Ice Aye in Norfli America a iid Europe. — Vplanii. Ill 
ten years ; or, where the ice-sheet had less englaeial drift, as 
a quarter or only a tenth as much, the smaller parts of a mo- 
raine belt would be made during the same thirty years in 
which elsewhere its most prominent portions were being de- 
posited. 
Comparison of Alaska and Greenland. 
The Malaspina ice-sheet in Alaska, reaching from the St. 
Elias range to the ocean, has been slowly retreating, like the 
Muir glacier and others of that country, during the past hun- 
dred years or probably much longer. On all its border for a 
width of a few miles, now thinned perhaps to a quarter part, 
or less, of the earlier depth, the waning ice is covered by its 
formerly englaeial drift; but, in that cold climate, the glacial 
movement is so very slow that forest trees, with luxuriant un- 
dergrowth of shrubs, and mau}?^ herbaceous flowering plants, 
grow on this drift l^'ing upon hundreds of feet of ice as re- 
vealed by stream channels. Advancing toward the interior, 
the explorer soon comes upon higher clear ice and neve, hav- 
ing risen above the plane of the englaeial debris, excepting 
along the course of belts of medial surface morainic drift, 
swept outward from spurs of the mountains. This ice-sheet 
partially suggests the conditions of the moraine-forming 
southern porthern of the North American and Eluropean ice- 
sheets during the Chaniplain epoch; but these had a climate 
much warmer than that of Alaska, with consequent far more 
rapid ablation and stronger glacial currents. 
In Greenland, on the other hand, the mean temperature lias 
probably been gradually lowered during several centuries past, 
since the prosperous times of the Norse colonies 900 to 500 
years ago. A great ice-sheet, 1,500 miles long with a maxi- 
mum width of 700 miles, covers all the interior of Greenland; 
and, although now its extent is less than during the Glacial 
period, it has doubtless held its own or mainly somewhat in- 
creased during several hundred years. While the snow and 
ice accumulation is ])redominant, no englaeial drift beconu'S 
superglacial ; but in the region of Inglelield gulf Chambcrliii 
finds the frontal ice-clitfs well charged with englaeial debris 
to a third or half of the total hights of 100 to 200 feet or more. 
The same ratio of the lower part of the ice-sheet containing 
drift would (juite certainly give it a thickness of 1,000 to 2,000 
