HUGHES : INGLEBOROUGH. 
191 
on the north side of the fault in the bed of the streams immediately- 
north of Clapham Tarn, while the Mountain Limestone comes 
on above it and rises in scars on every side. Xow, in order to 
find the Basement Bed, we must travel about a mile and a quarter 
due east till we come to the interesting sections under Norber 
Brow, two- thirds of a mile north of Austwick (Fig. 3). The 
Basement Bed here also rests on the Bala Limestone and Shale, 
but, as we follow it along the west side of Crummack Dale, instead 
of finding the Green Slate Series coming on as we did in Kings- 
dale and Chapel-le-dale, the order of succession is reversed, and 
we find the base of the Mountain Limestone resting on a synchnal 
of Silurian until we get to Austwick Beck Head, where the 
Bala Beds turn up again. 
We begin now to see the red deposits, which by-and-by 
we shall find in pockets all along the old pre-Carboniferous 
surface, but generally speaking the material of the basement 
conglomerate is still mutatis mutandis the same in character and 
mode of occurrence. Instead of the tough green schists we 
have now more fragments of the hard greywacke and sandy 
mudstones of the Silurian, but still there is enough to tell us that 
the Green Slate Series is not far off. About three miles to the 
north, where the Silurian sandstones begin to make a feature 
and deflect our boundary line, there are very large blocks of 
Silurian Grit and Sandstone in the base of the Mountain Lime- 
stone, I have already described the Basement Bed at Austwick 
Beck Head in connection with the Silurian Basement Bed, which is 
also seen there (vol. xiv.. p. 338, Fig. 14 and PI. L.). 
We now can trace the base of the Mountain Limestone 
almost continuously, ^\rLth springs thrown out here and there, 
and small changes in the character of the rock, down the east 
side of Crummack Dale. It was in one of the small exposures 
of the basement conglomerate seen here that I found the teeth 
of placoid fish, which M. Lohest determined for me as Lophodus 
Icevissimus and Copodus coniutus. Thence we turn east and pass 
along under the fine precipice which forms the southern front of 
Moughton and up the west side of Ribblesdale. In the great 
quarries south of Arco Wood the sharp line of demarcation 
