igo THE ORIGIN OF DERBYSHIRE SCENERY. 



The line of this fissure coincides in direction with the face of the 

 High Tor, and has been produced along the plane of joint. The 

 waters of the Derwent assisted by atmospheric agencies have 

 attacked the massive limestone along this plane and has removed 

 the material wh.ich once occupied the fissure, and what is now the 

 eastern face of the High Tor Cavern will some day form a 

 precipice similar to the High Tor, the mass of rock between 

 which and the fissure being disintegrated and removed. At the 

 present rate of erosion no fears as to the early removal of this 

 beautiful cliff need be entertained. 



Having said so much about the influence of these natural 

 planes of the rock on the results of erosion, attention may be 

 called to the step-like appearance of many hills, which is produced 

 by the outcrop of strata in which alternate beds are of differing 

 hardness. This may be seen at and near Ashover, Ravensnest, 

 and Butterlee. Or frequently if the strata do not differ in this 

 respect, the divisional planes will lead to the production of the 

 appearance referred to. Mr. Ward calls my attention to the 

 Harboro' Rocks as well illustrating this point 



Now let the case of a river flowing through a broad alluvial 

 valley be considered. The width of such valleys when compared 

 to the stream, by the action of which they are alleged to have had 

 their origin, is sometimes very astonishing. It need not be so, 

 however, when 'it is considered that frequently the rivers must 

 have been much wider than at present, and also that sub-aerial 

 denudation is tending constantly to widen the valley by reducing 

 the abruptness of the slopes, removing the material to lower 

 levels to be eventually transported to the sea, the final resting- 

 place of whatever is now raised above its surface. Almost 

 invariably, also, the river-course is extremely sinuous. 



Derbyshire offers several good instances of such rivers, as, for 

 example, the AVye from Rowsley to Bakewell, the Dove from 

 Rocester to Egginton, and other places. The former example 

 may be taken as typical, and the neighbourhood is well-known. 

 Fig. 9, B, is an enlargement from the Geological Survey Map of the 

 district. It will be seen that the river is verv sinuous, and, indeed, 



