Supposing, then, that we search for remains of palæocosmic men in river alluvia, or in caves of residence or burial, or in similar repositories, the question next arises, by what means can we distinguish their bones from those of later times? The following criteria are available: (1) The remains were in their present condition at least as long ago as the date of the earliest history or tradition. This evidence is of course of greatest value in those regions in which history extends farthest back. Thus the remains of early men in the Lebanon caves, which we know date much farther back than the arrival of the first Phœnicians and Canaanites in Syria, are in a different position, in so far as history is concerned, from those occurring in countries whose written history goes back only a few centuries. (2) The deposits containing these remains may underlie those holding relics of historic times, or may indicate different physical conditions of the districts in which they occur from those known within historic periods. This is the case with some river beds, as those of Grenelle, near Paris, and with the successive deposits in old caves of residence. (3) They may be accompanied by remains of animals now extinct in the regions in question, and whose disappearance and replacement by the modern fauna implies great lapse of time and physical changes; as, for instance, when we find that men have left remains of their feasts holding bones of the extinct woolly rhinoceros and his contemporaries, or in now temperate climates, those of the reindeer. (4) The remains themselves may indicate a race or races of men and a condition of the arts of life different from any known in the region in historic times. Thus we may have skulls and skeletons indicating men racially distinct from any now extant, and implements and weapons different from those in use in the times of history or tradition. We have now to consider what evidence of this kind vindicates the assertion that man existed on our continents in the second continental or post-glacial age, or, as others will have it, in the closing period of the glacial age, and was contemporary with the mammoth and other great beasts now extinct. This evidence, which has been accumulating with great rapidity and relates to many parts of the northern hemisphere, is too voluminous to be reproduced here.[16] But a few examples of it may be given, more especially from parts of the old world whose history extends farthest back and where explorations have been most extensive. [16] Reference may be made to Christy and Lartet, _Reliquiæ Aquitanicæ_; Quatrefages, _Homme Fossile_; Dupont, _L'Homme pendant les Ages de Pierre_; Carthaillac, _La France Préhistorique_; Dawkins, _Cave Hunting and Early Man in Britain_; _Fossil Men_ and _Modern Science in Bible Lands_, by the author.