Report of Progress ...Board of Commissioners for the Second Geological Survey, 1883 35 vols. are atlases. |
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Términos y frases comunes
anticlinal Azoic basin beds border boundary Brandywine Caln Chester county Chester valley chloritic Clay creek Coatesville color conglomerate corner crosses crystalline crystals Delaware county deposits Doe run Downingtown dyke east eastward exposures feet feldspar feldspathic formation fragments French creek furnace geological gneiss gneiss dips gneissic gneissoid granite half a mile hornblendic hornblendic gneiss iron kaolin Kennett Square Lancaster county lime limestone lode London Grove lower Mesozoic mica mica-schists micaceous milk quartz mill mineral mines Nantmeal narrow nearly northern occurs Octoraro outcrop Phoenixville Potsdam Potsdam sandstone Primal slates Prof quarry quartzite quartzose railroad red sandstone ridge river road rocks Rogers sand sandstone schists school-house Schuylkill serpentine short distance side South Valley South Valley hill station stone strata structure surface syenite synclinal talc-mica thickness tion township trap trough Valley Forge Valley limestone vein west branch West Chester West Marlborough western westward white sandstone
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Página 30 - Colonies in America, and to prevent the Erection of any Mill or other Engine for slitting or rolling of Iron, or any plating Forge to work with a Tilt Hammer, or any Furnace for making Steel in any of the said Colonies...
Página 197 - ... its average width at not less than eighteen inches. It is bounded by regular and well-defined, nearly parallel walls, the prevailing material of which is a coarse, soft granite, composed chiefly of white feldspar and quartz. " It would seem to be a pretty general fact that such of these veins as are confined entirely or...
Página 220 - Finally are to be mentioned the gravels of various recent periods which have been studied by Prof. Henry Carvill Lewis, first mentioned in some papers included in the published proceedings of the Mineralogical and Geological Section of the Academy of Natural Sciences of Philadelphia for 1877-1879, and soon to be fully described in his special Report on the Glacial Moraine in Pennsylvania (Z).
Página 197 - It would seem to be a pretty general fact, that such of these veins as are confined entirely or chiefly to the gneiss bear lead as their principal metal, whereas those which are included solely within the red shale are characterized by containing the ores of copper. But the zinc ores, viz : zinc-blende and calamine, prevail in greater or less proportions in both set of veins, existing, perhaps, in a rather larger relative amount in the copper-bearing lodes of the red shale.
Página ii - EB HARDEN, topographer, in charge of illustrations for reports, and general correspondence at head-quarters, 907 Walnut street, Philadelphia, to whom all business communications respecting the Work of the Survey should be addressed. Anthracite Survey. CA ASHBURNER, geologist, in charge of the Survey of the Anthracite coal fields ; address 907 Walnut street, Philadelphia.