Vol. 58. ] GLACIER-LAKES IN THE CLEVELAND HILLS. 507 
Hollins just below the 675-foot contour ; and as it fails to indent the 
650-foot contour, it is clear to me that it reached the quiet waters 
of a lakelet at 670 feet or thereabouts. 
Where this overflow terminates, a mass of gravel obstructs the 
valley of West Beck, which cuts over into the solid rock to avoid 
it, and so forms Nelly-Hay Force. This is probably both delta 
and moraine. 
Between the West-Beck valley and the valley of Eller Beck, on 
this parallel, there stands forward a bold spur, Two-Howes Rigg, 
against which the ice must have abutted, ponding up the drainage 
of West Beck; for there is a beautiful marginal overflow, Moss 
Slack, cutting round the shoulder of the hill and just getting through 
the 675-foot contour. The precise correspondence of level between 
the Murk-Mire outfall and the Moss-Slack intake cannot be 
fortuitous. 
The Moss-Slack overflow at its outfall-end cuts contours as low 
as the 625-foot contour, but below that an existing stream may be 
responsible. The way thence is open to Fen Bogs. (See Pl. XXII.) 
The evidence of these overflows proves that at the maximum 
extension of the ice a lake was held up in Eskdale to an altitude of 
over 725 feet, lowering to 714 feet; and assuming that it extended 
no farther than the gap at West-Bank House (near Kildale), it would 
have been about 11 miles long and not less than 400 feet deep: it 
would have had ramifications up all the tributary valleys. I 
propose for it the name of Lake Eskdale. 
Lake Eskdale drained by the Murk-Mire-Moor overflow into 
Lake Wheeldale, which stood at an altitude of 675 feet and was 
about 3 miles long. Its extreme depth was about 225 feet. 
Lake Wheeldale drained over Moss Slack at 675 feet into a small 
lakelet in the Eller-Beck valley, the extreme altitude of which, 
determined by the top of the Fen-Bogs notch,’ was about 650 feet. 
This lakelet, which I have always called the ‘ Vestibule,’ but which 
it may be more convenient to particularize by a geographical name, 
Eller-Beck Lake, was probably 150 feet deep. — 
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 Moor, whereby 
a‘ lateral escape ’ was opened in the Murk-Mire overflow so that the 
distal portion, Purse-Dyke Slack, was abandoned, and the outfall of 
the proximal half, Lady-Bridge Slack, was cut down below the 
700-foot contour. I do not think that this affected the Moss-Slack 
* In determining the site of an original watershed, it should always be borne 
in mind that an overflow cuts back as weil ascutsdown. I think that the 
origina] water-parting between Newton Dale and Eller Beck was at least as far 
back as Sear Nick, and Thack Sike was a tributary of Eller Beck. 
