28 Ascent of Cader Idris. 



the west with, a bold and striking headland called Tyrau 

 Mawr. For some distance, in an easterly direction, it consists 

 of a steep grass-covered slope, with frequent rocky projections. 

 On the surface of a large flat stone on the side of this slope I 

 noticed a distinct series of ice-grooves, only a little roughened 

 by the weather during the time that has elapsed since they 

 were imprinted. Further on, the escarpment graduates into a 

 line of bare rocky cliffs, with debris or " screes " strewn along 

 their bases. These cliffs are deeply indented with vertical 

 rents and passages, which often ramify backwards so as to 

 leave detached pillars. On approaching Llyn-y-Gader the cliffs 

 become more massive, and rise to an almost appalling height. 

 Here their bases are buried in screes, which run down into the 

 transparent waters of the Hyn. On the east, a continuous 

 wall of rock extends to the headland which frowns over the 

 town of Dolgelley; this headland terminates abruptly in a 

 cwm, or inland cove, on the southern side of which it sends 

 off a spur in the direction of the Arran range of mountains. 



The principal screes are to be seen in the neighbourhood, 

 and to the west of Llyn-y-Gader. They are partly derived 

 from the breaking down of the cliffs, and here and there a 

 large block has evidently very recently fallen ; but a distinc- 

 tion must be made between debris, strictly so called, and the 

 immense accumulations of stones to be found both at the base 

 and on the summit of the mountain. The ridge-like buttresses, 

 consisting of loose fragments, which, in many places, may be 

 seen underlying large fissures in the cliffs, are chiefly the result 

 of cataracts of stones which have tumbled down, not from the 

 cliffs themselves, but from the heaps of loose fragments on the 

 summit. These heaps, in many places several yards in depth, 

 have been scattered, piled on each other, and apparently forced 

 up the acclivity of the saddle-shaped eminence called Cyfrwy. 

 They are generally columnar and pentagonal in shape, and are 

 frequently made use of as gate-posts, lintels, etc. The number 

 of stones on this part of Cader Idris would probably be suffi- 

 cient to build a good-sized town. They are to be found in 

 smaller quantities on other parts of the mountain. How these 

 stones came there cannot be easily explained, even in the 

 present advanced state of geological theory. The agency of 

 land-ice is not applicable to a high and narrow table-land 

 where no ice-shed could have existed. The action of the sea, 

 assisted by ice-floes and coast-ice, at the time when the summit 

 of Cader Idris was slowly sinking beneath or rising above the 

 sea-level, would appear to offer the most probable explanation; 

 and to this agency we may likewise attribute the stupendous 

 accumulation of stones found lying beneath the mountain, in 

 positions where they could not have fallen from the neigh- 



