THE " GREAT ICE AGE." 135 



more glaciation than would be produced by sucli an ice- 

 sheet as that of the " paleocrystic " ice recently found by 

 Captain Nares on the north of Greenland. Progressing 

 northward, the glaciatiou begins to become visible, running 

 up to about 100 feet above the sea-level on the islands lying 

 westward and southward of Ost Vaagen. Further north- 

 ward along the coast of Ost Vaagen and Hindo, the level 

 gradually rises to about 500 feet on the northern portion of 

 Ost Vaagen, and up to more than 1,000 feet on Hindo, 

 while on the mainland it reaches 3,000 to 4,000 feet. 



A remarkable case of such variation, or descent of ice- 

 level, as the ice-sheet proceeded seaward, is shown at 

 Tromso. This small oblong island (lat. 69 40'), on which 

 is the capital town of Finmark, lies between the mainland 

 and the large mountainous island of Kvalo, with a long 

 sea-channel on each side, the Tromosund and the Sande- 

 sund; the total width of these two channels and the island 

 itself being about four or five miles. The general line of 

 glaciation from the mainland crosses the broad side of these 

 channels and the island, which has evidently been buried 

 and ground down to its present moderate height of two or 

 three hundred feet. Both of the channels are till paved. 

 On the east or inland side the mountains near the coast are 

 glaciated to their summits are simply roches moutonnees, 

 over which the reindeer of the Tromsdal Lapps range and 

 feed. On the west the mountains are dark, pyramidal, 

 non-glaciated peaks, with long vertical snow-streaks mark- 

 ing their angular masses. 



The contrast is very striking when seen from the highest 

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

 thickness of the ice-sheet in the course of its journey across 

 this narrow channel. Speaking roughly from my estima- 

 tion, I should say that this thinning or lowering of the lim- 

 its of glaciation exceeds 500 feet between the opposite sides 

 of the channel, which, allowing for the hill slopes, is a dis- 

 tance of about 6 miles. This very small inclination would 

 bring a glacier of 3,000 feet in thickness on the shore down 

 to the sea-level in an outward course of 30 miles, or about 

 half the distance between the mainland and the outer rocks 

 of the Lofodens shown in the engraving. 



