540 MR. P. F. KENDALL ON A SYSTEM OF [ Aug. 1902, 
Simultaneously, perhaps, with the formation of this valley, or 
possibly of an earlier date, coinciding more with the cutting of Grey- 
Heugh Slack, a magnificent channel was being excavated along 
the southern edge of the great amphitheatre near Stony-Marl 
Howes. 
I have been unable to satisfy myself that all the high ground 
bounding Robin Hood’s Bay on the south, which culminates in Stoup 
Brow (871 feet O.D.), was overriden by the North Sea ice-sheet; but, 
if so, the phase was avery brief one, and the ice-front broke up into 
a sinuate outline. The lobe, which was thrust into the upper bay 
formed by the escarpment of Estuarine Sandstone, would have a 
strong southerly component of its motion, if one may judge by the 
general phenomena of a boulder-transport in the coastal tract of 
Yorkshire ; and this conclusion is strengthened greatly by the direc- 
tion of the few glacial striations observed upon the rock-surfaces. 
One striated surface has been observed in Robin Hood’s Bay by my 
friends Messrs. H. B. Muff & 'T. Sheppard,* and I had the pleasure of 
seeing it under Mr. Muff's guidance. It occurs on the top of a hard 
bed of Estuarine Sandstone at Bay Ness, and the striz have a direction 
towards the south. The effect of a thrust in a southerly direction 
would be to cause the ice-lobe to stand well away from the escarp- 
ment at its north-westerly angle, while it would press much more 
closely against the very precipitous slopes on the south and south- 
east ; so that while in the north-west there would be a considerable 
lake to discharge by the Foulsike overflow, there would be only 
space for a series of small narrow lakelets along the southern edge. 
These lakelets appear to have drained for a long period by means 
of a marginal channel trenching the face of the escarpment, and 
attaining at last a depth of about 70 or 75 feet. This channel, 
about a mile in length, is now occupied in its lower half by a small 
rivulet, Burn-Howe Beck, but near the intake at Cook House it is 
streamless. 
Two related channels trench the western end of Stony-Marl 
Howe, and converge before opening into the head of Burn-Howe 
Valley, near the confluence with which the small stream that they 
at present conduct doubles back and flows into the Robin-Hood’s. 
Bay drainage, while the old course is still traceable as a dry valley. 
1 am convinced that the Burn-Howe channel continued to operate 
for a long period, yet not for the whole time during which ice- 
dammed lakes persisted in the district, as its thalweg falls steadily 
from the intake at Cook House to within about 600 yards of Jugger- 
Howe Beck, in which distance it has declined from about 610 or 615 
feet O.D. to 525 feet. Beyond that point, however, the slope is 
much steeper into Jugger-Howe Beck, namely, about 100 feet in 
600 yards. The steeper slope represents the more active cutting 
by Jugger-Howe Beck since the abandonment of the Burn-Howe 
channel by the Glacial waters. 
The recessed character of the grit-escarpment brought about, as 
1 Glac. Mag. vol. i (1896) p, 52. 
