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THE AGE OF ICE.

late at m; t b may show the origin of the block i, which is now going to sea as a buoy. In many cases the icebergs must carry with them stones frozen on the under side, as well as blocks perched on their backs. Dr. Kane speaks of ice-rafts, floating many miles out to sea—tables 200 feet long covered with large angular blocks and bowlders.

Fig. 5.
PSM V04 D667 Greenland glacier shedding an iceberg.jpg
Greenland Glacier shedding an Iceberg.

Though Greenland is said to be inhabited only upon the south and west coast, there is a record of an early settlement upon the side toward Iceland, with which there has been no communication for 400 years. The colony was planted about 1000 a. d., which flourished, and maintained intercourse with its mother-country till the beginning of the fifteenth century. Since that time, owing to the setting in of the arctic current, and the consequent gradual increase of ice upon the coast, the colony became inaccessible, and the records of it disappear from history. At various intervals between, 1579, 1751, etc., down to our own time, the intrepid Danes have striven in vain to reopen communication with their lost colony. This emerald coast, with valleys well stocked with reindeer and verdant glades, is now shut in by the pitiless ice-pack, and the fate of its inhabitants ought to excite the interest of the world. It would be very interesting to be informed of the condition of this colony: whether the increasing cold has enlarged the glaciers so as to push the dwellings out to sea, or whether the habitations are still standing, and a population has sprung up who know of the outside world only by tradition.[1]

Lake-Basins.—A strong argument for the former existence of glaciers over the northern regions comes from the excavation of basins from the solid rock for the reception of lakes. The country most traversed by the ice agency abounds in these rock-hollows. It is very evident that the glacier is the only agency which can well be called upon to explain these phenomena. Running water excavates only on a descending plane. Sea-water acts upon its level, while the glacier requires only a pressure from behind to enable it to ascend mountains. The upward movement of the ice is shown by the striæ to have been exceedingly common.

The glacier grinds hardest where the steeper slope is exchanged for a less inclination of its rocky bed; the tendency of this action is to

  1. Geological Magazine, vol. x., p. 541.