18 
KENDALL : THE GLACIER LAKES OF CLEVELAND. 
a marginal channel, which for the greater part of the distance 
is a mere slielf lacking an ice-ward retaining wall, but in some 
places that function is performed by some gravel mounds. The 
slielf runs out and disappears near the Hollins, in Wheeldale^ 
just below the 675-foot contour, and as it fails to indent the 
650-foot contour it seems clear that it reached the waters of 
a lake. Where the overflow terminates a mass of gravel obstructs, 
the valley of West Beck. Between the West Beck Valley and 
the valley of Eller Beck there stands forward a bold spur, Two 
Howes Bigg, against which the ice must have abutted, ponding 
up the drainage of West Beck (Fig. 4), for there is a beautiful 
N. S 
Fig. 4. 
SECTION FROM JUJ.IAN PARK TO TWO HOWES RIGG. 
marginal overflow Moss Slack, cutting round the shoulder of 
the hill, and just getting through the 675-foot contour. Thus, 
we have evidence that at the maximum extension of the ice Lake 
Eskdale, drained by the Murk-Mire Moor channel into Lake 
Wheeldale, which stood at an altitude of 675 feet, was three 
miles long and 225 feet deep. Lake Wheeldale drained by 
Moss Slack at 675 feet into a small lake in the Eller Beck Valley, 
which would have an extreme altitude of 650 feet, as determined 
by the overflow at Fen Bogs into Newtondale (Plate VI.). 
The period of occupation of the Hollins Channel was very 
brief, and a slight retreat of the ice-front caused the production 
of the much more important channel consisting of two segments — 
Lady-Bridge Slack and Purse-Dyke Slack. 
A further retreat of the Goathland lobe of the ice-sheet 
had for its first effect the withdrawal of the margin from Purse 
