322 The American Geologist. May, 1892 
CLIMATIC CHANGES INDICATED BY THE GLA- 
CIERS OF NORTH AMERICA. 
By Israen C. Russeti, Washington, D, C. 
Prof. Dufour has shown that the existing glaciers of Europe 
and Asia are retreating.* This is proof of a marked climatic 
change over a great area, within the last one or two decades, and 
renders it important to know if evidence of a similar change is 
furnished by the glaciers of other regions. Should it be found 
that glaciers on other continents are also retreating, it would not 
only be an interesting contribution to physical geography, but 
have an important bearing on the study of the causes of the 
Glacial Epoch. 
The data presented in this paper in reference to recent changes 
in the glaciers of North America, have been assembled in response 
to a letter addressed to the Director of the U. 8. Geological Sur- 
vey by Prof. Dufour, and is here published with the hope that it may 
lead to the accumulation of additional data in the same connection. 
Distribution of Existing Glaciers in North America. 
Glaciers may be arranged, provisionally at least, in three 
classes, viz:—alpine, piedmont and continental. It is also con- 
venient to designate those which enter the ocean and break off in 
bergs, as tide water glaciers. Examples of each of these types 
occur in North America. 
The glaciers of North America are confined to the Cordilleran 
system and to-the Greenland region. Small ice bodies are known 
to exist on the higher volcanic peaks in Mexico, but of these we 
have only indefinite information. Their southern limit in the 
United States is in the High Sierra of California, in about latitude 
37° N. The ice bodies in that region are small but have the 
essential features of the largest alpine glaciers. They are con- 
fined to cirques near the mountain summits and do not descend 
below a horizon 12,000 to 13,000 feet above the sea. In 
northern California, Oregon, and Washington, glaciers become 
more numerous, of greater extent, and extend to lower hori- 
zons than in the High Sierra. They occur about the summits 
of Mt. Shasta, Mt. Rainer, Mt. Baker, and several other peaks 
in the Cascade mountains, which have an altitude exceeding 
10,000 or 11,000 feet. In the Rocky mountains they begin 
at the south, with snow bodies in Colorado, which by some 
«Bull. Soc. Vaud Se. Nat., Vol. xvi, 1881, pp. 422-425. 
