Before the days of written history positive chronology is to some extent a matter of speculation, and until the beginning of this century it was little more than guesswork. But the discoveries of Cnossos provided synchronisms between the archæological remains of Egypt and Europe, and since then rival systems have arisen, all of which approximate more or less nearly to the truth. The palæolithic age, however, still remained in the region of guesswork, and wild and very discrepant attempts have been made to estimate its length. It is still the fashion for some writers to use inflated dates and to count years in hundreds of thousands, but the trend of the evidence produced of late is to encourage moderation, and it seems to me possible that the men responsible for the Fox Hall flints, if indeed they are of human workmanship, may not have been separated from their discoverer by a period of time exceeding 150,000 years. When matters are so problematical, cautious writers are prone to be content with a comparative chronology, or to speak in terms of millennia. This method has advantages, for such writers run little risk of having to confess that they have made miscalculations. On the other hand, the use of actual dates leads to clear thinking, and to gaining a vivid impression of the story, and since we have now good grounds for estimating such dates, (and I shall not be ashamed to own up if later discoveries prove my estimates to be incorrect), I have adopted positive dates throughout, indicating where special uncertainty exists and the direction in which modification may be expected. While the early palæolithic age is still a hazy past, and the middle palæolithic is not in much better case, the later palæolithic or reindeer age can now be shown to be relatively modern, while the _hiatus_ between that period and the neolithic age has disappeared. Thanks to the work of Baron de Geer[516] we have some foundation for a chronology of this period, and the results of this work have long been made known to English readers by Professor Sollas.[517] There seems to be little doubt but that the pause in the retreat of the Scandinavian ice by Lake Ragunda, which de Geer has dated at 5000 /B.C./, may be equated, as has been shown by Brooks,[518] with the Daun stadium of Penck.[519] The Fenno-Scandian moraines, on the other hand, can only be equated with the Bühl advance which took place towards the close of Magdalenian times, and this gives us a date of 7000 to 7500 /B.C./ for Magdalenian. The Goti-glacial moraines seem to indicate the second Würm maximum, and Sollas’ estimate for the interval seems eminently reasonable and has been adopted here; the first maximum of the Würm seems represented by the Dani-glacial line.