vfS Notices of Memoirs — Underground Waters, N.W. Tories. 



Aire Head Springs responded in two hours. With lai-ge flushes 



a rise in Malham Beck was also observed. 



, The chemical investigations were as follows : — 



Ammonium sulphate was put in below the Malham Tarn Sluice 

 on June 22, and appeared at Aire Head from July 4 to 11. Distinct 

 traces were also found at Malham Cove on the same dates. 



Common salt and fluorescein, put in at the Smelt Mill Sink between 

 June 22 and 28, appeared at Malham Cove from July 4 to 11. 

 , Fluorescein, put in at Tranlands Beck on June 22, appeared at 

 Scalegill Mill on June 23. 



. Ammonium sulphate, put into upper Gordale Beck on August 26, 

 appeared at the springs below Gordale Scar on September 7. 

 ,. Common salt, put into Cawden ' Burst ' on September 18, appeared 

 at Mire's Barn from September 23 to 27. 

 ■ Fluorescein put into the bottom of Grey Gill Cave was not traced. 



A geological investigation of the area showed that the limestone 

 is traversed by two sets of prominent joints, of which the master- 

 joints, which run in a north-west to south-east direction, are very 

 well developed. These master-joints are found to largely determine 

 the flow of the underground waters. The direction of these master- 

 Joints unites the Smelt Mill Sinks and Malham Cove directly, and 

 that may be taken as the direction of flow. A parallel line from 

 Malham Tarn Sinks would bring the water from them to Grey Gill, 

 a dry valley in the escarpment to the east of Malham Cove. No 

 evidences of moving water were found there. 



To the south of the Mid-Craven Fault the jointing of the lime- 

 stone is found to be variable ; but prominent joints were found 

 bearing in a north-east and south-west direction. If the Tarn water 

 followed these joints on crossing the fault it would traverse a 

 direction almost at right angles to its previous course, and following 

 the limestone in its bend underneath a synclinal of Yoredale shale, 

 would be likely to reappear at Aire Head Springs, which is the 

 nearest point for re-emergence on the southern side of the anticlinal. 



The master-joints north of the Mid-Craven Fault would similarly 

 <!arry the water which sinks into the bed of Gordale Beck south- 

 eastward into the limestone, and if, as it nears the fault, it followed 

 a set of joints running at right angles to the previous set, it would 

 oorae out at the springs at the foot of Gordale Scar, which was 

 found to be the case by the chemical tests. Gordale itself turns in 

 this direction from some cause. 

 : The conclusions of the Committee are : — 



1. That Malham Cove Spring discharges the water from Smelt 

 Mill Sink and the limestone area west of the dry valley; and under 

 certain conditions some of the Tarn water. 



2. That Aire Head Springs discharge the main portion of the 

 water disappearing down Malham Tarn Water Sinks. 



3. That Gordale Beck Springs discharge the water sinking in 

 Upper Gordale. 



4. That chemicals put into Cawden 'Burst' appeared at 

 Mire's Barn. 



