Excerpt from Bulletin of the Illinois State Laboratory of Natural History, 1915, 1916, 1917, Vol. 12 It is altogether likely that this ravine had its infant development accelerated by swampy depressions in the upland near to the lake. Such swamps or marshes within reasonable distance from the head of the cliff of the lake shore would, through seepage, make materials between them and the lake shore so mobile that the head of the gully would work inland with unusual rapidity. The influence of such de pressions in ravine formation can at present be seen in the vicinity of Glencoe. 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.