CHAPTER I.

CALIFORNIA.

SAN DIEGO COUNTY.

For the first time this county has entered the list of those producing bullion, and though the shipments are as yet small, they bid fair to improve rapidly.

The mines are situated forty-two miles northeast of the town of San Diego, in a range of mountains known as the Isabella Mountains. They were discovered late in the fall of 1869-it is said by a party of prospectors returning from Arizona-and the extraordinarily rich ore from the ledges first located, among which the Washington seems to be the most prominent, caused considerable excitement on the Pacific coast in the spring and early summer. This threatened to grow into a regular stampede at one time, but subsided soon when it was found that the riches were not available without the aid of considerable capital. Several districts were, however, organized, and a town, Julian City, sprang up at once in the heart of the region.

C. A. Luckhardt, M. E., who visited the locality early in 1870, reports to me the following:

Cuyamac or Julian mining district is situated in San Diego County, California, a distance of forty-two miles by stage-road, in a northeasterly direction from San Diego City, in a range of mountains called the Santa Isabella Mountains, which course north and south, lying between the Pacific Coast range and the San Bernardino range of mountains, and have an elevation of 3,000 feet above sea-level. It was located in the early part of 1870, and created much excitement, caused by exaggerations of the richness of the gold veins discovered. The Cuyamac Mountain, part of the Santa Isabella Mountain, is thickly covered with nut-pine timber, abounds in swcet-water springs, and has many very fertile plateaux covered with verdure. Julian City, the center of the district, contains about two hundred houses and tents, with a population of four hundred, which, however, is very varying. The main mass of the Cuyamac Mountain consists of mica slate and hornblendic porphyry, coursing northeast and southwest, standing almost vertical, and bounded westward by basaltic rocks, which have overflowed its western boundary of garnet porphyry. The veins are very numerous, lie on the western and southwestern slopes of the mountain, and run in almost every conceivable direction, subject to the irregularities of the hornblendic porphyry. The larger veins run northeast and southwest and are imbedded in the slate. Their dip is from 70° east to almost vertical. They are narrow and have no bold outcrop, and only in places have clearly defined walls been laid open. They have quartz as gangue, and vary from to 3 feet in width.

Although many locations have been made, it must not be supposed that each represents a vein. Many claims are often on the same vein, and many have nothing more than a few detached boulders, embedded in alluvium and debris, for a foundation. Gold is the only precious metal which the veins carry; accompanying it are traces of antimonblende,

results. Near to the city are two mill-sites, with reduction works-the larger one belonging to the Cervantes Mining Company-about threefourths of a mile from town, comprising three furnaces, crushers, &c., of thirty tons beneficiating capacity, the whole driven by water-power. Within one-fourth to one-half mile from Lone Pine runs Owen's River, which is navigable for flat-boats at all seasons of the year from Owen's Lake up to Owensville, a distance of sixty-five miles.

The mountains which bound Lone Pine Valley on the west, and which slope very abruptly eastward into Lone Pine and Owen's Valley, are worthy of mention. The most prominent peaks are Mount Whitney, 15,000 feet; Mount Williamson, 14,300 feet, and Mount Tyndall, 14,000 feet high. These mountains abound in timber lands, and furnish water in sufficient quantities for excellent mill-sites. Although timber is abundant, all lumber for building purposes comes, as yet, from a point fifty miles to the northeast of Lone Pine, and is, consequently, still high in price.

Cerro Gordo City, the center of the mining district, is situated about 7,200 feet above the ocean level, and nineteen miles by wagon-road in a southeastern direction from Lone Pine City. Its elevation above Lone Pine is about 2,000 feet. It lies in a deep ravine on the western slope of Inyo Mountain, and has at present about five hundred and fifty inhabitants. The mountains here are almost barren of vegetation, and there is but a limited amount of fuel. Water is very scarce. At present there are but three wells of from 20 to 60 feet in depth, and some water (3 to 4 inches) has been brought in pipes a distance of four and a half miles, which, however, is barely sufficient for home consumption. This fact has been a great detriment to operations at Cerro Gordo thus far, but in time it can be remedied by sinking more wells, and bringing water from a point nine miles north of the city in pipes or ditches and flumes. There is quite a supply at the locality spoken of, and the enterprise will involve a cost of not more than $80,000.

That portion of the Inyo Mountains in which Cerro Gordo mining district is situated consists of a single chain, having a general northwestern and southeastern course. It is not exactly detached from the Inyo range, but a depression of about 600 feet to the northward separates it apparently, while southward it falls gradually toward Owen's Lake. Its cañons and ravines have a general southwest direction, descending toward Owen's Valley; they are abrupt for about two miles from the mountain summit, but farther south the slope is more gradual, and low hills, for a distance of about two miles, intervene between the steeper parts and the valley. The main bulk of this range, which is called Cerro Gordo, is composed of metamorphic rocks, which contain heavy belts of crystalline and compact limestone, and are intersected by porphyries of various character. The lines of contact are promptly discernible, even where the slates are partly covered over by soil, the latter being mostly ferruginous clay-slates, but sometimes they are calcareous. The lower portion of the southwestern slope, about one and a half miles from Owen's Valley, shows a massive belt of siliceous slates. They run parallel with the main mountain-chain, dip southwest, and seem to be the division line between the sandstone formation of the lowest hills and the metalliferous belt of the mountain above. In this metalliferous belt, limestone is predominant. The veins occur either altogether in it, or as contact-veins. In the former case, the foot-wall of a vein is generally discernible by a clay-seam, forming the division line. The hanging and foot-wall of a vein are in many instances distinguished from one another by the different crystalline structure of the limestone, but

in most cases the walls are compact limestone, showing only here and there signs of a crystalline structure, while the vein-matter is a crystalline limestone. In the second case, that of contact-veins, we have generally slate overlying, quartz or quartzite predominating as veinmatrix, and compact limestone as foot-wall. The outcrops of these veins are often very bold and massive, but in many instances they have suffered a dislocation sideways, the cause of which is fully explained by the abruptness of the cañons. This is very apt to mislead as to the actual width or dip of a vein, and even as to its location.

The course of the veins is northwest and southeast, with a changeable southwesterly dip, except in the extreme northern portion of the district, where the veins turn more and more to an east and west course, and dip north. The northwest and southeast course is a general rule, but is not exempt from exceptions, as metalliferous cross-courses exist in the district: for instance, the Soledad vein, which strikes the St. Lucas and Abundancia at an angle of 65°, and has an almost north and south course, and dips west. Most of the veins dip from 70° to 60° except near the surface, where irregularities are naturally to be expected and are frequently met with. The veins of the district may be divided into two distinct classes, according to their contents, namely: 1. Those which carry mainly argentiferous galena ores; and 2. Those which carry principally copper ores.

The first class have invariably limestone, the second class predominantly quartz and quartzite, as vein-matter. The second class are best defined and the more massive of the two, and are also less subject to irregularities near the surface than the first class. They carry the larger amount of precious metal, and are in consequence termed 'silver leads' throughout the district, while the first class are known as 'lead leads.'

Local circumstances have been the cause, that up to the present time but a limited amount of work has been done on the veins, hardly sufficient to realize the actual merits of many of them. The aim of all work done so far has been always to produce in the shortest possible time the largest amount of ore in order to realize, and judicious work, namely, producing and developing at the same time, has been neglected. Every mining district in its infancy is, of course, subject to this, especially if its yield can be made available forthwith, as is and has been the case in Cerro Gordo ever since its discovery.

To facilitate a description of the ores I shall retain the terms in vogue in the district, calling the above first class "galena ores" and the second class "silver ores."

The ores of the district are of various nature and character, the latter undoubtedly attributable to the character of the rock, which forms the main bulk of the vein-matrix, and also to the nature of the rock which occurs in the immediate vicinity of the veins. They are argentiferous galena, (coarse and fine crystallized,) carbonate of lead, argentiferous copper ore, principally as gray copper ore, and iron pyrites in various stages of decomposition.

Subordinately occur antimonial silver ore with traces of speiss-cobalt, silver-copper glance, silver bearing malachite, azurite, sulphuret of silver, sometimes partly decomposed and mostly free from refractory metals, and native silver, which occurs often in the malachite and azurite.

Gold is found in traces only, and occurs mostly in the northern portion of the district, although some of the veins situated in the extreme southwesterly part of the district show it sometimes. Nearly all the veins carry, more or less of all the above-named ores, but, as stated

above, the veins bearing limestone as gangue matter have galena predominant, accompanied by iron pyrites, which, near the surface, are decomposed to oxides, coloring the entire vein-matter yellowish and red, and entirely veiling its texture. The ore in these veins, as far as can be observed by actual explorations made up to the present time, occurs in nests, pockets, and irregularly shaped deposits, which run generally parallel with and lie very close to the foot-wall of the vein. These vary in width from 1 to 15 feet, and have in several instances been worked to a vertical depth of 40 feet and over 120 feet in length on the strike of the vein, showing no signs of pinching; on the contrary, in two instances, a depth of 150 and 170 feet has been attained, where the iron pyrites are only partially decomposed, and here the silver value has been found unchanged in the ores. The lowest workings of the district have in no instance reached the water-level, and it is impossible to say how the silver value of the ores will hold out where they will be found entirely undecomposed. So far this has not changed at a depth where the accompanying iron ore changed its entire character, and this must lead us to expect a continuation of the silver value of the ores in depth. The galena occurs in various forms, from the coarsely crystallized to the granular and almost solid texture; and although the former theory of the German miners, that the finer and closer the crystals the richer is the ore in silver, is now considered wrong, this has nevertheless been found to be the case in Cerro Gordo. A sample of coarse crystals of galena, from the Union mine, 25 feet below the surface, yielded $84 32 in silver and 67 per cent. of lead, while a similar sample, from the same vein, taken from 60 feet below the surface out of the Santa Maria tunnel, where the accompanying iron pyrites were little, if any, decomposed, gave $91 13 in silver and 58 per cent. of lead. The finely crystallized galena from the Union mine, from about 40 feet below the surface, was found to contain 61 per cent. of lead and $117 53 in silver per ton of ore.

The class of veins bearing quartz as vein-matter and cupriferous silver ores carries galena only subordinately. The ores occur generally in seams from 2 inches to 5 feet wide, and can be followed with some degree of certainty as to duration in depth. They lie generally in or near the center of the vein, wide and narrow at intervals, and when, as is sometimes the case, they hug the hanging wall for some distance, they contain rich ores. But when the entire fissure from wall to wall is filled with ore, it is generally poor in silver and much mixed with veinmatter. In some instances the work done in depth on these veins has proven that the ore improves in quality and quantity as depth on the vein is attained, as, for instance, in the St. Lucas mine. The outcrop of this vein shows malachite stains profusely in many places, bearing $7 to $12 per ton in silver; 45 feet below the surface no highly oxidized copper ores are found, and 4 feet of the vein-matter bear $91 19 silver per ton.

Sampled cupriferous ores yielded in silver as follows:

A. A gray copper ore, containing antimonial ores, a refractory ore for smelting, which forms the greater portion of the ore of the St. Lucas mine, contained per ton $93 60 in silver.

B. A highly oxidized ore, containing silver-copper glance, forming an average of 1 foot in width of ore, 30 feet below the surface, in the San Ignacio mine, contained per ton $161 78 in silver.

C. A still higher oxidized ore, mostly antimonial, with stains of leadochre, some malachite, and azurite, forming a seam 6 inches wide in the San Ignacio mine, close to the surface, yielded $289 05 in silver and $40 51