Comentarios de la gente - Escribir un comentario
No encontramos ningún comentario en los lugares habituales.
Otras ediciones - Ver todas
Abundant America animal appear base beds belong birds body brown called Canada Canadian character coast collected colour common contain covered deposits described direction discoveries district evidence existence extending fact fauna feet formation fossils four genus Geological geologists gives gold ground hairs Hall head inches Indian interesting Island known Lake land latter length less limestone lines Linn localities Lower marked miles Montreal mountains Natural Natural History nearly notice observed obtained occur origin pass period places plants portion position present probably Prof published Quebec regarded region remains remarkable River rocks sand sandstone seen shales shells shore short side Silurian similar Sir William Logan slates Society species specimens strata surface tail thick tion upper various whole woods
Página 390 - Just previous to this time, in the Report of the Regents of the University of New York, for 1859, Professor Hall had described and figured by the name of Olenus two species of trilobites from the slates of Georgia, Vermont, which Emmons had wrongly referred to the genus Paradoxides. They were at once recognized by Barrande, who called attention to their primordial character, and thus...
Página 93 - ... like those of the Appalachian range. In truth, Mr. Hall observes, the carboniferous limestone is one of the most extensive marine formations of the continent, and is characterized over a much greater area by its marine fauna than by its terrestrial vegetation. " The accumulations of the coal period were the last that gave form and contour to the eastern side of our continent, from the Gulf of St. Lawrence to the Gulf of Mexico ; and as we have shown that the great sedimentary deposits of successive...
Página 211 - On the final causes of the sexuality of plants, with particular reference to Mr. Darwin's work on the Origin of Species.
Página 277 - On further scrutiny, with the aid of an opera-glass, two sharply cut and very narrow dark channels, bounding the principal ray, could be traced for ten or fifteen degrees from the nucleus ; while outside of them, on either side, were two additional faint rays. The whole issue of nebulous matter, from the nucleus far into the tail, was curiously grooved and striated. It was noticed that both the principal ray and the dark channels penetrated within the outline of the curved tail, the latter being...
Página 240 - ... animals ; the latter is not surprising when we consider that a considerable portion of the tissues of the lower marine animals is destitute of nitrogen, and very similar in chemical composition to the woody fibre of plants.
Página 88 - Sterry Hunt thus expresses himself: — ' We regard the whole Quebec group, with its underlying primordial shales, as the greatly developed representative of the Potsdam and Calciferous groups (with part of that of Chazy), and the true base of the Silurian system.' ' The Quebec group with its underlying shales,' this author adds (and he expresses the opinion of Sir W.
Página 332 - as many as two hundred of these concretions, varying in size from that of a small pea to that of a hazel-nut, to be passed after the administration of a single dose of Podophyllin and the Oil.
Página 404 - zone primordiale" of Bohemia — having no representative in the north-western Highlands, there is necessarily a complete unconformity between the fossil-bearing crystalline limestone and quartz-rocks with the Maclurea, Murchisonia, Orphile'ta, Orthis, Orthoceratites, etc., and those Cambrian rocks on which they rest. A great revolution in the ideas of many an old geologist, including myself, has thus been effected. Strengthened and confirmed as my view has been by the concordant testimony of Ramsay,...
Página 98 - ... beds will be the production within the greater synclinal of numerous smaller synclinal and anticlinal axes, which must gradually decline toward the margin of the great synclinal axis. This process the author observes appears to furnish a satisfactory explanation of the difference of slope on the two sides of the Appalachian anticlinals, where the dips on one side are uniformly steeper than on the other, p. 71. An important question here arises, which is this; — while admitting with Lyell and...
Página 92 - The metals of the sedimentary rocks are now however for the greater part in the form of insoluble sulphurets, so that we have only traces of them in a few mineral springs, which serve to show the agencies once at work in the sediments and waters of the earth's crust.