1910.] INLAND-ICE OF THE ARCTIC REGIONS. 129 



such bergs were ob-erved in process of calving by von Drygalski 

 and other members of his party. The same loud sound which had 

 been heard at the birth of bergs of the second class accompanied the 

 birth of those in the first class, but the movement of separation from 

 the glacier zvas visible at the same instant. A portion of the clifif 

 front was seen to separate from the clifif, being thereby thrown 

 somewhat out of equilibrium and started in a pendular vibration 

 which produced great waves in the fjord and increased slightly its 

 distance from the newly formed ice clifif. It was here observed that 

 the main pinnacle of the berg slightly exceeded in height the highest 

 pinnacles of the new glacier rim. This, it will be remembered, is 

 in contrast with the bergs of the second class which did not reach 

 to the height of the clifif. Bergs of the first class usually regain 

 their equilibrium after rhythmic oscillations and float away in an 

 upright position. The bergs of the second class often turn over 

 displaying the beautiful blue color of the lower layers. Salisbury's 

 two types of Greenland icebergs seem to correspond with von Dry- 

 galski's bergs of the first and second classes. ^^^^ 



The water waves which are sent out to the shores at the birth of 

 a great ice berg extend 50 kilometers or more within the fjord, driv- 

 ing the smaller floating bergs together and thus assisting in their 

 fragmentation and consequent dissolution. The calving of bergs of 

 the first class von Drygalski believes occurs where the depth of the 

 fjord has so far increased that the ice begins to leave the bottom 

 and assume a swimming attitude. The buoyancy of the water is, 

 he believes, thus the true cause of the separation of the bergs. 



Depths which are four to five times as great as the thickness of the 

 inland-ice above the sea level, are not measured in Greenland in front of 

 attached ice masses, because the latter become in that case broken up into 

 ice bergs.^^ 



This view gains strength from Salisbury's studies of the glaciers 

 ending in Melville Bay and apparently floated for a very short dis- 

 tance back from their fronts and generally in the middle only.^^°* 



University of Michigan, 

 Ann Arbor, Mich. 



"'•/owr. Geol., Vol. 3, pp. 892-897. 



"" E. von Drygalski, /. c, p. 404. 



""" Salisbury, Jour. Gcol, Vol. 3, 1895, PP- 885-S86. 



PROC. AMER. PHIL. SOC, XLIX. I94 I, PRINTED JUNE 18, I9IO. 



