REVIEWS 523 



snow layers of certain parts of the Ross Barrier, which is practically at 

 the sea-level. The snow particles are said to remain angular for two or 

 three years, which contrasts strongly with the rapidity of snow granula- 

 tion in warm and moist lands. These and other phenomena of like type 

 clearly show that the processes of granular growth and glacial consolida- 

 tion sometimes at least proceed with surprising dehberateness. With 

 little doubt, this is due rather to the persistence and continuity of the cold- 

 ness and dryness of the region than to any special intensity of these, 

 though they seem to be remarkably intense at times. 



In contrast to the unsurpassed display of the snowy, neve, and earlier 

 stages of glacierization, Antarctica offers only an exceedingly scant exhibit 

 of the later and more soHd phases of glacier development, particularly 

 those associated with the more forceful and distinctive work of glaciers, 

 such as the bruising, scoring, grinding, and polishing of rocks. Some 

 httle emphasis has already been laid on the fact that the sea cuts off what 

 might otherwise be the later glacier history of the main Antarctic ice 

 mantle and substitutes floating careers as derivative icebergs. But this 

 spectacular change, great as it is, does not seem to represent the whole 

 truth, for not a few Antarctic glaciers end on the land and it might be 

 expected that these would take on the same features and activities as 

 the short glaciers, or glacial tongues, in similar latitudes in the Arctic 

 region. A comparison with the latter, in almost identical latitudes, 

 shows that the two are markedly different. In both cases some of these 

 are tongues of the main ice-caps, while some are independent local devel- 

 opments. In the Arctic region the rule is vigorous action in the form of 

 rock-scoring and the development of schistose structure in basal portions 

 of glaciers with abundant insheared debris of all sorts and sizes. In 

 Antarctica, according to this report, such evidences of vigorous forceful 

 action are singularly scant. This appears very fully and explicitly in 

 the chapter on "Structure of Glaciers" (R. E.P) (pp. 223 ff.). Striated 

 bowlders, grooved and planed glacier bottoms and sides, rock-flour, and 

 true subglacial till are almost absent; indeed they are even conveniently 

 spoken of as simply absent. The schistose structure and insheared 

 glaciated material, so wonderfully displayed in the vertical sides and ends 

 of the glaciers of the corresponding Arctic region — particularly about 

 Inglefield Gulf — seem from this report to have no really parallel develop- 

 ment in Antarctica. There is, indeed, some banding and "silt layers" 

 in the lower parts of some of the glaciers, but in only one or two cases 

 do the authors find evidence which permits the supposition that the silt 

 could have come from the bottom (see pp. 230-31). Silt layers of surface 



