THE CENTRAL PLAIN. 
45 
and below which the valley alters its character, be- 
coming much narrower. 
Another “dead” valley leads from the Aar at 
Wildegg, below Aarau, to Mellingen in the valley of 
the Reuss. It probably marks the ancient bed of the 
Aar before that river had acquired its present course 
through the Jura north of Lenzburg. 
Gremaud has subsequently called attention to 
other similar cases. 
The Kleine Emmen rises north of Interlaken and 
has a well-preserved old valley across the plateau to 
the Aar at Aarburg, but has now abandoned its old 
course at Wiggern, and turns sharply round to the 
east, following a trough which carries it to the Reuss 
below Lucerne. 
The river system round Bern is also curious and 
interesting. From the direction of the upper Sense 
the natural course of the river would be by Wangen 
to Bern, and along the valley of the Urtenenbach to 
the Aar Valley below Soleure. In fact tlrere is here 
a broad valley, apparently once the bed of a con- 
siderable river. At present, however, it is occupied 
by three streams. In the upper part, by the Sense 
itself, which, however, near ThOrisch turns at a right 
angle to the west and falls into the Sarine. Below 
I'hbrisch is a small brook which falls into the Aar 
