Records of the Geological Survey of IndiaThe Survey, 1913 - Earthquakes Vols. 1- include Report of the Geological Survey, 1867- ; v. 32- include Review of the mineral production of India, 1898/1903- ; v. 75 consists of Professional papers, no. 1-16; v. 76 consists of Bulletins of economic minerals. |
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Aceratherium alluvium Amphicyon ancestral andesites antelopes appearance augite basal Bugti hills Burma Chindwin Chinji beds Chinji fauna clay concretionary correlation crystals cubic yard deposits depth Dhok Pathan zone Dorcabune Dorcatherium Elephas planifrons feet felspar fossiliferous fossils genus Geol gneisses gold grains per cubic granite gravel groundmass Hasnot Himalaya Hipparion horizon Hyotherium Kyobin lava limestones Listriodon lodes Lower Chinji zone Lower Manchhar Lower Pliocene Lower Siwaliks Lydekker magnetite mandible Mastodon Maung Merycopotamus Messrs Middle Siwaliks miles minerals Miocene molar Nagri occur older olivine P. L. renewal Perim Island Pikermi PLATE Pliocene pontian pontian of Europe Potamochoerus primitive punjabiensis quartz quartzites represented river rocks Salt Range sand sandstones sarmatian schists Shan sivalensis species specimen Stegodon stratigraphical surface Surv Survey of India Tatrot zone Tavoy Teleoceras Têng-yüeh Tertiary Tetrabelodon thickness tortonian tortonian of Europe Upper Chinjis Upper Siwaliks valley wolframite
Popular passages
Page 137 - ... the oceans. The excess of material represented by that portion of the continent which is above sea level will be compensated for by a defect of density in the underlying material. The continents will be floated, so to speak, because they are composed of relatively light material; and, similarly, the floor of the ocean will, on this supposed earth, be depressed because it is composed of unusually dense material. This particular condition of approximate equilibrium has been given the name "isostasy.
Page 137 - The adjustment of the material toward this condition, which is produced in nature by the stresses due to gravity, may be called the isostatic adjustment. The compensation of the excess of matter at the surface (continents) by the defect of density below, and of surface defect of matter (oceans) by excess of density below, may be called the isostatic compensation.
Page 137 - ... different portions of the same horizontal stratum may have somewhat different densities, and the actual surface of the earth will be a slight departure from the ellipsoid of revolution in the sense that above each region of deficient density there will be a bulge or bump on the ellipsoid, and above each region of excessive density there will be a hollow, relatively speaking.
Page 137 - Let the depth within which the isostatic compensation is complete be called the depth of compensation. At and below this depth the condition as to stress of any element of mass is isostatic, that is, any element of mass is subject to equal pressures from all directions as if it were a portion of a perfect fluid. Above this depth, on the other hand, each element of mass is subject in general to different pressures in different directions, to stresses which tend to distort it and to move it.
Page 136 - If the earth were composed of homogeneous material, its figure of equilibrium, under the influence of gravitation ° and its own rotation, would be an ellipsoid of revolution. The earth is composed of heterogeneous material which varies considerably in density. If this heterogeneous material were so arranged that its density at any point depended simply upon the depth of that point below the surface...
Page 136 - ... if all the material lying at each equipotential surface (rotation considered ) was of one density, a state of equilibrium would exist and there would be no tendency toward a rearrangement of masses. If the heterogeneous material composing the earth were not arranged in this manner at the outset, the stresses produced by gravity would tend to bring about such an arrangement; but as the material is not a perfect fluid, as it possesses considerable viscosity, at least пе¡ir the surface, the rearrangement...
Page 137 - The compensation of the excess of matter at the surface (continents) by defect of density below, and of surface defect of matter (oceans) by excess of density below may be called the isostatic compensation. Let the depth within which the isostatic compensation is complete be called the depth of compensation. At and below this depth the condition as to stress of any element of mass is isostatic, that is, any element of mass is subject to equal pressures from all directions as if it were a portion...
Page 157 - The present view now generally accepted is that the Indo-Gangetic depression is " a broad basin, shallow on the outer side and sloping gently inwards towards the Himalayas, from which it is separated by a steep wall resulting from the series of reversed faults which separate the older geological systems from the younger."7 Geological History.
Page 17 - K2O was found in a prospecting drift in the Pharwala salt, — what was presumably the same bed being struck in another prospecting drift 700 feet to the ENE In the Buggy section of the Mayo Mine the only seam of any importance that was found was traced for about 150 feet along its strike, which is ENE— WSW The dip of the bed is about 35°, its average thickness, two feet nine inches, and it carries 14'4 per cent of K2O. The seam thins out when followed upwards along the bedding ; in another chamber,...
Page 17 - ... per cent, of K2O. The seam thins out when followed upwards along the bedding : in another chamber, at a distance of 170 feet south from the nearest exposure, it was found to be only a few inches thick. The seam in the Nurpur mine is exposed only in one place which is difficult of access. It dips SSE at about 75° and at this point is six feet thick. A typical specimen from this deposit carried 14.1 per cent, of Kz O.