The igneous rocks, which occur more abundantly on the Pacific slope, are granites, either fine or very coarse-grained; porphyries, more or less feldspathic; and greenstones, all of which are cut by numerous dikes of extremely varied character. The granites, how ever, are very poor in veins of the precious metals, while the porphyries are highly metalliferous. In Sinaloa (Candelero) and Durango (San Dimas) we see that the_granites underlie the metallifercus porphyries, and that the greenstones, in Sonora, (near Hermosillo and in the vicinity of La Haciendita,) penetrate through them.

"The oldest sedimentary rocks which I have observed belong to the carboniferous series ; this is represented in the eastern part of Sonora by heavy masses of limestone, forming very high and rugged ridges, running a little west of north. The upturned strata are seen in many places to rest on granite. Argentiferous veins occur throughout this formation.

The next group of sedimentary rocks in order is the triassic; this forms isolated mountain groups in Sonora, and offers an interesting field for investigation. Instead of limestones, it is made up of heavy beds of quartzites and conglomerates, with coal-bearing clay shales; all of these are disturbed and elevated, and rest on greenstones, feldspathic porphyries, or granite. Wherever metamorphosed, the triassic rocks are auriferous and contain veins of silver ores. The metamorphic slates and limestones of the Altar and Magdalena districts, which include the richest gold placers of Sonora, may possibly be of triassic age; but the fossils collected are too imperfect to admit of this being determined. There are some reasons for believing those rocks to be rather of jurassic than of triassic age, as they differ in lithological characters from both the triassic and carboniferous of northern Mexico, * Proceedings Cal. Acad. Nat. Sciences, vol. III, pp. 245–258.

† See Emory, in Mexican Boundary Report, vol. 1, p. 41.

resembling rather the jurassic gold-bearing slates of the Sierra Nevada, in California; besides, they lie outside and to the west of the Sierra Madre. It may also be noticed that the gold which they furnish does not resemble that obtained from the triassic strata.

"The cretaceous period is also represented at the foot of the Sierra Madre, at Arivechi, in Sonora. The strata belonging to this series are chiefly argillaceous shales, and they rest upon porphyries and carboniferous limestone. They have been disturbed and elevated since their deposition. The fossils, which they contain in great number and in a fine state of preservation, will be noticed further on.

"All the above-mentioned formations were already in existence before the first eruption of the volcanic rocks took place. These latter are found scattered along the whole Pacific coast, and extend from the Gulf of California up to the very summit of the Sierra. It is very interesting to see the volcanic formations spread over so extensive a region, especially as there are no active volcanoes known in northern Mexico, and not even any indications of ancient craters or vents.

"MINES.-The richest and widest veins are those northeast of Mazatlan, near San Dimas, Guarisamey, &c., in Durango. These veins cut all the rocks older than the cretaceous, whether igneous or sedimentary. The mines of Sinaloa are richer than those of Sonora. In the former state the ore-bearing portion of the veins is from a few feet to several yards in width; in the latter, generally from one to two feet. In Durango and Sinaloa, gold, native silver, and sulphuret of silver occur, associated with galena, yellow blende, and iron pyrites. In Sonora the principal ores are argentiferous gray copper, with galena, black blende, copper pyrites, arsenical pyrites, carbonate of lead, ruby silver, arsenical silver, and gold. Each mining district is characterized by a peculiar system of veins; in all as many as 20 different systems have been observed. The most abundant vein stones are quartz, either chalcedonic, crystalline, or massive; brown spar; heavy spar; oxide of iron. The veins occurring in the metamorphic triassic rocks are usually parallel with the stratification, so that they lie nearly horizontal where the formation has been but little disturbed. As to the yield of the silver ores, it varies extremely, and it would be necessary to enter into a full description of all the different districts.to give an idea of it. It may be noticed, however, that the arsenical pyrites, which is auriferous in the Sierra Nevada, becomes argentiferous in the Sierra Madre. The veins vary in their direction from a little east to a little west of north; the richest ores near San Dimas run northeast and southwest. There are but few rich mines in Sonora, a state of which the mineral wealth has been much exaggerated. There are, however, some deposits of variegated copper, and veins of magnetic and specular iron.

"The annexed tabular statement will give the principal facts obtained with regard to the mines examined in northern Mexico ·