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by their superior hardness, resisted the wash of the breakers, 

 the land would gain upon the sea. Mr. Hull attributes the 

 presei-vation of Churchdown Hill to the resistance which the 

 Marlstone beds have made to the denuding agencies ; and it is 

 noteworthy to what an extent the compact layers of the Eagstone 

 form the capping of the escarpments of our hills, and appear 

 to have been the means of arresting the spoliation of the beds 

 beneath them. 



The moment any portion of the strata had risen above the 

 surface of the sea — even before they attained a position above 

 the flood tide, — at each ebb of the waters, subaerial denudation 

 would commence. Of the subaerial agents, the rainfall, accu- 

 mulating in streamlets, would act in the direction of the dip 

 of the strata, and speedily ctd channels in those directions. To 

 this I would refer as the cause of the tributary streams of this 

 district flowing in the direction of the dip of the strata. The five 

 principal streams which flow into the Brimscombe valley do so 

 from the north, and of the four which join then- waters to the 

 ISTailsworth stream, two flow towards the north, and two to the 

 north-east, but all have their direction in accordance with the 

 dip of the strata over which they run. 



Into the mode of operation by which such great results have 

 been accomplished, as are now generally ascribed to the power 

 of "Eain and Eivers," I have no intention of entering, but 

 will make one remark on the subject: — When we look across 

 one of our valleys, a mile or more wide, and see a stream at the 

 bottom, a few yards only in width, it is difEicult to realize what 

 relation that river has to such an excavation ; and yet, though 

 that river may at no period of its history have possessed twice 

 its present volume of water, .or have changed the direction of 

 its bed to any great extent, it has, in all likelihood, been the 

 chief agent in the formation of that valley. The stream must be 

 regarded as a cutting instrument, and as a carrier — chiselling 

 out its bed deeper and deeper into the strata, and all the while 

 canning off the spoils brought into it by rain, frosts, &c. This 

 siTbject is well illustrated at the heads of our valleys, where, 

 in many eases, it is seen liow the surface drainage of a large 



