272 UNDERGKOUND WATERS OF NORTH-WEST YORKSHIRE. 
into the limestone at P 37a (in dry weather it is entirely absorbed) 
and finally disappears at P 37 close to an old limekiln. 
In extremely wet weather the stream flows on over the 
surface past Gill Garth and joins the water from S 47 (Gillgarth 
Beck). 
The water sinking at both P 37 and P 37a again experi- 
ences the effect of the strong N. and S. jointing of the limestone 
and is carried at right angles to the slope of the ground to P 38, 
wliere, after an open course of about three yards, it again dis- 
appears, to emerge at two springs S 43 and S 44. A few yards 
below S 44, a small tributary comes in from S 52a, which was not 
affected by any of the tests and which therefore probably owes 
its existence to general surface drainage. The stream then 
flows on by P 39, where it again sinks, to Font Green Spring S 45. 
After passing through the wall, a portion of the stream again 
sinks at P 40 (the whole in seasons of drought) and emerges 
at S^6. From this point onwards it flows over the surface, 
forming Selside Beck, a tributary of the River Ribble. 
The next series of streams is one of the most interesting in 
the district, offering as it does a large number of j^roblems for 
solution. 
A number of streams, rising in the angle between Simon 
Fell and Park Fell, converge upon a line joining Alum Pot 
with Selside Village, and although they must flow very near 
to the series last described are not in any way connected with it, 
l)eing at a lower level. 
Alum Pot Beck is formed by the confluence of a large number 
of small streams, chief among which is South House Moor Beck. 
On the 6 inch Ordnance Map, Alum Pot Beck is shown as 
flowing over the lip of Alum Pot, but as a matter of fact this 
very rarely occurs, although there is a well-marked dry channel 
connecting the upper part of the Beck with the pot. 
In ordinary weather the whole of the waters of Alum Pot 
Beck sink at P 33, while the water from S 58, a small spring 
quite unconnected with the main flow, supplies the stream which 
flows over the lip of Alum Pot. 
