264 GREENLAND 



had gone on by themselves for some thirty miles east 

 of the northern arm of the fiord. It was on this occa- 

 sion that Berggren discovered Ancylonema, that small 

 polycellular alga forming the dark masses that absorb a 

 far greater amount of heat than the white ice and thus 

 cause the deep holes that aid in the process of melting. 



" The same plant," says Nordenskiold, " has no doubt 

 played the same part in our country ; and we have to 

 thank it, perhaps, that the deserts of ice which 

 formerly covered the whole of Northern Europe and 

 America have now given place to shady woods and 

 undulating cornfields." 



Nordenskiold looked upon Greenland and its icefield 

 as a broad-lipped, shallow vessel with chinks in the lip, 

 the glacier being viscous matter within it. As more is 

 poured in, the matter runs over the edges, taking the 

 lines of the chinks, that is, of the fiords and valleys, as 

 that of its outflow. In other words, the ice floats out 

 by force of the superincumbent weight of snow just as 

 does the grain on the floor of a barn when another 

 sackful is shot on to the top of the heap already there. 

 When the glacier reaches the sea it makes its way along 

 the bottom under water for a considerable distance, in 

 some cases, as near Avigait, for more than a mile. This 

 is where the water is too shallow for it to affect the 

 mass, which forms a breakwater ; though as a rule the 

 shore deepens more suddenly and the projection is less. 

 It was long supposed that the berg broke from the 

 glacier by force of gravity, but this is not generally so. 

 The berg is forced off from the parent glacier by the 

 buoyant action of the sea from beneath ; the ice groans 

 and creaks ; then there is a crashing, then a roar like 



