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(ew organic remains. In this, therefore, we have a palpable demonstration of violent 

 dislocation. After the deposit of the millstone grit, however recent that may be, as 

 compared with the Devonian, in whatever way the carboniferous deposits may have 

 accumulated, their present basin was produced by subsequsnt upheavals and disloca- 

 tions. The removal of the enormous masses of grit and limestone, which formerly 

 connected this outlier with the coalfield, and the formation of the present valley of the 

 TJsk— here five miles wide and nearly 2,000 feet deep — must be ascribed to such dislo- 

 cations, combined with the action of powerful currents. This, therefore, is manifestly a 

 "valley of denudation," and the detritus of the excavating process is seen piled up in 

 vast mounds and terraces of gravel near Abergavenny, and for miles on both sides ol 

 the river. Standing there, with Murchison in your hand, you could at once mentally 

 realise the process. Let us imagine it, somewhere about the chalk age, possibly at the 

 time of the great volcanic outburst which threw up the Giant's Causeway in Ireland, 

 and the Isie of Staffa, ic , — a hot, sultiy, heavy, and murky-looking day, with an awful 

 stillness in the air, — when suddenly a long-drawn, sepulchral howl or crash, is heard 

 at a distance, and a tremor and strange quivering; and surging are felt in the earth, 

 followed by a tearful wrench — a rending and toppling of mountains in chaotic confusion 

 — while beyond, the sea bottom madly leaps to the surface, driving the waters with a roar 

 to which that of Niagara is but a whisper, in a body several hundred feet deep, far up 

 into the gorges of Brecon and Radnorshire, and sweeping away in the recoil many 

 millions of tons of old red sandstone and mountain lime. Some such process as this 

 made the Welsh coal-fields accessible. And all for what purpose ? Merely that in the 

 19th century of the Christian era, "Molly might put the kettle on" for tea, or 

 Johnny have a Are to warm hi.s toes in winter, or the Naturalist Field Club to travel in 

 spring by express. Doubtless, it was done fsr Molly, and Johnny, and the Naturalist, — 

 not, however, as mere short-lived animals requiring food, or warmth, or even scientific 

 knowledge, — but as immortals placed here at school, in preparation for an incomparably 

 larger, nobler, truer, and more enduring existence. The issue will yet prove it was welL 

 Of tlie patches of modern Alluvium in the valleys of the TJsk and the Wye, — 

 around the lake of Llangorse — and in the flat near Talgarth, I need not speak. " He 

 who runs may read them," without any trouble. At certain points in tliem, however, 

 especially between Talgarth and Brecon, along the old tramway, there are occasional 

 drifts of sea sand, which are well worth studying, though I am not prepared satisfac- 

 torily to explain them. Note should be taken by compass of the exact direction of 

 the dip, and talus (or least abrupt side) of every hill you climb. Gravel heaps always 

 tell the story of their birth pretty plainly, if you will only mark carefully their relative 

 position and material. The boulders, many obviously of Scandinavian oiigin, strewed 

 over the surface, are in themselves a library, on the much controverted subject of 

 drifts. In the Black Mountains — he must be strangely blind who cannot find a thou- 

 sand indisputable examples of glacial action !— if my memory is not singularly treacherous, 

 the "mind's eye" m<ay see glaciers as clearly on the eastern side of Cwm Du (near 

 Crickhowell) as at Chamounix itself ! That perhaps is a bold saying, but it is neverthe- 

 less perfectly true. History falls not just now within my province, otherwise Mynydd 

 Troed would be a tempting pulpit from which to preach sermon.^, on or about the old 

 encampment on the Crdg, near Brecon, the mediajval monkish college not far from Crftg 

 Cadarn ; Prince Llewelyn, Lord Cobham, Cwm Pwcca, where Shakspere is said to have 

 written his "Midsummer Night's Dream ;" Walter Cradock, John Penry and Howell 

 Harris, Lady Huntingdon, Lord Oxford, the Marquis of Worcester's "Century of Inven- 

 tions," Ac, die. " Cum multis aliis, whose name is legion." The somewhat scampish, 

 mock-heroic Twm Sion Katty may be added in quality of a tail-piece ! Assuredly the 



