190 



Correspondence — H. T. Ferrar. 



features were due to denudation, glacial and preglacial, and which 

 were due to valley formation by movements of the earth's crust," and 

 hence in my report described what I saw, but made no deductions. 

 Now that I have gained further knowledge and experience I feel that 

 I can take up a definite position. I hold that the great transverse 

 valleys of Central South Victoria Land were not entrenched by glacial 

 erosion, but are disruption clefts due to the unequal foundering of the 

 land, the lioyal Society Eange having stood firm as the surrounding 

 continent subsided. 



I would go even a step further than Professor Gregory in denying 

 the erosive power of ice as such. In the first place I agree with 



Sketch-map showing shove-lines of Ferrar Glacier and its branches after 

 a submergence of 3,000 feet. 



Professor Garwood and Dr. Harker that the corroding action of 

 a partially buoyed up glacier snout, which is thawing above water and 

 melting below, is small. In the second place I do not see how 

 corrosion by pot-holing (p. 407), the evidence for which is meagre, can 

 deepen a valley indefinitely, for unless the water of the supraglacial 

 cascade escapes as a subglacial stream helow the bed level of the valley 

 a pool will be created and the water in it will form a cushion, and so 

 set a limit to the process. In the third case spur-truncation seems to 

 me to be brought about by the action of running water more than by 

 the rasping action of rock-charged ice. Between glacier side and 



