14 Among the Ancient Glaciers of North Wales. 
elevation of its bed. The direction of its flow must have heen very- 
nearly uniform, from its origin just beneath the ridge which con- 
nects Tryfan with Glyder Fach to its termination in the broad valley 
which the Capel Curig road pursues. Such a confirmation is un- 
favorable alike to the development of a large moraine and to the 
existence of that excess of pressure against the sides and bottom of 
the glacier which causes the deepest striations of the polished sur- 
face : and hence these indications cannot be expected to be found 
of so striking and unmistakable a character as in the '*Cwy Dyll,'* 
the great hollow of Snowdon, with its irregular bed and contracted 
orifice, or in the narrow outlet of the gorge of Aberglaslyn. Nor 
is the rock of a kind favorable to the preservation of the minuter 
traces of glacier action. Still, some may be seen of a peculiarly inter- 
esting and instructive nature. The extreme regularity of the bed 
of the glacier, the unusual absence of all disturbing or anomalous 
condi lions, has given rise to the formations of strise of great length 
and regularity. Some of those which score the rounded rocks on 
the southern flank of the valley are as much as fifteen or twenty 
feet long, and very distinctly marked. They are the more interest- 
ing as they intersect the line of stratification, and are crossed at 
right angles by the superficial markings caused by the dropping of 
water. From the upper end of the valley the view is very striking. 
If we stand by the shore of the ancient sea of ice which has now 
melted from the sight, we can define with precision the limits 
which bounded it on every side, and look down upon a succession 
of worn and rounded surfaces, which though upon a smaller scale^ 
are hardly less curious or characteristic than the old glacier bed of 
the Hollenplatte, which is crossed by the traveller from Meyringen 
While one considerable glacier thus poured from the eastern base 
of Tryfan, one of immensely greater extent — so long, indeed, that it 
would bear comparison with some of the existing glaciers of Switzer- 
land—streamed down to the northwest, occupying for many miles 
the valley of Nant Francon. This glacier had its origin in the ro- 
mantic amphitheatre of rocks and precipices which suriound Lake 
Idwal, one part of which is well known as the ''TwU Du," or 
** Devil's Kitchen," and extended for at least five miles down the 
valley towards the spot on Avhich Bangor now stands. The rounded 
and striated rocks which still tell the history of this glacier are to- 
be found in considerable abundance, and of very characteristic form 
and aspects, all along the Vale of Nant Francon. No better speci- 
