issured rock. Cases of deep cutting can be pointed out
where the clean bed of the stream is exposed, the rock which forms the
floor of the river not exhibiting a trace of fissure. An example of
this kind on a small scale occurs near the Bernina Gasthaus, about two
hours from Pontresina. A little way below the junction of the two
streams from the Bernina Pass and the Heuthal the river flows through
a channel cut by itself, and 20 or 30 feet in depth. At some places
the river-bed is covered with rolled stones; at other places it is
bare, but shows no trace of fissure. The abstract power of water, if
I may use the term, to cut through rock is demonstrated by such
instances. But if water be competent to form a gorge without the aid
of a fissure, why assume the existence of such fissures in cases like
that at Pontresina? It seems far more philosophical to accept the
simple and impressive history written on the walls of those gorges by
the agent which produced them.

Numerous cases might be pointed out, varying in magnitude, but all
identical in kind, of barriers which crossed valleys and formed lakes
having been cut through by rivers, narrow gorges being the
consequence. One of the most famous examples of this kind is the
Finsteraarschlucht in the valley of Hash. Here the ridge called the
Kirchet seems split across, and the river Aar rushes through the
fissure. Behind the barrier we have the meadows and pastures of Imhof
resting on the sediment of an ancient lake. Were this an isolated
case, one might with an apparent show of reason conclude that the
Finsteraarschlucht was produced by an earthquake, as some suppose it
to have been; but when we find it to be a single sample of actions
which are frequent in the Alps--when probably a hundred cases of the
same kind, though different in magnitude, can be pointed out--it seems
quite unphilosophical to assume that in each particular case an
earthquake was at hand to form a channel for the river. As in the case
of the barrier at Pontresina, the Kirchet, after the retreat of the
Aar glacier, dammed the waters flowing from it, thus forming a lake,
on the bed of which now stands the village of Imhof. Over this
barrier the Aar tumbled towards Meyringen, cutting, as the centuries
passed, its bed ever deeper, until finally it became deep enough to
drain the lake, leaving in its place the alluvial plain, through which
the river now flows in a definite channel.

In 1866 I sub