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American Auxology basin beds brachiopods Cambrian carbonate of lime Carboniferous character clay Coal Measures contains copper corals Cordilleran sea Creek Cretaceous deposits described Devonian dikes Dinichthys district drift englacial epidote epoch erosion eskers evidence exhibit fauna feet formations fossils genus Geological Survey geologists glacial glacier gold gorges gravel hight hills ice-sheet inches Iowa iron lake land later limestone loess Louis limestone lower Magnesian magnetite mass Mesozoic mineral mines Minnesota Missouri moraine mountain N. Y. Acad Newberry observed ocean Ohio origin Orthoceras Paleozoic paper period plants plates Pleistocene portion present probably Prof protoconch region Report ridges river rocks sand sandstone Science shales shell side Silurian silver siphuncle species specimens square miles stages strata streams structure surface Tertiary thickness tion Tucumcari U. S. Geol upper valley zinc
Página 352 - In their memoir on coral reefs and other carbonate of lime formations in modern seas, Messrs. Murray and Irvine show that temperature of the water has a controlling influence upon the abundance of species and individuals of lime-secreting organisms ; high temperature is more favorable to abundant secretion of carbonate of lime than high salinity.2 Taking the samples of deep-sea deposits collected by the Challenger...
Página 350 - The total annual rainfall on the land of the globe, and the relation of rainfall to the...
Página 207 - He was a Fellow of The Geological Society of America and the American Association for the Advancement of Science...
Página 364 - ... square miles, — or one-third of the land area of Europe. In North America nearly one-half of the total area was covered by the Paleozoic sea ; in South America it was considerably less ; and we know too little of the Asiatic and African continents to place any estimate upon their Paleozoic areas. I think, however, if we take one-fourth of the present land area as the territory covered by the Paleozoic seas we shall be considerably within the actual amount, even if we add to the surface of the...
Página 356 - This does not impress me strongly ; but from my experience among the Paleozoic rocks I agree with Sir A. Geikie, that "we can see no proof whatever, nor even any evidence which suggests, that on the whole the rate of waste and sedimentation was more rapid during Mesozoic and Paleozoic time...
Página 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 ooze are to be found even within the Arctic circle, in the course of the Gulf...
Página 198 - Notes on a few fossil plants from the Fort Union group of Montana, with a description of one new species.
Página 363 - ... gone on in the past as steadily and uninterruptedly as at present, subject to varying conditions of temperature, life, depth of water, etc. Area of deposition in Paleozoic time. — We have no proof that the salinity of the sea or the amount of calcium contained in it has varied from age to age since Algonkian time. If it has not, all of the calcium poured into the ocean during 2,000,000 years would have about equaled the amount now contained in the limestones of the Cordilleran area.
Página 366 - D. Dana is correct, the 19,000 feet of Paleozoic limestone in central Nevada would have required 3,800,000 years to have accumulated under the most favorable local conditions surrounding a coral reef. With the exception of large deposits of corals in Devonian rocks no appearance of a coral reef is recorded in the Cordilleran area.