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It is not known whether all these advances were cli- 

 matic or whether some were due to earthquake avalanch- 

 ing. That the two sorts of advances may be distinguished 

 when observations are made at the right time is indicated 

 by the fact that a general advance of the glaciers of Prince 

 William sound, which began with the 1600 to 1700 foot 

 (480 to 500 m.) advance of Columbia glacier in 1908 (last- 

 ing until 191 1 or later), and was continued in 1910 by the 

 advance of 14 other glaciers, seems to be climatic rather 

 than a result of the earthquakes of 1899 or that of October, 

 1900, or any later seismic disturbance. The 15 Prince 

 William Sound ice tongues (Columbia, Meares, Yale, 

 Harvard, Radcliffe, Smith, Bryn Mawr, Vassar, Wellesley, 

 Barnard, Baker, Cataract, Roaring, Harriman, and Black- 

 stone) which were advancing synchronously when observed 

 by Martin in 1910 are of variable lengths and sizes, and 

 in three years the Columbia has not advanced as much as 

 the Childs advanced in less than one year, under the earth- 

 quake impulse, nor is its crevassing so severe. Its rate 

 of motion increased from nine-tenths of a foot (-27m.) a 

 day in 1908, to 2 1-10 feet (-63m.) a day in 1910. Of 

 those listed above as advancing between 1899 and 1912 

 Childs and La Perouse, and probably Rendu and Rainy 

 Hollow glaciers, became suddenly crevassed, advanced 

 great distances, and as suddenly ceased their activity, in 

 these respects strongly resembling the nine Yakutat Bay 

 advances. Childs glacier increased its rate of motion from 

 about 6 feet (1 -8m.) a day in 1909, to 40 feet (12m.) a day 

 in 1910, and as suddenly slowed down again. It is realized 

 that all the features of earthquake-generated advances are 

 not yet known; but, when full information is available, 

 such advances should be readily distinguished from climatic 

 oscillations. Perhaps many or all of the advances listed 

 above are of the earthquake-avalanche type, and in that 

 case future advances may be expected in such of the longer 

 ice tongues in the severely-shaken portions of the 

 St. Elias, Fairweather, Coast, Chugach, Wrangell, and 

 Alaska ranges as have steep slopes and other conditions 

 favourable for the earthquake-avalanche type of advance. 

 Earthquake avalanching may even be responsible for 

 most large oscillations of mountain glaciers, as for example 

 in the Himalaya and other youthful, snow-capped mount- 

 ains which are still frequently faulted and shaken by 

 seismic disturbances. 



