AMONGST THE SOUTHERN ICE. 235 



split off tolerably evenly from the whole height of the cliffs, 

 for these are nearly always, when thus still water-worn at 

 their bases, perpendicular, and on our firing a shot at a ber« 

 cliff, the ice split off in this manner from the whole height of 

 the cliff. 



When there are crevasses in the ice at the level of the wash- 

 line leading into the ice from it, the wash of the waves hollows 

 out caverns which resemble in general form caves cut in the 

 same manner by waves on coast-lines, and have their mouths 

 wider at the levels of the wash-lines. 



The presence of caves is a proof that a berg has floated 

 at the level of the wash-line, along which they lie for a long 

 period. The remains of the upper part of the crevasse which has 

 assisted in the development of a cave, is often to be seen stretch- 

 ing up from its roof. Often by change of line of flotation of a 

 berg, a line of caves is carried up far above sea level, and three 

 or four caves disposed along an old wash-line are thus often to 

 be seen on the surface of a berg, the line being sometimes 

 horizontal, sometimes tilted. In a berg which has undergone 

 extreme denudation, or on a narrow spur of a young berg, a cave 

 may be excavated right through the berg and give rise to a 

 natural arch. A further degeneration of the arch gives rise to 

 an isolated pinnacle. 



The base of the berg under water beneath the wash-line beino- 

 supported by the water, does not split off at once like the cliff 

 above when cut into. Hence the waves constantly deepening 

 the wash-line as the cliffs fall, and eating their way into the 

 berg at the water-line, a platform of ice is left behind under 

 water, projecting at the base of the cliffs above it. After a 

 time the part of the berg above water losing weight, the berg 

 rises, and this platform is raised above water, and the berg thus 

 becomes two-storied or bi-tabular. 



A fresh wash-line is cut below the margin of the platform 

 now raised, and low perpendicular cliffs are formed round it. 

 A third platform may be formed in the same manner and raised, 

 and the berg may become three-storied. 



At the base of the older cliffs in each case, the old wash-line 

 is usually to be seen where the cliffs are joined by the platform 



