SCENERY OF SWITZERLAND. 
totally different character, the superficial parts pro- 
bably not differing greatly from modern lavas. 
These upper layers were removed by denudation, 
and on the surface thus exposed was deposited a 
great thickness of Sedimentary rock. Figs. 25 and 
26 show that on both sides of the Mont Blanc Massif 
and that of the St. Gotthard are folds of Secondary 
strata; these must have been originally continuous, 
and have passed over the intervening mountains in 
a great arch. 
Sorby, as already mentioned, considered that the 
Granites examined by him had cooled under a pres- 
sure equal to not less than 30,000 and in some cases 
even of 80,000 feet. 
While, then, we have still much to learn as to 
the structure of these Central Massives and their re- 
lation to one another, there are strong, not to say 
conclusive, reasons for regarding them — 
I (i) As an integral part of the general Alpine 
system, not as independent centres of upheaval; and 
(2) as complex systems of compressed folds and faults. 
