800 SoLLAS — A Map to show the Distribution of EsJcers in Ireland. 



glacier, Alaska, for example, the two streams issuing from the ice-front near the 

 sides of the glacier are several hundred feet above the level at which the two 

 streams emerge near the centre of the channel. There, also, streams of water of 

 more or less size, can occasionally be seen pouring out from the perpendicular front 

 of the ice a hundred feet or more above the surface of the inlet. Nor is it any 

 uncommon thing to see icebergs move off with water- worn tunnels in them which 

 are still well filled with gravel and pebbles. In the various depressions in the 

 surface of the glacier also, where, at times, extensive lakes of water are formed, 

 there is much accumulation and assortment of earthy material far back from the 

 terminal margin of the glacier." 



Another important contribution to our knowledge of melting glaciers is fur- 

 nished by Mr. Russell in his account of the Malaspina glacier of Alaska.* This 

 glacier the author regards as the type of a hitherto not fully recognised class, 

 which he terms '■'■piedmont glaciers," because they form at the foot of mountains, 

 by the union and expansion of tributary mountain glaciers. The Malaspina 

 glacier extends continuously from Yakutat Bay for seventy miles westward, and 

 has an average breadth of twenty-five miles. It is a vast, nearly horizontal plateau 

 of ice, having, at a distance of five or six miles from its outer border, an elevation 

 of about 1500 feet. After giving an account of the drainage of the glacier, the 

 author adds: — 



" The drainage of the Malaspina glacier has not been investigated as fully 

 as its importance demands ; but the observations already made seem to warrant 

 certain conclusions in reference to deposits made within the glacier by subglacial 

 or englacial streams. When the streams from the north reach the Malaspina 

 glacier they invariably flow in tunnels and disappear from view. The entrances 

 to these tunnels are frequently high arches, and the streams flowing into 

 them carry along great quantities of gravel and sand. . . . About the southern 

 and eastern borders of the glacier, where the streams emerge, the arches of the 

 tunnels are low, owing to the accumulation of debris which obstructs their 

 discharge. In some instances, as at the head of Fountain stream, the accumulation 

 of debris is so gi'eat that the water rises through a vertical shaft in order to reach 

 the surface, and rushes upwards under great pressure. . . . The streams flowing 

 from the glacier bring out large quantities of well-rounded sand and gravel, much 

 of which is immediately deposited in alluvial cones. This much of the work of 

 subglacial streams is open to view, and enables one to infer as to what takes place 

 within the tunnels. 



"The streams issuing from the ice are ever loaded with detritus, and, besides, 

 on emerging, frequently receive large quantities of coarse debris from the adjacent 



* Second Expedition to Mount St. Elias in 1891, by I. C. Russell. — 13tli Ann. Rep. U. S. Geol. Survey, 

 1893 ; and on Tlie Malaspina Glacier, The Journal of Geology, vol. i., 1893, p. 219. 



