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enabled them thus to defy the denuding agency that would otherwise have 

 levelled them. I must not stay to enter into detail here ; but I may remind you 

 of the probability of frequent risings and subsidences of the sea bottom, of rain- 

 falls possibly more severe and continuous than any which we are now accustomed 

 to, and of rivers more vast and irresistible than even the mighty Mississippi. 

 And to give you only one instance of what water can do in this way, it has been 

 calculated that 200 tons of solid matter is annually removed from every square 

 mile of the Cotteswold country by clear water, the chemical properties of the 

 water holding this matter in solution ; to say nothing of what is carried away in 

 suspension when the water is turbid and muddy. But this thought of what 

 has been achieved by denudation and by erosion (that is by washing off and by 

 scraping out), in the way of bringing the surface to the contour which we at 

 present view, leads to another very surprising one with which I will conclude. 

 More than once have I been privileged to hear Mr. Symonds in the field — and 

 who that ever heard him can forget the lucidity- and yet the depth of his 

 descriptions of the wonders that lie knew — more than once have I heard him 

 dilate on the marvellous picture presented to the imagination of what must have 

 been the condition of things even here where we now are at the close of the 

 Carboniferous period and before denudation had set in. " It is impossible to 

 doubt," he writes in one of his works, " that the mass of carboniferous deposits 

 once existed far above the present site of Herefordshire and much of Shropshire." 

 For reasons with which I need not trouble you now it is as clear as anything to be 

 learnt from deduction can be that the South Wales coal field, the coal basin of 

 Mitcheldean, and the small f.utlying detached portions of Carboniferous rocks to 

 be seen on the summits of Pen ("errig Calch, of Blorenge, and of the Clee Hill, 

 were at one time parts of one continuous sheet. These have been preserved from 

 denudation and remain : the rest has been worn away. Think what that implies. 

 The thickness of the lower Old Red (to the uppermost beds of which we have 

 reached to-day), has been put at its greatest as 2,500 feet, take that from the 

 maximum thickness of the Old Red system 10,000 feet, and you get 7,500. Add 

 to this the thickness of the carboniferous system, estimated in the South Wales 

 field to be upwards of 12,000 feet, and, whether those figures are uniform over the 

 area or not, you have at all events an immense mass which at one period of the 

 world's history filled to a great height the aerial space above us, and which has 

 been swept bit by bit away, leaving only in the spots indicated traces that it ever 

 was. You have the whole Carboniferous system taken away save from those 

 isolated points. Besides that you have the whole of the upper Old Red and the 

 whole of the middle Brownstones taken away from above the Cornstone hills and 

 valleys of Herefordshire from here as far as Leominster or Ludlow. And besides 

 that, still further, you have not only the Carboniferous and the upper and middle 

 Old Red, but you have the Cornstone, lower Old Red, series taken away too from 

 that part of Shropshire and Radnorshire which lies west of Corvedale up to where 

 the scanty remnants of the latter show themselves in tliose outliers of the Long 

 Mountain, Clun, Knighton, Presteign, and Old Radnor, which I asked you to 

 carry in your minds at the opening of my address. Such a process, of course, 

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