Glaucus | Page 8

That rock is the common Snowdon slate, which we
see everywhere. The two shoulders of down, right and left, are slate,
too; you can see that at a glance. But the stones of the pebble bank are a
close-grained, yellow-spotted rock. They are Syenite; and (you may
believe me or not, as you will) they were once upon a time in the
condition of a hasty pudding heated to some 800 degrees of Fahrenheit,
and in that condition shoved their way up somewhere or other through
these slates. But where? whence on earth did these Syenite pebbles
come? Let us walk round to the cliff on the opposite side and see. It is
worth while; for even if my guess be wrong, there is good spinning
with a brass minnow round the angles of the rocks.
Now see. Between the cliff-foot and the sloping down is a crack,
ending in a gully; the nearer side is of slate, and the further side, the

cliff itself, is - why, the whole cliff is composed of the very same stone
as the pebble ridge.
Now, my good friend, how did these pebbles get three hundred yards
across the lake? Hundreds of tons, some of them three feet long: who
carried them across? The old Cymry were not likely to amuse
themselves by making such a breakwater up here in No-man's-land,
two thousand feet above the sea: but somebody or something must have
carried them; for stones do not fly, nor swim either.
Shot out of a volcano? As you seem determined to have a prodigy, it
may as well be a sufficiently huge one.
Well - these stones lie altogether; and a volcano would have hardly
made so compact a shot, not being in the habit of using Eley's wire
cartridges. Our next hope of a solution lies in John Jones, who carried
up the coracle. Hail him, and ask him what is on the top of that cliff . . .
So, "Plainshe and pogshe, and another Llyn." Very good. Now, does it
not strike you that this whole cliff has a remarkably smooth and
plastered look, like a hare's run up an earthbank? And do you not see
that it is polished thus only over the lake? that as soon as the cliff abuts
on the downs right and left, it forms pinnacles, caves, broken angular
boulders? Syenite usually does so in our damp climate, from the
"weathering" effect of frost and rain: why has it not done so over the
lake? On that part something (giants perhaps) has been scrambling up
or down on a very large scale, and so rubbed off every corner which
was inclined to come away, till the solid core of the rock was bared.
And may not those mysterious giants have had a hand in carrying the
stones across the lake? . . . Really, I am not altogether jesting. Think a
while what agent could possibly have produced either one or both of
these effects?
There is but one; and that, if you have been an Alpine traveller - much
more if you have been a Chamois hunter - you have seen many a time
(whether you knew it or not) at the very same work.
Ice? Yes; ice; Hrymir the frost-giant, and no one else. And if you will
look at the facts, you will see how ice may have done it. Our friend
John Jones's report of plains and bogs and a lake above makes it quite
possible that in the "Ice age" (Glacial Epoch, as the big-word-mongers
call it) there was above that cliff a great neve, or snowfield, such as you
have seen often in the Alps at the head of each glacier. Over the face of

this cliff a glacier has crawled down from that neve, polishing the face
of the rock in its descent: but the snow, having no large and deep outlet,
has not slid down in a sufficient stream to reach the vale below, and
form a glacier of the first order; and has therefore stopped short on the
other side of the lake, as a glacier of the second order, which ends in an
ice-cliff hanging high up on the mountain side, and kept from further
progress by daily melting. If you have ever gone up the Mer de Glace
to the Tacul, you saw a magnificent specimen of this sort on your right
hand, just opposite the Tacul, in the Glacier de Trelaporte, which
comes down from the Aiguille de Charmoz.
This explains our pebble-ridge. The stones which the glacier rubbed off
the cliff beneath it it carried forward, slowly but surely, till they saw
the light again in the face of the ice-cliff, and dropped out of it under
the melting of the summer