Copperopolis were in operation, the price of freight to Stockton, the nearest shipping point, was $8 per ton, the distance being thirty-six miles. From that point it cost $2 per ton to San Francisco, whence it was sent to Swansea, Wales, at a further cost of $15 per ton. The total cost on each ton, mining, etc., included, when landed at Swansea, has been estimated at $50. Labor was then $4 per day. At this rate only firstgrade ores paid a profit; and with increasing depth, second-rate ores predominated. The consequence was the suspension of operations and the decay of the once flourishing town of Copperopolis. The principal mines are the Union, owned by Glidden & Williams, of Boston, Massachusetts, and the Keystone, the title of which is in litigation. Both of these claims are opened to a depth of from 400 to 500 feet, and have expensive and powerful hoisting and pumping-works.

The reopening of these mines will depend on the price of copper. This has been steadily decreasing in England since 1864, but the prospects of the trade are now much better than they were one year ago. The production of Chile, in 1869, reached the enormous amount of 55,000 tons, but it has since diminished to 49,000 tons, with prospects of a continued diminution. On the other hand, the demand for this metal is increasing.

Should the Stockton and Copperopolis Railroad be completed to Copperopolis, it is believed that with present prices of labor ($2 to $3 per day) these mines could be re-opened, and the second-class ores, of which large quantities are in sight in the mines, could be extracted and shipped with profit, as it is believed that the price of freight to Stockton would not exceed $1.50 per ton, and the total cost of laying down ores in San Francisco would not exceed $20 per ton, instead of $32 per ton, as heretofore. The re-opening of the mines, however, would require a large outlay of capital, and perhaps involve the erection of new hoistingworks. The Stockton and Copperopolis Railroad was completed as far as Milton, at the base of the Sierras, when operations were suspended in consequence of the closing of the mines. Ten miles more would complete the road, but its completion will depend very much on the price of copper in the marts of the world.*

The Mother lode.-The Mother lode of California is a vein, or, more properly, a series of veins of quartz which has been traced on a longitudinal line, with occasional interruptions, for a length of about seventyfive miles, from Bear Valley, Mariposa County, to Amador City, Amador County. Throughout the entire distance it has a general northwest and southeast course, and an almost uniform dip to the northeast of eighty degrees.

Whether this singular formation is a "lode" or a mere accidental occurrence of a series of veins on a longitudinal line in the same belt of slates, is a question on which eminent mining engineers have differed. It has been discussed in the report of J. Ross Browne of 1868, and in my report of 1869. Mr. Skidmore considers it as a defined lode, believing that recent developments, at various points, have a tendency to confirm this theory.

The most southerly well-defined outcrop of this remarkable vein is at the Pine Tree and Josephine mines, on the Mariposa estate, at an elevation of about 2,500 feet above sea-level. From this point it takes a northwest direction, striking across the numerous spurs of the Sierras which form the divides between the Tuolumne, Stanislaus, and Moke

*Since writing the above, I learn that operations have been resumed on the Unica Mine, at Copperopolis.

lumne Rivers and their tributaries, and terminates in the foot-hills of Amador County, the most northerly deep-developed claims being the original Amador and Keystone at Amador City, although many locations between these mines and the Cosumnes River are supposed to be on the same lode. Beyond the Cosumnes the lode is not traceable.

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Between its southern and northern extremities it is frequently broken up and lost, (invariably so at the intersection of the principal rivers,) making its appearance again at a distance of several miles, frequently in the form of a solid wall of quartz on the summits of isolated hills on the line of its strike, these croppings being visible for many miles. The most prominent of these hills are Piñon Blanco, Quartz Mountain, Whisky Hill, and Carson Hill. At these points the lode has widened with the "blossom" of the mountain, and presents the appearance of a system of parallel veins separated on the surface, and to an indefinite depth, by horse" matter, composed of nearly equal parts of slate and broken quartz. Locations have been made in the majority of such instances on the croppings, parallel to each other, one on the hanging wall and another on the foot-wall of the lode, these walls being sometimes separated, as at Quartz Mountain, Tuolumne County, by a distance of from 200 to 250 feet; but recent deep developments at various points would seem to indicate a tendency of these walls to narrow, which, at depths of from 1,000 to 1,200 feet, and in some cases less, would shut out the "horse" and develop a permanent fissure of from fourteen to eighteen feet in width.

The principal points at which mining has been prosecuted on the Mother lode, are Bear Valley, Princton, and Mariposa, in Mariposa County; Quartz Mountain and vicinity, near Jamestown, Tuolumne County; Rawhide and Tuttletown, in same county; Carson Hill, Angel's Camp, and Paloma, in Calaveras County; and Jackson, Sutter Creek, and Amador City, in Amador County; the deepest development having been made at Sutter Creek, where, at the Amador mine, a shaft has been sunk, and levels opened to a depth of 1,300 feet.

The entire length of locations made on the Mother lode is estimated at 180,000 feet, equal to half the distance between its northern and southern extremity. Many of these locations, however, run parallel to each other, and the ground continuously located would not exceed 100,000 feet, while the ground now in process of development (including only those claims on which work has been done in 1871) will not exceed 40,000 feet, exclusive of the Mariposa estate, on which operations are temporarily suspended owing to financial difficulties and litigation.

The longest break of the lode is between Angel's and Jackson, a distance of twenty-three miles, on which only one mine, the Paloma, near the south bank of the Mokelumne River, is generally acknowledged to be on the lode, though recent discoveries tend to prove the continuity of the lode between these points. At various other points the lode "dives" for several miles, and at one point, between Whisky Hill and the Rawhide mine, it is covered by the lava flow which constitutes Table Mountain.

Throughout the entire course of the lode we find many instances of failure, manifested by abandoned works and idle mills, but these are to be attributed either to mismanagement or to the injudicious location of works at points where no pay-chimneys exist. The early locations were made at any point where croppings appeared, and deep shafts were sunk, and mills erected on barren ground, without any effort to find the chimneys of the vein. In this way thousands of dollars have been uselessly squandered by men utterly ignorant of mining, and these H. Ex. 211—4

monuments of their folly have discouraged those who otherwise would have invested in quartz mining. Another cause for the stagnation of mining on this lode is the improvident manner in which work has been carried on, resulting in the exhaustion of the surface deposits, which were worked by open cuts at various places down to the water-line, when operations ceased until shafts could be sunk and hoisting-works and pumping-machinery erected, the owners of the ground having committed the common error of failing to keep their ground developed in advance of their milling capacity. Perhaps a third reason may be found in the superior attractiveness of the mines of the neighboring State of Nevada, where fortunes are made (and lost) with greater rapidity in mining operations.

The amount of ore crushed by mills on the Mother lode has been less for this year than for several years past. This is owing to a combination of circumstances not likely to occur again. The Mariposa estate, containing several of the most productive mines, has been involved in a litigation which has temporarily suspended operations. An unexampled drought prevailing over the State has closed many mills for want of water, and others are only running half their stamps. These claims are supplying ore far in excess of their present means of crushing. In addition to this a "strike" took place during the month of April, in Amador County, and the Oneida, Keystone, Amador, and other leading mines were closed for a period of nearly three months, resulting in a loss to the owners of nearly $2,000,000. This latter difficulty has now been adjusted, and the present season promises to give an ample supply of rain.

The prospects for the future are encouraging. At all points where great depth has been attained there has been a steady improvement in the quantity and quality of the rock. At Sutter Creek, the Amador mine has attained a depth of 1,300 feet, disclosing a vein of from 12 to 14 feet in width. The quality of the quartz here has improved with each successive level below a depth of 500 feet. At the Oneida, Keystone, and other deep mines, the same encouraging features are met with, while many claims heretofore partially opened are now erecting mills and powerful hoisting works. The development of the Paloma mine, owned by ex-Senator Gwin, near Mokelumne Hill, and of the Angel's Quartz Mining Company's mine at Angel's Camp, both of which, at lowest levels-400 to 500 feet-have opened rich and extensive zones, is exerting a strong beneficial influence on quartz mining, which is already being felt in the investment of home capital in this heretofore neglected branch of business.

Quartz veins in the granite belt.—In addition to the Mother lode, this region possesses other quartz mines which are yielding large amounts of gold. At an elevation of 4,000 feet, in the Sierras, an extensive series of veins has been opened in the granites, the most noted of which is the Confidence, sixteen miles east of Sonora, Tuolumne County, a mine scarcely known outside of Tuolumne County, yet producing, with forty stamps, from $30,000 to $40,000 monthly. Other claims of like characteristics are being developed to the north and south of the Confidence, but whether they belong to the same system, of which there is a strong probability, remains to be demonstrated. Among these is a recent discovery in the upper part of Calaveras County. The veins here present many striking features of interest. Like many of the most noted veins of California, they occur in fissures which have been opened in the earth's crust by the rending asunder of the rock formation across its stratification. The country rock is slate. This contains nu

merous dikes of traps, porphyritic green-stone, etc., occupying fissures which run transversely across the slate. There are several parallel fissures, nearly vertical, having a course of N. 40° E., with very solid and smooth walls, and from 5 to 12 feet wide. In these occur the quartz veins, the quartz occupying only a portion of the space, (3 to 9 feet,) the balance being filled by an accompanying vein matter differing from the country rock, and not found outside of the fissure walls. The whole of this vein matter is full of base metals, particularly the sulphurets of iron, deposited in a way that indicates a previous state of solution or possibly vapor; for besides being disseminated throughout the body of the rock, the faces of broken pieces, which had no seams visible to the eye, are often found coated with particles of metal, forming flakes which can be removed with a knife-blade. All of this material contains some gold, but the pay rock proper occurs in chutes of a peculiar kind of quartz, which is held by many of the miners to belong to the true chimneys of the precious metals. It is so thoroughly impregnated with the various base metals, especially the sulphurets of iron, lead, and zinc, that not an ounce of it can be found destitute of these. The gold is diffused in fine particles through the ore, as if an element of its composition. The ore of these lodes is of high grade.

Further west, in Calaveras County, we find the quartz mines of Railroad Flat and West Point, and in Amador County a group of promising mines, near Volcano. At these places hundreds of veins exist, yielding high-grade rock, but few of which are developed below the water-line. The future of these districts depends on the development of a few claims, considered as representative mines, on which work is now being prose cuted with the best indications of success. The discovery of pay rock in a mine, such as the Petticoat at Railroad Flat, on which a deep shaft is being sunk, will have a tendency to open more than fifty claims in the same vicinity.

Gravel mining.-The gold-bearing gravel deposits of the southern mines are not as extensive in area and depth as those of the central mining region, (described in my report of 1871,) neither is the topography of the country so favorable for the opening and draining of ground; but, on the other hand, the gravel will yield a larger amount of gold per cubic yard. This opinion is based on personal observation, and on the carefully prepared tables furnished by Mr. J. Rathgeb, of San Andreas, which will be found in this report.

The modes of occurrence of gravel deposits here are various. They occur, first, in well-defined ancient river channels, under a capping of lava which has filled the rivers of past ages; second, in isolated mounds or hillocks, evidently the remains of such channels, which, being unprotected by a covering of lava, have been broken up by the action of air and water; third, in basins or flats which have received and held the wash of these disintegrating river beds; and, fourth, in low, rolling hills, near the base of the Sierras, and beyond the reach of the lava flow. The richest deposits have been found on the flats on the east side of Table Mountain, at places where bars evidently existed in the ancient river, and the lava flow sought the deep channel, forming an elbow or curve on which the lava crust was very thin, or sometimes entirely denuded.

Table Mountain.-The most remarkable feature in the landscape of the southern counties is the great Table Mountain. This is a flow of basaltic lava covering an ancient river bed several hundred feet higher than the modern river-the Stanislaus-by which it is crossed through deep cañons at two points-Abby's Ferry and Byrne's Ferry. The basaltic

matter has a width of from 1,700 to 2,000 feet, and a thickness of about 150 feet; its elevation at Jamestown is about 500 feet above the surrounding country. Beneath this capping of lava is a stratification of sandstone sixty to one hundred feet in thickness; and underneath this, on the bed-rock of the ancient river, is found the cemented gravel from one to five feet in thickness, and in some localities exceedingly rich in gold. The distinctive tabular appearance of the mountain can be traced from Murphy's, in Calaveras County, where it has an altitude above sea-level of about 3,000 feet, to Knight's Ferry, Stanislaus County, where it is lost in the foot-hills of the Sierras on the eastern border of the San Joaquin Valley, a distance of thirty-six miles. At its upper end it is much broken up, but in Tuolumne County, below Abby's Ferry, continuous stretches of many miles occur with a gentle grade. Below Byrne's Ferry, where it is again cut by the Stanislaus, it is much broken, and is finally lost in the foot-hills.

Prof. J. D. Whitney, in his General Geology of California, (vol. 1) says of this mountain:

On approaching Table Mountain and examining the material of which it is composed, and the position which it occupies, it is seen at once that it is a vast lava flow, of which the upper surface remains very nearly at the level and with the form which it originally had at the time of its consolidation, while its edges and the surrounding country have been denuded and washed away, so that the topography of the region is entirely different from what it once was-in fact, it is almost the reverse of it. No one can deny that a stream of melted lava, running for forty miles down the slope of the Sierra, must have sought and found a depression or valley in which to flow, for it is impossible that it should have maintained, for any distance, a position on the crest of a ridge. Nor could the valley of the Stanislaus, now two thousand feet deep, have existed at that time, for this flow of lava is clearly seen to have crossed it at Abby's Ferry. The whole face of the country must, therefore, have undergone an entire change since the eruption took place, during which this mass of lava was poured out. The fact that the lava flow of Table Mountain took place in a pre-existing valley is not only capable of being demonstrated on general principles, but is confirmed by what has been shown, by numerous excavations beneath it, to be the character of the formation on which it rests. Professor Whitney estimates the amount of denudation which has taken place during the period since this lava flow took its present position at not less than three or four thousand feet of vertical height. The excessive hardness of the basaltic capping of the mountain has protected it from any appreciable amount of denudation and erosion. This is manifested by the scarcity of vegetation on its summit, where there is no soil of sufficient depth to support more than a few stunted shrubs.

The discovery of the auriferous character of the bed of this ancient river was made accidentally by some placer-miners working in the vicinity of Shaw's Flat, in 1854, at a point near the rim rock of the channel where the lava capping had been denuded. In the excitement which followed almost the entire length of the mountain was located, and hundreds of tunnels run to strike the channel. From the best data at our disposal we estimate the total length of tunnels run in this mountain at forty thousand feet, at a cost of not less than $800,000. The number of feet located was between sixty thousand and eighty thousand, many of these locations being parallel on the supposition that there were two channels. This idea probably originated from the fact that the river frequently changed its channel, as do modern streams. At the present time the wild spirit of speculation, which induced the expenditure of such large sums in running tunnels, has subsided, and mining is only carried on at a few localities, but generally with handsome returns. Some details of present mining operations in this mountain will be found in the description of Hughes's claim, (formerly Maine Boy's tunnel,) and the ground of the Table Mountain Tunnel Company, under the heading of "Tuolumne County."