300 TECTONIC GEOLOGY 



Bay of Whales (Framheim) to the Pole, Amundsen reached the foot of the great 

 horst in lat. 86'' S. He found it to extend approximately for at least 100 miles 

 farther in a direction S.S.E. and finally easterly, attaining altitudes of 15,000 feet 

 above sea-level. The rocks of the hoi-st, on the poleward side, drop sharply from these 

 great elevations to an altitude of a little over 10,000 feet. Still farther polewards, 

 to near 87° S-, the surface of the inland ice rose to about 11,000 feet, after which 

 it descended to about 10,260 feet (3127 metres) at the Pole. Captain Amundsen 

 provisionally considers that this great horst is probably a continuation of the 

 Andean Chain of South America. There can be no doubt that this horst is the 

 dominant structure of the Antarctic continent. 



In all probability this horst has a length of about 3200 miles. Its width, as 

 already stated, from opposite the south-west portion of Ross Sea to the point where 

 it was crossed by Amundsen, varies from about 50 miles to 100 miles. The interest- 

 ing question suggests itself, are the rocks of the horst folded after the manner of 

 those in the Andes ? As pointed out by H. T. Ferrar, the massive Beacon Sand- 

 stone formation terminates in steep, and in places precipitous, slopes along the 

 whole line of coast from beyond Cape North southerly to beyond the Royal Society 

 Range. It is probable that Beacon Sandstone caps the range from that point to at 

 least as far south as where Sir Ernest Shackleton's Southern Party, after ascend- 

 ing the granite and slate mountains of the horst in lat. SS'' 33' S., long. 170^ E., 

 reached the sandstone formation at an altitude of 6000 feet in 85° S. The sand- 

 stone formation there, containing seven seams of coal, thin portions of which at any 

 rate are of economic value, were found to dip gently at an angle of about 6° to 8° 

 towards the north-east.* There was no evidence at all of these rocks, which are 

 provisionally classed as of Gondwana Age, having been folded. On the other hand, 

 as described by Suess, the rocks of the South American Andes are strongly folded 

 throughout a great part of Peru and Chili, including Patagonia, strata as new as 

 Cretaceous being strongly involved in the folding. For example, at Staaten Island 

 tlie Cretaceous strata are much altered by pressure, and dip at nearly vertical 

 angles. At Depot Island, to the north of Granite Harbour, on the west coast of 

 Ross Sea, the ancient gneiss platform is folded parallel with the coast-line, but this 

 structure apjieared to be the exception rather than the rule. At Mount Nansen, 

 to the north of the Drygalski Ice Barrier Tongue, Beacon Sandstone strata appear 

 to be almost horizontal. Recently Amundsen has exhibited photographs of the 

 magnificent table-topped mountain, called by him Fridtjof Nansen, which make 

 it almost certain that this mountain, like Mount Nansen of the Drygalski Barrier 

 Region, is capped by gently inclined Beacon Sandstones. In the direction of Graham 

 Land the end of this horst, near Terre Louis Philippe, at Hope Bay, is distinctly 



* Only small pieces of coal about 2 to 3 inches long (50-8-76'2 millimetres) by about J inch thick 

 (12-7 millimetres) were secured by Shackleton's party from this seam. Shortage of food prevented 

 them from taking more. This was the first coal ever discovered in Antarctica. 



