Proceedings of the American Association for the Advancement of Science, Volume 42 |
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Common terms and phrases
A. A. A. S. VOL acid Algonkin alternating current American animals Archean argillite Association Biloxi blades Born Boston breeding cache Cambrian carbonate of lime Cegiha Charles chemical Chicago chips College Committee Conn Cordilleran sea Cretaceous curves D. C. ABSTRACT denudation deposition Died earth electromotive force engineering Eocene estimate evidence evolution F. W. PUTNAM feet flakes Geol geologic Henry heterodont homodont Indians John later limestones Madison mammals Marsupials Mass material mechanical sediments Mesozoic method Miocene molars Monotremes mountain observations ocean Ohio Oreodons Paleozoic paper period Perissodactyls Ph.D phenomena Philadelphia Placentals premolars present primitive Prof Puerco quarry River Rochester rocks Secretary Section sediments shaping Siouan languages solution species square miles stone strata structure surface teeth theory thickness tion tribes triconodont tritubercular ungulate Univ upper Washington William York
Popular passages
Page 164 - ... 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...
Page 133 - Consequently, if the theory be true, it is indisputable that before the lowest Cambrian stratum was deposited long periods elapsed, as long as, or probably far longer than, the whole interval from the Cambrian age to the present day ; and that during these vast periods the world swarmed with living creatures.
Page 150 - 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 Stream.
Page xxx - The objects of the Association are, by periodical and migratory meetings, to promote intercourse between those who are cultivating science In different parts of America, to give a stronger and more general impulse and more systematic direction to scientific research, and to procure for the labors of scientific men increased facilities and a wider usefulness.
Page 145 - Our knowledge of the conditions north of the 55th parallel is limited by the want of accurate geologic data. If Cambrian and Carboniferous rocks were not deposited in the Mackenzie river basin and also on the eastern side of the area now covered by Cretaceous strata, the inference is that during Cambrian and Carboniferous time there was a land area to the east and north of the northern Cordilleran sea that may have been tributary to the latter.
Page 43 - I deliberately put aside all teaching of theory, because it seemed to me high time that the facts should be examined by a purely inductive process ; that the nugatory results of all attempts to detect the existence of the Eulerian period...
Page 167 - I have increased the various factors above those usually accepted; thus, for mechanical sedimentation, the erosion of one foot in 200 years is used. If the usually accepted average of one foot in 3,000 years is taken the time period must be increased fifteen fold (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...
Page 137 - ... revised, with the view of ascertaining how far that interpretation may be capable of modification or amendment. But we must also remember that the geological record constitutes a voluminous body of evidence regarding the earth's history which cannot be ignored, and must be explained in accordance with ascertained natural laws.
Page 160 - The rate of one foot in 200 years is assumed as the most probable and 660,000 years as the time required for the removal and deposition of the 5,000 feet of post-Cambrian mechanical sediments. There is one factor that may need to be taken into consideration in estimating the time duration of the deposition of the mechanical sediments of the Cambrian and pre-Cambrian of the northern portion of the Cordilleran sea that would materially lengthen the period. Dr. George M. Dawson describes the...
Page 157 - ... tons per square mile; multiplying this by 400,000 the result gives the number of tons of carbonate of lime that were deposited in what we know of the Cordilleran sea in Paleozoic time, or 2,007,244,800,000,000 tons, or two billion million tons in round numbers. The following mode of presentation of the above was suggested by Mr. Willis : In order to proceed with a calculation of the period required to form this thickness of 15,000 feet of mechanical sediment plus 6,000 feet of calcareous sediment,...