34 MOUNTAINS. 



efflux of water which can be supposed to be fed from Gaping 

 Gill than that which is seen near the Cave mouth. In floods, 

 this opening, a broad depressed cavern, called in the country 

 'Little Beck head/ is not sufficiently large for the body of 

 water, which rushes from the hills above through the fissures 

 and hollow interior windings in the rock; and it then forces 

 itself a passage through the larger (supposed to be the original) 

 mouth. (Geol. Proceedings, 1848.) 



Probably not one but many threads of water unite Gaping 

 Gill an4 Little Beck head; probably the lines of subterranean 

 current vary from time to time ; stalagmites choke the old chan- 

 nels, while others are formed in new directions. When Mr. 

 Birkbeck descended the fearful gulf of Gaping Gill, he found at 

 about 80 feet a rush of water from the side a subterranean 

 stream emptying itself into this great opening. 



Through what periods of time, since first the rill issued in 

 some part of Clapdale, the excavation of limestone and for- 

 mation of stalactite have been continued, we cannot say. The 

 time consumed in the formation of even one stalagmitical boss 

 is not easily determined. One of these in Ingleborough Cave, 

 of a remarkable form, called the Jockey Cap, is fed by one line of 

 drops. It measures about 10 feet in circumference at the base. 

 The height is about 2 feet. It appears to contain about 8 cubic 

 feet, or 9,450,000 grains, of carbonate of lime. The drops were 

 collected by Mr. Farrer on the 9th of October 1851, after a rather 

 wet period, and it required 14| minutes to fill 1 pint, say 100 

 pints in a day. In this pint was found only 1 grain of calcareous 

 earth, or 100 grains a day. If the water were supposed to yield 

 up all its contained salt of lime, the number of pints of water 

 consumed in producing this boss of stalagmite =9,450,000 ; and 



9-450000 



the vears which elapsed in its formation = = #59 . In 



100 x 365 



drier seasons the water is probably richer in carbonate of lime. 



I am indebted to Mr. Farrer for the following notes, made in 

 1839 and 1845 : 



