The American Geologist, Band 12Newton Horace Winchell Geological Publishing Company, 1893 Includes section "Review of recent geological literature." |
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Häufige Begriffe und Wortgruppen
AMERICAN GEOLOGIST Archean AUXOLOGY basin beds brachiopods calcareous Cambrian carbonate of lime Carboniferous Cenozoic character clay Coal Measures contains copper coral Cordilleran sea Creek Cretaceous deposits described Devonian dikes Dinichthys district drift englacial Eocene epidote epoch erosion evidence exhibit fauna feet formations fossils genus Geological Survey GEOLOGIST glacial glacier gold gorges gravel hight hills ice-sheet inch Iowa iron lake land later loess Louis limestone lower magnetite mass mechanical sediments Mesozoic mineral mines Missouri moraine mountain N. Y. Acad Newberry observed ocean Ohio origin Orthoceras Owen Paleozoic paper plants plates Pleistocene portion present probably Prof protoconch region Report ridges river rocks Roem sand sandstone shales shell side Silurian silver siphuncle species specimens square miles stages strata streams structure surface term thickness tion torsion Tucumcari upper valley
Beliebte Passagen
Seite 351 - ... current of the Atlantic now sweeps through the Caribbean. From the vast deposits of carbonate of lime it might be assumed, a priori, that the waters of a Mississippi or Amazon were poured into it, but there is not any evidence of the existence of such a river, although the tributary area may have been very large in Cambrian and Carboniferous time, if the drainage of the country west of Hudson's Bay was to the westward. Conditions of Deposition. — With free communication into the open ocean...
Seite 198 - Notes on a few fossil plants from the Fort Union group of Montana, with a description of one new species.
Seite 353 - We have little knowledge as to the thickness of these deposits; still such as we have goes to show that in these organic calcareous oozes and muds we have a vast formation greatly exceeding in bulk and extent the coral reefs of tropical seas. They are most widely distributed in equatorial regions, but some patches of Globigerina oo/.e are to be found even within the Arctic circle, in the coarse of the Gulf Stream."!
Seite 362 - Irvine, in their valuable paper on coral reefs and other carbonate of lime formations in modern seas...
Seite 357 - Eureka section,§ the limestones of the Paleozoic measure over 13,000 feet in a section of 15,500 feet. This section includes only 350 feet of the upper beds of the lower quartzite series, which is upwards of 11,000 feet in thickness in the Schell Creek range of eastern...
Seite 350 - If we allot 50 tons to carbonate of lime, 20 tons to sulphate of lime, 7 to silica, 4 to carbonate of magnesia, 4 to sulphate of magnesia, 1 to peroxide of iron, 8 to chloride of sodium, and 6 to the alkaline carbonates and sulphates we shall...
Seite 346 - ... Algonkian time the growth of the continent has been by the deposition of sediments in the bordering oceans and interior seas and lakes within the limits of the continental plateau; and it is considered that the relative position of the continental plateau and the deep sea have not materially changed during that period.
Seite 366 - ... (21,000,000 years), or the area of denudation from 1,600,000 square miles to 24,000,000, — or three times the present area of the North American continent. In the estimate for the amount of chemical denudation the largest average is taken — 70 tons of calcium per square mile per annum — and the assumption made that all calcium derived from the adjoining drainage area was deposited within the Cordilleran sea.
Seite 190 - ... tendencies due to old age ; so that nearly every stage passed through by the higher genera has a fixed representative in a lower genus. Moreover, the lower genera are not merely equivalent to, or in exact parallelism with the early stages of the higher, but they express a permanent type of structure...
Seite 362 - ... and some indications as to the relative rate of accumulation of the different types of deposits among themselves. The most rapid accumulation appears to take place in the Terrigenous Deposits, and especially in the Blue Muds, not far removed from the embouchures of large rivers. Here no great time would seem to have elapsed since the deposit was formed, so far at least as the materials collected by the dredge, trawl, and sounding tube are concerned. " Around some coral reefs the accumulation...