Produced by Brendan Lane, Riikka Talonpoika, Jeroen van Luin and the Online Distributed Proofreading Team at http://www.pgdp.net [Illustration: _Dunes at Ipswich Light, Massachusetts. Note the effect of bushes in arresting the movement of the wind-blown sand._] OUTLINES OF THE EARTH'S HISTORY A POPULAR STUDY IN PHYSIOGRAPHY BY NATHANIEL SOUTHGATE SHALER PROFESSOR OF GEOLOGY IN HARVARD UNIVERSITY DEAN OF LAWRENCE SCIENTIFIC SCHOOL ILLUSTRATED WITH INDEX NEW YORK AND LONDON D. APPLETON AND COMPANY 1898, 1910 PREFACE. The object of this book is to provide the beginner in the study of the earth's history with a general account of those actions which can be readily understood and which will afford him clear understandings as to the nature of the processes which have made this and other celestial spheres. It has been the writer's purpose to select those series of facts which serve to show the continuous operations of energy, so that the reader might be helped to a truer conception of the nature of this sphere than he can obtain from ordinary text-books. In the usual method of presenting the elements of the earth's history the facts are set forth in a manner which leads the student to conceive that history as in a way completed. The natural prepossession to the effect that the visible universe represents something done, rather than something endlessly doing, is thus re-enforced, with the result that one may fail to gain the largest and most educative impression which physical science can afford him in the sense of the swift and unending procession of events. It is well known to all who are acquainted with the history of geology that the static conception of the earth--the idea that its existing condition is the finished product of forces no longer in action--led to prejudices which have long retarded, and indeed still retard, the progress of that science. This fact indicates that at the outset of a student's work in this field he should be guarded against such misconceptions. The only way to attain the end is by bringing to the understanding of the beginner a clear idea of successions of events which are caused by the forces operating in and on this sphere. Of all the chapters of this great story, that which relates to the history of the work done by the heat of the sun is the most interesting and awakening. Therefore an effort has been made to present the great successive steps by which the solar energy acts in the processes of the air and the waters.