W4s ON THE GEOLOGY AND STATISTICS 
peak of Snowdon, being 3561 feet above the level of the 
sea. 
Towards each extremity of the chain the mountains 
gradually decrease in height. The Rivels, on the south- 
western termination, are 1866 feet, and Penmaen Maur, 
on the north-east boundary, is 1400 feet above the sea^ 
These mountains present a noble, alpine group, conically 
peaked, craggy, and rugged in their outHne; and when 
their summits are gilded by the rays either of a rising or 
a setting sun, they afford one of the grandest objects of 
contemplation in England. 
The surface of this side of the basin is varied and broken 
into many inequalities. Little of it is level. The little 
vale of Ugivulchy, situate between Penmaen Maur and 
Penmaen Bach, is one of the levellest tracts of land of this 
side of the basin. There are other spots along the Car- 
narvon shore also tolerably flat, such as near the mouths 
of the Aber and the Ogwen ; and another tract, the largest 
between Carnarvon and Clynog, may be adduced as the 
levellest portions of the basin. For a considerable distance, 
in the vicinity of the Snowdon chain, great blocks of rock, 
immense boulders, quantities of large stones and gravel, 
strew and cover the ground, particularly where the Seiont 
issues from the ravine in which the lakes of Llanberris are 
situate. 
Scarcely so many streams have their sources on the 
western side of this chain, as those we have already de- 
scribed on the eastern. Among the largest are the Ugi- 
vulchy, the Aber, the Ogwen, the Cegin, the Seiont, the 
Goorfai, and the Nantle. 
The course of the Ugivulchy, which waters one of the 
sweetest vales of the Menai basin, is but very limited. 
The Aber proceeds from a deep wooded ravine, and, 
after passing the mouldering walls of Prince Llewellyn's 
4 
