THE UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 31 
In such a drought as prevailed then it was easy to demonstrate 
by the experiments described by the Chemical Sub-Committee 
that the water absorbed in the stream bed came out in Gordale 
Springs, which suffered only partial failure and never actually 
ceased to flow. 
The route followed by the water scarcely admits of doubt. 
The master-joints run obliquely across the beck and evidently 
carry the water away into the body of the limestone on the 
eastern side. At the waterfall the gorge makes a south-westerly 
turn, evidently determined by some structural feature of the 
rock, and it would appear that the same structural feature 
impels the underground w^ater flowing for some distance into the 
rock in a south-easterly direction to take a similar south-westerly 
turn in rough parallelism to the beck, and to reappear in the 
springs. 
3. Malham Tarn AVater Sinks to Aire Head Springs. 
This case has been reserved for the last because the difficul- 
ties it presents are much diminished by the light obtained from 
Gordale. 
The introduction has described how ]VIalham Tarn water after 
emerging from the Tarn flows off the Silurian area and for some 
distance over the Carboniferous Limestone before suffering com- 
plete absorption at the water sinks. 
From the point of disappearance a valley runs in a straight 
line, deepening steadily until, making a very sharp turn, it forms 
the great dry gorge which terminates above Malham Cove in 
a sheer drop of 260 feet. 
The point at which absorption of the stream is complete 
varies with the seasons. In very dry seasons it can be seen 
that the stream begins to dwindle directly the limestone area is 
reached, and at the first sink it wholly disappears ; but in more 
normal seasons two more sinks come into operation. In very 
wet times the surface stream continues down the valley and, 
as stated in the Introduction, it has been known to reach Comb 
Scar and Malham Cove also. Little doubt need be felt, therefore, 
