The Underground Drainage 



examining the bed of the stream, however, we saw signs 

 of pot-holing action similar to that which we had already 

 observed in surface streams, and also there were many 

 rounded pebbles beneath the water. It would therefore 

 appear that though the original opening had been 

 caused by solution of the limestone along a bedding 

 plane, the actual stream channel was, in part at least, 

 the result of mechanical erosion. 



Pursuing our journey through the cave, we had 

 occasionally to crawl along the flat rocks at the side of 

 the stream, and were sometimes compelled to take to 

 the water when the roof became too low to give us 



FIG. 26. Transverse section of a bedding-cave. 



passage room on the bank. Eventually the water rose 

 to within a few inches of the top of the passage, and here 

 of course we were brought to a dead stop, and had to 

 return to the second chamber. 



On entering the chamber we saw in front of us the 

 opening of the lower or canal tunnel, and at its farther 

 end observed a faint reddish light, which rapidly in- 

 creased in strength until eventually we saw that it was 

 the light from the torch carried by the men in our 

 canoe below the barrier. They appeared to be about 

 100 yards down the tunnel, and on our attracting 

 their attention by means of a whistle, one of them 

 climbed on to the weir with the torch, the flame of which 

 was then clearly visible. 



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