SCENERY AND TOPOGRAPHY 



has had a very different history from the nunatak. 

 Examples of both types are to be seen in the block 

 diagram of the Mackay Glacier (see Figure 24). 

 Thus Mount Suess is a nunatak. I doubt if the main 

 glacier ever surmounted it, though it is quite likely that 

 cirque-cutting gave rise to the sharp ridges and peaks 

 of its summit. To the north is Gondola Ridge, a 

 typical nunakol which was littered with moraine and 

 has only recently been freed from its ice covering. 

 Just to the southeast is Redcliff Nunakol of a similar 

 nature. 



JVafer Erosion. — We may conclude this chapter by 

 a brief reference to the agents w^hich have cut out 

 the Antarctic topography. Wind has not much power 

 in a land covered with ice and snow, though I give 

 a number of examples of wind transport and erosion 

 in my memoir. But I was especially struck with two 

 facts in my study of the Ross Sea area. Firstly, most 

 of the ice is stagnant nearly all the year round and 

 cannot therefore be eroding much. Secondly, although 

 the average air temperature was only 25° F. in the 

 warmest months, yet there was a great deal of running 

 water at far colder air temperatures. Thus on Sep- 

 tember 17th, 191 1, I noticed snow melting on black 

 rock when the air temperature was 25° degrees below 

 freezing. So that numberless examples of water 

 erosion were visible, such as gullies, meanders, terraces 

 and small deltas at mouths of streams. One of these 

 streams was twenty-five miles long and flowed under 

 the Koettlitz Glacier ice until the middle of March, 

 when the air temperature was —8° F. (i.e. 40° below 



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