io8 



GLACIERS 



rate in winter, while the vastly larger glaciers of the polar lands 

 have a correspondingly swifter flow. The great stream of ice 

 which enters Glacier Bay in Alaska has a summer velocity of 

 ^t^ s eventy fe et per day in the middle. 



Southeastern Alaska is a region where glaciers are developed on 

 a very extensive scale. The Malaspina is an immense ice-sheet, 

 having an area of 1500 square miles, which is formed at the foot of 



the St. Elias Alps 

 by the confluence 

 of several great 

 glaciers from the 

 neighbouring 

 mountains. Parts 

 of this vast accu- 

 mulation of ice 

 are stagnant and 

 deeply covered 

 with rock debris, 

 upon which there 

 is a luxuriant 

 growth of vegeta- 

 tion, with not less 

 than 1000 feet of 

 ice beneath it. 



In Greenland 

 and the Antarctic 

 continent the ac- 

 cumulations of ice 

 are on a scale not 

 elsewhere found, and these regions present conditions of great 

 geological interest. Greenland, except for a narrow strip along 

 the coasts, is buried beneath a vast ice-sheet, which can hardly be 

 less than 2000 or 3000 feet thick, and from which great glaciers 

 descend eastward and westward to the sea. In the interior only 

 a few isolated mountain peaks, or nunataks, rise through the ice 

 mantle ; except for these, nothing is visible but illimitable fields 



FlG. 35. — Vegetation on the Malaspina Glacier. 

 (U. S. G. S.) 



