50 Riinurks on Ike Fumialioii (>/' Alhivial Dcponiiea. 



ing to the form and situation of the banks which confine it, 

 either produce the level, extending across tlie bed of the river, 

 and terminating in a steep Itdge, or the central ridge termi- 

 nating in a gently inclined tongue. On the other hand, the 

 subsidence of the water will, in either case, produce new and 

 narrower channels. 



The advance of rocks into the track of a river, though it 

 produces a very rapid fall, where the rocks intrude, has the 

 effect of a partial dam, retarding the current higher up, and 

 hence causing an abundant deposition. Such appears to have 

 been the operation of that fine assemblage of insulated cliffs in 

 the valley of the Rhone, on one of which the Castle of Sion is 

 erected. The portion of the valley above these cliffs, between 

 Sion and Leuk, is studded with numerous hills of an entirely 

 different character. They are very abrupt, frequently flat- 

 topped, and some of them 200 feet in height. They appear to 

 be the remaining fragments of a thick bed of gravel, which has 

 subsequently been divided by numerous minor channels into 

 banks and islands. Another striking example of the same rela- 

 tion of protruding masses of rock in place to deposites of allu- 

 vium, presents itself in the Canton of Grisons. In going from 

 Chur to Reichenau we observe eight or ten very abrupt and 

 sharp hills of slate or limestone, rising through the plain, and 

 analogous to the eminer.ces about Sion ; and beyond them a 

 ridge, which appears to have extended across the valley, as the 

 corresponding portions of it appear on the two opposite banks of 

 the Rhine. At Reichenau occurs the well known bifurcation of 

 the Valley of the Rhine ; and, in each branch, we see proofs 

 that the water has formerly flowed at a much higher level over 

 its own alluvium, which it has worn into deep channels. These 

 appearances are the most remarkable in the Valley of Dom- 

 leschg, which is traversed by the Hinter-Rbein, The bed of 

 .gravel, instead of being divided into an assemblage of hillocks, 

 as is the case between Sion and Leuk, is here continuous, 

 though intersected to the depth of some feet by ancient chan- 

 nels. In one of these channels stands the village of Bonaduz. 

 From Reichenau we ascend by a road formed paitly along this 

 ancient channel, and in another part cut obhquely up the steep 

 border of the plain. The river now flows 150 feet or more be- 



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