94 
SCENERY OF SWITZERLAND. 
smaller is really the mother river. Immediately 
above the junction is the celebrated Perte dii Rhone, 
where the river narrows to about 15 metres,* and 
A 
Fig. 102. -Longitudinal Sectiim of the Perte du Rhone. 
when it is low disappears more or less completely 
for 20 km. running in a deep, narrow, winding, and 
often invisible bed. 
Fig. 103.— IVansversc Seition of the i*ertc du Rhone. 
This is due to the presence of horizontal layers, 
differing considerably in hardness. Fig. 102 re- 
presents a longitudinal, and Fig. 103 a transverse, 
section — a, a are hard Calcareous strata, b, b softer 
* Lenthferic, Le Rhone, vol. i. 
