go 
SCENERY OF SWITZERLAND. 
crystalline and Triassie pebbles in the Nagelflue, for 
instance, of the Rigi, but they do not belong to rocks 
found in the valley of the Reuss or on the St. Gott- 
hard. They resemble those of Lugano, Bormio, 
the Julier, and other districts far away to the south- 
east. 
We are not however dependent on these argu- 
ments alone, conclusive as they are. Remains of 
Secondary strata occur here and there in the Central 
district, and these are not fragments torn away from 
one another, but parts of a formerly continuous sheet, 
which have been preserved in consequence of being 
protected in the hollows of deep folds. That the 
Secondary strata were once continuous over the 
Central chain is well shown in the following section 
(Fig. 23) drawn from the Rhone to the Averserthal 
and cutting the Binnenthal, Val Antigorio, Val Ba- 
vena, Val Maggia, Val Ticino, Val Blegno, Val Mi- 
socco and Val St. Giacome. It will be seen that all 
these valleys are primarily due to great folds, and 
that in each case we find at the bottom of the val- 
leys remains of the Secondary strata nipped in be- 
tween the Crystalline rocks. 
Fig. 24 shows a section after Heim, from the 
Weisstock across the Windgalle to the Maderaner- 
thal. It is obvious that the valleys are due mainly 
