A. V. Jennings — The Landwasser and Landqiiart. 269 



of those wbicli are seen on the east bank of the lake and which 

 reappear north of the Monchalpthal. 



Eeturning now to the question of the course of the ancient 

 Landwasser, I have endeavoured in Fig. 3 to represent in diagram 

 its possible changes of position in relation to the Davos area. 



If we imagine the Schlappinathal brought into line with the 

 Laret-Landwasser valley, we obtain the present surface contour here 

 shown. If we take a point near the source of the Schlappina and 

 draw a line to the point near Glaris where the Landwasser now 

 flows on solid rock, we may get an idea of what might have been 

 the river-bed had the ancient Landwasser persisted to the present 

 day. The lines a and a^ drawn parallel to this at different heights 

 may therefore represent its course at different remote periods. The 

 cutting away of the western ridge may be represented by a succes- 

 sion of notches, b, b^ On the supposition that this cutting was 

 more rapid than the lowering of the river-bed there would have 

 come a time when one of the notches reached the line a, a\ and 

 the Landwasser was consequently diverted into the Pratigau. 



Subsequently the new river, the Landquart, widened its valley, till 

 this gradually approximated to its present size, represented diagram- 

 matically by o, o^ At the same time the Schlappina on the north 

 would be progressively lowering its level and nearing its present 

 position. On the south it may be supposed that the stream 

 representing the present Lareterbach would have lowered its bed 

 through a succession of stages represented by d and d^ The result 

 of this would be the production of a watershed between it and the 

 basin of the remaining Landwasser ; there would be a ridge or 

 divide just where, as a matter of fact, there is a deep lake. If the 

 Wolfgang-Drusatch ridge were of solid rock in situ it might at first 

 sight be thought to satisfy the required conditions, but it is 

 evident that its sudden drop of 350 metres on the south could not 

 be attributed to erosion by the Landwasser. This brings us to the 

 most important point of all : the striking fact that the bottom of the 

 lake is actually lower than the bed of the Landicasser at Glaris. 



It seems so impossible to reconcile this fact with any view but 

 that which supposes a northerly slope of the rock-floor of the valley, 

 that it appears scarcely necessary to pursue the subject further, 

 and we may summarize the results of our whole inquiry some- 

 what as follows : — 



(1) The theory of the former origin of the Landwasser in the 

 Schlappinathal is not tenable if the Wolfgang-Drusatch ridge is 

 solid. 



(2) If this ridge is an accumulation of Glacial age the hypothesis 

 may be still tenable, but only on the supposition that after the 

 diversion of the Landwasser, the Fluela and Dischma were also 

 iurned northward and produced a rock-bed sloping toward Klosters 

 from some watershed south of Davos. 



(3) This second possibility does not, however, dispose of any 

 of the difiiculties attending the cutting of the Casanna-Madrishorn 



