Fig. 321.—Tabular Antarctic iceberg separating from the shelf ice (after Shackleton).
In both the northern and southern hemispheres those bergs which have floated into lower latitudes have suffered profound transformations. Their exposed surfaces have been melted in the sun, washed by the rain, and battered by the waves, so that they lose their relatively simple forms but acquire rounded surfaces in place of the early angular ones ([Fig. 318], [p.291]). Sir John Murray, who had such extended opportunities of studying the southern icebergs from the deck of the Challenger, has thus described their beauties:
“Waves dash, against the vertical faces of the floating ice island as against a rocky shore, so that at the sea level they are first cut into ledges and gullies, and then into caves and caverns of the most heavenly blue, from out of which there comes the resounding roar of the ocean, and into which the snow-white and other petrels may be seen to wing their way through guards of soldier-like penguins stationed at the entrances. As these ice islands are slowly drifted by wind and current to the north, they tilt, turn and sometimes capsize, and then submerged prongs and spits are thrown high into the air, producing irregular pinnacled bergs higher, possibly, than the original table-shaped mass.”
Reading References for Chapters XX and XXI
General:—
I. C. Russell. Glaciers of North America. Ginn, Boston, 1897, pp. 210, pls. 22.
Chamberlin and Salisbury. Geology, vol. 1, pp. 232-308.