446 THE ICE AGE IN NORTH AMERICA, 



where no obstacle to its passage intervened, it seems to have 

 swept in one broad and continuous stream out — probably as 

 far as that of Scotland — into the Atlantic. The thickness 

 attained by the ice that flowed into the Irish Sea from Scot- 

 land, where it coalesced with the mer de glace coming from 

 the eastern seaboard of Ireland, and also, as we shall presently 

 see, with that creeping out from England and Wales, makes 

 it quite certain that the area now occupied by that sea must 

 at that time have been filled with glacier ice. . . . 



The North Sea was filled with a massive mer de glace con- 

 tinually advancing in a general south-southwestern direction, 

 the presence of which is distinctly traceable in the remarkable 

 deflections of the glaciation all along the seaboard of Scotland 

 from Stonehaven southward. It was simply owing to the 

 superior elevation and extent of the Scottish mountains that 

 the narrow strip of low-lying ground in the eastern maritime 

 districts of that country was not invaded by an alien ice-stream. 

 When we pass into England the hills become lower, and the 

 area of low ground between the hills and the sea increases in 

 breadth. There was thus less and less opposition offered to 

 the southward advance of the North Sea mer de glace as it 

 pressed upon the eastern shores of England, until eventually 

 it overflowed bodily and crept southward across the midland 

 table-land on its way to the valley of the Severn and the Bristol 

 Channel. This remarkable glacial invasion is proved not only 

 by the carry of local stones, and stones which have come south 

 from the northern counties and Scotland, but by the appear- 

 ance in the till at Cornelian Bay and Holderness of bowlders 

 of two well-known Norwegian rocks, which were recognized 

 by Mr. Amund Helland. . . . 



The ice which would thus appear to have streamed trans- 

 versely across England eventually coalesced with that which 

 overflowed from the basin of the Irish Sea southeast through 

 Cheshire, together with that which streamed east from the 

 Welsh uplands, and the united mer de glace thereafter made 

 its way into the Bristol Channel. Here it joined the thick 

 ice that flowed out to sea from the high grounds of South 

 Wales, the bottom-moraine of which is conspicuous not only 

 in the mountain-valleys of that region, but also upon the low- 



