How to Observe Geology

How to Observe Geology

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1835 edition. Excerpt: ...movement, and rendered more or less still according to circumstances. Notwithstanding the deposition in the sheltered places on the sides of estuaries, and at their heads, a time must come, supposing a large amount of detritus to be brought down during a series of ages, when the sheltered spots will be filled up, and an increase take place only at the head. The quantity of fine detritus r required to fill up the sheltered places, even supposing the increase at the head to be a constant quantity, will go somewhere, and would render the estuary waters gradually more turbid unless deposited. Now the deposit may either take place in the channel of the estuary itself, or be carried into the sea to be there distributed. The first supposes that the velocity of the tides is insufficient to cut it up when deposited, or prevent its being deposited at all; and the second, that it can escape into the sea. Some estuaries are so long, --such, for example, as that composed of the Bristol Channel, and its continuation up the tidal waters of the Severn, --that the surfacewaters at their mouths, if we may use the expression, are not turbid at any time of tide, while the whole of the turbid waters are apparently driven backwards and forwards by the tides in the more inland parts. To enable turbid waters to escape seaward under such circumstances, they must necessarily have a movement in such directions. Now the mere movement of the waters in a long estuary could not produce this effect if the line of turbid water did not come, at the lowest state of the ebb-tide, outside the estuary altogether, when probably, from the general movement of the tide on the open sea-coast, a portion of such turbid water would not again be forced into the estuary, as may be well observed.
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Product details

  • Paperback | 46 pages
  • 189 x 246 x 3mm | 100g
  • Miami Fl, United States
  • English
  • Illustrations, black and white
  • 1236583930
  • 9781236583932