THE VALAIS. 
I 2 I 
open, but from St. Maurice to Martigny it is com- 
paratively narrow, owing to the greater compactness 
of the rocks. Immediately below St. Maurice is a 
belt of dark, hard rock, belonging to the age of our 
chalk; then come Crystalline rocks — the eastern 
extremity of the Aiguilles Rouges Massif, with a 
synclinal containing Carboniferous Puddingstone, and 
slate, which is worked near Vernayaz. 
A short distance above St. Maurice the torrent of 
St. Barthelemy has formed the fine cone of Bois Noir 
(Fig. 1 09), and driven the Rhone to the foot of the 
Dents de Morcles. Fig. 108 gives a section across 
the valley at Martigny; it will be seen that the strata 
at the Pont des Martinets are reversed. 
The crystalline rocks consist of Chloritic schists, 
alternating several times with Mica schists. Prof. 
Golliez regards them as archaic sedimentary rocks 
much metamorphosed, but their age is still uncertain. 
They must be very ancient, for they are folded, and 
in his opinion this must have occurred before the 
deposition of the Carboniferous strata which lie un- 
conformably upon them. If this view be correct we 
have here evidence of three great periods of disturb- 
ance — firstly, that of the Chloritic schists, secondly, 
of the Carboniferous strata, which overlie the schists, 
