. British Antarctic expedition, 1907-9, under the command of Shackleton : reports on the scientific investigations ; geology. rst withany approach to accuracy. The great horst, as a whole, has not been seriouslyreduced by erosion since its inception as the result of faulting. Provisionally it maybe concluded that these ranges show signs of adolescence rather than of either youth or of maturity, t Peneplains. There is strong evidence of the horizontally bedded plateau sandstone,the Beacon Sandstone, having been deposited upon an ancient peneplain of crystalline * The photograph of Mount Fr
. British Antarctic expedition, 1907-9, under the command of Shackleton : reports on the scientific investigations ; geology. rst withany approach to accuracy. The great horst, as a whole, has not been seriouslyreduced by erosion since its inception as the result of faulting. Provisionally it maybe concluded that these ranges show signs of adolescence rather than of either youth or of maturity, t Peneplains. There is strong evidence of the horizontally bedded plateau sandstone,the Beacon Sandstone, having been deposited upon an ancient peneplain of crystalline * The photograph of Mount Fridtjof Nansen, 15,000 feet above the sea, published by Amundsen(The South Pole, vol. ii., facing page •iO) proves the plateau rocks to extend for at least 190 miles the Beardmore Glacier. t The fact must be emphasized that the great outlet valleys of the Antarctic have been cut down todepths of from 5000 feet to 8000 feet below the general original level of the plateau, that their width isfrom a mile up to about 15 miles, and their length from 30 to about 100 miles. Thus the Horst has beendeeply dissected. PLATE III. GENEKAL MAP SHOWING THE CHIEF PHYSIOGRAPHIC AND TECTONICFEATURES OF SOUTH VICTORIA LAND 8 VALLEYS OF THE HORST schists, gneiss, granite, slate, and altered limestone. A plateau of crystalline rock,extending eastwards from the eastern base of Mount Lister for a distance of about 10 to12 miles (18-19 kilometres) in width, appears to be a very ancient peneplain. This maybe a Pre- Beacon Sandstone peneplain, that is probably a Pre-Gondwana peneplain.*This has been re-discovered by erosion in Cainozoic time. Its height above sealevel varies from about 4000 feet to 6000 feet. The figure below is a generalpanoramic view from our winter quarters at Cape Royds on Ross Island, lookingwestwards over 50 miles (80 kilometres) across McMurdo Sound to the WesternMountains. Valleys. The Section, Plate V., shows the position and relative sizes of thesetransverse valleys, m
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Keywords: ., boo, bookcentury1900, booksubjectgeology, booksubjectpaleontology
