130 PROFESSOR JAMES GEIKIE ON THE 



that the epoch of local ice-sheets and large valley-glaciers was one also of partial sub- 

 mergence. This is further shown by the fact that in some places the glaciers that 

 reached the sea threw down their moraines on the 100-feet beach. It must have been 

 an epoch of much floating ice, as the marine deposits contain now and again many 

 erratics, large and small, and are, moreover, frequently disturbed and contorted as if 

 from the grounding of pack-ice. 



The phenomena which I have thus briefly sketched suffice to show that the epoch 

 of local glaciation is to be clearly distinguished from that of the latest general mer de 

 glace. I have long suspected, indeed, that the two may have been separated by as wide 

 an interval of time as that which divided the earlier from the later epoch of general glacia- 

 tion. Again and again I have searched underneath the terminal moraines, in the faint hope 

 of detecting interglacial accumulations. My failure to discover these, however, did not 

 weaken my conviction, for it was only by the merest chance that interglacial beds could 

 ever have been preserved in such places. I feel sure, however, that they must occur 

 among the older alluvia of our Lowlands. Indeed, as I shall point out in the sequel, it is 

 highly probable that they are already known, and that we have hitherto failed to recog- 

 nise their true position in the glacial series. 



Although we have no direct evidence to prove that a long interglacial epoch of mild 

 conditions immediately preceded the advent of our local ice-sheets and large valley-glaciers, 

 yet the indirect evidence is so strong that we seem driven to admit that such must 

 have been the case. To show this I must briefly recapitulate what is now known as to 

 the glacial succession on the Continent. It has been ascertained, then, that the Scandi- 

 navian ice has invaded the low grounds of Germany on two separate occasions, which 

 are spoken of by continental geologists as the " first " and " second " glacial epochs. 

 The earlier of these was the epoch of maximum glaciation, when the inland ice flowed south 

 into Saxony, and overspread a vast area between the borders of the North Sea and the 

 base of the Ural Mountains. This ice-sheet unquestionably coalesced with the mer de 

 glace of the British Islands. Its bottom-moraine and associated fluvio-glacial detritus are 

 known in Germany as lower diluvium, and the various phenomena connected with it 

 clearly show that the inland ice radiated outwards from the high grounds of Scandinavia. 

 The terminal front of that vast mer de glace is roughly indicated by a line drawn from 

 the south coast of Belgium round the north base of the Harz, and by Leipzig and Dres- 

 den to Krakow, thence north-east to Nijni Novgorod, and further north to the head- 

 waters of the Dvina and the shores of the Arctic Sea near the Tcheskaia Gulf. 



The "lower diluvium" is covered in certain places by interglacial deposits and an 

 overlying " upper diluvium " — a succession clearly indicative of climatic changes. In the 

 interglacial beds occur remains of Elephas antiquus and other Pleistocene mammals, and 

 a flora which denotes a genial temperate climate. One of the latest discoveries of inter- 

 glacial remains is that of two peat-beds lying between the lower and upper diluvium 

 near Griinenthal in Holstein.* Among the abundant plant-relics are pines and firs (no 



* Neues Jahrbuchf. Min. Geol. u. Palceont. ? 1891, ii. pp. 62, 228; Ibid., 1892, i. p. 114. 



