Climatic Changes Indicated by Glaciers. —Russdl. 323 
are considered as true glaciers, and increase in number and 
‘extent towards the north. In the Cordillera system in Canada, 
glaciers are numerous, but have been explored to only a lim- 
ited extent. Those best known are in the Selkirk mountains 
and on the Stikine river. Farther north in the same great mount- 
ain belt, many glaciers are known to exist, and in Alaska they 
reach their greatest development. As one follows the glacial belt 
northward the lower limit of perpetual snow descends lower and 
lower, until finally at the base of Mt. St. Elias its elevation is 
only about 2,500 feet above the sea. The glaciers extend below 
the snow line and reach sea level near the mouth of the Stikine 
river in about latitude 57°. From there northwestward to Cook’s 
inlet there are hundreds, if not thousands, of magnificent ice 
streams which descend nearly to the ocean level, and scores which 
enter the ocean and breaking off form bergs. Local glaciers 
clustering about high peaks, occur on the Alaskan peninsula and 
the Aleutian islands. This great glacier belt is approximately 
3,000 miles long. The most thoroughly snow and ice covered 
portion is in the region about’ Mt. St. Elias, where not less than 
30.000 square miles of exceedingly mountainous country is com- 
pletely buried beneath a vast névé field which is drained by 
glaciers of the alpine type flowing both north and south. Those 
flowing south are the more important. On gaining the flat lands 
between the base of the mountains and the sea, they expand and 
form Piedmont glaciers. Of these, the Malaspina glacier, having 
an area of about 1,500 square miles, is the best known example. 
An interesting fact in connection with the distribution of glaciers 
on the west coast of North America is that their northern limit is 
less than one hundred miles north of Mt. St. Elias. Mountains 
in central and northern Alaska having an elevation of 4,000 or 
5,000 feet are without snow during the summer and no glaciers 
exist upon them, As is now known this region was not glaciated 
during the Glacial Epoch. 
On the east side of North America existing glaciers are con- 
fined to Greenland and to neighboring islands. The ice sheet coy- 
ering Greenland is of the continental type and, as is well known, 
is the largest existing ice body in the northern hemisphere. The 
glaciers on the islands west of Greenland are of the alpine type, 
and many of them are known to be of great size, but their ex- 
ploration is far from complete. 
