THE results of the explosions made by the German Greenland Expedition to determine the thickness of the Greenland ice-cap have been awaited with much interest, owing to their widespread geographical and geological bearing. Two theories have been advanced as to the structure of Greenland. According to one theory, it is a high plateau capped with ice, and the rapid flow of the Greenland glaciers is due to their steep gradient. According to the rival view, Greenland, like Ireland, is a saucer-shaped land, consisting of a rim of mountains with the central hollow filled by ice, which flows outward over the surrounding highlands. Carvill Lewis adduced Greenland in support of the assumed covering of the Irish Sea by a dome of ice which then flowed over the Welsh mountains to the height of 1300 ft. Croll claimed that the Greenland ice was as thick as its height above sea-level, in support of his view that the ice at the south pole is 24 miles thick. Croll s estimates of the thickness of the Greenland ice-cap were declared impossible, in accordance with Lord Kelvin s calculations as to the maximum possible thickness of ice.