In the preceding Chapter, the remains of Palaeolithic Man were studied in relation to the associated animals (especially mammals), and again (so far as possible) in connection with the accompanying implements. In the comparison of the different types of implement, evidence was adduced to shew that certain forms of these are distinctive of corresponding geological horizons. Of the three series, (1) human remains, (2) mammalian remains, (3) stone implements, the first two, (1) and (2), have been compared as well as (1) and (3). A comparison between (2) and (3) has now to be instituted. And this is of interest, for mammalian remains have been found in the presence of implements where no human bones could be discovered. Moreover the expectation is well founded, whereby the mammalian fauna will prove to supply information unobtainable from either human skeletons or implements by themselves. That information will bear upon the climatic conditions of the different phases which mark the geological history of Man. And in this way, a more perfect correlation of the past history of Man with the later geological history of the earth may be fairly anticipated.
In Chapter IV, use was frequently made of the expression 'southern,' 'temperate' or 'sub-arctic,' in connection with the various groups of mammals mentioned in Table A. And while the geological period is limited, during which these investigations are profitably applicable, yet the matter is one of no small importance. For the very fact that the fauna can be described in one case as 'southern' in character, in another as 'temperate,' suggests some variation of climate. And the relation of the history of Man to the great variation of climate implied in the expression 'Glacial Period,' may be reasonably expected to receive some elucidation from this branch of study. It will be noticed that Man himself is at present comparatively independent of climate, and even in earlier times he was probably less affected than some other animals. But while the importance of these studies must be recognised, it is also very necessary to notice that as elsewhere so here the difficulties are great, and pitfalls numerous.
It is no part of the present work to attempt a history of the stages through which opinion passed in developing the conception embodied in the phrase 'Ice-Age.' Long before that idea had been formulated, the presence of animal remains both in cave and alluvial deposits was a matter of common knowledge. The late Professor Phillips is believed to have been the first to make definite use of the terms 'pre-glacial' and 'post-glacial' in reference to the later geological formations (1855). And to the pre-glacial era that geologist referred most of the ossiferous caves and fissures.