ACTION OF RIVERS. 
203 
terraces on which the Lakes Tom and Ritom aie 
respectively situated, and which correspond to those 
of Campolungo and Tremorgia on the other (W.) side 
of the valley. Relow them is another tei race at a 
height of 1350 metres, on which Altanca stands, ihis 
terrace can be traced for some distance, and bears 
a series of villages— Altanca, Ronco, Beggio, Catto, 
Osco, etc. In the valley of the Ticino there is a 
second series of still more important towns, at, or at 
least little above, the present river bed, but in other 
cases, as, for instance, along the Plessur, which falls 
into the Rhine at Chur, the present river bed is 
quite narrow, and the villages are on an old river 
terrace high above the present water level. 
Fig. 55 represents a group of river terraces in 
the Val Camadra. 
