Vol.:58..] GLACIER-LAKES IN THE CLEVELAND HILLS. 533 
Lower down the Stonegate Valley,some features are seen which are 
connected with the stage of retrocession marked by the lower phase 
of Lake Eskdale. At Stonegate-Gill Wood, just south of the hamlet 
of Stonegate, there is a mass of Drift, mainly gravel, but apparently 
more clayey in its lower part, which has evidently blocked up the 
original valley and caused a deviation to the western side, where a 
fine gorge nearly 200 feet in depth has been cut, the lower 100 to 
125 feet in solid rock. The fact that this deflection is to the west- 
ward, while the southern tributaries of the Esk are thrown to the 
eastward, is interesting, as it indicates very plainly the position of 
the ice. 
The last chapter in the Glacial history of Eskdale and Northern 
Cleveland which I have deciphered is very clearly recorded by a 
series of overflow-channels cutting through the northern water- 
shed above Egton Bridge. ‘The northern face of the hills here forms 
a great amphitheatre about Ugthorpe and Hutton Mulgrave, and is 
prolonged in the great spur extending due northward parallel with 
the Stonegate-Tranmire channel for about 3 miles. On the east- 
ward, another spur runs in a northerly direction. The main water- 
shed rises into a fairly sharp crest, culminating at 850 feet above 
Ordnance-datum in Kempston Rigg. The central portion of the 
amphitheatre is broader and lower, and for a space of about a mile 
is only about 700 feet above O.D. (See map, Pl. XXIV.) 
The retreat of the ice from Kskdale carried the melting front, 
step by step, backward up the northern slopes of the Esk Valley, . 
until it fell entirely behind the crest. It withdrew similarly from 
the Stonegate Valley in an easterly direction, and halted on the 
watershed, where a series of gravelly mounds are seen with 
strongly-channelled fronts overlooking the valley. In the retreat, 
many treuches were cut by streams flowing from the melting ice: 
some of these, as the ice-front drew back behind the watershed, 
cut steadily backward through the crest, and produced a set of over- 
flow-channels for the discharge of a series of small lakelets formed 
along the margin of theice. One or two failed to cut through the 
watershed, and therefore their share in the system of extraglacial 
drainage was simply to carry off water flowing down the front of 
the ice. An example of the latter type slightly notches the water- 
shed on Egton Low Moor immediately above the 700-foot contour. 
Three true lake-overflows cut the watershed more deeply. These 
are, in order from east to west :—-(1) Middle-Carr Slack, which makes 
-a slight trough through the watershed near Lady-Cross Gate, but 
deepens to a pronounced feature in its lower course. (2) Stonedale 
Slack, a very fine ravine which now cuts the crest in a very marked 
fashion. A curious cross-channel connects these two valleys near 
their head. The two channels probably were of brief occupation, 
and their strong development in their lower parts, as compared with 
the heads, is consistent with the view here adopted, that they were 
primarily channels carrying the direct drainage of the glacier, 
(3) The third overflow is of a very different type—it is a great 
Q:3.G.8. No, 231. 20 
