are very difficult otherwise to understand. We are, indeed, irresistibly reminded of the figure given by Sir Charles Lyell[1] from a view taken by Lieut. Bowen, or the boulders drifted by ice on the shores of the St. Lawrence. I wish that I could transfer this view to our pages; but Sir C. Lyell's work must be in the hands of almost every geologist, and it will, perhaps, therefore, be unnecessary for me to quote the accompanying description, accurately as it portrays what must, I think, have been taking place in the valley of the Somme thousands of years ago, just as it does in the St. Lawrence at the present time. Nor does the physical evidence only, point to a more arctic climate during the period now under consideration; the fauna also tells the same tide. The Mollusca, indeed, do not afford much evidence, but though mainly the same as those now living in the country, they have rather northern tendencies, 85 out of the 43 species being at present found in Finland.[2] With the mammalia the case is different. The Reindeer, the Musk Ox, the Norwegian Lemming, and the still more Arctic Myodes torquatus, all of which occur in the drift, are decidedly indications of a cold climate. The circumstances attending the discovery of the Tichorhine rhinoceros in Siberia, the fact of the Mammoth of the Lena being enveloped in ice so soon after death that the flesh had not had time to decay, as well as the manner in which these extinct Pachydermata were provided against cold, all tend to show that the Elephas primigenius and the Rhinoceros tichorhinus, unlike their congeners of to-day, were inhabitants rather of Arctic than Tropical climates. That there are in this argument two weak points, I must frankly admit. In the first place, it may be objected that the Hippopotamus major, of which bones occur in the drift, could scarcely nave existed in a cold country. Mr. Prestwich, indeed, suggests that this species may, perhaps, like its gigantic relatives, have been fitted to flourish in an arctic climate. But there is some difference of opinion as to its occurrence; it has not yet been found in the "diluvium" of Germany, (Sir C. Lyell, Supplement to Manual, 1857, p. 8), and though remains of it have undoubtedly occurred in the drift gravel of the Somme, there is some reason to believe that they are not in quite the same condition as the bones of the Elephant and Rhinoceros; it is possible, therefore, that they may belong, as Dr. Falconer suggests, to an anterior period. Secondly, it might also be argued, that the animals above- mentioned, though at present confined to the colder regions, may once have lived in temperate countries. Until lately we should have regarded the Tiger as an essentially tropical animal; yet it is now known to be common in the neighbourhood of Lake Aral, in the forty-fifth degree of north latitude; and "the last Tiger killed, in 1828, on the Lena, in lat. 5214°, was in a climate colder than that of St. Petersburg and Stockholm."[3]
