Transactions . lomerate, of solid white quartz in twolayers, as shown, spotted with pyrite. One specimen of theconglomerate shows an oblong fragment of hornblende-gran-ite, highly charged with pyrite, measuring 1 by in. in sec-tion, lying in the cement. The vein is crossed by joints whichdip eastward; some of these are seen to pass through the con-glomerate, and others do not. The cement is quartzose, and some broken crystals of quartzare seen lying in it. It is fairly charged with pyrite, muchmore so than the solid quartz of the vein. A panning-test 166 PEBBLES AND CONCRETIONS IN METALLIF
Transactions . lomerate, of solid white quartz in twolayers, as shown, spotted with pyrite. One specimen of theconglomerate shows an oblong fragment of hornblende-gran-ite, highly charged with pyrite, measuring 1 by in. in sec-tion, lying in the cement. The vein is crossed by joints whichdip eastward; some of these are seen to pass through the con-glomerate, and others do not. The cement is quartzose, and some broken crystals of quartzare seen lying in it. It is fairly charged with pyrite, muchmore so than the solid quartz of the vein. A panning-test 166 PEBBLES AND CONCRETIONS IN METALLIFEROUS VEINS. was made of a few pounds of the conglomerate, which wasfound to contain several grains of comparatively coarse gold. On the whole, the vein has a poor appearance, yet a milling-test yielded about 15 dwt. of gold to the ton. About midway between the fourth and sixth levels, patchesof conglomerate have also been observed in the stopes of themain vein, looking north, or in the direction of the dip, as. * A, Hornblende-granite in thin layers (sheared); B, Fluccan of blue clay; (7,Patch of conglomerate in quartz ; D, Solid quartz spotted with pyrite ; E, Horn-blende-granite. Fig. 4.—Cross-Section, Showing the Wedging Out of the Conglomerate. sketched in Fig. 5. One of these patches which occurred nearthe center of the vein measured 18 in. on the line of strike andwas 12 in. thick. On either side it appears to merge imper-ceptibly into the ordinary structure of the vein. The otherpatch, about 2 ft. long and 1 ft. thick, was on the foot-wall andcontained large lumps of conglomerate. The depth of thepatches was not ascertained, but it probably does not exceed afew feet. The ore at this point, although above adit-level, PEBBLES AND CONCRETIONS IN METALLIFEROUS VEINS. 167 shows traces of oxidation only; it consists of pyrite, sphaleriteand galena scattered in a hard quartz matrix. The vein is from5 to 6 ft. thick and carries from 8 to 15 dwt. of gold per ton. Some of the q
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
