236 The American Geologist. October. 1902. 
peared to be such periods in connection with the glaciers of 
the Alps, viz., enlargement from 1800 to 1815, diminution 
from 1815 to 1830, enlargement from 1830 to 1845, diminution 
from 1845 to 1875, and enlargement from 1875 onward. 
These periods are quoted by one of the text-books, yet it will 
be noticed that they are remarkabl}- regular, and it would seem 
that sufficient study had not been given to the subject to war- 
rant these conclusions. At a later date Prof. Forel * 
states that the periodicity of glacial variations is much longer 
than was formerly believed to be the case. "It is possible," 
he says, "that the cycle of variation is 35 to 50 years." 
Beginning with 1850 or 1855 the glaciers steadily decreased 
up to 1875. At that time they apparently began to increase 
again in the Mont Blanc region. 
■ In, a summary by Dr. H. F. Reid t concerning glaciers 
in 1899, the following statements are made: 
"Swiss Alps. — As we approach the end of the century the 
advance of a number of glaciers which began in 1875 ^^^s 
gradually died out. Only one glacier was known to be ad- 
vancing in 1899; nine were doubtful, and fifty-five were cer- 
tainly or probably retreating." % 
"Italian Alps. — Eight glaciers show retreat and two ad- 
vance. The glaciers of the French, Swedish and Norwegian 
Alps are either stationary, or show a slight retreat. Photo- 
graphs of the small Kiagtut glacier of Gre,enland show a re- 
treat of several hundred meters between 1876 and 1899. The 
Victoria glacier near Lake Louise, Alberta, is retreating, and 
the Illecellewaet shows an average retreat since 1887 of about 
15.8 meters per year. In Russian Asia the glaciers are re- 
treating, while in the Himalayas the condition is more or less 
uncertain. It is probable that the majority are stationary or 
advancing slightly." 
In the volume published by the U. S. Geol. Survey on "Ex- 
plorations in Alaska" § it is shown that the Alaskan glaciers 
were formerly much more extensive than now, and show 
evidence of continued retreat. It is also indicated that Alaska 
was never under a continental ice sheet as was the eastern 
*Am. Jour, of Science, Vol. .144, 1892, p. 342. 
tJour. of Geolog>% Vol. !>, 1901. pp. 250-254. 
JFrom report of Prof. Forel. 
§Twentieth Annual Report U. S. Geol. Survey, Part 7, 1S9S. 
