II G 
Danish shell-mounds. The exclusion of the waters of the 
North Sea from the Baltic, with which they formerly com- 
municated by a strait across southern Sweden, caused the 
waters of the Baltic to lose a great proportion of their salt- 
ness, and occasioned the deterioration in the marine fauna on 
the east of Sweden. This change in the size of the marine 
shells has occurred since this strait was closed, and since the 
creation of the shell-mounds on the Danish coast. Now, the 
ridge in question, observed by Sir C. Lyell, is 100 feet above 
the Gulf of Bothnia, and on the top of it repose several huge 
erratics, which must have come into their present position 
since the Baltic was divided from the North Sea, and since the 
epoch of the Danish shell-mounds, in one of the oldest of 
which an object of bronze has been found. 
20. A similar case to this has been observed in Scotland by 
Mr. James Smith, of Jordanhill, who found a large boulder 
on the lowest ancient beach of the west of Scotland, which in 
his opinion could only have come there on floating ice. In 
the estuarine silt of the corresponding beach on the east coast 
have been found the bones of the Greenland whale associated 
with human implements. The presence of this Greenland 
whale corroborates the testimony of the boulder as to the 
Arctic character of the climate on these coasts at this time, 
and we are enabled to form some idea of the probable period 
when this severe climate prevailed in Scotland from the 
character of the objects found in the silt of the Carse of 
Stirling, and with the ancient canoe3 dug up from the banks 
of the Clyde. Some of these objects must necessarily have 
come from the more civilized regions of the Mediterranean. 
21. The recent transportation of these erratics illustrates 
and strengthens my main argument for the recent date of the 
glacial epoch ; for while this epoch had at this time passed 
away, the seas were still invaded by floating ice, and the 
climate of the Caledonian coasts had by no means becomo 
what it is now. And we learn that no great lapse of time is 
necessarily involved in such a change of climate. 
22. I have mentioned that in Switzerland, among the mass 
of the Alps, where the ice lingered as late as it did in the 
north, there are also no traces of palmolitliic man, and that in 
proportion as we rccedo from this glaciated area we encounter 
the indications of the presence of man. Now, there is just 
outside of this Alpine region, near the eastern extremity of 
the Lake of Constance, a station of paleolithic date, called 
Schussenried. The fauna and flora observed here wore Arctic 
in character, and the only remains of the extinct animals were 
