284 THE ICE AGE AND* ITS WORK. 



ties wlieiioe tliey coukl only have been bronght across tlie sea. The 

 direction of the glacial stii;e and of the smoothed side of ice- worn rocks 

 also indicate that the shallow seas were all filled up by ice. - - On all 

 sides of Ireland, except the sonthern coast, the ice flowed outward, but 

 on the ncH'theast the flow was diverted southward, and on the extreme 

 north, westward, by the pressure of the overflowing ice sheet of Scot- 

 land which here encountered it. In like manner, the ice marks on the 

 east coast of Ireland and the west coast of Wales are diverted south- 

 ward by the mutual pressure of their ice sheets, which, together with 

 that of the west of Scotland, filled up St. George's Channel. That such 

 was the case is further ])roved by the fact that the Isle of Man is ice- 

 bound in a general direction from north to south, and to the summit 

 of its loftiest mountains, which rise to a height of over 2,000 feet. This 

 could only have been done by an ice sheet flowing over it, and this view 

 is further sui)ported by some most remarkable facts in the dispersal 

 of local erratics. These are always found to the south of the places 

 where they occur in situ, never to the north; and, what is still more 

 noteworthy, they are often found far above the native rock. Thus 

 bowlders of the peculiar Foxdale granite are fonnd about 1,400 feet 

 higher than the highest point where there is an outcrop of this rock. 



The Scotch ice sheet flowed outward on all sides, bnt on the east it 

 was met by the southward extension of the great Scandinavian ice 

 sheet. On the extreme north the meeting of these two ice sheets 

 resulted in a flow to the northwest which glaciated the Orkney Islands, 

 wliile the Shetlands, much farther north, received the full impact of 

 the Scandinavian ice alone, and are therefore glaciated from the north- 

 east. The dividing line of the Scotch and Scandinavian ice sheets was 

 in the North Sea, not far from the east coast of Scotland; but farther 

 south, at Flamborough Head and Holderness, the latter impinged on 

 our coast, bringing with it enormous quantities of Scandinavian rocks. 

 Many years ago Prof. Sedgwick described the clift's of bowlder clay at 

 Holderness as containing " an incredible number of smooth round 

 blocks of granite, gneiss, greenstone, mica slate, etc., resembling none 

 of the rocks of England, but resembling specimens derived from vari- 

 ous i)arts of the great Scandinavian chain." These are mixed how- 

 ever with a number of British rocks from the north and west, indi- 

 cating the meeting ground of the two conflicting ice sheets. Similar 

 blocks occur all along the coast as far as the cliffs of Cromer in Norfolk. 

 Across the peninsula of Flamborough about 2 miles west of the light- 

 house there is a moraine ridge containing a few Scandinavian bowlders, 

 but mainly composed of British rocks. These latter consist of numer- 

 ous carboniferous rocks from the north and northwest, together with 

 many of Shap granite — a peculiar rock found only on Shap Fell, in the 

 eastern side of the Lake District, together with a few of Galloway 

 granite. These facts, it will be seen, add further confirmation to the 

 theory of great confluent ice .sheets indicated by the ice-markings upon 



