Necessity of a general acquaintance with the outlines of Geology—A time in which there was no life possible on the globe—Length of this period—On the formation of rocks—The record imperfect—The three great periods in animal life on the globe—Paleozoic age—Animal and vegetable life of this period—The Mesozoic age—Animal and vegetable life of this period—Advance noted—Abundance of reptilian life—First appearance of birds—Nature’s methods of work—The Cenozoic age—Geological outline—Sketch of the Eocene age—Of the Miocene age—What is sufficient proof of the presence of man—Discussion of the Thenay flints—The Pliocene age—Animal and vegetable life of this age—Was man living during this age?—Discussion of this subject—Summing up the evidence—Conclusion. For a clear understanding of questions relating to early man, a more or less extensive acquaintance with Geology is required. This is by no means a difficult task to accomplish. What so interesting as to understand at least the outlines of the history of life on the globe? To see how, following a definite plan, the vast continents have grown to their present size and form; to see how animal and vegetable life have evolved successively higher and higher forms; to see where in this wondrous drama of creation, this strange unfolding of life, the first faint, indecisive traces of man’s presence are to be found; to learn what great changes in climate, in Geogony, and in life, had occurred before man’s appearance, let us pass in brief review the history of early geological periods. As we have already stated, there must have been a very long period of time during which no life was possible on the globe. Of this era we know but little; for we find no strata of rocks of an earlier date than we know life, in its simplest forms, to have existed.2 Still we are not less confident of the existence of this era, and the mind can dimly comprehend the scene, when a nearly shoreless ocean surged around the globe.3