298 TECTONIC GEOLOGY 



Antarctic Sector is seimrated from the mainland by longitudinal canals, such as 

 Gerlache Strait and Orleans Channel. In fact this part of the Antarctic continent 

 has dissolved itself in archijielagoes, which form a series of " panzer-horsts." This 

 geographic condition perhaps persists westwards to King Edward VII. Land, but 

 the recent discoveries of Roald Amundsen, together with the few observations of the 

 Japanese Expedition under Lieutenant Shiraze, suggest that there are considerable 

 land masses to the south of King Edward VII. Land. East of this fractured and 

 sunken area in the Western Hemisphere and west of it in the Eastern Hemisphere 

 rise the Antarctic Andes, as Amundsen holds, towering to heights of 15,000 feet 

 (4572 metres) in Mount Frithiof Nansen, and to nearly 13,000 feet (3962 metres) 

 in Mount Lister in the Royal Society Range. Beyond the slopes of the Antarctic 

 Andes, facing the Atlantic and Indian Oceans, vast plateaux extend inland, in places 

 for a distance of over 1000 miles (1610 kilometres) back from the ocean. This 

 plateau for the most part rests on a foundation of crystalline rocks of Pre-Cambrian 

 ao-e. In South Victoria Land the Pre-Cambrian Complex is followed by Cambrian 

 limestones, recalling the sequence in the eastern part of the Cordillera Real of the 

 Bolivian Andes,* but not its structure, for in South Victoria Land no evidence of 

 folding or overthrustinof, like that which characterises the Bolivian Andes, has as 

 yet been detected. 



In South Victoria Land the Cambrian limestones and slates are followed by a 

 vast sandstone formation, possibly of more than one geological age, mostly hori- 

 zontally bedded, its higher strata containing coal seams, fossil wood and leaves, 

 together with bony plates of some fish-like animal. f This plateau recalls that of 

 Southern Brazil, with the coal-measures at the base of the Santa Caterina System, 

 of Permo-Carboniferous age, the gneissic platform of the Falkland Islands with the 

 Gondwana beds of Speedwell Island, or possibly the Rha?tic plant-bearing beds of 

 the Pre -Cordilleras of South America, and the Trias-Jura Coal-measures of Tasmania. 

 It is even possible that the topmost sedimentary beds of the Antarctic Horst, in 

 the Ross region, may ascend as high as the freshwater Puca Sandstones of South 

 America, which with their Deinosaur remains are classed as Cretaceous. J 



Like the Permo-Carboniferous and Trias-Jura Coal-measures of Tasmania, those 

 of South Victoria Land are invaded by huge sills and dykes of granophyric quartz- 

 dolerite. 



The affinity of the American Sector of Antarctica with the South American 

 Andes is clear and obvious. Strata, chiefly of Mesozoic age, are there folded, mostly 



* "The Face of the Earth," Suess, English translation by Sollas, vol. iv. p. 47.3. 



t These were discovered by Messrs. T. Griffith Taylor, B.Sc, &c., and F. Debenham, B.Sc, of the 

 British Antarctic Expedition of 1911-13 under Captain R. F. Scott, M.V.O., R.N. They were found 

 in fragments of Beacon Sandstone at Suess Nunatak, inland from Granite Harbour, in the region of the 

 Mackay Glacier. These have subsequently been shown by Dr. A. S. Woodward to be of Devonian Age. 



J The chronological classification of these rocks will be made clearer when the fossil plant material 

 obtained by Captain R. F. Scott's recent Antarctic Expedition is elaborated. 



