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abundant acid coarse tuff acid fine tuff acid tuff acid volcanic breccia actinolite amount amygdaloidal amygdules analyses andesitic andesitic breccia appears biotite Bull calcite cents chalcopyrite chemical chlorite clinozoisite color compression Conrad Hill copper country rock crystals dacite Davidson County dense description.—The diabase east Emmons epidote feet feldspar fine-grained Flat Swamp Creek Flat Swamp Mountain Flat Swamp Ridge flows folds formations fragments gabbro gabbro dikes gangue GEOLOGICAL AND ECONOMIC Gold Hill grains groundmass hand specimen igneous rocks jointing Joseph Hyde Pratt Jour kaolin Kemp Mountain lenses mass massive microscope miles minerals N. C. Geol narrow nature North Carolina northeast northwest occurs outcrops phenocrysts plagioclase Plate Posta9e probably pyrite pyrrhotite quartz quartz veins region represent rhyolite schistosity schists sericite sericite schists shaft siliceous silicified Silver Hill Silver Valley slate belt slate series sphalerite stringers sulphides trend tuffs and breccias weathered surface Yadkin zinc
Seite 24 - B 293. A reconnaissance of some gold and tin deposits of the southern Appalachians, by LC Groton, with notes on the Dahlonega mines, by W.
Seite 26 - ... of chemical alteration and mineralization; which in turn was succeeded by a long period of erosion and weathering. The rocks have suffered to a variable degree from all these factors. In general, each formation has a massive and a mashed or schistose phase, with every gradation between the two.
Seite 26 - Wide bands of a sedimentary, slate-like rock, composed of varying admixtures of volcanic ash and land waste, have the greatest areal extent. Intercalated with these occur strips and lenses of acid and basic volcanic rocks, represented by fine- and coarse-grained volcanic ejecta and old lava flows. The acid rocks include fine tuffs, coarse tuffs, and breccias, chiefly of a rhyolitic and dacitic character; together with flows of rhyolite and dacite. The basic series embraces fine tuffs, coarse tuffs,...
Seite 143 - Out of print. 14. The Mining Industry in North Carolina During 1906, by Joseph Hyde Pratt, 1907. 8°, 144 pp., 20 pi , and 5 figs. Postage 10 cents. Under the head of "Recent Changes in Gold Mining in North Carolina...
Seite 13 - Chapter VI is a detailed description of the mines and prospects in the district, followed by a discussion regarding the genesis of these ore deposits. The results obtained in -the investigation are summarized in Chapter VII. There is an appendix to the report which gives a bibliography of the Cid Mining District. This report has been prepared by Dr. Joseph E. Pogue, Jr., who did the field work in 1908 and conducted the laboratory investigations in the Petrographical Laboratory of Yale University....
Seite 110 - There are two systems of veins traversing the hill; one consists of veins parallel to each other and to the strike of the schists, while in dip they frequently, perhaps it may be said generally, cut the schistosity at a slightly more westerly angle. The second system differs from the first in being entirely independent of each other and of the country rock, in strike and dip.
Seite 20 - Brecciated Conglomerate: This is the most remarkable mass of this division of the system. It has an argilaceous or chloritic base. The mass is composed in the main of fragments of other rocks mostly retaining an angular form, but frequently, rounded and worn rocks are inclosed in the mass.
Seite 111 - There are four shafts sunk in the property, as shown in the map (Fig. 4). In the No. 1 shaft a large body of ore was entered at the depth of 98 feet. At the depth of 105 feet a drift was run some 40 feet north and 90 feet south along and in this body of ore, exposing a thickness of 5 to 10 feet, all of which is stated to contain gold in paying quantities.
Seite 105 - successful process was introduced by Mr. Nininger, of Newark, NJ It consists of a down-draught jacket furnace, through which the fumes of lead and zinc are carried downward in condensers, where they are met by a spray of water, the liquor being led to vats where the lead oxide is deposited, while the zinc remains in solution and is subsequently precipitated as zinc oxide. The matte, carrying copper, gold, .and most of the silver, is tapped from the well of the furnace and cast into pigs.