Chemical and Geological Essays

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J.R. Osgood, 1875 - 489 Seiten
 

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Seite 241 - Hudson, the Green Mountains of Vermont, and the White Mountains of New Hampshire.
Seite 403 - Logan attempted a new explanation of the stratigraphy of the region; declaring at the same time, that "from the physical structure alone no person would suspect the break which must exist in the neighborhood of Quebec ; and without the evidence of the fossils every one would be authorized to deny it." [Ibid, page 218.] The typical Potsdam sandstone of the New York system, as seen in the Ottawa basin in northern New York and the adjacent parts of Canada, affords but a very meagre fauna, including...
Seite 60 - Shaler, in the proceedings of the Boston Society of Natural History, both of which appear in the GEOLOGICAL MAGAZINE for November last. As summed up by Mr. Shaler, the second hypothesis supposes that the earth "consists of an immense solid nucleus, a hardened outer crust, and an intermediate region of comparatively slight depth, in an imperfect state of igneous fusion.
Seite 243 - ... series, and are intimately associated with beds of iron ore, generally a slaty hematite, but occasionally magnetite. Chrome, titanium, nickel, copper, antimony, and gold are frequently met with in this series. The gneisses often pass into schistose micaceous quartzites, and the argillites, which abound, frequently assume a soft, unctuous character, which has acquired for them the name of talcose or 6 ADDRESS OF EX-PRESIDENT HUNT.
Seite 78 - As the solid crust sinks together to follow down after the shrinking nucleus, the work expended in mutual crushing and dislocation of its parts is transformed into heat, by which, at the places where the crushing sufficiently takes place, the material of the rock so crushed and of that adjacent to it are heated even to fusion. The access of water to such points determines volcanic eruption.
Seite 401 - Calciferous, and it is brought to the surface by an overturn anticlinal fold with a crack and a great dislocation running along the summit, by which the Quebec group is brought to overlap the Hudson River formation.
Seite 47 - ... glass ; which keeps up the temperature beneath it, directly, by preventing the escape of radiant heat, and indirectly by hindering the condensation of the aqueous vapor in the air confined beneath. Now we have only to bear in mind that there are the best of reasons for believing that during the earlier geological periods, all of the carbon since deposited in the forms of limestone and of mineral coal existed in the atmosphere in the state of carbonic acid, and we see at once an agency which must...
Seite 37 - ... application ; so that we may suppose that all the elements which make up the sun or our planet would, when so intensely heated as to be in...
Seite 403 - ... possessed regarding the position of the shales containing the trilobites, I have the testimony of Sir WE Logan, that the shales of this locality are in the upper part of the Hudson River group, or forming a part of a series of strata which he is inclined to rank as a distinct group, above the Hudson River proper. It would be quite superfluous for me to add one word in support of the opinion of the most able stratigraphical geologist of the American continent.
Seite 229 - ... early times, which not only rendered possible the accumulation of such great beds of ore, but oxidized and destroyed the organic matters which in later ages appear in coals, lignites, pyroschists, and bitumens. Some of the carbon of these early times is, however, still preserved in the form of graphite...

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