ANTARCTIC GEOLOGY 325 



great ice strait?" The balance of evidence summarized in the pre- 

 ceding pages suggests to the present writers that neither is the case. 

 The apparent occurrence of fault blocks upon the floor of Weddell 

 Sea, the finding of Archaeocyathidae limestones as erratic blocks 

 still farther north in the same sector, the trend of the mountains seen 

 by Amundsen, the extension of the Beacon sandstone to King George 

 V Land, the occurrence of similar sandstone erratics in the seas off 

 Kemp and Enderby Lands — all suggest that the major portion of the 

 continent is one tectonic unit forming a great shield against which 

 the Antarctandes of Graham Land are folded as a continuation of 

 the long South American and sub-Antarctic ridge. Graham Land 

 south of 68° S. latitude is geologically a terra incognita. Does the 

 Andean chain die out against the Antarctic shield or are the trend 

 lines swung westward towards the Pacific? 



It would seem that one of these alternatives is the solution to this 

 problem of the Antarctandes, and to that end the investigation of 

 southern Graham Land and the land sighted by Charcot in the region 

 west of Alexander I Land would do much to clear present obscurity. 

 That the Antarctandes link up across the continent with the Queen 

 Maud Range (and South Victoria Land), as has frequently been 

 suggested, seems geologically improbable. We have noted above 

 that the trend of the Queen Maud Range as last seen by Amundsen 

 from 88° S., if projected, would strike the Weddell Sea area. 



Field Work in Critical Areas and the Use of Aircraft 



It is unfortunate that nothing definite is known of the geological 

 constitution of these mountains (apart from Mt. Betty and the 

 suggested presence of Beacon sandstone on Mt. Fridtjof Nansen), 

 though it may reasonably be expected that they are similarly con- 

 stituted to those through which Beardmore Glacier cuts. For the 

 clearing up of the main problem a transcontinental journey similar 

 to that projected by Shackletoh would be invaluable, but much 

 light could be thrown upon the problem by less ambitious programs 

 in critical areas, such as that between King Edward VII Land and 

 Graham Land, which unfortunately is of all areas of the coast line 

 the most difficult to approach. The time-honored methods of the 

 past generation have failed before the barrier of pack ice which is 

 here particularly difficult to penetrate. The expedition of the future 

 may, however, be in a position to renew the attack either by airplane 

 from bases on the flanks, by seaplane from the pools within the outer 

 portion of the pack ice itself, or by dirigible from the continents to 

 the north. Reconnaissance, the conveyance of sledge parties to 

 suitable points of attack, and supply of the necessary stores to enable 

 the attack to be kept up, are all part and parcel of the r61e likely to be 



