32 



It has been very properly objected by Mr. Witchell, that if 

 the sea has had a share in the formation of our valleys, it ought 

 to have left traces of its former presence. That such have not 

 been met with, I would suggest that all traces of this occupa- 

 tion of these valleys by the sea, as would be afforded by its 

 depositing shells or sands, have been lost by the subsequent action 

 of subaerial agents. At the close of the Glacial Period, and 

 whilst the sea and land assumed their present relative levels, 

 the surface of the land, largely denuded of vegetation, must 

 have been in that condition on which subaerial agents of 

 denudation must have acted with great effect to remove all 

 such marine deposits. 



The action of Ice during the Glacial Period must have largely 

 assisted in abrading the hill-sides of this area. 



The result of these various agencies has been the production 

 of a district singularly varied in its external features, and this 

 from causes so well described by Hugh Millek, in his early 

 work, " The Old Red Sandstone," that I will quote from it here. 

 He writes"* : — 



"In all the sedimentary formations, the peculiarities bf scenery 

 "depend on three circumstances — on the Plutonic agencies, the 

 " denuding agencies, and the manner and proportions in which 

 ^'the harder and softer beds of the deposits on which these 

 " operated alternate with one another. There is an union of the 

 "active and the passive in the formation of landscape ; that 

 ^'which disturbs and grinds down, and that which, according to 

 "its texture and composition, affects, if I may so speak, a peculiar 

 "style of being ground down and distm-bed ; and it is in the 

 '^passive circumstances that the peculiarities chiefly originate. 

 "Hence it is that the scenery of the Chalk differs from the scenery 

 "of the Oolite, and both from that of the Coal Measures." 



These effects are well illustrated on the hiU-sides of this 

 district. Where these consist of the Upper Lias, steep banks 

 have been produced ; the more yielding Sands, where not covered 

 up by fallen Rock-beds, have formed more gentle slopes, usually 



* At page 246, sixth edition. 



