THE CENTRAL PLAIN. 
49 
changes in the course of the Rhine from Eglisau to 
Coblenz indicates this, as well as the fact that 
neither the Rhone, the Rhine, nor the Aar have yet 
been able to regularise their beds. They are 
divided by ridges into distinct sections with different 
inclinations. 
The result of the general inclination of the plain 
is that the Lower Aar runs at the foot of the Jura, 
and that a succession of rivers, the Upper Aar, 
Emmen, Suhr, Aa, Reuss, Limmat, Glatt, Toss, and 
Thur, at approximately equal intervals, run from S.E. 
to N.W. into the Aar and the Rhine. 
But while it is clear that the rivers formerly ran 
at a much higher level than the present, and have 
excavated their valleys, the great deposits of river 
gravel, etc., show that the valleys were at one time 
even deeper than they are now, and were sub- 
sequently filled up to a certain height. The present 
period is again one of erosion. The rivers are at 
present deepening their beds, but in the lower por- 
tions of their course have only cut down to their 
former level in a few places, as, for instance, the 
Limmat below Baden. In others where this is ap- 
parently so, for instance the Aar at Brugg, and 
the Rhine near Irchel, Kaiserstuhl, Laufenberg, and 
Rheinfelden, though the present bed is cut into the 
Scenery of Switzerland. I/. ^ 
