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the mountain was actually opened from within by an earthquake； and
when the strata fell together again； the portion at either end of
the chasm； being perhaps crushed together with greater force；
remained higher than the centre； and so the water lodged between
them。 Perhaps it was formed thus。 You will at least agree that
its formation must have been a grand sight enough； and one during
which a spectator would have had some difficulty in keeping his
footing。
And when you learn that this convulsion probably took plus at the
bottom of an ocean hundreds of thousands of years ago； you have at
least a few thoughts over which to ruminate； which will make you at
once too busy to grumble； and ashamed to grumble。
Yet； after all； I hardly think the lake was formed in this way； and
suspect that it may have been dry for ages after it emerged from
the primeval waves； and Snowdonia was a palm…fringed island in a
tropic sea。 Let us look the place over more fully。
You see the lake is nearly circular； on the side where we stand the
pebbly beach is not six feet above the water； and slopes away
steeply into the valley behind us； while before us it shelves
gradually into the lake； forty yards out； as you know； there is not
ten feet water； and then a steep bank； the edge whereof we and the
big trout know well； sinks suddenly to unknown depths。 On the
opposite side； that flat…topped wall of rock towers up shoreless
into the sky； seven hundred feet perpendicular； the deepest water
of all we know is at its very foot。 Right and left； two shoulders
of down slope into the lake。 Now turn round and look down the
gorge。 Remark that this pebble bank on which we stand reaches some
fifty yards downward： you see the loose stones peeping out
everywhere。 We may fairly suppose that we stand on a dam of loose
stones； a hundred feet deep。
But why loose stones？ … and if so； what matter？ and what wonder？
There are rocks cropping out everywhere down the hill…side。
Because if you will take up one of these stones and crack it
across； you will see that it is not of the same stuff as those said
rocks。 Step into the next field and see。 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 sun； to form
a huge dam across the ravine； till； the 〃Ice age〃 past； a more
genial climate succeeded； and neve and glacier melted away： but
the 〃moraine〃 of stones did not； and remains to this day； as the
dam which keeps up the waters of the lake。
There is my explanation。 If you can find a better； do： but
remember always that it must include an answer to … 〃How did the
stones get across the lake？〃
Now；