178 SCIENCE IX SHOUT CHAPTERS. 



The contrast is very striking when seen from the highest 

 part of the island, and is clearly due to a decline in the thick- 

 ness of the ice-sheet in the coarse of its journey across this 

 narrow channel. Speaking roughly from my estimation, I 

 should say that this thinning or lowering of the limits of 

 glaciation exceeds 500 feet between the opposite sides of the 

 channel, which, allowing for the hill slopes, is a distance of 

 about 6 miles. This very small inclination would bring a 

 glacier of 3000 feet in thickness on the shore down to the sea- 

 level in an outward course of 30 miles, or about half the dis- 

 tance between the mainland and the outer rocks of the 

 Lofodens shown in the engraving. 



I am quite at a loss to understand the reasoning upon which 

 Mr. Geikie bases his firm conviction respecting the depth of 

 the ice-sheet on the low grounds of Scotland and Scandinavia. 

 He seems to assume that the glaciers of the great ice age had 

 little or no superficial down slope corresponding to the inclina- 

 tion of the base on which they rested. I have considerable 

 hesitation in attributing this assumption to Mr. Geikie, and 

 would rather suppose that I have misunderstood him, as it is a 

 conclusion so completely refuted by all we know of glacier 

 phenomena and the physical laws concerned in their produc- 

 tion ; but the passages I have quoted, and several others, are 

 explicit and decided. 



Those geologists who contend for the former existence of a 

 great polar ice-cap radiating outwards and spreading into the 

 temperate zones might adopt this mode of measuring its thick- 

 ness, but Mr. Geikie rejects this hypothesis, and shows by his 

 map of " The Principal Lines of Glacial Erosion in Sweden, 

 Norway, and Finland," that the glaciation of the extreme north 

 of Europe proceeded from south to north ; that the ice was 

 formed on land, and proceeded seaward in all directions. 



I may add to this testimony that presented by the North 

 Cape, Sverholt, Nordkyn, and the rest of the magnificent pre- 

 cipitous headlands that constitute the characteristic feature of 

 che Arctic face of Europe. They stand forth defiantly as a 

 phalanx of giant heralds proclaiming aloud the fallacy of this 

 idea of southward glacial radiation ; and in concurrence with 

 the structure and striation of the great glacier troughs that lie 

 between them, and the planed tableland at their summits, they 

 establish the fact that during the greatest glaciation of the 

 glacial epoch the ice-streams were formed on land and flowed 

 out to sea, just as they now do at Greenland, or other parts of 



