done during the following two years. At present, and for more than a year past, none of the claims have been worked. Among the few important mines in this district are the La Solidad, Copper Hill, and Occidental. On the first named, at the depth of one hundred feet, the lode was found to be about seven feet wide. This is the deepest shaft in the district.

The geological formations and ores in this district are precisely the same as those already described in San Luis Obispo and Mariposa counties, and the same disturbing causes have broken up the lodes, which range in the same direction within a few degrees.

Plumas county mines.-The copper mines in Genessee valley, Plumas county, are the highest on this coast, the valley in which they are located being à small basin of a few miles in circumference, embosomed high up among some of the loftiest peaks of the Sierra Nevadas, which are clustered together in the northeast of this county. This portion of Upper Plumas contains some of the most magnificent scenery to be found on the coast. Immense granite ridges are seen rising bare and bleak two and sometimes three thousand feet above the densely wooded ridges at their base, while below, cañons thousands of feet deep form courses for the waters, which look like silver threads as they go meandering through the black gorges that lead them to unite with the waters of the Feather river, thousands of feet still further below. Nature appears to have performed some of her mightiest labors in this locality. Subterranean fires have piled up the molten rocks thousands of feet high, for the highest peaks are composed of lava, while the floods of water have worn the frightful cañons which furnish the bed for the present insignificant streams. Amid the very centre of so much ruggedness, caused by nature's greatest forces, Genessee valley forms a beautiful contrast, with its grassy fields and the curling smoke of its smelting furnaces and other evidences of the power of man. The belt of copper ores already referred to passes through this valley in a course ranging north twentyfive degrees west. As may well be imagined, in such a country, the lode has been extensively dislocated; but by examining the unshifted bodies of the containing slates, which may be traced for many miles, as well as the form and composition of the lodes, it is proved that this is part of that great belt. The chief copper

mines, the Cosmopolitan, are located about five miles from the village of Taylorville, and three-fourths of a mile from a ranch which was originally located in the valley by a Mr. Gifford. They were discovered in the beginning of 1862. The inaccessibility of the place and the broken character of the country preclude the possibility of this ever becoming a very important copper mining locality. Nevertheless, parties interested in these mines have erected smelting works which have cost upwards of $30,000, and made several tons of good regulus by a process invented by a farmer named J. C. Chapman, who never had any knowledge or experience in copper smelting till the discovery of these mines. As long as the parties interested in this enterprise could obtain plenty of oxides, carbonates, and silicates of the metal, which were quite abundant and very rich at the commencement of their operations, they obtained regulus sufficient to pay expenses; but as soon as they reached the sulphurets in the lode the works had to stop, as they were not adapted to operate on this class of ores. At the present time they are not in operation. These works were put up by Bolinger, Blood & Co.

At a depth of sixty feet the lode on the Cosmopolitan mine was found to be about fourteen feet wide, containing about ten per cent. of metal. It lies between the granite and limestone on this claim. The metamorphic slates and serpentine, which accompany the copper all through this State, are here a few hundred feet to the south.

Del Norte county mines.—The Alta district, in Del Norte county, is situated on what is known as the "low divide," an extensive plateau on the summit of a lofty range of mountains which divide the valley of the Illinois river from the

Pacific ocean. These mountains run through the northern portion of California and the south of Oregon, for more than one hundred miles, and cross the western branch of the Sierra Nevadas at nearly right angles.

Altaville, the centre of this district, is about fifteen miles northeast from Crescent City, Del Norte county. There are a great number of mines in the district; many of them have been extensively worked, and probably one thousand tons of good ore has been shipped from them since their discovery, in 1860. Among those which have shipped ore are the Alta, Union, Pacific, Lady Belle, Chrysopolis, Comstock, Diamond, Express, Pearl, Copper Hill, Excelsior, and a number of others. The Alta was the first mine worked in the district, and is the only one worked at present.

The mines in this district are not connected with the great copper belt so frequently alluded to in this report. This runs several miles to the east, where the Siskiyou mountains connect the counties of Yreka, in California, with Josephine, in Oregon. The ores in the Alta district are quite distinct in deposition, appearance, and character from those found in the mines on the great belt. The deposits are separate and distinct; of probably the same age and origin, as they are similar in other respects to those found around the base of Mount Diablo, and in the coast range further south. The first forty-two tons of ore shipped by the Alta company averaged forty-five per cent., and sold in San Francisco for $7,000 cash, the cost of their extraction and delivery not exceeding $2,000. They were red oxides, chiefly, of which there was a large body nearly three feet wide and fifty feet long, near the surface, but this was soon exhausted, as there is no well defined lode on the ground. In fact it is doubtful whether there is a consecutive body of ore of fifty feet in length in the whole district. The croppings of what are supposed to be lodes-nearly a dozen of them-are seen ranging nearly north and south for many miles, but the body of ore beneath these croppings is so irregular in position, owing to the distortion of the serpentine in which they are contained, that it is almost impossible to tell in what direction the average of them do lie.

The Alta Company have sunk a shaft on their mine to the depth of nearly four hundred feet without finding a regularly defined lode. They meet with bunches of ore, chiefly yellow sulphurets of a very low grade, varying in size from a mere film to ten feet thick, but not sufficiently connected to make the mine profitable to work under the existing state of the copper market. This mine is exceedingly well situated for obtaining its ore cheap, if a large body of it should be found, as drifts could be run into the hill at a great depth at comparatively little cost.

The Rockland district is located about fifteen miles east of the Alta district, above described, and about thirty miles from Crescent City, Del Norte county, California. The mines in this district are located on the great copper belt, which may easily be traced in the vicinity for nearly twenty miles, in the direction of N. 28° W., the general trend of this belt, by which it may be followed from where first noticed, north of Los Angeles, to about twenty-five miles west of this district, which is a few miles within the limits of the State of Oregon. There are several other districts within this State in which important copper mines have been located on this belt; but time will not admit of any reference. being made to them. The Queen of Bronze, near Waldo, Josephine county, the most valuable copper mine in Oregon, is located on this belt, about sixteen miles west from this point. Extensive smelting works have been erected on this latter mine, and thousands of tons of ore have been exported from these mines, which, as has been already stated, have been discovered since 1860.

There are some peculiarly interesting features connected with the copper mines of this district, which have a tendency to throw considerable light upon the subject of the action of volcanic forces on metallic ores, because in this vicinity an enormous volcanic dyke, nearly one hundred feet wide, approaches

the copper belt at an obtuse angle, within a hundred feet, and it is within this point of proximity that the large masses of metallic copper mentioned above were discovered. Another point in the same connection may be here mentioned. The age of the rocks containing the copper, throughout the whole extent of the great belt, has been tolerably well ascertained to be between the triassic and tertiary eras, and as this volcanic force, which has caused the conversion of the ores into metals from one end of it to the other, must have been exerted subsequently, the opportunity here afforded to examine the largest and most clearly defined dyke on the coast is very important.

Mount Diablo district. The principal copper mines in the Mount Diablo district are located about the northern base, and up the side of a spur of Mount Diablo, called Mount Zion, and along the north side of Mitchell's cañon, near the town of Clayton, Contra Costa county. The first discovery of these mines was made in 1860, and considerable work was done on several of them for about two years, in efforts to discover the lode, but without success, as there is no lode in the mountain. The copper found here is not connected with the great cupriferous belt, but exists in detached bunches and masses, as is the case in the Alta district, in Del Norte county, described above. The croppings of the patches of ore here run north and south, as they do at, Del Norte. Some metallic copper has been found on the north side of Mitchell's cañon, but in every case, after reaching a few feet below the surface, the ore, when found in bodies sufficiently large to take out, has been found of a very low grade; ten tons of selected ore shipped by the Keokuk company did not yield more than eight per cent. It is doubtful whether the mines in this district will ever pay to work.

Peavine district.-The Peavine district was discovered in 1864. It is located a few miles east of the Henness pass, in Washoe county, Nevada, one portion of it being within three miles of the line of the Central Pacific railroad. The district embraces an era of ten miles square, in which there are a great number of claims of considerable importance. The ores in all these mines are entirely distinct from those found in California, as well as the containing rocks. They are usually much contaminated with quartz, but they contain a large per cent. of gold and silver. The completion of the Central Pacific railroad to within a few miles of the district has given considerable impetus to prospecting, and a great number of companies are preparing to take out ore, the railroad company having informed those interested that it would carry ores to Sacramento, from any point in the Henness pass, for $9 per ton. The ores of most of these mines being silicates, carbonates, and oxides, are very easily concentrated, a fact which the owners of the Bay State mine appear to be aware of, as they are putting up a small furnace, on Haskell's plan, to operate on all the ores they can purchase, as well as what they can obtain from their own mine. No ores of any consequence have been shipped from this district, in consequence of the distance to a market; but in 1864 a Doctor Landszwert made a number of large bars of fine copper from them, which were exhibited at the State fair, at Carson City, in that year. These bars contained $150 per ton in gold, and about $250 per ton in silver, according to the doctor's assay.

Lower California mines-Of the copper mines in Lower California but little of an authentic character is known. The Sancè mine, as described by Mr. W. Thompson, an old Cornish miner, who was superintendent of it for three or four years, is located near Loretto, a place in the province of Comondu, about thirty miles from the coast, where there is a good harbor. The lode is described as being from eight to ten feet wide, enclosed between walls of slate and granite. It has been extensively explored by shafts and levels, and about five hundred tons of ore have been shipped to Europe, where it sold for about five hundred dollars per ton. This ore, specimens of which have been brought to San Francisco, is of a very peculiar character, being a sort of talcose gangue,

containing flattened scales of metal of various sizes, from several feet in length and breadth, to small specks like fine gold dust. Many of the larger masses of this copper are covered with an incrustation of metallic silver, the only similar combination of these two metals found on this coast, though the combination of metallic copper and silver is quite common at the Lake Superior copper mines. This mine has not been worked for nearly two years.

Arizona mines.-The mines in Arizona, from which ores have been sent to San Francisco, are located on both banks of Williams's Fork of the Colorado river, where, there is but little doubt, will very soon be one of the most important copper mining districts on this coast. The existence of the deposits of ore now in course of development at this point was well known for several years before the discovery of the mines in California. A quantity of the ore from some of the mines about Mineral Hill was sent to Boston, as early as 1858, and examined by Doctor Jackson, the distinguished mineralogist of that city, who pronounced them of extraordinary richness. But a variety of causes, among which the want of means for transporting the ore was the chief, prevented any advantage being gained by the discovery till 1862 when the owners of the Planet mine shipped about one hundred tons of their ore to San Francisco, where it sold for a price that left a profit of upwards of $100 per ton over and above all expenses for its extraction and transportation, the land carriage from the mine to the river, about twenty miles, having been done by pack-mules. A good road has been cut to connect the mines with the river since that time.

There are nearly fifty good mines in this district on both banks of the river. The Planet is the most important on the south, and the Mineral Hill on the north. The greatest activity has prevailed among these mines during the past year, and about 1,500 tons of ore have been shipped from them all collectively; the principal shippers being the Planet, Great Central, Mineral Hill, Philadelphia, Mountaineer, Mammoth, Copper Hill, and Occidental. Ten times the quantity shipped might have been sent had there been means for taking it away. Gentlemen just returned from these mines state that there are upwards of 1,000 tons of ore that will average 40 per cent., now lying on the river bank ready for shipment. The steamers and two or three schooners employed in the trade are wholly inadequate for the purpose.

Some of the mines in this district have been extensively explored by means of shafts, tunnels and drifts, and in nearly every case the body of ore has increased in importance in proportion to the extent to which it has been developed. The Mineral Hill company have run a tunnel on their mine for the length of 350 feet, out of which, while cutting, they took nearly 1,000 tons of ore of an average of 30 per cent, the whole work from the surface being in a body of ore. The ore in none of the mines in the district is found in a regular lode, as in the mines in California, but the whole country appears to be formed of the ores of iron and copper, the hills for miles around being colored red by the iron, or green and blue in patches where waters containing carbonate of lime in solution have percolated through the copper.

In running the tunnels and drifts through this extraordinary material, the miners run considerable risk of injury by being crushed by heavy masses of ore, which, having been held in place by large quantities of powdery oxide of iron, drop out when they are undermined in cutting the drifts. When such blocks fall out, in some cases hundreds of tons of this dry powder, which is nothing more nor less than iron rust, will come rushing down and block all further work till the opening can be timbered up.

The great body of ores found in the district being black and red oxides, silicates and carbonates, all of a character that admit of conversion into regulus by the application of heat alone, and by a single process, several of the companies have erected extensive smelting works. Martin & Greenman, who are

largely interested in the Mineral Hill mines, are putting up works that will cost nearly $100,000 when completed.

Some of the ore taken from this extraordinary hill are so exceedingly rich in gold, that a 10-stamp battery is being erected to crush the ore and work it for the gold, by the ordinary processes adopted for saving gold from quartz; the tailings will be afterwards smelted for the copper they contain, nearly 40 per cent. The gangue rock of nearly all these Arizona ores is composed of spathic iron, heavy spar and quartz; the ores found in California being free from gangue rock, though they are generally mixed with the containing slate or serpentine. Knowles & Lightner, another firm, extensively engaged in these Arizona mines, are also putting up smelting works on their ground. The Great Central company have a set of such works in active operation, and turning out large quantities of good regulus of about 80 per cent.

Most of the labor done about these mines is performed by natives, Mexicans and Chinamen. Not more than one-fourth of the workmen are Americans or Europeans.

Aubery City is located on the north side of the fork, and would soon become quite an important place of business if sufficient tonnage could be obtained to carry away the ore that could be furnished by the mines in its neighborhood.

3.—THE GEOLOGICAL FORMATIONS IN WHICH COPPER IS FOUND. Peculiarities of formations.-There are peculiarities about the geological formations in which the copper ores are found on this coast, which derive an interest from the great extent of country over which they can be traced. For instance: Not a single important body of such ore has been found on this coast, either among the coast range, the foot-hills, or among the Sierra Nevadas, except in the immediate vicinity, if not actually in serpentine or other magnesian rocks or matamorphised slates. This is the case in all the districts above described, the only exception being at Hope valley, Amador county. For the hundreds of miles over which the great belt of copper ores can be traced, it is never found except in one or the other of these rocks, and invariably without any gangue rock, except this containing slate or serpentine. This great belt of copper ore is never formed except in the immediate vicinity of the auriferous slates and quartz. As has already been mentioned, all the copper found on this coast contains a large per cent. of gold, and many of the most important auriferous quartz lodes contain a considerable per cent. of copper ore. In some sections of the State the gold itself is so much alloyed with copper that it is not more than half as valuable as that obtained from other sections. The numerous fossils that have been discovered in both the auriferous slates and in the vicinity of the great copper belt, prove that both formations belong to the same geological era. It may therefore be reasonable to suppose that the same causes which produced the one, at the same time produced the other. The nature of these causes has not been sufficiently studied to be of any practical use; though the subject involves many important practical and scientific points, such as the compilation of facts and the, observations of practical men in the department you have just inaugurated may throw much light upon.

The costs of working the copper mines.-The cost of working the copper mines on this coast is, under the present system, a great impediment to the development of this source of national wealth. Expenses of copper mining are much influenced by three conditions: the convenience of the mine to the market for its product, the kind of labor employed, and the position of the mine in reference to facilities for working it.

The mines at Copperopolis, which are most favorably located with reference to the convenience for sending their ores to market, pay, on an average, about $8 per ton to carry their ore from the mine to the ship which carries it to the