170 Notes on the Caverns of Derbyshire^ 



descending deeper into the bosom of the rock. Another stream, a little 

 further west, penetrating into the same rock, follows a passage upon 

 the same level as the valley, into which it again issues at the other 

 side, and, after coursing some time down the vale, loses itself fin- 

 ally in the main or southerly ridge. This passage can, when the 

 water is low, be penetrated and explored throughout the whole of 

 its extent. 



Beyond these, further to the westward, several streams of water 

 may be seen entering the limestone rock at different points, and in 

 almost immediate succession. 



These swallows present in most places the interesting feature 

 of their having at one time or other changed their place ; while 

 the streams supplying them, before upon a level with the valley, 

 now form for themselves secondary valleys as it were, confined m 

 their limits by the size of the stream, and following a course at 

 right angles to the main valley. Two separate entrances are then 

 left, one above the other ; the lower one alone receiving the influx 

 of waters. In some cases, the waters, previous to their entrance 

 into the lower swallow, buried themselves in the earth, obviously 

 to join one still deeper, and thus the two openings above grounJi 

 are left dry. 



We were able to trace different causes for this fact ; the most 

 common one appeared to arise from the scooping effects of the 

 \vaters, which, by lowering their channel, necessitated the enlarge- 

 ment of their present swallows, or the formation of a new one. 

 But they were also occasioned by the blocking up of their former 

 passage, which we have seen occasioned by the falling in of masses 

 of rock and portions of the strata, leaving sometimes apertures to 

 the day beyond the first swallow ; and also by the labours of man, 

 anxious to preserve his cattle from accidents that ensue by their 

 falling into these holes, or their being borne in times of overflows 

 down these hidden streams of water. The magnitude and sudden 

 increase which these streams sometimes assume is remarkable, and 

 their current is at that time proportionally rapid and impetuous. 



Notwithstanding the occasional diminution of the elevation of 

 these swallows, they still remain a considerable height above the 

 cavern of the Peak, which pours into Hope Vale a tributary 

 stream of water ; nor is there much probability that any imme- 

 diate effect of time will produce an equality of level in the two 

 valleys. 



The fact that objects, when allowed to follow the course of the 

 waters, entering at the swallows, occasionally re-appear with the 

 stream that issues into Hopig Vale, and the evidence derived from 

 their relative situation, and from the existence of analogous cases, 

 can leave no doubt of the immediate connection which exists be- 

 tween the two. 



', This relative situation at once combines the evidence of the com- 

 parative quantities of water, of the geological probabilities, and the 

 physical necessities for the exit of the waters on the earth's surface. 

 Analogous facts furnish us %ith similar chemical or mechanical 



