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gretted that no fossils occur in this limestone; but its lithological character refers it to a recent epoch.
Two miles farther east, on the southwest slope of a bold ridge, and running along it, occurs the Conquest lode. A belt of talc-slate, about 50 feet wide, runs here through syenite in a northwest and southeast direction, dipping 20° northeast into the hill. In it occur seams of quartz, sometimes running apart from each other and parallel, and then joining again, but the main direction is always parallel to the slates. This quartz is in places surprisingly rich in gold. The southeast end of the claim is about 275 feet above the bottom of the ravine. Progressing from here toward the other end of the claim, the following work has been done on it:
The discovery-hole, 10 feet deep at this end, shows three seams of quartz of respectively 2 feet, 1 foot, and 6 inches width, with horses of slate between, making the whole width of the vein at this point about 7 feet. The quartz is mostly dense and white here, only the middle seam being porous and iron-stained. The next opening is 30 feet to the northwest, 6 feet deep, and shows the same arrangement of the seams. One hundred feet farther are three small shafts, exposing the same character of the vein. In the open cut and 15-foot incline, and a 10-foot incline met with further on, iron-stained quartz in many small seams is seen, and some spurs join the vein, coming in at right angles from the hanging wall. Next, in an incline 45 feet deep, the vein is 6 feet thick, and, for the first time, solid, iron-stained, and containing visible free gold. An open cut exposes the vein from here for 30 feet; another one, 20 feet long, is a short distance farther on; and here the vein is much scattered again, but the ore is very rich. The main work on the vein, two very large open cuts and a shaft 70 feet deep, are next reached. The vein-matter is scattered here over a width of 30 feet; but much free gold can be seen in the quartz seams. Here the zone of slate makeş a sudden turn more to west and is not much opened below this point. In the last-mentioned open cuts and shafts spots of the size of a fist and larger are seen in the quartz and the slates, entirely filled with soft pulverulent hydrated oxide of iron, which prospects exceedingly rich in coarse, free gold; it is worth $19 per ounce. At least 1,200 feet of the 1,600 feet located are more or less opened, and the ore so far has been found good. It is the intention of the owner to tap the vein by a tunnel which, with a length of 150 feet, would strike the lode at least 200 feet below the croppings. There is much ore taken out from this vein and ready for reduction; but so far no machinery has been erected.
The Constantia is six miles southeast of the foregoing. The trail, as long as it crosses the main mountain, leads over syenite and tale-slate; but as soon as it descends to the lower foot-hills on the east it strikes greenstone and metamorphic slates, all running northeast and southwest. In a belt of talc-slate lies the Constantia. It is an enormous vein, the croppings of which are seen for over 1,000 feet. For that distance it is from 30 to 50 feet wide, but at both ends it becomes much narrower and finally disappears. The vein dips 25° southeast. Much of this quartz vein is porous and highly iron-stained, and in one of these softer layers a shaft 50 feet deep has been sunk. There are from 20 to 30 tons of ore on the dump which shows free gold occasionally. Some of the quartz was formerly worked in arrastras at Tyson's wells, about four miles to the east, where the nearest water is found in a deep well, and the result is reported to have been a yield of from $20 to $35 per ton. But nothing has been done on the vein for several years.
Farther to the southeast, near the road to Wickenburg, many veins
containing lead and copper were located several years ago; and some of them were opened by shafts and tunnels, but none of them have been in operation during the last two years.
The gold placers in the vicinity of La Paz, which extend over an area of at least twenty miles in all directions, deserve some notice. A very good history of them is given in J. Ross Browne's report of 1868, and it remains only at the present time to say a few words as to their probable origin. They are undoubtedly of local origin. The syenite and the metamorphic slates contain many large quartz veins, but the almost incredible number of small gash-veins in the slates and greenstone have probably furnished most of the gold. The gravel is not rounded, like fragments of stone exposed to the action of running water for a long time, but angular and sharp-edged. There is very little earth mixed with it on the sides of the gulches and none in the ravines themselves. The gravel is never deep, hardly exceeding a depth of 5 feet.
There being no water in the vicinity, nor in such a position that it could be brought to the placers, the gold has been so far extracted by dry-washing. A machine constructed for that purpose was in operation in some of the gulches during last year, but it had lately been moved from the place where it was known to have been at work, and I could, therefore, not witness the operation. The results reached with it are claimed to be very satisfactory. As only the coarse gold can be got by dry-washing, these placers must be still far from being exhausted, though they have been worked over to a great extent. The amounts taken out formerly per hand per day are reported fabulously high, but much more gold remains now, though for the present inaccessible, than has ever been taken from these diggings.
Eureka district.-This district is forty-two miles north of Arizona City on the Colorado River, and the veins are from one mile to fifteen miles east of the river. The district is an old one, having been organized in 1862. The country rocks are granite, slates, and porphyry, and the veins are mostly contact-veins, striking west-southwest and eastnortheast, and dipping at an angle of about 45°.
The Margarita is 3 feet wide and has been opened better than the other veins by numerous shafts and levels. The gangue in depth is mostly calespar and quartz, which carries argentiferous galena containing from $60 to $100 in silver. Much ore has been shipped from this vein to San Francisco.
The Rosario is within a short distance of the river. The shaft is 60 feet deep and contains a 2-foot vein, which carries mostly zinc-blende containing $7 per ton in silver. At other places the same vein contains galena, assaying as high as 74 ounces per ton in silver. A tunnel, now in 200 feet, is intended to strike the shaft at 300 feet.
The Buena Vista, Bronze, and others have also been opened in this district and all of them carry argentiferous galena. None of these mines were in operation in 1870.
Across the Colorado at this point, on the California side, the same belt of rocks appears. Here five or six mines are opened, mostly occurring in the neighborhood of trachyte dikes. They contain galena with · iron pyrites, and this ore is both argentiferous and auriferous.
The Mammoth is a representative vein of this kind. The shaft is 80 feet deep. The arrangement of the ore in this vein is rather peculiar, different minerals lying in slightly inclined layers above each other in the same vein, as, for instance, in the first layer, galena, the second, iron pyrites, the third, zinc-blende, &c. These pyrites yield, by assay, 2 ounces gold per ton, and 0.77 ounces silver; the blende, 5.83 ounces silver; the
galena, 122.47 ounces silver. Higher up on the mountain the galena in the same lead is very solid and contains 57.5 per cent. of lead.
Mr. Peabody worked another vein on the same side of the river, specimens from which assayed 61.5 per cent. of lead, 55.5 ounces silver, and 0.17 ounces gold per ton.
Castle Dome district.-This district is situated opposite a point on the Colorado River, thirty miles above Arizona City and inland to the east about twenty miles. It was organized in 1863 and 1864, and some of the mines have been in operation more or less ever since. The district has its name from a dome-shaped butte, which towers several hundred feet above the crest of the mountain chain, and is visible for great distances in all directions.
Castle Dome district has a very rugged surface, and the mines are not easy of access. Water is rather scarce, and wood is confined to cottonwood, mesquite, ironwood, and palo verde, the first only near the Colorado, while the two latter kinds occur in limited quantity in all the dry washes and ravines from the mountains.
The Castle Dome Mountains are an isolated range running northwest and southeast, and extending twenty-five miles from a point near the Gila toward the northwest. The range is entirely destitute of vegetation. The rocks constituting it are granite, metamorphic slates, basalt, and porphyries; the erupted rocks especially give to the outlines of the chain that ragged appearance so characteristic to it.
Prospecting in the mountains proper has so far been devoid of satisfactory results. Exceptional seams of yellow and blue talcose clays are met with; also several large veins of hard, dense quartz, slightly tinged with oxide of iron, but they are not auriferous. One of these veins can be traced through the mountains for several miles, having withstood the action of the elements, while the neighboring rocks were destroyed and washed away for many feet in depth. This ledge is from 3 to 20 feet wide, strikes north 400 west, and dips about 25° southwest. On one casing beautiful dark dentritic forms are seen, and pieces of this sometimes contain visible gold; but on the whole the vein is barren. The district was first entered by Americans in 1863, but old and abandoned mines with shrubbery of many years' growth upon their dumps, a well-beaten trail to the Gila, piles of slag and traces of ruined Spanish furnaces near that river, clearly demonstrate that this ground was known and worked by the Mexicans prior to the occupation of the country by Americans.
The founders of the district (as is related by one of them) labored under the delusion that galena was nearly pure silver, and that in the possession of mines here they had a "big thing." They suffered from want of water, provisions, and mining supplies; yet they worked here during the summer heat, Sundays and nights, as well as by day, sustained by the consciousness of being in luck. No efforts were made to explore mines or to extract ores; all their energies were centered upon the acquisition of ground by posting notices and complying with the district regulations in regard to work, &c. Several months elapsed before satisfactory assays could be obtained, when the mere word "lead" destroyed their hopes, and dispelled their bright illusions as the splash of a stone effaces the reflection of scenery from the face of a placid lake. The reaction was great, and the disappointed miners were easily called away by the reports from La Paz, Weaver, and other rich placers. Castle Dome was again a solitude. Later, the establishment at San Francisco of smelting furnaces and lead-works created a demand for lead ores, which again brought this district into notice, and veins here were worked with varying success until the opening of sim
llar mines in California and Nevada, from being nearer at hand, diverted the attention and money of capitalists, who had been promoting operations down here. Many promising veins were abandoned for want of capital. This winter work has been resumed on several lodes with highly gratifying results. The books of one mine, the Flora Temple, show that the first 100 tons of ore were placed upon the dump, cleaned and ready for transportation at an expenditure of less than $900, which includes cost of tools, supplies, and every expense incurred in the discovery and opening of the mine. The ore is an argentiferous galena, and assays 63 per cent. lead and 39 ounces silver per ton. The mines are perfectly dry, no moisture having been found at the greatest depth yet reached. On the score of security, economy, and facility for working, the absence of water underground amply compensates the trifling inconvenience of having to use it from barrels. Water is hauled to the mines from the Colorado River by the teams employed in carrying ores down to the landing. Fuel is abundant in the ravines, which are well stocked with a species of lignum-vitæ, known here as "ironwood." The country rock in the small district in which mines are actually worked is slate and granite. The most prominent lodes appear to be true fissure-veins, running north-northwest and south-southeast, dipping indifferently to east or west. The principal characteristic is a gangue of fluor-spar, tinged pink or green, and sometimes beautifully crystallized. The Castle Dome mine, now being worked with great vigor, contains 2,200 feet, acquired by location and purchase. One hundred and sixty feet have been opened and worked to the depth of 56 feet, producing some 500 tons of shipping ores. The greatest depth attained in exploration is 104 feet. Surface explorations clearly establish its continuity. It is producing ores of excellent quality, assays of metal now in transitu to San Francisco ranging from 58 per cent. to 69 per cent. lead, and $23 to $190 silver per ton.
This mine is particularly interesting from the diverse character of its contents and the beauty and richness of many of their combinations. Sulphurets and carbonates, and a half-decomposed galena, dull in color and exceedingly rich in silver-chemical composition as yet unknown-are generally selected for shipment; the poorer carbonates and sulphurets being retained with an ultimate view to smelting at the mine or at the Colorado River. The strike of the vein is north 44° west; dip, 150 west. The foot-wall is a talcose slate, with a pink tint. The vein-matter contains many combinations of clay, tale, gypsum, fluor-spar, &c., of constantly varying color and consistency. The vein proper varies in width from 2 feet to 8 and 10. The shipping-ore generally occurs in compact seams, from 3 inches to 2 feet in width, though frequently met with in kidney-formed masses in spar and in the argillaceous and talcose vein-matter. The expense of extracting and cleaning the ore varies with the character of the vein. The following figures will be found as nearly correct as it is possible to give them :
Extraction and cleaning, (estimated)
Sacks, per ton, (estimated).
Freight to Colorado River, (actual figures)
Lighterage to reduction-works, (actual figures)
Total expense per ton
$10 00 2.00 10 00 15.00
1 50 150
The Buckeye was worked very profitably last spring, until the approach of hot weather, by Messrs. Butterfield. Work has not been resumed yet this winter, though the mine shows plenty of ore and invites labor. It is of the same general character as the Castle Dome. The Flora Temple was first opened this winter; has three incline shafts sunk to a depth of 50 feet, and the necessary drifts to facilitate communication and ventilation. From this limited amount of work (the stope remaining untouched) 150 tons of clean ore have been extracted.
The Poorman is yielding galena of first-rate quality, and its owners appear well satisfied.
The Prosperity, Don Santiago, Nonpareil, and other veins, are being prospected with very promising results.
I am indebted for much of the above information to Mr. Geo. Tyng, superintendent of the Castle Dome mine, and to Mr. Julius Sieback, a mining expert of Arizona City, who has had much experience in the Colorado River mines and elsewhere.
The placers of Gila City.-Some sixteen to eighteen miles east of Arizona City, the Castle Dome range crosses the Gila. On the low foothills on both sides of the river, the valley of which is here about a mile wide, and in all the ravines and gulches in them, occur gold placers. They have been worked for many years, and although they have been worked over by dry-washing to a great extent, they are still rich in fine gold, which could not be reclaimed by that process.
The main mountain range consists here of granite and syenite, which is traversed by greenstone dikes. The foot-hills consist altogether of metamorphic slates, which contain a great number of small gash-veins and bunches of iron-stained quartz. As in the case of the La Paz placers, I think that the gold in the placers comes from these slates.
The placers extend along both banks of the Gila for ten or twelve miles, and several small towns like Gila City, Los Flores, and Oroville, owe their origin to the first gold excitement. They are now deserted and only inhabited by a few white men.
At Gila City a San Francisco company has during the last year erected works to pump the water from the Gila up into a reservoir on top of the highest foot-hills in order to work the placers of the vicinity by hydraulic power. They use a 9-inch pipe through which they pump the water, and their works had just been completed when I left the Territory. The first ruu they had made satisfied them of the value of the placers, and they were eager to continue their operations.
The gold shown to me was mostly coarse, but of very fine quality, being worth $19 75 per ounce. I was told that their apparatus for saving the fine gold had not been completed, but was to be put up soon. If the gold left in these placers is really sufficient to pay for such an expensive way of working them, the field is undoubtedly sufficiently large to last for years.
At Los Flores, on the opposite side of the river, a small five-stamp mill has been at work for a part of the year crushing gold quartz from some small veins in the vicinity. The enterprise seems to be a success, as an addition of five stamps to the mill is contemplated.
Most of the placer-mining in the vicinity is done by Mexicans and Indians, and for that reason it is very difficult to get any reliable data as to their yield, unless the shipments of Wells, Fargo & Co.'s office at Arizona City may be taken as a criterion. These amount to little less than $75,000 during the year, but much of this comes undoubtedly from other sources in the Territory.