JOWETT AND MUFF : GLACIATION OF BRADFORD, ETC. 237 
both at the upper and lower ends of the Salter Royd gap (p. 231), 
and is more or less clear in the case of other overflow channels. 
It is due to the ice standing actually up to the head of the dry 
valley and forcing the water to flow for some distance between 
the ice and the hillside previous to its escape across the divide. 
The level of the Xewsholme Lake at the time the Griff Wood 
channel was in operation was just under 900 feet. 
A slight shrinkage of the ice opened a channel at Wide Lane 
immediately to the east of the last. This channel has an intake- 
level of 860 feet. It is shallow at its head, but deepens con- 
siderably in a sudden descent of its floor, where it passes through 
the highest part of the ridge. 
Between the lower ends of the Wide Lane and Gritf Wood 
channels there is a small rounded hill, known as Boston Hill, 
and isolated by a small valley which slopes steeply from the 
end of the Griff Wood channel to the Wide Lane Valley. A 
small section near the top of the hill exposed yellowish clay 
with rounded and angular stones, but it is not certain that the 
whole hill is composed of drift. A boring by iron rods put down 
in the middle of the Wide Lane channel, opposite the end of 
the cross-valley from the Griff Wood cliannel, passed through 
18^ feet of peat, gravel, blue clay, and gravel without reaching. 
" solid " rock. At the mouth of the cross-valley solid rock 
was reached at depths varying from two and a half to five feet. 
The surface was here about three feet above the place where the 
first boring was put down. The Wide Lane channel would 
thus appear to have been cut down about three yards below 
the mouth of the cross- valley. The origin of tlie latter is very 
obscure. 
A small oscillation of the ice-front, before the Griff Wood 
channel was finally deserted, is probably indicated by the small 
cut, which runs from the upper part of the Griff Wood channel 
towards the Wide Lane one along the northern edge of Griff 
Wood. 
The next overflow-channel is a shallow valley cutting 
through the watershed at Race Moor Farm (Cure's Lathe on 
the old edition of the 6-inch map), about 400 yards east of the 
Wide Lane Valley. Its intake-level is 870 feet above O.D. 
