36 
SCENERY OF SWITZERLAND. 
places turned over on itself, so that we should in 
this case have a repetition of the conditions of the 
Jura {see p. i8); nearly horizontal strata to the 
north, then a series of folds, becoming more and 
more accentuated to the south, and finally turned 
over at the south edge. 
To this, however, I shall refer again in the next 
chapter, and will here only observe that it would ac- 
count for the enormous thickness of the Nagelflue at 
the Rigi; and also for the want of conformity be- 
tween the strata, where the Nagelflue and Cretaceous 
strata meet, as, for instance, at the Vitznauerstock 
on the Lake of Lucerne. 
The rivers are now mostly cutting into the old 
river terraces, and deepening their beds. 
The elevation of the Alps, as already mentioned, 
commenced during the Eocene period, but was much 
more active during the Miocene. 
The last period of compression and folding was 
later than the Miocene period, for we find the whole 
series of sedimentary strata from the Verrucano to 
the Miocene folded together. 
Between the Alps on the south, the Jura and 
the Black Forest on the north, the great plain of 
Switzerland was under water and received the 
material brought down by torrents from the rising 
