of the geology except on a basis of accurate geography, I long since commenced gathering our materials into shape with the idea eventually of publishing a map of the mining counties. Such a map has been partly prepared, and will be submitted to the legislature, in order that they may have the means of judging for themselves whether the completion and publication of this piece of our work may be advisable. The already warmly expressed wishes of many persons interested in mining throughout the State seem to me to point very clearly in that direction. The map, as now prepared, is about six and a half feet by four in dimensions, and covers an area of about nine thousand square miles, extending from Stanislaus County on the south to Plumas County on the north. I propose, however, to extend it in both directions, so that it may be published in four sheets, each reaching across the Sierra from foot-hills to summit, and so arranged that the sheets may be had separately, or the whole combined together into one map.

Immediately after the resumption of the survey, the services of Mr. Amos Bowman were engaged, and he was directed to begin a minutely detailed exploration of the mining belt of the Sierra, with the especial object in view, however, of collecting all the data necessary for a full report on the gravel deposits worked by the hydraulic process. Mr. Bowman took the field in April, 1870, Mr. W. H. Pettee joining him in July, and these gentlemen spent nearly all the remainder of the year in working out the geology and mapping the detailed topography between the Yuba and American Rivers. In the mean time Mr. W. A. Goodyear commenced on the detailed survey of the mining belt of the Sierra lying to the south of the North Fork of the American River, and continued in the field until driven out by the inclemency of the season, having reached a point as far south as Sutter Creek, Amador County.

In the prosecution of this work a large amount of valuable information has already been collected, both of a geographical and geological character. It is confidently expected that the final elaboration of all our materials, with the accompanying maps and sections, will exhibit the phenomena of the gravel deposits of the Sierra, in regard to which there has been so much discussion and such a multiplicity of opinions, in a new light, and that many difficulties which have hitherto perplexed the miners will be solved. It is my desire that this work should be continuously and vigorously prosecuted, until a full and detailed map of the whole western slope of the Sierra has been prepared, accompanied by a corresponding report. This, it is expected, can be accomplished during the next season, if the pecuniary means are forthcoming, the map and report being completed during the following winter.

The question how and when the geological portion of the survey reports shall be published is one that has been much considered; but in the prevailing uncertainty in regard to the moods of the legislature, and the amount which is to be expended on the survey, it has been found impossible to answer it. Some persons have been so unreasonable as to expect a geological map of the State before a geographical one was or could be got ready. As fast as the sheets of the Central California map are engraved we shall color the geology upon them, and we shall do the same with the map of the whole State, which will probably be colored in time to be exhibited to the next legislature, during the coming winter, (1871-72.) As soon as the maps are ready, it will be time to prepare for the publication of the geological volume to accompany them. The engraving of the sections necessary for this volume should also be begun as soon as possible. It is my impression that the geological part of our work can, by condensation and the use of small type, be compressed into two volumes, with an accompanying atlas of maps, sections, and other illustrations. It also seems, at present, as if the best division of the two volumes would be to allot the general geology to one and the economical geology to the other. In that case the first one would contain a systematic description of the geology of California, arranged in chronological order of the formations; while the other would be devoted to a discussion of the character, mode of occurrence, and value of the useful mineral and metallic combinations which they contain. One volume would be for the use of the scientific and general public; the other for those especially engaged in developing our mineral resources.

The labors of the State Geological Survey have now reached a point where many practical advantages may be expected to follow the publication of the results of their investigation relative to the gravel deposits, their extent and mode of occurrence, and the causes of their distribution. In this investigation, the history of past and present work in the mining region has been carefully prepared, and is chiefly valuable as an aid in estimating the extent and value of the undeveloped ground which yet remains. The survey has already more than paid for the sums of money expended in its prosecution, by revealing to the world the almost inexhaustible extent of our mineral wealth. Capital has thereby been attracted, and universal confidence in our resources prevails. It is to

be hoped that this useful work may not be stopped at this time, when we are about to reap the reward of the patient and careful labors of Prof. Whitney and his assistants.

Meteorology of California.-The meteorology of California has an important bearing on the general prosperity of the State, as well in its relations to the mining interest as to that of our agricultural prosperity. In future the subject will have a still greater interest on account of its relations to gold production, in consequence of the numerous great undertakings projected or under way for controlling the waters of the State and economizing them for mining and agricultural purposes, and the extensive development of our unworked gravel deposits, which so largely depend for success on copious and regular rains.

The subject has received careful attention for years past on the part of a few scientific gentlemen, who have, from time to time, published the results of their observations for the benefit of the community. Among these are Dr. T. M. Logan, of Sacramento, and Mr. Thomas Tennent, of San Francisco, who, for over twenty years, have kept accurate record of the rain-fall at those places. Recently the Government has established branches of its Signal Service Department at various points on the Pacific coast, and their records and observations will, in future, prove of great utility to the miner and the farmer, as well as a benefit to science at large.

I select for publication the table of Dr. Logan, which I prefer because his observations are made in the central portions of the State, and in closer proximity to the mining region than those of other observers.

The records of the rain-fall of the State differ greatly in various localities, depending on the topography of the country. In San Francisco and in the coast counties it appears to be about twenty per cent. more than in the great valleys of the Sacramento and San Joaquin. In Nevada City, at an elevation of about 2,500 feet above sea-level, the fall of rain has been more than double that of the valleys. Higher up in the Sierras deep snows fall, which do not melt until late in the summer, when they furnish in a wet year the supplies of water necessary to hydraulic operations and quartz mining.

It will be observed that during the past three years (1868, '69, '70,) the aggregate rain-fall has been only 38.68 inches, which is but little more than that of many single years, and much less than fell in any other three consecutive years since the settlement of California by the Americans. The consequence has been a material diminution of the gold product in the face of a greater amount of development and exploration. Hydraulic operations have been almost suspended, and even the quartz-mills have been obliged to shut down or run at half their capacity for want of water.

The present season, however, has opened auspiciously, and promises to equal our best years in the supply of water. The rain-fall for the first three months of the season, up to end of December, has reached 12.02 inches at Sacramento. It is now believed the fall for the season, October, 1871, to May, 1872, will reach thirty-six inches.

The following table prepared by Mr. F. B. Pilling, of the United States Signal Service Corps of San Francisco, will show the distribution of the rain-fall for December, 1871. It will be observed by comparison with Dr. Logan's table, that rain-fall at San Francisco was 3.77 inches in excess of that of Sacramento for same period.

Table showing daily and monthly mean of barometer and thermometer, and amount of rain-fall for the month of December, 1871.

Mining inventions and improvements.-The past year has not been noted for the introduction of many new or important appliances useful to the mining industry, but several inventions have been brought to a greater degree of perfection, and are now coming into more general use, with the most favorable results to economy in mining.

Hydraulic machinery.-In the gravel and hydraulic mining regions of the State, the improved pipes and nozzles for projecting a large quantity of water under great head or pressure against the gravel banks, have been thoroughly tested and found to be valuable accessories in the extensive and economical working of our auriferous deposits, and may be said to have revolutionized this branch of mining. The pipes in general use are those of Messrs. Craig and Fisher, of Nevada City, and Mr. R. Hoskins, of Dutch Flat, which are described in the report for 1871, pages 63 to 65. I doubted last year whether 1,000 inches of water could be successfully thrown through one nozzle in hydraulic mining. That doubt can no longer be entertained. The Dutch Flat Blue Gravel Company (on the Taeff ground-see my last report, p. 84) have been throwing 1,200 inches through a Hoskins pipe, with 432 feet head, and are now constructing a pipe to throw 2,000 inches. In fact, hydraulic mining is assuming proportions heretofore scarcely dreamed of.

Quartz-crushing machinery.-In quartz-mills there has been one invention which possesses the merit of novelty in the application of crushing power. This is a trip hammer quartz-crusher, invented by Mr. J. D. Crocker, of Virginia City, Nevada, and lately introduced in California. A small five-stamp crusher was exhibited at the mechanics' fair of San Francisco in September of this year, and attracted much attention and favorable comment from persons interested in mining.

The chief improvement in this invention consists in operating light stamps on the principle of the tilt or trip-hammer, whereby quick, sharp

blows are made, with very light stamps, and with less proportionate power, according to weight of stamp and frequency of blows, than is required in operating heavy stamps with a direct lifting action. The advantage of sharp, quick blows with a light stamp, must be obvious to