Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: GEOLOGICAL REVOLUTIONS. Perhaps nothing has so much retarded the solid progress of geology as a single aphorism laid down by Sir Isaac Newton, and accepted by subsequent astronomers. He concluded, after certain mathematical computations, that the unequal diameters of the earth at its poles and equator were the result of centrifugal force exerted at the equator, in consequence of planetary rotation. What mathematicians pronounce unalterable law, speculative philosophers and the boldest thinkers shrink from questioning. For nearly two centuries, the present obliquity of the earth's axis to the plane of the ecliptic has been maintained by astronomers as a stable fact; and the physical results of unceasing rotation are supposed to become more pronounced and permanent from age to age. Even within three years, an eminent geologist of the United States has declared his conviction, that the North- American continent is undergoing steady geological development from the embryonic form impressed upon the earth's crust as it began to shrink by the radiation ofits primal heat. More recently still, a noted Harvard professor of mathematics has announced an opinion, based on purely geographical considerations, sustaining this view ; and he expresses the conviction, on what he considers indubitable proof, that the obliquity of the earth's axis to the plane of the ecliptic has never undergone the slightest change since the dawn of creation. Indeed, the eternal fixation of the earth's axis at an inclination of 23 28' to the plane of its orbit seems to have become a settled astronomical idea ; and the explanation of all geological anomalies, such as the location of fossil flora and fauna of tropical species in the temperate and frigid zones, has been bent to conform to it. For instance,...