VOL. XVII. (3) 



EXCURSION— BRECON 



291 



retaining-walls. On the south side was the valley of a tributary of the 

 deeply sunk River Usk ; on the north, that of the Llyfni, the stream that 

 finds its way through Llangorse Lake into the River Wye. The return 

 drive to Brecon was via Talybont, where there is an interesting old bridge. 



On Wednesday the party left Brecon by the Brecon and Mcrthyr Railway 

 to Torpantau. The railway runs along the sides of a magnificent valley, and 

 is justly claimed by the local guide-books to be " one of the loveliest railway 

 rides to be had anywhere in Wales." From Torpantau Station (1,300 feet) 

 the old road from Merthyr to Brecon arcoss the moorland was followed. 

 A mile away down the valley was seen the Pentwyn reservoir at Dol-y-gaer 

 with the chimneys of Dowlais beyond ; while in front, in the valley, lay the 

 reservoir that supplies Merthyr and Dowlais. 



Arrived in the gap on the east side of Cribyn (Plate XXXI., fig. i), lunch 

 was partaken of, after which the Members skirted the peak and climbed to 

 the summit of Pen-y-Fan, 2,905 feet. Wind-driven clouds of mist pre- 

 vented a continuous view over the surrounding country ; but from time 

 to time glimpses were caught of the cwms with their precipitous 

 head-walls. Descending a short distance, the party came out again into the 

 sunshine and saw the moraine-contained tarn called " Llyn-cwm-Llwch," 

 the long cwms, and the smooth grass-covered dividing spurs which project 

 northwards like long fingers. In the distance lay Llangorse Lake with 

 Mynydd Troed beyond. 



Mr Richardson explained that the Brecon Beacons and the Black Moun- 

 tains are composed of Old Red Sandstone, and that while in prc-glacial times 

 the outlines of the Beacons were probably much more rounded, in Glacial 



Fig. I. — Cwnillwch Falls, Brecon Beacons. 



