It is at a sudden bend in the hills that you come unawares upon the astonishing vision, but before you reach that point the landscape clothes itself in sack-cloth and throws ashes on its head as if it realised that the green pastures were to end in the Valley of the Shadow of Death, and it must drape itself seemly. In winter especially there is a look of Sodom and Gomorrah about the place—a charred, lifeless look that is weird and depressing. On the one hand the slender stems of ash and hazel, rising grey from the grey hill-slope, seem as though some storm of fire had swept them. Here and there a dead tree, stripped of its bark, still mocks the power of the wild winds that are forcing it earthwards. On the left the cragged hill sweeps round in a quick semi-circle to shut in the valley. Like ragged ramparts its serrated, rocky outline shows crisp against the sky; screes of loose stone, from which here and there a huge boulder uprears its bulk, cover the sides; and other boulders, hurled down by successive avalanches, line the bank of the stream. This, however, is only the cheerless bodement of what is beyond. When the sweep of the semi-circle forces you round the curve of the hill the vision of stern grandeur and majesty may well rob you of speech. The hills have drawn together until they almost meet, but they are no longer hills—they are stupendous, unscaleable precipices of rock, three hundred feet high. Grim and forbidding—black rather than grey—they offer no hospitality to the foot of man; but jackdaws and ravens make their home there, and birds of prey may sometimes be seen perching on the crags. Into this roofless cavern—for there is evidence that the beetling rocks that project overhead once met in a great arch—the stream projects itself by a series of waterfalls which roar in time of flood like the “young lions” of Wordsworth’s fancy, and rushes along its stony channel scattering white foam upon the piled-up boulders that almost fill the floor of the chasm and make progress difficult. Steps have been cut in the rock beside the lower waterfall so that even the inexpert may climb to the “upper air,” and on their way to the higher reaches of the stream may trace out for themselves the course of the great convulsions that gave to Mawm its wonderland. Level with the summit of the cliffs is the moor with its far-stretching fissured platforms of grey limestone. Awe-inspiring even in brilliant sunshine the chasm is really “terrific” at night. Then the frowning cliffs roof themselves in with blackness and the roar of the Stygian stream is direful. Man shuns it, and the birds that shriek and chatter there are birds of ill-omen.