The leading purpose df this volume was determined by the following enactment, being section 1, chapter 121, of the Laws of 1876. "The people of the State of Wisconsin, represented in Senate and Assembly, do enact as follows: Section 1. That in the preparation of his final report, the chief geologist be, and he is hereby authorized to collate the general geology and the leading facts and principles relating to the material resources of the State, together with practical suggestions as to the methods of detecting and utilizing the same, so as to constitute the material for a volume suited to the wants of explorers, miners, land owners, and manufacturers, who use crude native products, and to the needs of the schools of the State, and the masses of intelligent people who are not familiar with the principles of geology; said volume to be written in clear, plain language, with explanations of technical terms, and to be properly illustrated with maps and diagrams, and to be so arranged as to constitute a key to the more perfect understanding of the whole report." To subserve the purposes thus legally defined, the volume will be found to consist of three distinct portions; Part I, embracing the General Geology of the State, with explanatory matter; Part II, consisting of lists of the minerals, rocks and life-products of the State, with descriptions and auxiliary discussions; and Part III, embracing industrial descriptions and practical suggestions with reference to the leading natural resources of the State.