THE VALAIS. 
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their upper parts, open into the main valley by 
narrow, and often, inaccessible gorges. 
Similar cases also occur on the north side. The 
gorge of the Jollibach at Nieder Gestelen (Jolebach 
on some maps) is 200 to 300 metres deep, and in 
places only a few metres in width, cut through Cal- 
careous rock. It is quite inaccessible, and in its 
great height as well as in its extreme narrowness 
almost equals the celebrated gorge of the Trient. 
Prof. Desor proposed for such gorges the special 
name of “Roflas.” 
Between Gampel and Raron the synclinal fold 
which has given rise to the Rhone valley divides; 
one branch diverges northwards through the Aar 
massif in the direction of the Aletsch glacier, the 
other has determined the line of the river. 
The Swiss geological maps do not, unfortunately, 
show this very clearly, because the country north 
and south of the valley were mapped by different 
observers, and the strata are coloured differently. 
There was, moreover, at first much, and is still some, 
difference of opinion as to the age of the Schists on 
the south side of the Rhone from Turtmann to 
Grengiols, which are coloured light brown on Studer 
and Escher’s map, violet on that of Heim and 
Schmidt, and dark brown on sheet ifi of the great 
