that the great blocks of the Alps and Scandinavia were floated away on icebergs, and so dropped on the sea bed or on the temporarily submerged land. That icebergs are detached from the land with stones on their surface is known to northern navigators; it is a phenomenon well understood in the Gulf of Bothnia; and, to an imaginative mind, the mer de glace, with its border of moraine, might seem a natural component of such a glacier current as that to which the Salève, the Jura, and the borders of the Lake of Geneva are supposed in this hypothesis to owe their accumulated blocks. It is thought to be a plausible argument in favour of this speculation, that the blocks of granite, porphyry, limestone, &c. are grouped together in distinct patches according to their local origin, both in the vicinity of the Alps and on the plains of northern Germany.[1]
Icebergs are merely the broken-off ends of glaciers, which descend to the sea, or the detached fragments of icy cliffs generated on the coasts of circum-polar regions. When liberated they are carried by oceanic currents through various and often great distances, till, melted, overthrown, or stranded, they yield up the stony masses, which glaciers had brought down, or shore ice had raised up, and thus encumber the sea bed with the spoils of distant lands. When the antarctic expedition had reached 78 south latitude, the vessels were stopped by a barrier of ice, from 100 to 180 feet in height, and 300 miles in extent from east to west; beyond these cliffs of ice, a range of lofty mountains was visible about 60 miles distant, the westernmost of which appeared to be 12,000 feet high. From the face of these ice-cliffs masses were constantly breaking off, and floating northward, bearing with them fragments of rock, probably derived from the mountains from which the glaciers appeared to descend. In the lat. of 66° and 67°, at a distance of 700 miles from the glacier, the ice formed a floating barrier, through which the ships could with
- ↑ See Lyell's Geology, Brongniart, Tableau des Terrains; De Luc's Letters, &c.
