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Show 184 probable there will be interruptions, cessations, for a longer or shorter time, as may be inferred from the terraces all along the coast of Southern California, indicating unmistakably the shore- lines of the ocean during the cessations in preceding periods. ON TUB METALLIFEROUS VEINS OP CALIFORNIA AND SEVERAL PECULIAR ORES. In regard to mineral wealth, California occupies a prominent position, not only with reference to the quantities of the precious metals, but also to those metallic elements that occur but sparingly in other countries. Gold, silver, platinum, mercury, copper, lead, antimonv, arsenic, tungsten, tellurium, molybdenum, bismuth, chromium, manganese, iron, nickel, cobalt, zino, are found in various ores. A series of the most important ore- veins, among them some discovered quite recently, lie in Inyo and Mono Counties, for description of which the reader is referred to the general report. Attention is only invited here to some peculiarities connected with them; above all, the walls slickensided to such a degree of perfection and to an extent rarely witnessed in other mining regions. The Hemlock lode, in the Panamint Mountains, shows this phenomenon on a grand scale and of extraordinary beauty. Another peculiarity are the so- called " horses," large bowlders of wall- rock that became detached and dropped into the fissure during the process of vein- making. Further mention must be made of the " breaks," large holltfw fissures encountered occasionally in the walls. The " horses/' as well as the " breaks," are doubtless dne to volcanic disturbances ; the former to earthquakes before the vein was filled, the latter long after the perfection of it. If we look at the fissure- veins, on one hand, and observe on the other the immense masses of erupted rocks in those mountains, one cannot fail to suspect a connection, and to ascribe, with Baron von Beust, the production of fissures to volcanic forces, or earthquakes that accompanied the eruption of molten rocks. But how, may we ask, were these cracks filled with vein- matter f Neither the lateral infiltration nor the injection hypothesis are sufficient to account for all peculiarities met here, but if we consider- with Elie de Beaumont- the veins as the product of hot waters which entered charged with mineral salts these immense fissures from beneath and filled them to the brim, we may easily explain the presence of the quartz-ite, the carbonate of lime, carbonates of lead and copper,* as well as the occasional banded structure of the veins, the deposits being made at first upon the walls of the fissures, and gradually filling up to the center. If the character of the mineral water changed after a certain period, a change of the nature of the deposit would of course be the result, and thus the banded structure seen occasionally in veins accounted for. The deposition of vein- matter from the hot waters is partially due to a loss of temperature of the water, partly to a loss of carbonic acid in contact with the air at the fissure surface. The formation of the metallic sulnhurets might be explained by the subsequent entering of waters charged with sulphurated hydrogen, converting the metallic carbonates into the sulphurets. t No country abounds to such a degree with hot springs as California and Nevada, and here it is especially the vicinity of mining districts where they are encountered. There are thermal springs in Death and Panamint Valleys, adjoining the Panamint Mountains with their veins; there are others in the Coso range, near the mines of Darwin, another near Blind Spring mining district, and again between Carson City and the famous Virginia City mines. In one of the latter, the Imperial Mine, the working-men struck, a few years ago, hot water emitted with such force that they could not escape a thorough scalding of their feet. Who would deny that the system of thermal springs was formerly much more extensive in California than at present, if one sees the glaring and decisive marks they have left, the cones they had built, the coatings! produced f It may be that thermal springs are forming at the present day far beneath the surface mineral veins, and their final filling may ne the result of many springs dying out after certain periods, the channels becoming closed up. It may also be, that if large quantities of water of certain hot springs be analyzed, traces of metals, as lead, copper, or silver, could be discovered. I add here an interesting passage quoted from Cotta's " Ore Deposits," page 531: " It appears from Dau-bree* s researches, that the mineral water of Plombieres still deposits minerals which are characteristic for the variety of lodes mentioned, and it is by no means impossible that there, at a corresponding depth below the surface, such lodes are still forming.' 1 • There is not a single metallic carbonate that would not be a little soluble in water charged with free carbonic acid. tA singular fact worth recording is that, as a rule, the lead- mines of Mono and Inyo Counties are in limestone, while the copper- ores occur as an impregnation of quartz-ite ledges in primitive or erupted rocks. XA fine specimen of a snow- white coating over paleozoic limestone is seen on the eastern slopes of the Buena Vista Mountains, three miles east of Cerra Gordo. |