THE BERNESE OBERLAND. 
155 
up to it, as for instance the Gamchi glacier at the 
head of the Kienthal. 
Indeed, though the great wall is unbroken, blocks 
of granite and gneiss, which must have come from 
the central massif are found to the north of the wall. 
The amount of denudation has therefore been 
enormous. The central peaks of gneiss and granite- 
gneiss, the Bietschhorn, Gr. Nesthorn, etc., tower up 
to a great height; but in our imagination we must 
replace on their summits, not only beds of Crystal- 
line schists, such as those which form the Tschingel- 
horn, the Breithorn and the Finsteraarhorn itself; but 
over this again we have to pile the whole series of 
the Secondary strata, whose enormous thickness the 
great wall of the Bernese Oberland enables us partly 
to realise. Like the Titans of old we must pile Ossa 
on Pelion in our imagination, and realise that as in 
the Greek myth, so also here it has been stripped off 
by the powers of the air. 
The present configuration of the surface is there- 
fore mainly the woi'k of denudation, and w’hile the 
longitudinal valleys are on the whole tectonic, the 
transverse or cross valleys which cut into and in 
some cases almost across the massif, the Trifl glacier, 
the two Grindelwald glaciers, the Aar, the Reuss, etc., 
are valleys of erosion. The highest peaks are some- 
