KKXJJALL: THE (iLACIKIi LAKES OF CLEVELAND. 
of Biller Howe farmhouse, and on to the junction of a Uttle- 
nameless beck, south of " the Island.'' with Jugger Howe Beck. 
The margin is well defined along the whole line by the extension 
of the drift and pebbles, and by the occurrence of the marginal 
channel which carried the drainage from Lake Iburndale and 
the ice-free country within the watershed. 
From the point where Biller Howe Dale makes a right- 
angled ])end to the south, a series of three high-level channels^ 
can be traced running parallel with the great gorge which at 
present carries the scanty drainage of this area (Plate X.). These- 
three are really not so much an aligned sequence as one channel, 
the course of which has been intersected by two modern streams. 
The third segment cuts across the spur called " The Island," 
and its lower course has been adopted b}^ a modern stream 
forming a deep gorge at its confluence wdth Jugger Howe Beck. 
Tlie first segment runs behind Biller-Howe farmhouse, and 
it is a streamless gully of about 20 feet in visible depth, but 
is known to contain at least 15 feet of peat near the 
house. Its intake is seen as a notch in the skyline 100 feet 
above the floor of Biller-Howe Dale. The second segment is. 
a moss-swamp forming a deep trench across Biller-Howe-Turf 
Rigg. The third, rather less sharply-cut, segment continues in 
accurate alignment across the spur called " The Island," and 
its lower course has been adopted by a modern stream, forming 
a rocky gorge 100 feet deep at its confluence with Jugger-Howe 
Beck. ' 
Beyond this point, a breach was made in the watershed on 
Jugger-Howe Moor ; this separated the Robin-Hood's Bay 
drainage from that of tlie Hellwatli Burn, which now flows into- 
the Derwent drainage, but formerly entered the sea near Burnis- 
ton. The margin of the ice-sheet appears to have stood for 
a very short time at its farthest point of advance, then to hav& 
retreated rather rapidly for a time to a position about which it 
lingered for a very long period. 
The first effect of the retreat appears to have been to produce 
a great sinuation of the ice-margin w^hich withdrew from Biller- 
Howe Dale, and uncovered a large part of Sneaton Moor. A large 
channel, Grey-Heugh Slack, w^as now^ developed running along the 
