Ascent of Gader Idris. 29 



bouring cliffs. A scramble over tlie latter to the lake (Llyn- 

 y- Gader) of which, they form the western barrier, is about as 

 severe an exercise for a pedestrian as can well be imagined ; 

 though the only real danger to be apprehended is a sprained 

 ankle. 



The small, round, and deep lake-basins form the most 

 remakable feature of the scenery of Cader Idris. The two 

 best known are Llyn-y- Gader and Llyn Cae. The first may 

 be found on the north side of the mountain, immediately 

 under the Gader peak. It embraces about half a circle, and is 

 bounded by high cliffs. The lake is dammed in by a ridge of 

 stones, beneath which, in all probability, there is a solid rocky 

 barrier, so as to give this hollow the character of a true rock 

 basin. The water has no visible egress, though there can be 

 little doubt that it percolates through the outer part of the 

 stony barrier. It is not surprising that early travellers should 

 have looked upon this basin as a volcanic crater formed by 

 explosion, and that the neighbouring accumulations of stones, 

 already mentioned, were the effects of the explosion. It is, how- 

 ever, to be regretted that the most modern guide-book writers 

 should borrow their geology from the days of Pennant, and 

 speak of pumice-stone, and other subaerial volcanic products, 

 as being found on Cader Idris. In a certain extensively- 

 circulated guide-book not only is this error perpetuated, but 

 Llyn Gwernan, two miles from Dolgelley on the old Towyn 

 road, is called Llyn-y-Gader, and the latter is left without a 

 name ; while Wilson is represented as having painted Llyn- 

 y-G-ader, whereas it is well known that Llyn Cae was the 

 subject of his celebrated picture. It is a pity that guide- 

 book writers should not take the trouble to visit the spots they 

 attempt to describe. No geologist would now regard Llyn-y- 

 Gader as a volcanic crater. It has evidently been scooped out 

 of the alternating slaty and submarine volcanic rocks of which 

 the mountain consists ; but the cause of the excavation admits 

 of difference of opinion. This basin, as well as Llyn Cae, may 

 certainly have been deepened by ice, but its situation would 

 appear to preclude the idea of a glacier having formed the 

 whole of the crateriform hollow. The undermining action of 

 a tidal current, at the time or times when the rocky rampart of 

 Cader Idris was a sea- cliff, would appear to be the explanation 

 most in accordance with our knowledge of the effects of recent 

 geological causes. During the glacial submergence the exca- 

 vation may have been completed, if not principally effected, 

 and the sea may have been powerfully assisted by the action 

 of coast-ice. 



On proceeding along the usual route, and before you 

 arrive at the base of the Gader peak, you suddenly behold the 



