Excerpt from The Pleistocene Features and Deposits of the Chicago Area The following report, based upon my personal investigations, collections and studies, during a period of many years, has been prepared by invitation of the Board of Managers of the Geological and Natural History Survey of The Chicago Academy of Sciences. As directed by the Board the report covers an area comprising all of Cook and Du Page Counties, nine townships in the northwest part of Will County, and a portion of Lake County, Indiana. This territory might be thought sufficiently large to furnish an attractive field and ample material for the investigation and study of lichens, yet with the exception of the most common species, a few of which are cosmopolitan in their habits, the explorer will meet with a dis appointment not to be experienced further south and west in regions-where the conditions of the soil, the geological features of the country, and the climate favor a larger development of species. Hence mountainous districts and the extreme South offer the great est variety oi forms, those of Florida being largely semi-tropical and identical with West Indian and Central American species, especially in certain genera, as Graphis and Arthonia. However, in the field under our consideration, enough varieties occur to form an excellent preliminary course of study, fitting the student for larger views and greater results when he has become familiar with the Parmelias and Physcias which are so abundant on oaks and other trees along the lake shore and in the wooded islands of the prairies. 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.