Glacier IVork. — Scott. 237 
part of North America." In a recent Russian report^ on the 
glaciers of the Caucasus mountains, of thirteen glaciers ob- 
served, all were retreating ; those on the northern slope at. the 
rate of 66 feet per year, those on the southern, at 75 feet per 
year. t 
Line of Loiucr Limit. 
The line of lower limit of glaciers varies of course with the 
geographical location. In the Alps where the line, of perpetual 
snow is fixed at about 7500 feet above sea level, the line of 32'' 
is about 2000 feet ; and the line of lower limit, about 5000 feet 
below the snow line. In some parts of the Arctic Region the 
32° line is at an altitude of 3500 feet. In Norway, the line of 
lower limit is about 4000 feet below the 32° line. In 
Chili glaciers touch the sea level at 46° 40' south latitude. ■'• 
The line of lower limit of perennial snow is about 2000 feet 
above the sea level in the >Mt. St. Elias region, where so many 
glaciers become united in the great Malaspina glacier of the 
Piedmont type. This glacier has an average breadth of 20 
to 25 miles, and an area of about 1500 square miles, or about 
midway between the states of Rhode Island and Delaware. 
This remarkable glacier will again be mentioned in connection 
with the subject of moraines. 
Glacial Drainage. 
^lost of the Alpine glaciers are drained principally by 
streams issuing at their ends from beneath. It is worth 
noting that a feature of Greenland glaciers is that the char- 
acter of drainage does not coincide with the drainage common 
to Alpine glaciers. "It is the rare exception," says Salisbur/, 
of Greenland glaciers," that a visible stream of any size issues 
from beneath a glacier at its end."t 
- The water that without doubt issues from the glaciers, 
passes through or under debris, rather than over it. The sides 
of a glacier, it is said, rarely rest against the valley, but 
usually have a stream between the ice wall and the side 
of the gorge. Very few streams are found on the ice surface, 
as the water plunges into the crevasses soon after formation. 
Occasionally englacial drainage takes place, and the water may 
issue in a great stream from the centre of a mass of ice at its 
♦Le Conte, text- book. 
tJour. of Geology, 189G. 
