Vol. 58. ] GLACIER-LAKES IN THE CLEVELAND HILLS. 551, 
hollow in the form of a series of connected basins. The hollows 
open to the westward, and are closed at the eastern end, so that the 
enclosing hill has the form of a deep loop. ‘he surfaces of these 
hollows are strewn with very large boulders of Jurassic sandstone, 
weighing perhaps from 2 to 10 cwt. each. The whole surface of 
the hills was no doubt at one time covered with such blocks, for 
all the drystone walls are composed of them. A section cut 
through the deposits by Thirley Beck showed a packed mass of 
large and small boulders. The source of these materials is not far 
to seek—the excavation of Oxdale Slack would provide enough for a 
hundred such hills, but their transport and accumulation I find it 
difficult to explain. | 
The second singular feature displayed in the valley is a remarkable 
and gigantic ‘in-and-out’ on the north side of it at the water- 
shed. A valley loops back into the hillside for a distance of a 
quarter of a mile, then returns to the main valley, so that it winds 
in and out again behind a central ridge of solid rock more than 
50 feet high. The explanation which would ordinarily be given, is 
that it was a detour effected by a stream to evade the ice-margin, 
and thisI believe it tobe. At thesame time it is difficult to explain 
both its situation and the fact that such fall as the valley displays is 
to the eastward, not to the westward as might have been expected. 
Upon the latter point, however, it may be noted that two small 
streams which enter the bend of the loop have been conveyed in an 
artificial channel across and for some distance down the very level 
floor to the east. The western limb of the loop is very boggy, and 
there may be a mass of peat there which perhaps. conceals a 
westerly slope of the floor. 
(c) Burniston to Scalby. 
This tract of country presents few features of which the inter- 
pretation is clear. On the west, the heights of the Suffield-Moor 
escarpment constitute a possible landward barrier against which 
glacier-lakes might have been upheld, but the distance is very small, 
only about 14 miles. Moreover, above, the 400-foot contour, the 
escarpment is very steep and unindented: no~ recesses occur in 
which lakes could be maintained. At and below the 400-foot 
contour, the country is much more diversified; but a difficulty is 
encountered which has not previously been experienced—two direct 
overflows occur, one at each end of the area, and a slight differential 
recession of the ice-front might open the one or the other: 
At the northern angle of the escarpment, a long spur of Mae 
deposits continues northward for half a mile, and I regard this as a 
moraine marking a halt in the recession of the ice. Behind the 
moraine, a shallow overflow falls to the northward. -It shows a 
later phase in which the channel exhibits what I have termed 
‘downstream dichotomy’: the ice-front receded a little, and allowed 
the overflow-waters to escape down the eastern and inner side of 
the moraine, 
ope 
