Amotig the Ancient Glaciers of North Wahs. 15 
men of a rocher moutonne exists in Switzerland than is to be seen on 
our left hand, as we are descending the valley, at the bridge just 
below Lake Ogwen, and within a few feet of the road. On the other 
side, the rocks rise precipitously above the road, and the glacier 
mnst have been borne with great force against the wall of rock 
which there checked its progress and altered its direction. Although 
the rock is not of a very durable kind, it is conspicuously rounded 
to a height of some 250 feet, where the limits of the glacier level are 
apparent. The upper rocks overhang the lower, and are very rough 
and jagged, with a trace of rubbing. Below the road on the left 
hand, terrace after terrace of rock is rounded and smoothed. This 
is the part of the valley where the glacier traces are most prominent 
and striking. Here, they actually obtrude themselves upon the eye, 
but they do not cease for many miles. The gently descending line 
of the glacier level may be easily traced from the road along the op- 
posite side of the valley, the smoothing action being the more ap- 
parent from the contortion of some of the strata, as seen in the upper 
and unworn faces of the rock. Between five and six miles from 
Bangor is a very interesting group of rocks which crop out from the 
turf in a little wood above the road. They formed somewhat of an 
elevation in the glacier bed, and have consequently been subjected 
to severe pressure. They are worn very round and polished quite 
smooth, and the striae are most distinct, passing sometimes up-hill, 
over the undulating surfaces. 
The most striking evidences of glacier action, however, are to be 
found in the great hollow of Snowdon, which is literally full of 
them. From some distance above the Copper Lake, almost to the 
bottom of Nant Gwynant, they stare at us in the face at every step. 
The " Cwm Dyll " was one vast mass of ice from whose bosom the 
peak of Snowdon rose to the height of some 1000 or 1200 feet at 
most. Urib Goch, Grib-y-ddysgyl, Snowdon, and Lliwedd formed an 
amphitheatre of mountain peaks enclosing the great Snowdon 
glacier, as the chain of the Aiguille Verte and the de I'Echand 
guard the Jardin and the glacier du Talefre ; names doubtless 
more familiar to American travellers than those of the subsidiary 
peaks in the Welsh mountain ranges. A large proportion of the 
rock in the basin of the Snowdon range is very hard and smooth, 
and has preserved, in singular freshness, even the minutest scratches. 
It is curious to trace, as we descend from the summit of Snowdon 
into the bosom of the hollow, the gradually diminishing inclination 
of the glacier and its increasing pressure, as marked by the dimin- 
