Annual Report of the Board of Harbor Commissioners Volume 5, PT. 1871

Annual Report of the Board of Harbor Commissioners Volume 5, PT. 1871

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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. 1871 edition. Excerpt: ...to the prayers of the Harbor Commissioners, and has provided for arresting its progress. Of oar Atlantic sea board from Quoddy Roads to Key Biscayne, one-sixth part is rock-bound, one-tenth composed of drift antecedent to the present geological epoch, and the remainder sands winnowed out by the waves. Beaumont estimates that "one third of the sea borders of the world is defined by the littoral cordon," i.e., is shaped in outline by sands cast up or strewn along by the sea. Shingle levees appear to me to be worthy of careful study, because they are the best natural measures of the power of storm waves, and I have made the dimensions of this one at Scituate a special subject, in order to ascertain to what height the dikes, required further down the beach, must be carried in order to prevent the overflows that now frequently occur. The portion of the shingle levee which lies between Third and Fourth Cliffs is about four thousand three hundred feet in length, with a general elevation of sixteen feet above the plane of high-water, and a base of two hundred feet. It is composed of round and oval stones, those near the water line of the seaward side being the largest, and those upon the summit the most flattened. Paving stones are gathered from the lower portions of the outside, but upon the summit the average size may be stated at three and a half inches maximum diameter, and one inch thick in the middle. The crest of the levee appears to the eye perfectly horizontal, and but slightly curved back from a straight line. The table of level-lings given below, however, shows that there are depressions at either extremity, and that it is only the highest portion that is very near the horizontal for any considerable distance. Longitudinal Section of Shingle...show more

Product details

  • Paperback | 34 pages
  • 189 x 246 x 2mm | 82g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236670817
  • 9781236670816