Excerpt from Handbook of West American Cone-Bearers The presence of such a large number as sixty species of cone-bearing trees in Northwest America, is due, principally, to the fact that they are really natives of more northern or more elevated regions, from which they were expelled ages ago, by the extreme cold of the last Ice-Age; which, in turn, retreated before a Thermal Age, during the prevalence of which the plants returned from the southern hemisphere and spread over the temperate plains, or became stranded upon the cool mountains - finding homes only where their constitutions and their environment permit the maintenance of life and perpetuation of their species. 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.