CARTER : GLACIATION OF DON AND DEARNE VALLEYS. 423 
Wharfedale, and Airedale glaciers, that I would attribute the 
first phase of glaciation in the Dearne and Don, followed by 
a glaciation by the Stainmoor ice, and associated with a com- 
plicated series of glacier lakes. 
The succession of phenomena suggested is as follows : — 
In the early stages of the Glacial Period Yorkshire seems to 
have stood 200 feet higher than at present, for along the great 
Triassic valley, stretching from >.'ewcastle to the Midlands, 
there is a drift-filled hollow* which at Gateshead is 140 feet, 
at Cawood 74 feet, and at Barnby Dun 170 feet below O.D. 
With the lowering of the temperature at the commencement 
of the Ice Age, the Highlands of Scotland, the Cheviots, the 
Lake and Welsh Mountains, and the Pennine Chain would be 
centres of great snow-precipitation, and would give rise to 
glaciers radiating by the principal valleys from their snow-fields. 
As the cold became more intense these local glaciers would be 
augmented, and spreading out fanwise in the plains would 
become confluent. By this means it is probable that before 
the Norwegian ice began to make its influence felt on our coast- 
line the vales of Mowbray and York would be choked with ice 
from the valleys of the Pennine Chain. When by the inter- 
ference of the Scandinavian ice the Scotch glaciers were deflected 
into the Irish Sea and down the Northumberland and Durham 
coast, the ice-stream overflowed from the Vale of Eden by 
Stainmoor Pass into Teesdale. At first it found free access 
seawards by Teesmouth, but then, obstructed in its turn by 
the Scandinavian glacier, was forced to overflow, all way 
of escape northwards being blocked, through the wide gap 
between the Cleveland Hills and the Pennine Highlands into 
the plain of Mowbray and York. This Stainmoor glacier was 
evidently large and powerful and able to thrust aside and 
over-ride the Vale of York ice, and, preventing all further 
eastward flow of the Pennine glaciers, crowded them back 
against the lower slopes of the Permine Chain. Thenceforward 
it would appear that the two ice-streams moved in parallel 
lines as far as Airedale, where the Pennine ice, yielding to 
the vigorous thrust of the Stainmoor glacier, was forced into 
*P. F. Kendall, Proc. Yorks. Geol. and Polytec. Soc, XV., 1. 
