204 



THE EVOLUTION OF DERBYSHIRE SCENERY. 



Derbyshire, we have the Yoredale Rocks, consisting of sandstones 

 and shales ; and above these, the Millstone Rocks. The Yoredale 

 shales present characteristics of great importance, giving rise to 

 peculiarities of scenery worthy of note. These shales are 

 peculiarly friable, breaking up' readily in most cases into small 

 and somewhat lenticular fragments, and in other cases being 

 finely laminated, breaking up in the hand into laminae scarcely 

 thicker than paper. Such shales, although undergoing no marked 

 chemical change under the action of water, are readily disinte- 

 grated. 



We have also another fact to take into consideration. 

 Owing to the structure of these shales, they readily undergo 

 change of form, due to the pressure of the overlying Mill- 

 stone rocks, giving rise, where the Millstone rocks have 

 been cut through, forming valleys in the shale, to interesting 

 local phenomena, of which one is mentioned hereafter. The 

 succession of grits and shales in the Millstone series gives rise to 

 the long lines of escarpments or '' edges " of grit, which form so 

 marked a characteristic of Derbyshire scenery. Where fully 

 developed, as along the east side of the Derwent Valley north of 

 Baslow, the three grits give rise to three escarpments overlooking 

 the river, viz., Derwent Edge, overlooking the village of Derwent 

 (Kinderscout Grit) ; Strines Edge, a mile behind it (Rivelin Grit) ; 

 and a mile and a half still further behind is Sugworth Edge 

 (Rough Grit). Nearer Hathersage are Bamford, Stanage, and 

 White Edges, respectively of the above rocks. In section, and, 

 of course, when looked at in the direction in which these edges 

 run, the contour takes the form shown in Figure i. 



Fig. I. 

 A, Derwent. B, Denvent Edge. C, Strines Edge D, Sugworth Edge. 



The production of these edges are of interest. Their formation 



