The quicksilver resources of California . entinization process. This supposi-tion finds confirmation in the fact that deposits from solfataricsprings can be traced from the Manhattan to the Boston mine. 78 QUICKSILVER RESOURCES OF CALIFORNIA. The intense chemical actions which have undoubtedly takenplace in this zone, and the great amount and variety of sulphurcompounds found therein, indicate undoubtedly close connec-tion with igneous actions, and can hardly be attributed exclu-sively to the reducing agency of organic matter or ferrous saltson waters carr^-ing sulphites or sulphates in soluti
The quicksilver resources of California . entinization process. This supposi-tion finds confirmation in the fact that deposits from solfataricsprings can be traced from the Manhattan to the Boston mine. 78 QUICKSILVER RESOURCES OF CALIFORNIA. The intense chemical actions which have undoubtedly takenplace in this zone, and the great amount and variety of sulphurcompounds found therein, indicate undoubtedly close connec-tion with igneous actions, and can hardly be attributed exclu-sively to the reducing agency of organic matter or ferrous saltson waters carr^-ing sulphites or sulphates in solution. [SeeGenesis of Ore Deposits, pages 34S-350.] The mine is opened by two shafts. The original shaft, inwhich the works are at present prosecuted, is on the southeast-ern part of the mineral zone near the furnace. This shaft is600 feet deep, but the lowest level at present in operation is at390 feet. Below that level the works are under water. Thesecond shaft is 640 feet northwest of the furnace, and has beensunk to a depth of 400 Fig. 24. Boston Miue—Section over the mineralized zone. Footwall vein in stratum of breccia (20-40 ft.).Silicified serpentine 100-200 ft. wide, inclosingore bodies forming the serpentine vein. Decomposed serpentine. Hanging-wall vein. Clay. Shales 100-200 ft. ^de. Sandstones carrs-ing some cinnabar. The three parallel veins can be said to be inclosed in serpentine,for the clay on the hanging-wall vein shows by its structure tobe decomposed serpentine. The gangue in the hanging-wallvein is more or less decomposed opaline. That of the foot-wall vein is also opaline, but much less decomposed. The ser-pentine of the central vein is silicified. The ore forms in themultitudinous seams traversing the serpentine, mainh in adirection parallel to the general northwest strike of the ore shoots in the vein are very persistent in depth as faras opened up, and up to 200 feet long. The vein fillings beingall sili
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