ANTARCTIC ADVENTURE AND RESEARCH 



miles across and has a rear wall some eight thousand 

 feet high. The absence of any collecting ground at 

 the head of many of these cirques certainly indicates 

 that they are not due to normal glacier erosion. ]\Iy 

 Antarctic experience led me to believe that nivation 

 (i.e. thaw-and- freeze chipping) as described by Hobbs 

 in his book, Existing Glaciers (1911), is the major 

 process involved. I give a full discussion, based on- 

 local examples, in my book. Physiography of Mac- 

 Miirdo Sound (1922). 



Charles Darwin advised young naturalists to seek 

 for evidence of evolution in a given group of organisms 

 among the specimens themselves. If enough samples 

 are present there are, said he, likely to be many differ- 

 ent stages represented. Applying the same principle in 

 Antarctica, I believe that I can see varying stages in the 

 evolution of the topography of the Taylor Valley indi- 

 cated in adjacent land- forms (see Figure 8). Thus 

 all along the Royal Society Range to the south is a suite 

 of eleven cirque valleys extending over some thirty 

 miles in length, which constitutes a ''Fretted Upland," 

 as Hobbs terms it. These usually contain small stag- 

 nant glaciers, which the first observers called 'Tee 

 Slabs." Such glaciers are situated at the heads of the 

 valleys concerned. Above these lower cirques are sev- 

 eral series of smaller cirques in the scarp of Lister 

 itself, in shape looking as if a giant had pressed his 

 thumb repeatedly into a slope made of putty. The 

 writer believes that this type of cirque topography is 

 the first which developed on the onset of the Ice Age. 



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