1. The discovery of gold in California makes the year 1848 an era in the history of that country. It was accidentally found, in the Spring season, in the diluvial soil, by some persons digging the sluiceway for a mill. Specimens of the various kinds of the metal and its matrix were forwarded to the War Department by the chief military officer in command, in the month of August. These specimens were not received at the War-Office till early in December. I examined them in the library of that office, on the 8th of that month. They consisted of thirteen specimens of various minerals, chiefly gold in some of its metallic forms.
2. Judged by external character, the specimens admitted of being grouped in the following manner:
- Small masses of native gold, in the separate form of grains and scales, or minute plates, from which all extraneous matter had been cleanly washed.
- Similar forms of equally fine, and highly colored masses, with the loose residuary iron sand of the washer.
- Masses of scale-form gold of an ounce or more in weight, but offering no other peculiarity of character.
- An ovate mass of two ounces weight, having a portion of its original matrix of quartz still adhering.All the scale-form, and lump gold, exhibits, more or less distinctly, the marks of attrition, and of having been carried in its alluvial association in the valley of the American fork of the Sacramento, some distance from its original position. It is of the sub-species of gold yellow native gold of the systems the Gold-gelber Gediegen Gold, of Werner. The specific gravity of this variety, in its refined state, is generally from 17,000 to 19,000. By analysis, it is sometimes found to contain very minute portions of silver and copper.1
The preceding notices embrace all the specimens of native gold in the thirteen separate packages received at the War-Office, exclusive of the caddy, named in Colonel Mason s report. The following comprise the other mineralogical species sent.
- Native masses of a metal of a light steel grey color, approaching to white, of considerable weight. These are scale-form; resembling in this, and in size, the scale or plate gold. They present the peculiar color of platina, which it is difficult, how ever, to distinguish from palladium. The specific gravity of native platina varies between 15,601 and 18,947, but reaches, in its original state, 23,000.2
- Angular masses of a white mineral, of a dull metallic lustre and coarse granular fracture, which has the external characters of iron pyrites.
- A lump of red-colored ore. This mass is a large and heavy specimen of the ore of mercury, called cinnabar, and is well characterized as the dark red variety of the systems.3
3. In appreciating the gold formation of California, we may derive some light from the history of the discovery of this mineral in other quarters of the globe. Much of the native gold of Asia, Africa and Europe, of ancient periods, was found in earthy deposits in the beds or valleys of streams, or plains which have been produced from the disintegration, gradual degradation, or removal of pre-existing rocks. The early sources of gold bullion, of which the bed of the Pactolus is a memorable example, have been long exhausted. And as the surface gold of later ages has been picked up, or washed out, its origin has been generally traced to fixed veins in contiguous mountains, where the expense of crushing the hard rock has been found to be well-nigh equal to, and sometimes more than, the value of the gold. In other cases there has been a complete exhaustion, as at the Lead-hills in Scotland, where, in the time of Queen Elizabeth, £100,000 sterling was obtained in a few seasons from the alluvial soil. (Jameson.)
4. A very large proportion of the native gold of South America, which has yielded more gold than any other part of the world, is explored in diluvial or disintegrated soil, which is generally found spread out at the foot of mountains or out bursting valleys from table-lands. Such, too, was the position of the Mexican gold, although, at present, it is mined chiefly in quartz veins, in connection with silver and other ores, in mountains of mica-slate and gneiss. It is altogether probable, and would be in accordance with recorded facts in other parts of the world, that such should also be the relative position of the native gold to the original gold-bearing veins in California. The fact of the existence of virgin gold in the plains of that province was not unknown to the Spanish. Humboldt, prior to 1816, mentions that there is a plain of fourteen leagues (forty-two English miles) in extent on the California coast, with an alluvial4 deposit, in which lumps of gold are dispersed, (vide Nueva Espania.) The same author states that a lump of gold was found in Choco weighing twenty-five pounds, and that another was obtained near La Paz, in Peru, in 1730, which weighed forty-two pounds. He gives the annual produce of the gold mines of the Spanish American colonies at 25,026 pounds Troy. The gold of Brazil is chiefly washed from the sands of rivers and other earthy and unconsolidated deposits, which stretch at the foot of a high chain of mountains running nearly parallel to the coast, from 5° to 30° of south latitude. From this region nearly 30,000 Portuguese marcs of gold are annually exported to Europe, making the annual produce of gold of the gold mines of Spanish and Portuguese America, 45,580 pounds Troy; equal to 9,844,280 American dollars.
5. Whatever be the extent, value, and permanency of the gold distributed in the diluvium or later river deposits of California, and it cannot be doubted to be relatively valuable, we should adopt, in relation to it, a policy which, while it respects the experience of science, and the results of mining and metallurgy in other countries, commends itself to our institutions by its comprehensive and practical features.
6. It is one of the traits of the metalliferous diluvial deposits of the United States, that they spread over extensive areas of surface; that they lie at very considerable elevations above the present water-level of adjacent seas, lakes, and rivers; that they are, as a consequence, free from the general power of action which these waters, in their present state, can exert upon the areas as such; and that the exploration and working of the beds is attended with comparatively little labor or expense, so long as the effort is confined to the soil. It would appear, in contemplating this question of diluvial action, as if it had exerted itself with greater force and violence, and with a more degrading power, upon our high lands and summits than in the old world, so as to demolish the solid surface of rocks, and break them up, to a greater depth, and to scatter their disrupted veins of mineral matter over more extensive districts.
7. Such are the impressions in examining the remarkable diluvial and injected deposits of galena of Missouri, Iowa, and northern Illinois; the gold debris and pebble diluvium of the Appalachian spine in the Southern States; and the widespread copper-boulder diluvium of the basin of Lake Superior. In each of these cases the original metal-bearing rocks have been broken down by ancient diluvial action, and scattered over wide areas of country. In each case, also, the first discovery, or eventual working of these extemporaneous mines, was accompanied by a public excitement, hundreds and thousands rushing to the field; and in each case the explorations terminated, after the most extravagant anticipations of easily-got wealth, in tracing the origin and supply of the drift deposits to contiguous veins in the undisturbed rocks.
8. No determinations can be safely made upon the extent and permanent value of the gold deposits under consideration. Our actual knowledge of the geography and resources of the country is limited. Of its geology and mineralogy, further than conclusions can be guessed at, from the loose letters of the day, and the examination of the specimens which are named above, and the assays of the mint, we know nothing. Its coast latitudes, and the height and distance of its interior positions, are, it is believed, accurately described and fixed, and made accessible, together with a valuable amount of information collected of its vegetable physiology, and military and maritime advantages, by the several officers of the navy and army, who have reported and published the results of their observations.
9. In the geographical memoir accompanying Colonel Fremont s map, communicated to the Senate, in compliance with its resolutions of the 5th and 15th of June last, the Sacramento and San Joacquin Rivers are described as the natural development of one valley, whose waters, rising at opposite extremities, meet in its center, and unite their channels before reaching tide-water at the head of the Bay of San Francisco. Both rivers are represented as drawing their sources and chief tributaries from the Sierra Nevada chain of mountains, through a wide belt of “foot-hills.”
These are covered, to a considerable extent, with large oaks, pines, and some other deciduous and perennial forest-trees, and afford in their valleys and plains extensive and valuable tracts of fertile soil, fit for the purposes of agriculture.
10. There is no description of the range, dip, or geological constitution or character, of the hills and elevations reputed to yield gold; of the soils which rest upon their tops, sides, or valleys; or of the rock formations of higher altitudes; this intrepid and accurate observer, having confined his attention chiefly to the topographical features of the country, and the various phenomena which determine its capacity for supporting animal and vegetable life. It is seen, as an incidental feature of his notes, that the plains of the Sacramento and San Joaquin are covered with the debris and drift soil of higher altitudes, whose deposition may be regarded essentially as the result of diluvial, and not river action. In the present state of our information, we must regard the native gold, scales and lumps, as one of the elements of this reproduced mass. How far they have been transported is unknown. Whether the beds are deep or shallow, extended or limited, has not been observed. Whether the gold is found in the valleys or depressions exclusively, or also on the hills or plains, is equally unknown. In order to form just conceptions on the subject, it would be desirable also to ascertain whether, if the elevated lands afford gold, it is in the same relative proportion to the soil, gravel, and sand, as in the valleys; whether there are any appearances, in the dry runs or sides of hills, of the loose materials being in the state of a debris, which has not been far removed; or any other indication of the proximity of fixed veins.
11. It is known from the history of the earliest discovery of gold that volcanic rocks, certainly lavas and the newer formations, never yield it; and it cannot, therefore, be supposed to come from the vitreous peaks and eminences of the Sierra Nevada. This bold mountain chain, which, under several names, extends along the Pacific coast, from Mount Elias to the Gulf of California, has probably lifted up, on its western sides, the granites, clay-slates, mica-slates, clay-porphyries, and other strata, whose detritus and comminuted fragments are found in the Valley of the Sacramento, HI the shape of pebbles and sands. Such, at least, in the absence of all observation, may be presumed to be the true position of these gold deposits. Colonel Fremont, in approaching that part of the Sacramento, which is now the theatre of gold washings, observed “a yellowish, gravelly soil” along its eastern banks. (Geog. Mem., p. 23.) He is speaking of the permanent upland soil, which he states to be 560 feet above the level of the sea, and high above the influence of the floods of the rainy season. Here, then, is evidence of the diluvial character of the general soil, and of its origin in higher positions. Mount Tsashtl, which is stated by him to divide the lower from the upper Valley of the Sacramento, is placed by that observer at 14,000 feet above the sea; which is nearly the height of Mont Blanc. (Geo. Mem., p. 25.) This stream, he observes, falls not less than 2000 feet in twenty miles, in passing, at the base of this mountain, from its upper to its lower Valley. This denotes a marked altitude for all its eastern tributaries, which flow immediately from the foot of the continuous line of the Sierra Nevada. Many of these tributaries are nearly dry, except in the rainy season, when they are swelled to torrents, which must exert a powerful action upon the loose materials of their beds.
12. Here we perceive another class of phenomena, which may materially affect the value, position, and permanence of the California gold deposits. The whole weight of the popular testimony derived from letters, a species of testimony which, in this feature, may be admitted, is in favor of the position of the metal in the transported soil; nothing but bars, shovels, and pickaxes being necessary to pursue the search. There is no affirmation that any person is pursuing a rock-vein, or has employed a blast. There is some reason to believe that the scale gold is of the oldest era, and that it has been transported the longest distance from its original veins. These minuter pieces approximate, in this respect, to the dust gold of the African coast, which has been found along the low, sandy, alluvial shores of that country, for the space of 130 leagues, at very great distances below the interior high lands, and without, so far as is known, ever having been traced to its original beds. Were the degraded inhabitants of that coast required to be paid but a moderate per diem for the time they devote in its search, and filling it in the quills of birds to be offered to traders and mariners on the coast, it is not probable that the commerce or circulating medium of the world would be enriched thereby another aroba.
13. There is but one further source of testimony respecting the value and position of these beds, which does not differ, however, in the general view it presents, from the preceding. Colonel R. B. Mason, in his report of the 17th of August last, that is to say, about three months after the first discovery of gold on the Rio de los Americanos, visited that location, and describes the position of the gold deposit as constituting ” the bank close by the stream.” The sides of the hills were covered with tents and bush arbors. This deposit, as witnessed in the washings, was made up of “coarse stones,” “earthy matter,” “gravel,” and ” gold mixed with a heavy, fine, black sand.” This gold ” is in fine, bright scales;” being, if the preceding views are well taken, of the oldest era, or the class of deposits in which the gold is farthest removed from its parent bed. In ascending the stream, in its south fork, twenty-five miles higher, he found the country became more broken and mountainous, and covered with the species of pine (Pinus lambertiana), the value of which first led to the discovery. He was now at the distance of fifty miles from the confluence of this stream with the Sacramento; and he estimates the hills at “about 1000 feet above the Sacramento Plain.” This was the position of the original discovery, which was made in the bottom of the stream, in a newly washed “bed of mud and gravel,” washed out of a millrace. At a still higher point, on the north banks of the stream among the mountains, in the bed of a dry run, he visited another locality, where coarser pieces of gold were found. All the gold was found in the beds or on the immediate banks of watercourses, in a gravelly soil. Such deposits had been found to yield gold, whenever examined in ” the numerous gullies or ravines that occur in that mountain region.” It was invariably ” mixed with the washed gravel, or lodged in the crevices of other rocks.” None had been found in its matrix in fixed rocks. The country is much broken and intersected in every direction by small streams or ravines, in all which, so far as explored, gold had been found. The circle of the discoveries was every day enlarging. It had then extended north of the Rio de los Americanos to the Bear River, the Yuba, and the los Plumas, or Feather River; from the beds and ravines of which gold was brought by the Indians and by others. It had also extended south to the Cosumnes, a tributary of the San Joaquin.
14. Such is the description of an officer who personally visited the principal theater of mining operations, who conversed with the persons of chief note concerned in these extemporaneous and precarious searches, and with the operative diggers of every sort, and who has transmitted, as the result of this visit, the several specimens of gold and other minerals herein noticed. About seventy miles from south to north, and fifty miles from west to east these having been the directions of discovery, were embraced within its extreme points.5
15. There is too little known, however, of the geological character, origin, and extent of this deposit to determine the principal points upon which its ultimate value and permanency may turn. Are we to consider the hill-diluvion as the source whence the deposits of gold in the ravines and valleys have been washed by the spontaneous action of the rivers and floods of centuries? If so, it is certain that these rich deposits will be exhausted in a comparatively short period; and the undisturbed elevated tracts of pebble-drift must be relied on to sustain the supply. The proportion of gold this elder stratum may yield will, doubtless, be less than the valley and gully deposits, and may but moderately reward the laborer for his search, if it reward him at all. If, on the contrary, the gorges and valleys which have had their outflow from the disintegrated schists and quartz, and .the crystalline and granular rock formations which probably lie at the foot of the Sierra Nevada an elevation which, agreeably to facts above noticed, is at least two thousand feet above the lower and central waters of the Sacramento, then the search must be extended up and across the valleys, in order that it may terminate in fixed mines. In any view, careful and scientific examinations are necessary to arrive at just conclusions.
It appears that the gold is found in valleys of denudation crossing the stratification, and that the deposits, which are by the spring freshets rendered alluvial, are renewed with the freshets of every season. That these will contain less and less gold every season after a period, and finally yield too small a percentage to reward labor, is very probable, and nearly certain. At that period, fixed mining in the gold-yielding strata with quartz veins must commence. The quartz veins and the gold veins will, from recent information, be found one and the same, and their perfect geological identity may be relied on, although no gold may be perceptible to the eye, if present at all, for distances in the range of the veins.
As yet we are without a geological account of the district, which is the reason of this paper being retained, and printed with these materials. Meanwhile, the subject of the Indian claim to remuneration for the territory is one which should be met on grounds of entire justice and benevolence.
Analysis at the United States Mint, has determined the value of the gold specimens sent by the Secretary of War, to be, before melting, $18.05 per ounce, and after refining, $18.50 denoting an extraordinary degree of purity in the native gold. ↩
Platina has been found at only two places in South America; namely, at Choco, in New Grenada, and at Barbacoa, between 2 and 6 north latitude; and this metal has never yet been traced north of the straits of Panama. It is associated with palladium and iridium. It occurs, in these localities, in diluvial soils, along with grains of gold, zincon, spinel quartz and. magnetic ironstone. We may expect all these associations to be verified in the deposits of California. ↩
The most important mines of cinnabar now known, are at Almaden, in Spain, which have been worked upwards of two thousand years; at Idria, in Friaul; in the Palatinate; and at Deux Ponts, in Spanish America. The specific gravity of the Almadian ore is 7.786. The word cinnabar was anciently applied to the drug called Dragon’s-blood.
- Arenaceous magnetic ironstone, of its usual form, color, lustre, and specific gravity. This ore is the residium after washing away the alluvial matter from the grain and scale gold, and has been transmitted to denote that fact, and not as attaching any importance to its value. ((This mineral is distributed widely in the rocks and soils of the United States. It constitutes an element in all the rich alluvions of the Mississippi Valley, and is very abundant on the shores of the upper lakes, where it is driven up by the waves; but being heavier than the silicious sands, it sinks at the water s edge, while the former are winnowed out by the winds, and form banks at higher altitudes. Tons of it together, lie in this pure form, on the banks of Lake Superior. ↩
This term was vaguely applied, at the era, to two distinct classes of phenomena. ↩
Subsequent discoveries, embracing the period up to October, 1850, denote this development of native gold to reach, in its extreme points, not less than one thousand miles, namely, from the Gold Mountain in S. E. California to Oregon. ↩