FOEMS OF BERGS. 
453 
great table-land with perpendicular sides. This was 
the most frequent form of the bergs, and the most im- 
pressive. I have measured some that were thirteen 
hundred yards on a single face. 
But the adj ustment of the glacier to the country on 
which it is built generally prevents such a symmet- 
rical equilibrium. One or another of its great sides 
will be inclined toward the water, destroying the vert- 
ical character of the rest, and giving the effect of a 
sloping hill rising from the sea. Over bergs of this 
form, and they also were very numerous, you walked 
as over a terrestrial surface, met by every diversity of 
configuration, valleys, gorges, hills, plains, and preci- 
pices. 
A third form, so abnormal as to characterize a class, 
but at the same time comparatively rare, was that of 
a mass, which, probably by continued avalanche mo- 
tion, had acquired such an irregular form, such a dis- 
proportion, perhaps, between its width and depth, that 
its centre of gravity, as it fell, was not within the sub- 
merged mass. Its equilibrium was therefore uncer- 
tain, and its side sometimes what had been at first its 
surface. 
With some exceptions, the different forms of the 
berg could be derived from these; their subsequent 
changes being dependent on atmospheric or aqueous 
erosion, or both, or on accidental fractures, and on 
changes of equilibrium consequent on the others. 
These last were productive of the most eccentric diver- 
sities. Great tongues, which had become cavernous 
under the action of the waves, would rise bristling into 
the upper air; and gnarled peaks, stained with the 
silt through which they had plowed, cut in darkened 
pinnacles against the sky. 
