IO 
ALASKA GLACIERS 
glaciers. That which was accessible to us had been 
accessible to our predecessors also, so that at several 
points we could compare present with past condition ; 
and, for like reason, whatever record we might make 
could readily be used by the investigators of the future. 
Effort was accordingly made to visit as many as possible 
of the glaciers already described and mapped, and at all 
points visited to secure an intelligible record of the exist¬ 
ing status. 
The plural pronoun in the preceding paragraph is 
not the conventional affectation of modesty, but springs 
naturally from the consciousness that the facts I am 
to present were not wholly of my own observation. In 
grouping the material for publication it seemed to my 
colleagues in geology, Emerson and Palache, as well 
as to myself, that it would be better to classify by sub¬ 
jects than by observers, and as glaciers fell to my 
share, I have absorbed the glacial observations made 
by these gentlemen. I am greatly indebted also to the 
map work of Gannett, to the historical data and fertile 
suggestions of Muir, and to the timely cooperation of 
Dali and Coville. 
Before taking up the description of the glaciers, a few 
words will be devoted to the terminology connected with 
their broader classification. The distinction between al¬ 
pine glaciers (sometimes called glaciers proper) and con¬ 
tinental glaciers (also called ice-sheets) has long been 
recognized. Alpine glaciers are fed by neves in high 
mountains and as rivers of ice descend mountain valleys. 
Continental glaciers gather on broad plains or plateaus 
and spread outward. Russell, as a result of studies in 
Alaska, recognized a third type, the piedmont} A pied¬ 
mont glacier is a broad sheet of ice resting on a lowland 
1 An Expedition to Mount St. Elias, Alaska. By Israel C. Russell. Nat. 
Geog. Mag., vol. hi, p. 121, 1891. 
