THE EVOLUTION OF DERBYSHIRE SCENERY. 



209 



the stream takes to its underground course. There are, for 

 example, numerous "swallows" along the junction of the Yoredales 

 with the limestone. Again, an open fissure is sufficient to 



A B 



^m^^^^ 



A, The Waterfall. B, 



Fig. s. 



Mineral lode and small cave. C, Old valley-route, 

 underground route belmv. 



viih present 



determine the commencement of the subterranean course, and, 

 bearing in mind the relationship between fissures and mineral 

 lodes, it would be remarkable if the latter were not closely 

 connected with swallows. A case in point is the Waterfall. The 

 chasm occurs at the intersection of the Cross Low and the Black 

 Hole Veins ; and there are numerous instances which point to 

 the fact that these underground streams frequently follow the 

 course of the lodes.* 



Many of the Derbyshire caverns consist in part of worked- 

 out mines and in part of natural chambers encountered 

 in following up the mineral vein. The huge underground 

 chasm intersected in working the Speedwell Level near 

 Castleton is a good example ; while Mr. Ward notes that 

 Deepdale Cave illustrates this. On the north-easterly side of 

 this cave is a longitudinal fissure, doubtless connected with the 

 lode which runs by here. This, together with the direction of 

 the plane of stratification, has determined the shape of the cave. 



* Pippin Swallow, near the waterfall referred to, is a good example. It 

 is produced in a lode, indeed the longer axis of the chasm is in a line with it. 



IS 



