292 UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 
Gill Hole, a fault marked on the maps of the Geological Survey, 
passes through the pot, while several others, e.g.. Alum Pot, 
Rift Pot [PI. XXXVIII., Fig. 1], and Long Kin West, strongly 
suggest a similar origin. It will be seen that a displacement, 
however small, and whether vertical or horizontal, involves the 
fracture of the limestone from top to bottom. Such con- 
tinuous fractures are certainly present in the deep pots, though 
owing to the darkness and the accumulation of stalagmite it is 
extremely difficult to detect small displacements (faults). 
4. Some, at least, of the caves and pot-holes are of pre- 
Glacial age, as, for example. Alum Pot and many of the deep 
pot-holes which are now partially filled with glacial debris, 
while others, such as Long Kin West, possibly owe their origin 
to glacier streams during the Glacial Period. 
5. So strong is the influence of the joints in the limestone 
upon the direction of flow of the underground waters that there 
are several instances in which streams are carried beneath a 
surface watershed so as to emerge in a different drainage basin 
from that in which they took their rise. 
6. As at Malham so in this district there occur streams 
which cross each other during their subterranean journeyings 
and others which pass beneath those on the surface of the ground. 
Arthur R. Dwerryhouse. 
