In studying the subjects thus indicated it will be necessary first to notice shortly the history of the earth before the human period, and its condition at the time of man's introduction. We may then inquire as to the earliest known remains of man preserved in the crust of the earth, and trace his progress through the earlier part of the anthropic or human period, in so far as it is revealed to us by the relics of man and his works preserved in the earth. We shall then be in a position to inquire as to the form in which the same chain of events is presented to us by history and tradition, and to discover the leading points in which the two records agree or appear to differ. It may be necessary here to define a few terms. The two latest of the great geological periods may be termed respectively the _pleistocene_ and the modern, or _anthropic_, the latter being the human period or age of man. The pleistocene includes what has been called the glacial age, a period of exceptional cold and of much subsidence and elevation of the land, in the northern hemisphere at least. The modern, or anthropic, is for our present purpose divisible into two sections--the early modern, or _palanthropic_, sometimes called quaternary, or post-glacial, and which may coincide with the antediluvian period of human history; and the _neanthropic_, extending onward to the present time.[2] [2] The terms 'Palæolithic' and 'Neolithic' have been used for the men of the Palanthropic and Neanthropic ages; but these are objectionable, as implying that these ages can be best distinguished by the use of certain stone implements, which is not the fact. I have preferred, therefore, to call the earlier races of men _palæocosmic_, and the later _neocosmic_, where it may be necessary to refer to them _as races_; while the _periods_ to which they belong are respectively the _Palanthropic_ and _Neanthropic_. By the use of these terms all ambiguity will be avoided. CHAPTER II THE WORLD BEFORE MAN Man is of recent introduction on the earth. For millions of years the slow process of world-making had been going on, with reference to physical structure and to the lower grades of living creatures. Only within a few thousand years does our globe seem to have been fitted for its highest tenant. The evidence of this is to be found in any text-book of geology. I propose here merely to present the history of the earth in a series of word-pictures, introductory to our special subject. Our first picture may be that of a nebula, vast and vaporous, containing the mixed and unconsolidated materials of the sun and planets--a void and desolate mass, slowly aggregating itself under the influence of gravitation.