Excerpt from Geological Survey of Illinois, Vol. 7: Geology and Palæontology This volume has been prepared and will be published under the provisions of an act of the Thirty-second General Assembly, author izing the publication of Volume 7 of the Geological Survey of Illinois, approved May 26, 1881. 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.