HUGHES : INGLEBOROUGH. 
295 
The Main Limestone. 
We have now reached the highest limestone seen on Ingle- 
borough, namely the Upper Scar Limestone of Sedgwick, and 
the Main Limestone of Phillips, also known as the Twelve Fathom 
Limestone. This occurs on Ingleborough between the 2,100 and 
the 2,200 feet contours. A small fault, running west-north-west 
and east-south-east, and passing just south of the cap of grit, 
throws tlie limestone down on the south, and shattering the 
rocks beyond in both directions, though it cannot be clearly 
traced, may account for the position of some of the swalloAV 
holes, such as Tatham Wife Hole, and springs, such as those 
at Fell Beck Head. 
A smaller crack running north and south accounts for the 
springs on either side of the north-east corner east of Swine 
Tail. 
On the south point of the triangular summit this limestone 
is well exposed, being seen in numerous swallow holes through 
the peat and shale on Little Ingleborough, and cropping out in 
broken and interrupted scars all round the hill. It is not easy 
to measure the thickness because of the peat and debris which 
overlap it and the masses of talus which obscure the base, but 
about 48 feet of it can be seen along the south-east side, while 
in the north-west precipice, though the top is covered, about 
40 feet of limestone may be seen resting on six feet of calcareous 
sandstone, and that on 10 feet of shaley sandstone which rests 
on the massive beds of sandstone last described. 
The Main Limestone of Ingleborough is separated by about 
a quarter of a mile of drift and peat from that of Simon Fell, 
where, owing to the normal dip to the north and east, it is about 
100 feet lower. The observed dips, however, do not indicate 
this, as the rock is somewhat irregular, dipping along the south 
margin in a southerly direction, and, at the north extremity, 
falling to the north. This, however, may be due to the break- 
down of the rock owing to subterranean denudation of the 
limestone rather than to original folding. In one case there is, 
running north-north-west and south-south-east near the north- 
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