jected the Finsteraarschlucht to a close examination. The
earthquake theory already adverted to was then prevalent regarding it,
and I wished to see whether any evidences existed of aqueous erosion.
Near the summit of the Kirchet is a signboard inviting the traveller
to visit the Aarenschlucht, a narrow lateral gorge which runs down to
the very bottom of the principal one. The aspect of this smaller
chasm from bottom to top proves to demonstration that water had in
former ages been there at work. It is scooped, rounded, and polished,
so as to render palpable to the most careless eye that it is a gorge
of erosion. But it was regarding the sides of the great chasm that
instruction was needed, and from its edge nothing to satisfy me could
be seen. I therefore stripped and waded into the river until a point
was reached which commanded an excellent view of both sides of the
gorge. The water was cutting cold, but I was repaid. Below me on the
left-hand side was a jutting cliff which bore the thrust of the river
and caused the Aar to swerve from its direct course. From top to
bottom this cliff was polished, rounded, and scooped. There was no
room for doubt. The river which now runs so deeply down had once been
above. It has been the delver of its own channel through the barrier
of the Kirchet.

But the broad view taken by the advocates of the fracture theory is,
that the valleys themselves follow the tracks of primeval fissures
produced by the upheaval of the land, the cracks across the barriers
referred to being in reality portions of the great cracks which formed
the valleys. Such an argument, however, would virtually concede the
theory of erosion as applied to the valleys of the Alps. The narrow
gorges, often not more than twenty or thirty feet across, sometimes
even narrower, frequently occur at the bottom of broad valleys. Such
fissures might enter into the list of accidents which gave direction
to the real erosive agents which scooped the valley out; but the
formation of the valley, as it now exists, could no more be ascribed
to such cracks than the motion of a railway train could be ascribed to
the finger of the engineer which turns on the steam.

These deep gorges occur, I believe, for the most part in limestone
strata; and the effects which the merest driblet of water can produce
on limestone are quite astonishing. It is not uncommon to meet chasms
of considerable depth produced by small streams the bed