UNDERGROUND WATERS OF NORTH-WEST YORKSHIRE. 289 
Silurian rocks, and the line from the sink where the fluorescein 
was introduced to the spring runs X. 55° W. — that is, in the direc- 
tion of the master joints in the limestone. 
Thus, again, it was demonstrated that the direction of 
underground flow is determined by that of the master joints. 
It is also of much interest to note that the spring S 119 
lies in one of the valleys of the Silurian floor, as will be seen by 
comparing the direction of the line of outcrop with that of the 
contour lines [PI. XXX.]. 
The springs S 110, S 113, S 114, S 115, S 117, S 118, S 120, 
S 121, S 122, S 122a, S 124, and S 125, having been unaffected 
by any of the tests employed it is concluded that they discharge 
the water collected by the open joints on the extensive clints 
on Lead Mines Moss and White Scar. 
The River Greeta. [PI. XXX.J 
An interesting piece of work was the tracing of the under- 
ground course of the main stream in Chapel-le-Dale. 
This stream flows underground in many places in normal 
weather, but when in flood occupies a well-worn channel on the 
surface. 
The upper part of the stream, above Weathercote, is known 
as Winterscale Beck, the portion between Weathercote and 
God's Bridge as Chapel Beck, and from that point down to 
Ingleton as the River Greeta. 
The stream rises on the moors near the tunnel of the Midland 
Railway, above the Ribblehead Viaduct, and soon sinks in a 
series of pot-holes, there being, however, a well-marked open 
flood channel. 
The whole stream again comes to the surface at the mouth 
of Gate Kirk Cave, S 107, and another large spring a few yards 
away. 
It then flows through several large pools, and again goes 
underground at P 85, leaving the stream bed dry, to again emerge 
about 70 yards further down at S 109. It again sinks at the foot 
of Haws Gill, P 87, where it is joined by the water from Eller 
Keld Spring (S 106 and S 106a). 
G 
