KENDALL : OBSKRVATIONS ON THE (JLACIEK LAKES. 
43 
Throxenby Mere channels, mark a synchronous, more extensive, 
and more prolonged forward movement at a later period. 
I have observed in other parts of the country similar evidence 
of fluctuations of the ice-margin, notably in the country west of 
Ripon, in the Cheviots, the Vale of Eden, and the nortliern face 
of the Lammermuirs. 
(3) Comparison of the Levels reached by the Ice-martjin round 
the Cleveland Area. — The levels attained by the ice-margin round 
the Cleveland area, as indicated by the lake ])henomena and 
•distribution of drift-deposits, present some a]:)parent anomalies, 
which, however, admit of a very simple explanation. Tlie large 
general map which accompanies this paper (Plate XIV.) shows 
by a series of arrows the direction in whicli I suppose tlie ice to 
have been moving at the stage of maximum extension of the 
ice, and it shows also the approximate position of tlie margin. 
It will be observed that there is a general decline of the margin 
from North to South which might not unreasonably l)e ascribed 
to the dwindhng of the ice-slieet as it extended further and 
further from its source. But when the levels attained along the 
northern face are compared it is seen that the margin rises in 
a westerly direction and readies a much higher altitude along 
the great escarpment above Carlton and Ingleby Greenhow tlian 
on the hills above Moorsholm and Iburndale, though further 
from the source of the ice. Why is tliis i Well, it must be 
observed that we are dealing witli the edge of the ice. and the 
height to which it will rise is dependent as much u])on the character 
of the obstacles which it has had to surmount as upon the thick- 
ness of the stream or sheet which it bounds. 
It will be noticed that the ice which bore in upon the great 
Cleveland escarpment (the real Cleve-land, or land of cliffs) 
traversed a great plain with scarcely a hillock to obstruct^ its 
passage, whereas that which was driven in upon the hill country 
further east, though descending from the same great flood, was 
hampered and the force of its onset weakened by its struggle to 
surmount the broken ground confronting its march. 
The same principle is most instructively illustrated by the 
drift phenomena of the countr}^ between the cliffs at Peak and 
the terminal moraine on the brink of the great gorge of Jugger 
