Report Volume 14, PT. 2

Report Volume 14, PT. 2

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1905 edition. Excerpt: ...with the Middle Huronian. Fragments of greywacke-slate are cemented together by the light colored Middle Huronian arkose. Lot 4 in the twelfth concession of Lorrain. in the district have claimed that all this fragmental material was pyroclastic in origin. The present writer has disproved this, the fragmental material at some of the contacts being clearly derived from the older series close at hand. To account for the undel composed and angular character of much of the fragmental material, thewriter is inclined to the belief that desert conditions prevailed in this region at the time some of the Middle Huronian rocks, at least, were formed. Of course, much of the material in the Lower Huronian, after we get above its base, and much of that in the uppermost part of the Middle Huronian is well rounded and shows the effects of water action. The writer does not pretend to say that there is no pyroclastic material intermixed with the fragmental material of the Huronian. The association of some of the strata is puzzling. It is diflicult to understand, for example, how certain large boulders of granite in the conglomerate, which forms part of the highest outcrops of the Lower Huronian, have been carried so far from their parent masses. These large boulders are found over much of the district, and there are now no outcrops of granite in the neighborhood of many of them. Then some of the delicately banded greywacke slate may represent volcanic dust or fine grained pyroclastic material. In the present state of our knowledge we have little warrant for claiming that the granite boulders, often two or three feet or more in diameter and distant a couple of miles from exposures of the rock, indicate glacial conditions during Lower Huronian...show more

Product details

  • Paperback | 48 pages
  • 189 x 246 x 3mm | 104g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236789296
  • 9781236789297