JOWETT AND MUFF : GLACIATION OF BRADFORD, ETC. 241 
that it was in operation when the Newsholme Lake discharged 
by the Branshaw Wood gap. 
The north-west shoulder of the ridge below the intake- 
level of the Cutshaw channel presents many terraces in the solid 
rocks, but no distinct gaps through the ridge were noticed. 
PHENOMENA OF RETREAT. — THE NORTH SIDE OF AIREDALE. 
At the period of maximum glaciation the conditions did 
not admit of the formation of any lakes fringing the north side 
of the Airedale glacier. During the retreat of the ice, however, 
lakelets were formed at the heads of Morton and Howden Becks. 
The Outlets oj the 3Iorion Lake. — The highest outlet of 
the Morton Lake is indicated hy Spa Dyke, a very shallow 
channel situated one mile east-north-east of Morton. It cuts 
through the ridge which separates the valley of Morton Beck 
from that of Eld wick Beck, and carries off the water of some 
springs which rise within the natural drainage area of Morton 
Beck. The surface level of the Morton Lake at this period 
was 940 feet. A lower outlet occurs at Morton Stoop, a well- 
marked gap, through which the road from Morton to Hawksworth 
runs. Its intake- level is 905 feet. 
The shrinkage of the ice off the spur opened successively 
a number of small channels, some of which do not quite cut 
through the watershed. The lowest channel, however, is a 
large valley with steep sides and a flat floor. It is situated 
miles X.X.E. of Bingley, and slopes in the direction east by 
south (see PI. XVII., Fig. 1). After cutting through the water- 
shed it turns at its upper end almost due noith, and runs for 
some distance as a shallow valley nearly parallel to the 
contours. The deflection is thus away from the ice-front, as 
in the cases noted on the south side of Airedale, and is due 
to a similar cause. The surface level of the Morton Lake 
would at this period sink from 770 to 745 feet above CD. 
There is no evidence in the presence of overflow channels 
that glacier lakes ever existed in the valleys of Eld wick or 
HaAvksworth Becks. It has been shown that during the retreat 
of the Airedale ice the Wharfedale ice occupied tlie north-eastern 
1) 
