EUROPEAN GLACIAL DEPOSITS. 263 
than those of the earlier epochs that will present themselves. 
The distribution of the interglacial and glacial deposits of Europe 
shows this clearly enough. Nota trace of the Scanian bowlder- 
clay has been recognized in Britain, but it is probably repre- 
sented by the lowest-lying bowlder-clay of the south Baltic 
coast-lands. Again but for the Norfolkian beds we should never 
have known that a genial interglacial epoch followed after the 
passing of the Scanian stage. The area of glacial erosion was 
so enormously extended during Saxonian times that preéxisting 
superficial beds in northern and northwestern Europe were 
almost completely obliterated. Under the Polandian ice-sheet 
great erosion likewise took place, but the area affected was not 
quite so extensive. Hardly a trace of the Scottish lower bowl- 
der-clay (Saxonian ) occurs in the mountain regions, it is only in 
the low grounds that it puts in an appearance—becoming more 
and more conspicuous as the peripheral areas occupied by the 
minor mer de glace (Polandian) are approached. The same tale 
is told by the corresponding deposits on the Continent. Ina 
word it is in the peripheral areas of glacial accumulation that 
the deposits of the immediately preceding interglacial epoch are 
most abundantly preserved. If this be true of the Helvetian 
and Polandian, it is true also of the Neudeckian and Mecklen- 
burgian stages. The Neudeckian beds are met with chiefly in 
the southern coast-lands of the Baltic. So again we cannot 
expect to meet with plentiful relics of the Lower Forestian 
stage in the mountain valleys which were subsequently occupied 
by the local glaciers of the Lower Turbarian. It is only in 
places where these glaciers descended to the low grounds or 
entered the sea that they were likely to override interglacial 
deposits and to cover these with their moraines. And this, as 
we have seen, is just what happened in Scotland—the fifty-foot 
raised beach clearly underlies the terminal moraines of Lower 
Turbarian times. 
Similar phenomena confront us in the Alpine Lands. It is in 
the ‘‘Vorlander” and the lower reaches of the great mountain 
valleys that the successive glacial and interglacial stages are 
