162 
SCENERY OF SWITZERLAND. 
to be due to human workmanship, but the evidence 
is not altogether conclusive. 
It has happened no doubt to many of us to stand 
on some mountain-top when the surrounding summits 
have been covered with snow, and the intervening 
valleys have been filled with a thick white mist, 
which, especially in the early morning light, can 
hardly be distinguished from snow. In such a case, 
we have before us a scene closely resembling that 
which the country must have presented while it was 
enveloped by the ice of the glacial period. 
The geologists of Bavaria have brought forward 
strong evidence for the belief that in Bavaria and 
Swabia there were three periods of great extension 
of the glaciers with intervals of a milder climate; 
and Dr. Du Pasquier, who has especially studied the 
fluvio-glacial deposits of Switzerland, considers that 
they confirm this view. 
The first cold period is, he considers, represented 
by the so-called “Deckenschotter,” of which perhaps 
the best known example is that on the summit of 
the Uetliberg near Zurich, at a height of 400 metres 
above the lake. It is a coarse gravel, more or less 
cemented together, and in which many of the pebbles 
have perished and disappeared, leaving rounded 
