10 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 

 Ball 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 



*An Expedition to Mount St. Elias, Alaska. By Israel C. Russell. Nat. 

 Geog. Mag., vol. in, p. 121, 1891. 



