HUGHES : INGLEBOROUGH. 
365 
and subject them to careful examination, macroscopic, micros- 
scopic, and chemical, and to compare them with the rocks of 
other areas from whose equivalents they may have been derived. 
The probability is that this conglomerate has been washed down 
from pre-Carboniferous ranges on the north, running with the 
strike W.N.W. and E.S.E. As the hade of the fault and the dip 
of the beds are both to the north, when the angle of dip and 
the amount of the hade are the same, the same bed lies along 
the fault as they both rise to the west, but when they are not 
equal, whichever is the lowest of the two, namely, the hade or 
the dip, creeps out furthest south, and if they or the slope up 
the flank of the valley vary, then the relative positions of the 
fault and of the outcrop of the bed will change accordingly. 
The variation in the thickness of the bed of conglomerate further 
complicates the structure, but still its leading features can be 
made out. 
It appears to be a lenticular mass thinning out to tlie E.S.E. 
It may be that there was a pre-Silurian protuberance connected 
with the sharp anticHnal fold seen in the bed of the stream 
immediately north of the fault. However that may be, the base 
of the Silurian is here represented by a very thin bed of cal- 
careous mudstone, with a conglomerate made up of small pieces 
of various felspathic rocks. Above this comes a thin bed of 
tough, whitish calcareous mudstone full of fragments of trilobites, 
among which the following species have been detected : — 
Phacops eleyans, Boec. and Sars. 
Cheirurus. 
Encrinurus punciatus Briinn. 
These are succeeded by blackish, flaggy shales with purple bands, 
which have yielded some fossils. The limestone may be the 
equivalent of the limestone of Spengill, near Sedbergh, in the 
area north of Ingleborough, and both call for work, and 
would probably repay it. 
The distinctive fauna of the Graptolithic Mudstone, or 
Stockdale Shale, has not been yet detected here. 
The basement beds of the Siluiian are next seen at Austwick 
Beck Head (see d of section. Fig. 5)*. It is exposed on the 
* Reprinted from Proc. Yorks. Geol. and Polytec. Soc, Vol. xiv., p. 338. 
