At the head of the Pass of Nant Francon, and behind the huge, dark, threatening shoulder of Carnedd Dafydd, Llyn Ogwen stretches along for about a mile or so, hemmed in at its further extremity by a low range of hills. In Cumberland this lake would be called a tarn, as would also Llyn Idwal, a sort of miniature Wastwater, which lodges in a hollow, among deep and gloomy precipices, a few hundred yards to the left. "This," wrote Leland, "is a smoule poule, where they say that Idwalle, Prince of Wales, was killed and drounid." "No human ear but Dunawt's heard Young Idwal's dying scream," says the ballad in which the tradition is enshrined. The appearance of the place may well have suggested either the legend in modern or the crime in ancient days. In stormy weather the surroundings of the little lake are inconceivably wild and forbidding, and the wind swirls about in this hollow of the rocks until Llyn Idwal boils like a sea. [Illustration: PASS OF LLANBERIS (_p. 205_).] Ogwen is a lake of gentler and more serene aspect. At its foot, under Carnedd Dafydd, where the coach-road crosses, its waters, with those from Llyn Idwal, form the Falls of Benglog, so well described by an older writer that his words shall be made to serve the purpose here. "The highest Fall," observes Bingley, "is grand and majestic, yet by no means equal to the other two. At the second, or middle, Fall the river is precipitated, in a fine stream, through a chasm between two perpendicular rocks that each rise several yards above. The mountain, Trivaen, fills up the wide space at the top, and forms a rude and sublime distance. The stream widens as it descends, and below passes over a slanting rock, which gives it a somewhat different direction. In the foreground is the rugged bed of a stream, and the water is seen to dash in various directions among broken masses of rock." At the lowest fall "the stream roars with great fury, and in one sheet of foam, down an unbroken and almost perpendicular rock. The roar of the water, and the broken and uncouth disposition of the surrounding rocks, add greatly to the interest of the scene." And from these Falls of Benglog one looks down the wide, treeless vale of Nant Francon, a broad, peaty marsh, the bed of some ancient lake, as it would appear, hemmed in by dark ridges of mountains. [Illustration: CARNARVON CASTLE (_p. 206_).]