2o8 THE EVOLUTION OF DERBYSHIRE SCENERY. 



formed, it may be pointed out that the ravine which runs for 

 some distance from the entrance of Peak Cavern is due to the 



A 



Fig. 4. 



A, Sfiarroiv Pit. B, Trough-shaped valley west of Casileion. C, Windv Knoll, and 



belowy the ' Bottomless Pit ' o/the Speedzuell Mine. D, Peak Cavern. E, Hojie Dale. 



same cause, the roof of the cavern having here fallen in, and the 

 debris in the course of time removed. It will readily be seen 

 that with a further lowering of the general surface, a larger portion 

 of the cavern will be opened out, forming an overground stream 

 with precipitous banks. This further step in the evolution of 

 Derbyshire scenery will, however, doubtless require some 

 thousands of years for its completion, unless the present 

 rate of erosion is greatly increased. A portion of the water 

 which issues from the Peak Cavern is possibly derived from the 

 limestone hills a little farther south. It is very probable that the 

 huge chasm known as Eldon Hole communicates with Peak 

 Cavern ; and there is an old story to the effect that a goose, 

 which fell down this hole emerged at Castleton. 



Another good example is to be seen in the Waterfall near 

 Foolow, of which a section, giving a view of the interior, 

 is shewn in Fig. 5, the arrows indicating the direction of 

 the flow. An examination of the district shows that there is a 

 dry valley, representing the old watercourse, extending from the 

 great open chasm which gives rise to the waterfall, to the end of 

 Middleton Dale. Part of this old channel is known as Linen 

 Dale. At present the stream pours into the chasm and 

 disappears, to find its way, together with the waters from 

 neighbouring "swallows," to the valley of the Derwent by way 

 of Middleton Dale. Various causes determine the spot at which 



