Excerpt from The Climatic Factor as Illustrated in Arid America The present volume is an attempt to determine the sequence and character of such variations on the basis of evidence in the drier portions of America from Guatemala on the south to Idaho on the north. A large number of phenomena from the diverse fields of geology, archeology, history, and botany seem to agree in indicating that during the past years North America has been subject to pronounced climatic pulsations similar to those which appear to have taken place in Asia and other parts of the Old World. In the temperate portions of the Eastern Hemisphere the climate of the past appears on the whole to have been distinctly moister than that of the present. The change from the past to the present, however, does not seem to have been gradual and regular, but pulsatory or cyclic, so that certain periods have been exceptionally dry, while others have been wet. In America the same appears to be true. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.