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



As it is here taken for granted that the glaciation of the Dale 

 district was accomplished by a sheet of land ice of great thickness, 

 none of the arguments which have been used to establish that point 

 has been brought forward again. Mr. Tiddeman has proved its 

 existence clearly enough in much of the country to the south of 

 Swaledale ; as, therefore, the glaciation of the Dale district to the 

 north of the ice-shedding line resembles in every respect that to the 

 south, there can be no reasonable doubt that they are both the re- 

 sults of one and the same cause. 



If we now turn to the northern part of the country immediately 

 to the west of the line marked A, taking up the evidence where it 

 was left at the north-east corner of the Howgill Fells, we find that 

 the drift on the limestone escarpment at Ash Pell is largely made 

 up of Silurian stones, most of which have probably come from the 

 Howgill Fells. Among these occur a small proportion of Old Red 

 stones that may have been derived from the strip on the south 

 side of the Lune. In following this drift towards the north we find 

 the Silurian and Old Red stones becoming less and less common ; 

 and to the south of Kirkby Stephen they seem to be quite lost in the 

 great accumulation of drift from the limestone country to the south. 

 Just at this point, however, we meet with the Brockram, of which 

 not a fragment has been found in the drift to the south of its pre- 

 sent area of outcrop. A little distance to the north of its southern 

 margin it begins to occur in the drift, glaciated like the stones that 

 it is associated with, and from that line northward it is characteristic 

 of the Eden-valley drifts over a large area. 



It has been before pointed out that none of this rock in place lies 

 above the 700-foot contour-line ; but in following it in the drifts, 

 in proportion as we advance towards the north-east, so we find it 

 getting higher and higher, until, in the drifts that lie on the great 

 line of watershed, it occurs at 1300 feet above the sea, or very 

 nearly on the summit of the lowest pass of Stainmoor. There are 

 other instances (to which reference will presently be made), in which 

 the Brockram occurs at much higher levels. 



Setting aside for the present any consideration of the evidence 

 collected in Swaledale, it will be well to consider one of the only 

 two theories of any value that have been advanced to account for 

 the transportal of the Eden-valley drifts over Stainmoor. 



It has been mentioned that none of the Brockram in place lies 

 above the 700-foot contour-line, while the lowest pass of Stainmoor 

 that any of it has gone over is, in round numbers, 1350 feet above 

 the sea ; that is to say, it is 650 feet above the highest rock of the 

 kind in place. If it was carried over imbedded in floating ice, we 

 shall be obliged to suppose that all the Brockram that went over 

 Stainmoor was first frozen into the ice while the sea-level stood 

 between the present 400- and 700-foot contours, and then that it 

 was detained everywhere just a little to the north of the southern 

 margin of the rock in place, until the relative levels of land and sea 

 changed another 650 feet, after which the ice-rafts floated over and 

 began dropping their burdens as they passed eastwards towards the 



