The American Geologist: A Monthly Journal of Geology and Allied Sciences ..., Volume 4Geological publishing Company, 1889 |
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Outras edições - Ver todos
The American Geologist: A Monthly Journal of Geology and Allied ..., Volume 26 Visualização completa - 1900 |
The American Geologist: A Monthly Journal of Geology and Allied ..., Volume 15 Visualização completa - 1895 |
The American Geologist: A Monthly Journal of Geology and Allied ..., Volume 29 Visualização completa - 1902 |
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Acad Archean Arkansas augite beds bowlders Cambrian Canada Carboniferous character chemical classification coal Congress contains Cretaceous crust crystalline crystals deposits described Devonian drift earth epoch evidence existence fact fauna feet feldspar formation forms fossils fragments genera Geol geological map geological survey geologists glacial glaciers gneiss granite Gryphaa heat Hill hornblende Huronian ice-sheet Indiana iron Jour Jura Jurassic Keewatin lake Superior Laurentian limestone lower Marcou mass Mesozoic meteoric meteorites Mexico miles min.-By minerals Minnesota Missouri moraine mountains Naticopsis nebula Neocomian notes observations Ohio Olenus origin Ostrea Owen Paleozoic paper pitcheri plate portion present probably Prof professor pyrite quartz region river rocks sandstone schists sections shales Silurian species specimens strata stratigraphic stratigraphy striæ structure surface temperature Tertiary Texas theory thickness tion Trenton Triassic Tucumcari unconformity upper valley valve Winchell
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Página 278 - have taken place less than twenty million years ago, or we should have more underground heat than we actually have, nor more than four hundred million years ago, or we should not have so much as the least observed underground increment of temperature. That is to say, I conclude that Leibnitz's epoch of emergence of the
Página 200 - and in those in which a rotation has been set up, are in all probability, due to streams of meteorites with irregular motions out of the main streams, in which the collisions would be almost nil. It has already been suggested by professor G. Darwin [Nature volume xxxi, 1884-5, p.25]—using the gaseous hypothesis—that in such
Página 200 - luminosity being an evidence of condensation along lines of low velocity, according to a well known hydrodynamical law. From this point of view, the visible nebula may be regarded as a luminous diagram of its own streamlines." 15 The question naturally arose whether a swarm of
Página 68 - I therefore immediately commenced engaging sub-agents and assistants, and proceeded to St. Louis; there (at my own expense, to be repaid to me out of the per diem of the men employed) I laid in about three thousand dollars worth of provisions and camp furniture, including tents, which I caused to be made for the
Página 282 - and judging from the recent revival of geodesy and astronomy in Europe, and from the well-nigh general activity in mathematical and geological research, we may hope if not expect that the end of the present century will signalize a similar epoch of productive activity. The minima periods which followed the
Página 279 - compressive extension," thus keeping the nucleus compact and continuous. A little later the same idea was worked out independently by Mr. Charles Davison, and it has since received elaborate mathematical treatment at the hands of Darwin, Fisher, and others. The doctrine requires for its application a competent theory of cooling, and hence can not be depended on at
Página 276 - whole subject is still so largely a matter of opinion that in discussing it one may not inappropriately adopt the famous caution of Marcus Aurelius,— "Remember that all is opinion." It does not appear that Fourier reached any definite conclusion on this question, though he seems to have favored
Página 276 - with most favor, are that the conductivity and thermal capacity of the entire mass remain constant, and that the heat conducted to the surface of the earth passes off by the combined process of radiation, convection, and conduction, without producing any sensible effect on surrounding space. These or similar assumptions must be made before the application of theory
Página 197 - compared with the dimensions it must have possessed before any planets had been formed. 3 The nebulae have long been suspected to belong to the order of cosmic existence which served as the starting point of those rotations, annulations and planetations which marked the history of our system. The constitution of the
Página 272 - The'orie de la Figure de la Terre " in 1743. By the aid of this conception Clairaut proved the celebrated theorem which bears his name, and probably no idea in the mechanics of the earth has been more suggestive and fruitful. It was the central idea in the elaborate investigations of Laplace, and received at his hands a development which