An Introduction to Geology, Illustrative of the General Structure of the Earth: Comprising the Elements of the Science, and an Outline of the Geology and Mineral Geography of England

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J. Harding, 1815 - 492 pages

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Page v - Michell, was the first person who appears to have had any clear views respecting the structure of the external parts of the earth : they were made public in a valuable paper on the cause of earthquakes, in the Philosophical Transactions, 1759. About twenty years afterwards, Mr. John Whitehurst published his "Inquiry into the original State and Formation of the Earth." His observations were principally confined to the rocks and strata of Derbyshire. Independently of its speculative opinions, this...
Page 302 - Here (says he) scenes of ruin every where appeared around me; but my attention was quickly turned from more remote to contiguous danger, by a deep rumbling sound, which every moment grew louder. The place where we stood shook most dreadfully : after some time, the violent paroxysm ceasing, I stood up, and turning my eyes to look for Euphemia, saw only a frightful black cloud. We waited till it had passed away, when nothing but a dismal and putrid lake was to be seen where the city once stood.
Page 232 - In this plain, future geologists may trace successive strata of freshwater formation, covering the subjacent crystalline limestone. The gradual deposition of minute earthy particles, or the more rapid subsidence of mud from sudden inundations, will form different distinct beds, in which will be found remains of fresh-water fish, of vegetables, and of quadrupeds. Large animals are frequently borne along by the rapidity of the current, and precipitated down the cataracts : their broken bones, mixed...
Page 132 - Causeway the columns rarely exceed one foot in breadth, and thirty feet in height : they are sharply defined, and the columns are divided into smaller blocks, or prisms of one foot or more in length, which fit neatly into each other, like a ball and socket. The basalt is close grained, but the upper joint is cellular. The columns are most frequently formed with five o» six sides; but some have seven or eight, and others not more than three.
Page 287 - the beds of the metilliferous limestones are separated by beds of Basaltic rock, called toadstone. When a vein of lead is worked through the first limestone down to the toadstone, it ceases to contain any ore, and often entirely disappears; on sinking through the toadstone to the second limestone, the ore is found again, but is cut off by a lower bed of toadstone under which it appears again in the third limestone. In strong veins particles of lead occur in the toadstone, but in very small quantities.
Page 146 - Where it crosses the coal strata, and comes in contact with the seams of coal, the substance of the coal is for several feet converted into soot. At a greater distance from the basalt, the coal is reduced to a coke or cinder, which burns without smoke, and with a clear and durable heat. At the distance of fifty feet from the dyke the coal is found in its natural unaltered state.
Page 66 - ... except in Alpine situations, where it presents the appearance of having broken through the more superficial strata of the earth, the beds of other rocks in the vicinity rising towards it at increasing angles of elevation as they approach it.
Page 301 - A deep rumbling noise, like tbat of carriages over a rough pavement, — a rushing sound like wind, — or a tremendous explosion like the discharge of artillery, immediately precede the shock, which suddenly heaves the ground upwards, or tosses it from side to side, with violent and successive vibrations. The...
Page 313 - may be considered as one immense volcano, occupying more than seven hundred square leagues of surface, and throwing out flames by different cones, known by the denominations of Cotopaxi, Tungurahua, and Pichincha. In like manner," he adds, "the whole groupe of the Canary Islands is placed as it were on one submarine volcano.
Page 298 - In recapitulating the state of our present knowledge, it is obvious that we know with certainty, that the flotz and primitive mountains have been produced by a series of precipitations and depositions formed in succession; that they took place from water which covered the globe, existing always more or less generally, and containing the different substances which have been produced from them.

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