562 MR. P. F, KENDALL ON A SYSTEM OF [Aug. 1902, 
western wall of the Seamer-Scarborough valley, a small lake dis- 
charged by Waydale Lane, and cut the notch which severs the end 
of the spur. The peculiar ‘ dry’ condition of the gravel at Hutton 
Bushel, and the common occurrence of fragmentary marine shells, 
would be readily explained by the hypothesis here proposed ; but 
it would be exceedingly difficult to explain their occurrence in a 
lake-beach, whether the lake were closed by ice or by moraine. — 
It is a singular circumstance that no trace whatever can be found 
either of beach or of moraine along the foot of the Chalk-escarpment 
which forms the southern margin of Lake Pickering; but the 
explanation which seems to me most probable is that there was a 
deficiency of materials, both for the beach and for the moraine. The 
supply of moraine may well have been small, as compared with 
that upon the north side, for the glacier-lobe would have a south- 
westerly impulse which would bring upon the north side an ice- 
margin that had rasped a large tract of hilly country, while on 
the south side comparatively clean ice would come in. 
Another important difference between the two sides of the valley 
is, that on the north side occurs the long dip-slope of the Corallian 
rocks, which would be drained by many streams carrying gravels. 
Moreover, on the same side the enormous gorge of Forge Valley 
yielded its waste to provide deltaic materials. On the south 
side, the short escarpment-slope of the Chalk would contribute very 
short torrential streams carrying but little detritus, and no overflow 
appears to have taken place from other lakes. 
IX. SreQuENcE OF THE Ick-MovEMENTs. 
In the section dealing with the Drift-deposits (§ VI, p. 489), I 
reviewed the evidence which has led me to the conclusion that there 
were three main ice-movements affecting the Cleveland area— 
a northern, from Scotland and Northumberland, not previously 
recognized; a western, proximately from the Stainmoor Pass and 
the Valley of the Tees; and an eastern, from the North Sea, and 
more remotely from the area lying to the ‘northward of the Skager- 
Rack and the Baltic. 
It now devolves upon me to endeavour to show the way in votiteh 
their very complex interactions produced the phenomena that I 
have described. 
The fact that rock-grooves running from north-west to south- 
east across Hob Hill were disclosed by clearing away the Lower 
Boulder-Clay—the oldest Glacial deposit of the distriet—may, I 
think, be taken to imply that in the country north of the Cleveland 
Hills ‘the western ice was the first upon the ground. This inference 
is greatly strengthened by Mr. Barrow’s observation that the Lower 
Boulder-Clay consists mainly of materials from the actually under- 
lying rock or the rocks cropping out immediately to the west- 
ward’; and when it is remembered that one of the rocks borne by 
this stream, the Shap Granite, is not only dispersed along the whole 
coastline of Yorkshire, but even far down into Lincolnshire, and 
' Mem. Geol. Surv, ‘ North Cleveland’ 1888, p. 66. 
fee OP es 
