68 DEEPDALE CAVE. 



rocks. It differs considerably from the gritty variety found in 

 like situations in districts where the limestone is more or less 

 dolomitised, as described in the second report of Rains Cave. 



With these facts before us, we can proceed to the considera- 

 tion of the origin and history of our cave. The fissure that has 

 just been noticed, is a portion of a mineral vein stretching in a 

 W.N.W. and E.S.E. direction, from High Cliff, half a mile west 

 of Deepdale, to the vicinity of Chelmorton Low. The outcrop 

 of this " rake '' in the valley-side can be distinctly traced a few 

 dozen feet lower down the valley, just beyond the point where 

 it bends to the N.E. One portion is cleared of its contents, 

 apparently naturally, and forms a fissure-like cave at a higher 

 level than the one which is our subject. The heaps of sparry 

 refuse on the valley-side below indicate that the vein has been 

 worked, but certainly to no great extent. It hades, or leans, to 

 the left, that is, north, exactly as the fissure in the second 

 chamber does ; and it is of about the same width. It is almost 

 beyond a doubt that this fissure is a denuded portion of the same 

 vein. There is a small cave high up the opposite side of the 

 dale which has all the appearance of having also originated in a 

 cavity of the same vein. A reference to the accompanying dia- 

 gramatic plan will facilitate the reader's grasp of the above state- 

 ments. 



The reader may have observed that natural cavities are very 

 common in mineral veins and in the parent rock immediately 

 adjacent. This is in great measure due to the fact that the 

 mineral fillings of these veins are not so hard as the rock ; and 

 that having been deposited from solution in water they are very 

 susceptible of re-soUition. The great depth and length of these 

 veins are, moreover, very convenient lines of subterranean drainage. 

 When, in consequence of the lowering of the land-surface by 

 denudation, the portion of the vein now exposed in Deepdale 

 was brought within range of the action of surface-water, it 

 is not extraordinary that it should have become part of 

 a line of drainage. Once pervious to this water, by no matter 

 how small a channel, it was a mere matter of time for this 



