4 o0 REVIEWS 



area o\ deep*sea deposits clearly indicates a very deep submergence of 

 this region, probably during the Jurassic period. The deposits probably 

 occur in geosynclines developed at the edge of the permanent Australa- 

 sian continental segment. 



R. C. M. 



Glaciology of the South Orkneys: Scottish National Antarctic Expedi- 

 tion. By J. H. Harvey Pirie. Trans. Roy. Soc. Edin., 

 XLIX, Part IV, pp. 831-61. Figs. 14, pis. 11, including one 

 map. 

 The South Orkneys have such a climate that the line of perpetual 

 snow is practically at sea-level; the summer temperatures are rarely 

 above freezing-point. The mean annual temperature is 2 2?7 F. The 

 mean temperatures of the warmest and coldest months are 3i?5 and 

 i2?oF., respectively. Foehn winds having passed over the central 

 highlands sometimes produce as high a temperature in midwinter as in 

 summertime. 



The islands are almost entirely snow-covered throughout the year. 

 The resulting glaciers are characteristically antarctic in type. The 

 surfaces are practically all covered with neve, there are no surface 

 moraines, crevasses are rare except at escarpments, the whole mass of 

 the glaciers shows stratification, and the glaciers terminate in sea-cliffs. 

 The land- relief gives rise to various forms of glaciers: 



I. Ice-sheets, including: 



a) Inland ice. 



b) Ice caps of the Norwegian type. 



c) Much of the Spitzbergen type of ice caps. These are ice sheets which 

 conform to the topography, overlying both valley and hill. 



II. Glaciers properly so called, 

 c) Valley glaciers. 

 /») Suspended cliff glaciers. 



III. Piedmont glaciers. 



These cover the low slopes between the mountain sides and the seashore. 

 They end in cliffs from 15 to 20 meters high; their surfaces are uniform 

 and snow-covered, having a gentle slope from the sea to the hills behind. 

 They are fed by local precipitation and are not dependent upon snow-field 

 reserves; they show well-marked horizontal stratification. 



IV. Glaciers of the coastal belt and shelf. 



a) Shelf-ice, such as the Great Ross Barrier. 



/)) Ice-foot glaciers which lie in the zone between land and sea. They 



are composed of layers of neve ice formed in place chiefly of'drift snow 



supplied by wind action. 



