Vol. 58.] | THE GLACIATION OF TEESDALE, WEARDALE, ETC. 601 
‘Group of striated surfaces along the line of the Whin-Sill 
escarpment, north of Chollerton. 
16. Surface of dolerite, near Colwell, S. 80° E. (550 feet). 
17. Surface of sandstone, near Swineburn Castle, 8. 26° H. (450 feet). 
18. Surface of sandstone, on Barrasford Common, 8. 50° EK. (400 feet). 
19. Surface of limestone, half a mile east of Gunnerton, S. 20° H. (500 feet). 
Group of striated surfaces on the line of the escarpment of 
the Great and Little Limestone, line of the Roman Wall, 
east of the North Tyne (96). 
20. Surface of sandstone, near Wall, 8S. 14° E. (500 feet). 
21. Surface of basalt-dyke, at Crag House, 8S. 25° E. (600 feet). 
22. Surface of sandstone, near Fallowfield, 8. 30° EH, (650 feet), 
23. Another surface of sandstone, S. 58° H. (650 feet). 
24. Surface of sandstone, 1 mile north-east of Acomb, S. 52° E. (700 feet). 
(4) Boundaries of the Ice at the Period of 
Maximum Glaciation. 
I have mentioned (p. 582) that the ice formed on the eastern 
slopes of Cross Fell sent an arm down the valley of the South Tyne 
towards Alston. This forms the commencement of the glacier- 
system of the South Tyne, and at the period of maximum glaciation 
it filled the valley up to a height of 1800 feet above sea-level. 
In the neighbourhood of Lambley, the glacier of Alstondale 
became confluent with a lobe of ice which came from the Irish- 
Sea Basin over the northern end of the Pennine Chain and 
through the valley of the Irthing, and extended in a northerly 
direction up to the Scottish Border, This great stream of ice then 
moved eastward down the valley of the South Tyne, and across the 
wild stretch of undulating moorland to the north of the Roman 
Wall, until it reached the valley of the North Tyne, deflecting to 
the eastward the glacier which came down that stream, as is shown 
by the direction of the striz on the left bank of the river and in 
the neighbourhood of Redesdale. The effects of this thrust have 
been traced up to the south-eastern slopes of the porphyrite-hills of 
the Cheviots.' 
The northern boundary of this great glacier cannot be traced, as 
it seems to have been confluent with ice flowing in a general south- 
easterly direction round the flanks of the Cheviot massif. From 
the general absence of boulders of Lake-District rocks east of 
the North Tyne, I should infer that the ice which passed eastward 
over Redesdale was that proper to the North Tyne, the boundary 
of the western ice lying approximately on an east-and-west line 
drawn through Chollerton. 
The southern limit, on the contrary, can be traced with great 
accuracy by the series of lakes and overflow-channels which were 
produced along that line. The boundary, at the maximum extension 
of the ice, passed across the northern end of Whitfield Moor (97), 
’ P. F. Kendall & H. B. Muff, Geol. Mag. 1901, p. 513; Rep. Brit. Assoc. 
1901 (Glasgow) p. © 46, 
