64 
HUGHES : INGLEBOROUGH. 
of Trochoceras giganteum Sow., though I have procured it from a 
higher horizon near Dent. Considering the enormous extent of 
bedding face exposed, fossils cannot be regarded as common, 
yet some can generally be obtained, but the locality is not nearly 
so rich as the quarries at Dry Rigg on the same horizon further 
south in the upturn of the synclinal. 
About 300 yards further south, we come to Combs Quarry, 
Fig. 5, which is very much higher in the series. The flags 
have here also been worked right up to the precipice so that we 
have the Silurian and the overlying Mountain Limestone seen in 
one vertical section about 100 feet in height. The dip is about 
40° to 45° to the south, and the inconspicuous cleavage transverse 
to it at a very high angle. Strong master joints traverse the 
rock and, dividing it into large blocks, greatly facilitate the work 
of quarrying. 
Dry Rigg runs out in a kind of promontory forming the 
southern boundary of the ancient tarn, now converted into 
a peat moss, which forms such a conspicuous feature at the 
foot of the upper flat valley of Horton. This, with its rapids 
below, corresponds as a geographical feature with Chapel-le-dale 
and Kingsdale and their gorges running down to Ingleton. For 
this reason it seems probable that these surface features are 
largety due to the conditions prevailing during the recession of 
the ice rather than to the different character of the rocks traversed, 
and therefore the explanation will be discussed under the head 
of glacial phenomena rather than as illustrating the varieties of 
rock in the line of our section. Along this ridge many quarries 
have been opened, and here the greatest number of specimens has 
been obtained from the Horton Flags, amongst which were all 
those mentioned on p. 67, except Trochoceras gigcmteum. The 
fossils, especially the corals, commonly occur here in calcareous 
concretions. The rest of the section calls for no special remark. 
The Austwick Flags and Grit rise in the crushed and faulted 
southern limb of the synclinal fold, and strike in an easterly 
direction along the great strath that runs to Austwick, but as 
I have already pointed out (vol. xiv., pp. 144, 145, Figs. 4, 5) 
these beds were probably reduced to much their present surface 
level by denudation in pre-Carboniferous times. 
