CUTTRISS : NOTES OX THE CAVES OF YORKSHIRE. 
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Scars, through Malhara and across Wharfedale to Nidderdale. 
North of this main line of dislocation is another fault, very near 
the first one at Austwick, which continues eastward in a fairly 
straight line, about a mile and a quarter separating the two faults 
at Malham. The long triangular area enclosed by these faults 
forms a district peculiar to itself in the character of its caves. The 
limits of the extension of the Carboniferous Limestone towards the 
north and east cannot be so easily defined owing to the dip causing 
the rock to be obscured by the overlying strata. For the purpose 
of this paper we can, however, make an arbitrary boundary. From 
Leek Fells the line will wind round Kingsdale, up Chapel-le-Dale 
to the head of Ribblesdale, then down the east side of that dale, 
skirting Cam Fell, and Pen-y-ghent and across to Clapham. This 
will include nearly the whole of the Carboniferous Limestone, north 
of the Upper Craven Fault, which is of interest from the point of 
view of the present subject. 
The limestone consists of a hard, compact series of calcareous 
beds, mostly of a light grey or bluish colour, almost without division 
by shales or clay. On Gragareth, Whernside, Ingleborough, and 
Pen-y-ghent, it attains a thickness of about 500 ft."^ 
Above this are a series of shales, limestones, and sandstones, 
collectively named by Prof. Phillips the " Yoredales " from the 
valley of that name, where they attain their greatest development. 
The combined thickness of these rocks on Ingleborough is about 
700ft. t These limestones are of a different character to the Carboni- 
ferous Limestone, being, as a rule, more impure and in comparatively 
thin beds, with the shales and sandstones between. As a result 
they are not favourable to the formation of large caverns and deep 
fissures on Ingleborough and the surrounding hills. Towards the 
east, as in Wharfedale and Nidderdale, the Yoredale limestones 
attain a much greater thickness, and some extensive underground 
chambers have been formed in them. Above the Yoredales lies the 
*This is measured from the base to the present exposed surface, which is 
about 100 ft. lower than the actual top of the Carboniferous limestone, allow- 
ing for a total thickness of 600 ft., as given in the Memoir of the Geological 
Sun-ey of the District, 1890, p. 24. 
t Davis and Lees, West Yorkshire, 1878, p. 80. 
