292 PREHISTORIC EUROPE. 



we may well ask, are the marine deposits which must at one 

 time have cloaked these low grounds — where are the clay-beds 

 and sandy deposits and beach-accumulations which must have 

 been laid down contemporaneously with the interglacial beds at 

 Ness and Garrabost ? The low grounds in question are sprinkled 

 solely with till, and dotted with morainic rubbish and erratics. 

 Instead of marine deposits, we see only the marks of a recent 

 and severe glaciation. Every vestige of the last interglacial 

 occupation by the sea (with the two exceptions mentioned) has 

 been swept away by the ice-sheet, whose bottom-moraine was 

 rolled over the shell- beds at Ness and Garrabost. And the 

 principal mass of these deposits occurs in the very position 

 where, as I have pointed out more particularly in another place, 

 the ice-sheet must necessarily have exerted less grinding power. 1 

 The distribution of the boulder-clay and interglacial accumu- 

 lations of the Continent furnishes us with abundant evidence 

 of the same kind. It is not, for example, in the mountain- 

 regions of Scandinavia that we meet with great sheets of boulder- 

 clay and intercalated deposits of interglacial age. If our atten- 

 tion were confined to the mountain-valleys we should probably 

 never discover that there had been more than one glacial 

 epoch — the ice of the latest cold period having, as a rule, swept 

 away every recognisable vestige of the beds pertaining to 

 the cold and mild epochs that preceded it. But when we ad- 

 vance southwards into Scania and Denmark — the drift accumu- 

 lations become thicker — underneath the youngest till many 

 fragments of earlier glacial and interglacial deposits are pre- 

 served. And this holds true, likewise, as we have seen, with the 

 drift accumulations of Northern Germany. These are known 

 to attain a great depth, for they represent the bottom-moraines 

 of several successive glacial epochs, together with the marine 

 and freshwater beds which were formed during mild interglacial 

 eras. The latter, however, frequently testify to the enormous 

 weight of the ice which overflowed them — they are compressed 

 and often violently puckered, twisted, and thrown into inextri- 



1 Quart. Joum. Gfeol. Soc, vol. xxxiv. p. 862. 



