Notices of Memoirs — Underground Waters of Craven. 73 



It was decided that the first piece of work should consist of an 

 investigation of the iindergronnd flow of water in Ingleborough. 

 This hill forms with its neighbour, Simon's Fell, a detached massif, 

 which is peculiarly suitable for investigations of this nature. The 

 summit of the group is formed of Millstone Grit, then follow 

 Yoredale Shales and Sandstones, the whole resting on a plateau of 

 Carboniferous Limestone. Many streams rise on the upper slopes 

 of the hills and flow over the Yoredales, but without exception their 

 waters are swallowed directly they pass on to the Carboniferous 

 Limestone, to reappear as springs in the valleys which trench the 

 plateau. 



The Committee first turned its attention to tracing the water 

 which flows into Gaping Ghyll hole. It was generally believed 

 that the water issued at a large spring immediately above the bridge 

 at Clapham Beck Head and immediately below the entrance to 

 Ingleborough Cavern. On April 28 specimens of the water from 

 this spring were taken for analysis before the introduction of any 

 test. Two cwt. of ammonium sulphate was then put into the water 

 flowing into Gaping Ghyll, and at the same time the amount of the 

 water was gauged and found to be equivalent to 251,856 gallons 

 per diem. A few hours later a second quantity of 2 cwt. of the same 

 substance was introduced. On the same day 1^ lb. of fluorescein in 

 alkaline solution was put into a pot-hole known as Long Kin East, 

 about 1,^00 yards north-east of GapiTig Ghyll. 



In view of the important influence which the direction of the 

 joints in the limestone had been found to exercise over the flow of 

 underground water,^ the direction of the joints in the limestone 

 clints in the neighbourhood of Long Kin East was taken, and was 

 found to be N.N.W. to S.S.E., and to run in such a direction as to 

 lead to the probability that the water would reappear at the springs 

 at the head of Austwick Beck, and these were consequently watched. 



The ammonium sulphate put in at Gaping Ghyll reappeared at 

 the large spring at Clapham Beck Head on tlie morning of May 3, 

 and continued to flow until the evening of May 6, when the water 

 again became normal. Thus the time occupied by the ammonium 

 sulphate in travelling from Gaping Ghyll to Clapham Beck Head, 

 a distance of one mile, was about five days. No ammonium sulphate 

 was found in any of the other springs in Clapdale. This result 

 proved beyond doubt that Gaping Ghyll was connected with Clapham 

 Beck Head. 



The fluorescein put in at Long Kin East showed itself at Austwick 

 Beck Head, but not at any of the neighbouring springs, on May 11, 

 having taken over thirteen days to travel, the delay being probably 

 due to the small amount of water flowing at the time of the 

 experiments. 



These results are of considerable importance, as they definitely 

 reveal two lines of divergent movement of these underground 

 waters, and indicate a subterranean watershed of much interest. 



^ See previous invcstigatious of the Yorks. Gcol. and Polyt. Soc. Committee. 



