1 88 



THE ORIGIN OF DERBYSHIRE SCENERY. 



would carve for itself a sinuous course, wearing its channel 

 vertically and laterally. The slope which the banks of the river 

 would assume would depend largely upon the natural divisional 

 planes of the rock, and these are well marked and regular in 

 limestone. Take a case where the strata have a gentle " dip " as in 

 Fig. 6. Here the running water wears its way most easily along 

 the stratification and jointing planes, and it will readily be seen 

 from the diagram — which represents a section across the river 



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channel — that the tendency will be for the river to attack and 

 encroach upon its eastern bank, undermining and separating the 

 rock in rectangular masses, which become broken up and trans- 

 ported to lower levels — ultimately to the sea. It will be seen 



