Excerpt from Bulletin of the Museum of Comparative Zooelogy at Harvard College, in Cambridge, Vol. 7: Geological Series, I N o. 1. - Notes on the Geology of the Iron and Copper Districts of Lake Superior. By M. E. Wadsworth. There are probably no regions of like extent in the United States that have attracted greater interest or attention than the Copper and Iron districts of Lake Superior. The most discordant views have been held concerning their geology, and the origin of their ore deposits. There are also probably no districts in this country which have been more accu rately studied, taking all of the conditions into consideration, than these were some thirty years ago. The geology, including the origin of their ore deposits, was then, for the time and methods of study, stated with a remarkable degree of accuracy, so far as it has been our province to observe or judge. It would not, then, be our duty to write concerning these districts, were it not that the almost universal belief of geologists at the present time regarding one, and in some respects the other dis triot, is so entirely at variance with the facts as we interpret them. Before giving the facts it is necessary to present to the reader some of the various ideas held regarding the geology of both districts. We shall, however, in the main confine ourselves to those parts which we have visited, except so far as observations elsewhere have a bearing upon our work, or upon the questions which we wish to discuss. 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.