Excerpt from The Correlation of Geological Faunas: A Contribution to Devonian Paleontology In the year 1881 I began a series of investigations for the purpose of discovering the laws which determine the association of fossils in fauna] aggregates and their modifications in relation to geographical distribution and to vertical succession, in order to apply those laws as guides to the correlation and classification of geological formations. While these investigations have been in progress many other workers have joined in the search. Many statistics have been gathered, and observations have been extended over a wide field. A few important results have been attained, and the nature of the problem is now more clearly understood than at the outset. It seems, therefore, that this is a fitting time to review the progress already made, and to point out the more prominent results achieved and the paths along which future investigations may be guided with most promise of success. 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.