We may also conclude that such land
will become in the course of ages almost everywhere scored and polished like the
rocks which underlie a glacier. The discharge of ice into the surrounding sea
will take place principally through the main valleys, although these are hidden
from our sight. Erratic blocks and moraine matter will be dispersed somewhat
irregularly after reaching the sea, for not only will prevailing winds and
marine currents govern the distribution of the drift, but the shape of the
submerged area will have its influence; inasmuch as floating ice, laden with
stones, will pass freely through deep water, while it will run a ground where
there are reefs and shallows. Some icebergs in Baffin's Bay have been seen
stranded on a bottom 1000 or even 1500 feet deep. In the course of ages such a
sea-bed may become densely covered with transported matter, from which some of
the adjoining greater depths may be free. If, as in West Greenland, the land is
slowly sinking, a large extent of the bottom of the ocean will consist of rock
polished and striated by land-ice, and then overspread by mud and boulders
detached from melting bergs.
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