146 
HUGHES : INGLKBOROUGH. 
The north and south valleys, Kingsdale, Chapel -le-d ale, Crum- 
mack, and Ribblesdale, have apparently suffered considerable glacial 
and post-glacial erosion. 
Faults. — The existence and effect of faults has often been 
mentioned in describing the relation of the various formations to 
one another, but the phenomena connected with faults call for 
special treatment. 
Nowhere, even in this district, can the behaviour of the rocks 
along a great fault be so well studied as in the gorge of the Twis 
or Greet above Ingleton, at the sharp elbow made by the stream 
where it is caught in the crushed and fissured rock and carried 
out of its southerly course for a quarter of a mile or so to the 
Fig. 6. 
SECTIOX ACROSS THE TWlS OK GREET ABOVE INGLETON. 
south-east. The Bala limestones and shales are exposed along the 
bed of the stream, and pass under a great mass of drift on the left 
bank, while on the right bank, which is the downthrow side of 
the fault, the Mountain Limestone stands in a wall some 200 feet 
high, above which rises a precipitous broken slope for about 
200 feet more before we reach the level of the broad limestone 
terrace througli which the gorge has been cut (see Fig. 6). 
The upper part of the face of the limestone cliff overhangs 
its base in agreement with the inclination or hade of the fault 
to the downthrow side, and sweeps down stream in bold curves 
which represent the original winding course of the fault. What 
is most striking in this section is the swelling irregular surface 
