4 6 SCOTT'S LAST EXPEDITION [December 
to feci that there is this plain of negotiable ice 
behind one- 
Saw two sea leopards this evening, one in the water 
making short, lazy dives under the floes. It had a 
beautiful sinuous movement. 
I have asked Pennell to prepare a map of the pack ; 
it ought to give some idea of the origin of the various 
forms of floes, and their general drift. I am much inclined 
to think that most of the pressure ridges are formed by 
the passage of bergs through the comparatively young 
ice. I imagine that when the sea freezes very solid it 
carries bergs with it, but obviously the enormous mass 
of a berg would need a great deal of stopping. In support 
of this view I notice that most of the pressure ridges 
are formed by pieces of a sheet which did not exceed 
one or two feet in thickness — also it seems that the screwed 
ice w r hich we have passed has occurred mostly in the 
regions of bergs. On one side of the tabular berg passed 
yesterday pressure was heaped to a height of 15 feet — 
it was like a ship's bow wave on a large scale. Yesterday 
there were many bergs and much pressure ; last night 
no bergs and practically no pressure ; this morning few 
bergs and comparatively little pressure. It goes to 
show that the unconfined pack of these seas would not 
be likely to give a ship a severe squeeze. 
Saw a young Emperor this morning, and whilst trying 
to capture it one of Wilson's new whales with the sabre 
dorsal fin rose close to the ship. I estimated this fin 
to be 4 feet high. 
It is pretty to see the snow petrel and Antarctic petrel 
