EDEN VALLEY AND YOEKSBZIEE-DALE DISTEICT. 71 



that covered them at the climax of the Glacial Period. But one 

 may venture to assume that the very slightly glaciated rock-surfaces 

 above the 2200 contour-line on the western side of the Dale district 

 prove that the ice cannot have had a much greater thickness than 

 the height of the highest ridge of land over which it can be proved 

 the ice-sheet flowed. Apart from the evidence of the limited amount 

 of glaciation on hard rock- surfaces, we seem to get other evidence 

 in favour of this supposition in the fact that the soft shales and thin 

 interbedded flagstones that occur on the highest ground of the Dale 

 district nowhere exhibit any of that remarkable surface-crushing and 

 contortion so often met with on the surface of beds of the same 

 character at lower levels. After considering all the evidence, there 

 does not seem much probability that the surface of the ice of the 

 Dale district ever rose much above the 2300 or 2400 contour, if it 

 ever was so high as that. If we assume that the ice reached an 

 elevation of 2400 feet above the sea about the line of departure, the 

 fact that it flowed away to the north would seem to prove that the 

 Eden-valley stream must have had a lower surface. Had it been 

 higher, some of the ice from the Dale-district Fells would have been 

 ponded back, and must have flowed southwards from the Eden 

 valley. It is clear that the lower strata of the ice did not do so ; 

 but there is only the negative evidence that no Eden- valley drift- 

 boulders have gone south of line B anywhere, and that the ground 

 rises more than 1500 feet above the sea, to prove that the upper part 

 of the ice did not flow southwards from the Eden valley. 



Erom what has been stated about the causes that impelled the 

 Eden -valley ice over Stainmoor, it will be seen that the thickness 

 of the ice that came from the southern uplands of Scotland need 

 not have been greater than the local ice of the Lake district. Mr. 

 Ward finds no striae above the 2500 contour-line. As this ice 

 flowed steadily away northwards, it would seem to prove that in the 

 north-western part of the Eden valley the Scotch ice cannot well 

 have exceeded 2400 or 2500 feet in thickness — a conclusion which 

 harmonizes well with that derived from the investigation of the Dale- 

 district glacial phenomena. 



Glacial erosion. 



Such a sheet of ice as that with which the area treated of in this 

 paper was enwrapped must have exercised a very powerful denuding 

 force upon the low-lying parts of the country ; but there seems as 

 yet no satisfactory means of determining what thickness of rock 

 was removed from any given spot. One thing, however, is tolerably 

 clear : although the great ice-sheet did undoubtedly deepen many 

 valleys where these happened to lie in its course, there are other 

 cases in which it can be shown that the ice has tended to make 

 them relatively shallower by grinding down the inter veniDg ridges, 

 in districts where the lower parts of the ice were forced across the 

 lines of drainage. 



In one part of the Eden valley, near Crosby Garret, we have 

 satisfactory proof that the deep hollow in which Scandal Beck now 



