UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 275 
for some distance it is only 18 inches in lieight it fully justifies 
its name. 
Wliit-a-Green Spring rises on the higlier slopes of Park 
Fell (a spur of Simon Fell), at a lieight of 1,600 feet, and flows 
over tlie surface of the Yoredale Rocks till it reaches the Mountain 
Limestone at 1,250 feet, where it sinks at P 29. 
A trial with fluorescein resulted in joroving that this water 
flows out at S 55 and joins the Long Churn System at P 30. 
The channel by which the stream flows from P 29 to S 55 
can be traced for a considerable distance by means of a series 
of openings to the surface, and the passages were actually 
traversed throughout almost their entire length, although in 
many places the water was three feet deep. The exploring 
party was eventuall}^ stopped by the roof coming down to the 
water level. 
In the same enclosure is a small spring marked S 53, which 
never yields much water and is quite dry in seasons of drought. 
The water of this spring is derived from the drainage of a peat 
bog, which owes its existence to a patcli of glacial drift resting 
on the limestone. 
The water sinks at P 28 and issues, as proved by a fluorescein 
test, at S 55, along with that from P 29. 
The underground junction of these two streams was after- 
wards traced, though it was found to be impossible to follow 
the whole length of the passage, the roof being too low, and there 
being deep pools of water lying in the bottom. 
It may be mentioned in passing, that as this was a short 
run, methylene blue was first tried for the test ; but although 
only a small quantity of water was flowing at the time, the 
colour was not seen at S 55, while one-fourth the quantity of 
fluorescein succeeded two hours later under precisely similar 
conditions. 
This concludes the investigation of the streams flowing 
into the passage at the bottom of Alum Pot, and the further 
course of the water from the bottom of that chasm will now be 
described. 
Alum Pot is a huge rift in the limestone (PL XXXIV.) 
which descends vertically to a depth of some 200 feet, and is 
