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anticline Appalachian associated barite basin beds Big Walker Blue Ridge breccia Brush Mountain building stone Business Creek calamine Cambrian Carboniferous cement materials cent chalcopyrite chert Cluxi coal field coal-bearing commercial conglomerate copper crystalline deposits developed district dolomite east erosion extensive fault feet in thickness feldspar Flat Top fluorite folds formation fullers earth galenite geologic Giles County gneiss Gossan Gossan Lead granite gypsum hematite important iron irregular Kimberling lead and zinc lime limestone limonite Little Walker Mountain Lower Carboniferous magnesian magnetite manganese masses mica mined mineral Montgomery-Pulaski Moun Mountain province non-metallic occurs Ordovician Oriskany outcrop Oxide Pocahontas portion Price sandstone principal pyrite pyrrhotite quartz residual clays River rocks sand sandstone schist seams sediments shale shows Silica slopes smithsonite Southwest Virginia Southwestern Virginia sphalerite strata sulphide surface talc Tazewell territory tion usually variety varying veins waters western widely distributed Wolf Creek Mountain Wythe County zinc and lead
Page 31 - is distributed through the clays in an irregular manner in the form of pockets or lenticular masses, rarely as distinct beds; as veinlets and stringers cutting the clays in all directions; as single nodules or concretionary masses assembled in the clays; and as small disseminated grains scattered through the
Page 30 - over many parts of the area for use as a furnace flux, for limemaking in building and agriculture, for building stone, for road metal and ballast, and for the manufacture of cement, both Portland and natural. The limestones which have been quarried to a greater or less extent over the area west of the Blue Ridge
Page 33 - The sedimentary clays represent deposits which have been laid down under water, one layer on another, the materials composing them consisting of the products of rock decay, which have been removed by erosion from the land surface, and washed down into the lakes, or seas, where they have finally settled. These are abundant in both the Coastal Plain
Page 16 - The bulk of the sulphide ores belong to the disseminated replacement breccia type. As a rule, the process of replacement has played an important part in the ore formation, but in some instances very little replacement of the limestone by the ore is indicated. In the latter case the ore would be more properly designated a straight breccia type in which
Page 16 - The breccia zones are associated with faulting and folding. Not all parts of the breccia zones are mineralized, but the ore is distributed at somewhat irregular intervals. Where mineralized, and so far as can be judged,
Page 32 - along the base of the mountains bounding it. In a similar manner, many of the valleys west of the Great Valley show these limestones and shales, higher formations occurring on the separating ridges.
Page 31 - The ore is usually partially or entirely crystalline, of a dark steel-blue color, and the nodular type, which prevails nearly always, displays the complete or partially layered or concentric structure of concretionary masses.
Page 26 - and retain their original composition. In the valley the rocks have been steeply tilted, bent into folds, broken by faults, and to some extent altered into slates. In the mountain district faults and folds are important features of the structure, but