Principles Of Geology

Principles of Geology PDF
Author: Sir Charles Lyell
Size: 78.49 MB
Format: PDF, ePub, Mobi
Category : Geology
Languages : en
Pages : 824
View: 5346

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A Republic In Time

A Republic in Time PDF
Author: Thomas M. Allen
Publisher: Univ of North Carolina Press
ISBN: 0807831794
Size: 59.28 MB
Format: PDF, Mobi
Category : History
Languages : en
Pages : 275
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The development of the American nation has typically been interpreted in terms of its expansion through space, specifically its growth westward. In this innovative study, Thomas Allen posits time, not space, as the most significant territory of the young

The Athen Um

The Athen  um PDF
Size: 52.62 MB
Format: PDF
Category :
Languages : en
Pages :
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A Manual Of Elementary Geology The Ancient Changes Of The Earth And Its Inhabitants As Illustrated By Geological Monuments

A Manual of Elementary Geology  The Ancient Changes of the Earth and its Inhabitants as Illustrated by Geological Monuments PDF
Author: Sir Charles Lyell
Publisher: Library of Alexandria
ISBN: 1465573925
Size: 16.70 MB
Format: PDF, Docs
Category : Geology
Languages : en
Pages : 512
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In the preliminary chapters of "The Principles of Geology," in the first and subsequent editions, I have considered the question, how far the changes of the earth's crust in past times confirm or invalidate the popular hypothesis of a gradual improvement in the habitable condition of the planet, accompanied by a contemporaneous development and progression in organic life. It had long been a favourite theory, that in the earlier ages to which we can carry back our geological researches, the earth was shaken by more frequent and terrible earthquakes than now, and that there was no certainty nor stability in the order of the natural world. A few sea-weeds and zoophytes, or plants and animals of the simplest organization, were alone capable of existing in a state of things so unfixed and unstable. But in proportion as the conditions of existence improved, and great convulsions and catastrophes became rarer and more partial, flowering plants were added to the cryptogamic class, and by the introduction of more and more perfect species, a varied and complex flora was at last established. In like manner, in the animal kingdom, the zoophyte, the brachiopod, the cephalopod, the fish, the reptile, the bird, and the warm-blooded quadruped made their entrance into the earth, one after the other, until finally, after the close of the tertiary period, came the quadrumanous mammalia, most nearly resembling man in outward form and internal structure, and followed soon afterwards, if not accompanied at first, by the human race itself. The objections which, in 1830, I urged against this doctrine, in so far as relates to the passage of the earth from a chaotic to a more settled condition, have since been embraced by a large and steadily increasing school of geologists; and in reference to the animate world, it will be seen, on comparing the present state of our knowledge with that which we possessed twenty years ago, how fully I was justified in declaring the insufficiency of the data on which such bold generalizations, respecting progressive development, were based. Speaking of the absence, from the tertiary formations, of fossil Quadrumana, I observed, in 1830, that "we had no right to expect to have detected any remains of tribes which live in trees, until we knew more of those quadrupeds which frequent marshes, rivers, and the borders of lakes, such being usually first met with in a fossil state." I also added, "if we are led to infer, from the presence of crocodiles and turtles in the London clay, and from the cocoa-nuts and spices found in the isle of Sheppey, that at the period when our older tertiary strata were formed, the climate was hot enough for the Quadrumana, we nevertheless could not hope to discover any of their skeletons, until we had made considerable progress in ascertaining what were the contemporary Pachydermata; and not one of these has been discovered as yet in any strata of this epoch in England."

Evolution Principles And Processes

Evolution  Principles and Processes PDF
Author: Brian K. Hall
Publisher: Jones & Bartlett Publishers
ISBN: 144966654X
Size: 45.81 MB
Format: PDF, ePub, Docs
Category : Science
Languages : en
Pages : 442
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Written for those with a minimal science background, Evolution: Principles and Processes provides a concise introduction of evolutionary topics for the one-term course. Using an engaging writing style and a wealth of full-color illustrations, Hall covers all topics from the origin of universe, Earth, the origin of life, and on to how humans influence the evolution of other species. He brings together the principles and processes that explain evolutionary change and discusses the patterns of life that have resulted from the operation of evolution over the past 3.5 billion years. This overview, coupled with numerous case studies and examples, helps readers understand and truly appreciate the origin and diversity of life. Important Notice: The digital edition of this book is missing some of the images or content found in the physical edition.