CHAPTER I. CALIFORNIA. The collection, in the State of California, of statistical and descriptive matter for the present report has been attended with more than usual difficulties and disappointments. The system of circulars and blanks which has been tried on former occasions, in the absence of adequate means for the employment of competent resident correspondents, has received another faithful trial resulting in almost total failure. Even those owners and superintendents of mines or mills who would be quite ready to furnish information orally on personal solicitation or to permit a free inspection of their works by a competent reporter have declined or neglected to respond to written requests. It is much to the credit of my agent, Mr. W. A. Skidmore, that he has been able, in the face of such embarrassments, to prepare a tolerably full and trustworthy account of the mining industry of the State. An acknowledgment should also be made to several friends who have afforded him valuable assistance, and particularly to Mr. Charles Gale, who has assisted in the preparation of the matter relating to quicksilver; Mr. T. M. Balch, who has furnished valuable information relative to the coal, and Mr. James D. Hague, who has done the same for the iron of Sierra County; and to Dr. Henry Degroot for important data. Special thanks are due, also, to Messrs. J. H. Crossman, of Auburn, Placer County; Mr. J. H. Becket, of Grass Valley, Nevada County; Mr. John Rathgeb, of Calaveras County; and Mr. Lewis Chalmers, of Alpine County. Due credit is given elsewhere to other contributors. The product of the State for 1873 is estimated by Mr. Valentine, superintendent of Wells, Fargo & Co.'s Express, as follows: This branch of mining has attracted more than usual attention during the past year, both at home and abroad. From all parts of the State I bear of the consolidation of claims in the hands of large companies and the commencement of extensive works of development, while in other claims of magnitude, such as the North Bloomfield, Milton, and Union, in Nevada County, and others in Sierra and Plumas Counties, the preliminary work of years is rapidly approaching completion. Once opened, these mines pay with more regularity and certainty than any other class of mining, and are, therefore, in great favor with English investors in mining property. It is a matter of difficulty to obtain the results of American hydraulic claims, since most of them are not incorporated. No printed reports are made, and sometimes no accounts are kept. The details of the opera tions of some of the largest companies will be found under the headings of the respective counties in which these properties are situated, particularly under the heading of Nevada County, where the extensive works of the North Bloomfield Company are described in detail. The mode of occurrence, methods of working, and probable origin of these vast accumulations of auriferous gravel, generally known as Deep Placers, have been frequently described in former reports. Nevertheless, in view of the increasing attention these deposits are receiving, manifested by the investment of large sums in mining enterprises of this class, and in view of the fact that each report falls into the hands of many new readers, I have deemed it advisable to publish such descrip tions as may throw light on this interesting subject. A report made during the year 1873 to an English company, by Professor B. Silliman. of New Haven, and which has not been published in this country, contains an excellent summary, part of which is here quoted: Theory of formation.-It is susceptible of proof from numerous well-established facts that at the close of the geological epoch just prior to the appearance of man upon the earth, the whole of the western slopes of the Sierra Nevada Mountains, the Alps of Calfornia, were, below a certain horizon, covered by a vast spread of alluvium, owing its origin, probably, to the action of extensive glaciers, which have left the evidence of their former presence everywhere in the higher Sierra. The glaciers furnished the transporting power that brought from above the fragments which, by long-continued action of running water, were worn into the smoothly rounded bowlders, gravel, and sands forming the gold-bearing alluviums. The melting of the glaciers, as their lower skirts reached the warmer zones, furnished the water for these ancient rivers, whose beds are now found far above the level of the present river-system, and whose courses are generally crossed by the valleys of the modern streams. This condition of things continued long enough to permit the acctmulation of beds of gravel, the gold-bearing alluvium, to a depth and extent unknow anywhere else in North America; and, if we speak of auriferous deposits, unequallei elsewhere in the world. Of the thickness of this accumulated material we have evidence in numerous places, where it has been protected from the action of subsequent denudation by a capping of volcanic materials. In many such places it reaches a thickness of 500 feet. Usually, however, it has been denuded to one-half of this thickness, often less; and in many regions has been swept completely away. Subsequent to the glacial and alluvial epoch to which the gold-bearing gravels are referred, there was a period of intense volcanic activity, the evidence of which is seen most conspicuously in the Table Mountains of California, so called, which are cappings of basalt forming highly characteristic ranges, which portions of the ancient gold-bearing gravels are extensively explored in Tuolumne County by tunnels driven beneath the basalt cappings into the ancient river-beds. Following the outpourings of the volcanic matter there has evidently been an epoch of very active denudation by running water which has broken up and removed the volcanic cappings, leaving them entire only here and there as landmarks showing the ancient levels, and sweeping away also vast areas of the old alluvium and redistributing it as secondary or shallow placers at lower levels. This denudation was probably consequent on the sudden disappearance of the vast system of glaciers which up to that time crowned the entire range of the Sierras with ice. It was greatly raore energetic in the southern portion of the Sierras than in the northern, where the mass of ancient alluvium remaining is much greater than it is in the former region. The extent of the ancient alluvium, as well as the energy of the power which produced: originally, and subsequently denuded it, becomes apparent on a study of the phenomena, carrying to the mind an overwhelming conviction. These extensive deposits of gold attracted the attention of the early adventurers in California, and were called "hill diggins;" but their real nature and significance were not at first fully understood, and, being generally much above any sources of watersupply then available for washing, they received but little attention. Especial were they overlooked while the rich spoils derived from their secondary removal 1 denudation were available, with no other means than the miner's pan, shovel, ari pick, upon those productive "bars" of adjacent rivers and in rich "gulches" wher the gold (derived in large measure from the denudation of the ancient alluvium) lay open to the first comer in a concentrated form. So complete was the removal of the gravel in some of the southern counties that the gold, left behind by its weight, lay upon the naked rock, covered only by a few inches of vegetable mold, as at Mokelumne Hill, where, in the limits of a single "claim" 15 feet square, the precious metal to the amount of $50,000 has fallen to the lot of a single adventurer. In some parts of the State, and especially in Nevada, Sierra, and portions of Placer County, the volcanic outpourings consisted of ashes. and fragmentary materials, consolidated into heavy beds of volcanic mud with fragments of scoria, tufa, and baselt, which are found accumulated on the higher portions of the ridge between the Middle and South Yubas, and elsewhere, to the height of many hundred feet. Northward, above Oroville, in Butte County, the basaltic cappings occur again, similar to those of Tuolumne County, and known as Table Mountains. Where these overlying masses or cappings of volcanic matter have been removed, or where a bank or section has been exposed by hydraulic washing, we have an opportunity of observing the different strata. The lower or bed-rock stratum generally consists of large stones and masses of water-worn rock which have apparently been torn up and moved by the action of torrents of swiftly-running water. Next above, we find rounded bowlders and pebbles, generally consisting of quartz, and strongly cemented by pressure and perhaps chemical action; and still above, alternate layers of sand, gravel, decayed vegetation, petrified wood, lignite, and a layer which is known as pipe-clay by the miners, but which is evidently a clay sediment deposited during periods of overflow in slow running water, and in all respects similar to the sediment deposited every few years by the Sacramento River, over lands adjoining its banks during periods of overflow. The conclusion is irresistibly reached by an examination of these banks, sometimes exposed to a height of 300 feet or more, that their contents were deposited at first by swift torrents, and subsequently by alternating high and low water. In some places the ancient streams seem to have widened into lacustrine expansions, and here we have the phenomena of beach deposits. An instance of this is found in the Union gravel claim of Howland Flat, Sierra County, where a drift of over 1,000 feet across the channel has failed to disclose any evidence of an approach to the center of the channel, which would be evidenced by a "falling off" of the bed-rock. This drift is run under a lava capping many hundred feet in thickness. Character of the deposits.-The term "blue-gravel" has come into general use among hydraulic miners, to distinguish in general between the upper or poorer beds of the deposit and the lower and richer portions which have often, but not always, a peculiar bluish color that has come to be considered characteristic of the rich portions of the gravel. The bluish color is due to the reducing power of organic matter, chiefly vegetable fiber, acting upon the salts of iron present. The latter have become the principal cementing material, compacting the gravel and sand into a firm conglomerate so strong near the "bed-rock," as sometimes to require the use of gunpowder to prepare it for action of the water. When exposed to the action of the air and atmospheric waters, this blue color disappears and the mass becomes yellowish and reddish, and sometimes brilliantly colored with various tints of purple and red. It loses at the same time a great part of its firmness and often crumbles to powder, even the pebbles of a certain sort "slacking" to a sandy consistency. The blue color has no necessary connection with the presence of gold, the fact being that the deposit is richer in gold as it nears the "bed-rock," and that the cementing material is bluish only because it has been beyond oxidizing influences. |