HUGHES : rN'GLEBOKOUGH. 
273 
talus extends from the face of the limestone cliff over the imper- 
vious floor provided by the shale. A covering of travertine and 
clay from various sources covers the talus and overlaps on to 
the shale. In flood-time, when the crevices of the limestone 
are full and the talus is charged to bursting point under the 
pressure due to the head of water in the limestone, the springs 
break through here and there, where the clay covering is thinner 
or other conditions favour the outburst, and jets of water, some- 
times as much as two feet in height, issue from the ground. These 
springs carry carbonate of lime in solution, and mud and sand 
and gravel in suspension, and throw both doTVTi around the 
opening so that a mound, like a volcanic cone, is built up, on the 
top of which is a perennial or intermittent spring of water (see 
Diagram, Fig. 3). 
As a result of all this chemical wasting away of the 
limestone, the water that issues from the caves and springs 
is very hard, and when aerated, the lime, which it had held 
in the more soluble form of a bicarbonate, is thrown down, 
forming the masses of stalactite and stalagmite that line the 
caves, and the patches of travertine that so often help us to 
find the position of the limestones on the flanks of Ingleborough. 
Fig. .3. 
DIAGRAM ILLUSTRATING THE MODE OF FORMATION OF THE CONE SPRINGS 
IN JENKIN BECK, EAST OF INGLETON. 
a. Springs. 
b. Clayey deposit from springs and rainwash from hillside. 
c. Stony talus. 
d. Yoredale shale. 
e. Mountain limestone. 
/. Watercourses in limestone. 
