272 J. CrolL — Boulder-clay of Caithness. 



course, but it would be met by the still more enormous masses of ice 

 coming off a coast line of more than 700 miles beyond the most 

 northern point shown in the accompanying diagram. And, besides 

 this, the ice entering the Arctic Ocean from Lapland and the northern 

 parts of Siberia, except the very small portion which might find an 

 outlet into the Pacific through Behring's Straits, would have to pass 

 along the Scandinavian coast in its way to the Atlantic. No matter 

 what the depth of this trough may have been, if the ice from the 

 land, after entering it, could not make its escape, it would continue 

 to accumulate till the trough became blocked up ; after this, the 

 great mass from the land would move forward as though the trough 

 had no existence. The only path for the ice would be by the Orkney 

 and Shetland Islands. Its more direct and natural path would, no 

 doubt, be to the south-west, in the direction of our shores ; and ia 

 all probability, had Scotland been a low flat island, instead of being 

 a high and mountainous one, the ice would have passed completely 

 over it. But its mountainous character, and the enormous masses of 

 ice at the time proceeding from its interior, would effectually prevent 

 this, and the ice of Scandinavia would be compelled to move round 

 by the Orkney Islands. The two huge masses of moving ice — the 

 one from Scotland and the much greater one from Scandinavia- 

 would meet in the North Sea, probably not far from our shores, and 

 would move, as represented in the diagram, side by side northwards 

 into the Atlantic as one gigantic glacier. 



This cannot be regarded as an anomalous state of things. In 

 Greenland and in the Antarctic continent the ice does not break up 

 into icebergs on reaching the sea. It moves along the sea bottom in 

 a continuous mass until it reaches water sufficiently deep to float it. 

 It is quite possible that the ice at the present day may nowhere 

 traverse a distance of three or four hundred miles of sea bottom, but 

 this is wholly owing to the fact that it finds water sufficiently deep 

 to float it before having travelled far. Were Baffin's Bay and Davis's 

 Straits, for example, as shallow as the North Sea, the ice of Greenland 

 would not break up into icebergs in these seas, but cross in one 

 continuous mass to and over the American continent. 



The medial line of the Scandinavian and Scottish ice-sheets would 

 be situated not far from the east coast of Scotland. The Scandinavian 

 ice would press up as near to our coast as the resistance of the ice 

 from this side permitted. The enormous mass of ice from Scotland, 

 pressing out into the North Sea, would compel the Scandinavian ice 

 to move round by the Orkneys, and would also keep it at some little 

 distance from Scotland. Where, on the other hand, there was but 

 little resistance offered by ice from the interior of this country (and 

 this might be the case along many parts of the English coast), the 

 Scandinavian ice might reach the shores, and even overrun the 

 country for some distance inland. 



There is another cause which might tend to force the Scandinavian 

 ice down in the direction of our shores. The western half of 

 Gothland is striated in the direction of N.E. and S.W., and that this 

 has been effected by a huge mass of ice covering the country, and 



