"A Contribution To The Geology Of The Northern Black Hills" by John Duer Irving presents a detailed geological survey of a significant region in South Dakota. This study offers invaluable insights into the geological composition, mineral resources, and historical mining activities within the Northern Black Hills. Irving's work meticulously documents the stratigraphic layers, tectonic structures, and mineral deposits, providing a comprehensive understanding of the area's geological history. Originally published as part of the broader geological investigations of the United States, this contribution remains a vital resource for geologists, environmental scientists, and historians interested in the geological evolution and resource management of the American West. It serves as a foundational text for understanding the complex interplay between geological processes and human activities in a region renowned for its natural beauty and rich mining heritage. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.