A trustworthy scheme of the relative chronology of culture (as denoted by the forms of implements), of mammalian variation and evolution (as shewn by the fauna), and of great climatic oscillations has not yet been obtained, but it has not been shewn to be unattainable. Meanwhile the schemes outlined in Table B mark a very great advance upon their predecessors. It may be of interest to note that Professor Penck believes that the several periods varied both in duration and in intensity. Their relative proportions are shewn in Professor Penck's diagram (Fig. 25). The smaller oscillations, following the close of the last great glaciation (Würmian), should be noticed. CHAPTER VI HUMAN EVOLUTION IN THE LIGHT OF RECENT DISCOVERIES In this, the concluding Chapter, account is taken of the bearing of the foregoing discoveries and discussions, in relation with the light which they throw on the story of human development. A. Up to a certain point, the evidence is strikingly favourable to the hypothesis of human evolution. By this is meant the gradual development of the modern type of skeleton found in association with a large and active brain, capable of manifesting its activity in a great variety of ways. Most of the oldest human skeletons just described, differ from this type. Although a difference cannot be demonstrated in respect of cranial capacity, yet those older skeletons are usually distinguished by the heavier jaw and by stout curved limb-bones of such length as to indicate an almost dwarf stature. Still these indications, even though marking a more primitive status, point undeniably to human beings. Passing beyond these, a few fragments remain to suggest a still earlier stage in evolution. And with these at least we find ourselves definitely on the neutral ground between the territories of man and ape, though even here on the human side of that zone. In the same way, and again up to a certain point, the characters of human implements confirm the inferences drawn from the skeleton. For the older implements are re-gressively more and more crude, and an increasing amount of skill is needed to distinguish artefact from natural object. Again, the associated animals seem to become less familiar, and the percentage of extinct species increases the further we peer into the stages of the past.