350 THE VOYAGE OF THE 'DISCOVERY' [Appx. 



The presence of the Beacon Sandstone formation proves that 

 water in times past had at any rate an important constructive 

 action, and even since the deposition of the sandstone and the 

 intrusion of the plateau dolerites, water seems to have had a destruc- 

 tive effect upon the original plateaux of the Royal Society Range. 



Chemical Action. — Decomposition of rocks by chemical action 

 is more obvious in the dry climate of South Victoria Land than in 

 other areas where rain removes the soluble salts as soon as they 

 are formed. The common occurrence of soluble crystalline salts 

 in the moraines has already been mentioned, and perhaps the fact 

 that many ponds among the moraines are extremely saline to the 

 taste suggests a clue to the peculiar distribution of the soluble 

 matter. 



Frost Action. — In high southern latitudes the precipitation of 

 water-substance is very small, and therefore frost-riven rock masses 

 are not very conspicuous. As wind usually removes thin coverings 

 of snow from bare rock surfaces, it is only on the edges of local 

 snow-fields that thawing and freezing can take place with any 

 degree of regularity. Snow is drifted by the wind on to the north 

 side of Castle Rock during the winter, and during the summer great 

 masses of rock are split off and litter the area at its foot. Cathe- 

 dral Rocks likewise face north, and appear to be more subject 

 to frost-action than the more isolated peaks of the Western 

 Mountains. 



The Action of Ice. — The types of surface clearly due to ice 

 action are rather inconspicuous. A few roches uwiitonnees have 

 been observed in Granite Harbour and on the foothills of the 

 Royal Society Range, but owing to the extremely low mean 

 annual temperature the ice appears to be more conservative than 

 erosive in its action. 



Transport has taken place on a great scale in the past, but 

 now, owing to the almost stagnant condition of the ice, it has 

 practically ceased. The icebergs, which appear remarkably free 

 from foreign matter, are the chief agents of transport at present, 

 and, as we have seen, they always carry matter from a higher to 

 a lower latitude. So great is the quantity of loose rock material 

 on the surface of the land that one is tempted to speculate on the 

 effect that would be produced if a slight increase of the ice were 

 to bodily remove this covering and distribute it over the clayey 

 floor of the Ross Sea. 



In conclusion, it is my pleasant duty to briefly express my 



