60 J. G. GOODCHILD ON THE GLACIAL PHENOMENA OF THE 



Turning now to the southern end of the line marked A on the 

 map, and which runs very nearly along the line of contact of the 

 Silurian and Carboniferous rocks, we get evidence of a much more 

 satisfactory character. To the east of this line we find that the 

 drift is wholly made up of Carboniferous stones, while fragments of 

 the adjacent Silurians are very rare, if not entirely absent ; but on 

 some parts of the west side of the line, Carboniferous drift extends 

 some distance over the wonderfully moutonnes Silurians, while 

 isolated boulders of Carboniferous origin range almost up to the 

 summit at the north end of Barbon Pell. Further to the north the 

 Middleton Fells afford evidence of the same kind, the Carboniferous 

 drift from Dent having been thrust over part of the Silurian area, 

 while to the east of the line A Silurian stones are not yet known to 

 occur at all. 



Any geologist who looks at the eastern corner of the Middleton 

 Fells from Bysell, or from Helms Knot, cannot fail to notice the 

 remarkable instances of glaciation on a large scale which these 

 fells present. Professor Hughes long ago pointed this out in a 

 paper read before the Leeds Philosophical Society. In lithological 

 character these Silurians consist of alternations of hard and softer 

 beds, tending under ordinary circumstances to weather into terraces 

 that follow the lines of gentle curvature of the beds. When seen 

 from a little distance, especially if the sun is not too high, the 

 terraces are seen to be traversed by a great many roughly parallel 

 ruts, which cross the strike of the beds at small angles. For short 

 distances the glacial grooves coincide with the strike of the softer 

 beds, and then mount the next bed above, and so on to the summit, 

 beyond which the ice seems to have held its course nearly along the 

 strike of the beds down to the Lune valley. Professor Hughes has 

 pointed out that the ice-sheet must have split against the east corner 

 of the Middleton Fells near Coum Scar, so that one branch of it 

 flowed nearly along the course of Barbon Beck. 



On the south side of Dent no satisfactory evidence can be got from 

 the scratches ; but on the eastern end of Bysell others occur on the 

 top of the ridge with a direction about W. 30° S. It will be seen by 

 the map that to the east of this several other strise, having nearly 

 the same direction, occur at various levels up to the 2000-foot 

 contour, and that these high-level scratches seem to be in no way 

 affected in their general direction by the form of the adjoining 

 ground. In the cases just referred to there is no direct evidence to 

 show which way the ice moved, although it is tolerably clear that 

 the ice that overrode the Middleton Fells did not start from either 

 Rysell or Widdale Fell, as the scratches do not radiate from the 

 highest ground there, but point as if they went clean over it. 



The writer has long suspected that part of the ice that filled the 

 hollows where Widdale Beck, Snaizholme Beck, and Duerly Beck, at 

 the head of Wensleydale, now flow, moved up those dales instead of 

 down them, as would have been thought likely. In the two first- 

 named dales the drift has not helped to make this point clear ; but on 

 searching on the high ground to the east of Dod Fell, at the head of 



