Geology is essentially a history of the earth and its inhabitants. It treats of rocks and of the agencies and processes which have been involved in their formation and from the rocks and their structures it attempts to make out the various stages through which the earth and the living things which have dwelt upon it have passed. It is one of the broadest of the sciences, and brings under consideration certain phases of other sciences. This book deals with some account of matters of general interest which come into the domain of geological sciences. The whole work forms a most creditable addition to scientific literature. It is of so advanced and serious a character that not only students but professional geologists as well cannot fail to benefit greatly from a careful study of its pages. The element of discussion, so important in many debatable problems of geology, has seldom been made so prominent a feature of a geological treatise; and although this adds decidedly to the difficulty of study, it cannot fail also to add greatly to the value of the knowledge gained from the study. This work is admirable for its sciences, for its literary perfection, and for its unequalled illustrations. It is one of the indispensable books for the library of every working geologist and every one who wishes to be an up-to-date teacher of geology.