The Pleistocene Features and Deposits of the Chicago Area

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Page 2 - Managers of the Geological and Natural History Survey of The Chicago Academy of Sciences : WILLIAM K.
Page 31 - Evanston there has been, during the thirty years from 1860 to 1890, a strip about i50 feet in width, undermined and carried into the lake. This amounts to about 500 acres, representing at present valuation nearly one million dollars' worth of property. Relief. — The west ridge rises with a somewhat abrupt slope about twenty-five feet above the plain along the Des Plaines River. On the inner (eastern) side there is a gradual descent of...
Page 56 - Considerable study of the movement of water in Lake Michigan has been made by the Chicago Drainage Commission, largely under the direction of Professor Cooley. As a result of these investigations, which involve not only a study of bottle papers, but also a thorough canvass of the opinions of lake captains and an examination of breakwaters, Mr.
Page 56 - ... is capped by a thin deposit of sand and has layers of sand interstratified with it in its thickest part. The presence of this gravel makes it impossible to suppose that the old land surface has been buried by the drifting of material from the lower beach. There seems no escape from the conclusion that the lake stood at a lower stage than the level of the second beach before that beach and the bar under discussion were formed. The Third or Tolleston Beach — This beach receives its name from...
Page 58 - The following measurements were made to ascertain the amount of the abrasion of the west shore of Lake Michigan, in Milwaukee county, since the government survey made in 1835 and 1836.
Page 56 - March 31, the draws of the highway bridges across the Chicago River, the North Branch of the Chicago River, and the South Branch of the Chicago River need open on signal only if at least 48 hours notice is given. However, the bridges need not open during those periods of time specified in (a)(l) (i), (ii) and (iii) of this section.
Page 52 - Brown-stained gravel, capping summit and slope 18 to 3o inches 2. Fine gravel, fresh or stained but little. 24 to 48 3. Sand, very thin at top, but increasing toward side of bar o to 36 4. Fine gravel, increasing like No. 3 ! o to 48 " 5. Fine gravel, nearly 4 feet in thickness, which passes upward from near the east side of the excavation, assuming a nearly horizontal position beneath the crest of the ridge 4o to 48 6.
Page 55 - It contains pieces of mangled wood and has been disturbed by waves. Between the peat and the yellowish blue till, which forms the base of the exposure, there is a gravelly sand 6 to 18 inches in thickness, which appears to be a lacustrine deposit. The peat is immediately overlain by about 5 feet of sand, above which there is a bed of coarse gravel. The gravel is thin near the borders of the bar, but has a thickness of 1 1 to 12 feet beneath the highest part.
Page 9 - Aftonian, interval of recession or deglaciation. 3. Kansan drift sheet of the Iowa geologists. 4. Second interval of recession or deglaciation. 5. Illinoian drift sheet. 6. Third, or preloessial, interval of recession or deglaciation. 7. lowan drift sheet and main loess deposit.

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