Page:Polar Exploration - Bruce - 1911.djvu/93

Rh they are very much smoother and more rounded-off than the rocks on the shores of warmer seas. They are, in fact, quite polished. The reason is not far to seek, for to the depth of a fathom or so the sea becomes frozen solidly during the winter, and when summer comes and the pack breaks up, this and even heavier ice is driven along the shore and grinds over the rocks, rubbing and polishing them and preventing seaweed from growing there. Naturally also, for the same reason, one need not expect to find shore animals, and, as a matter of fact, shore fauna is very scanty in the Polar Regions. There may be a few limpets in a relatively deep crack, or a few amphipods and a stray fish, but there are few hiding-places for them among rocks so depleted of weeds. No sessile animal is safe from being crushed and scoured off the rocks by stranding ice. Even on a sandy shore there is little, though there is better chance here, especially if it does not shelve steeply. Worms, copepods, ostracods and the like may sometimes be found in abundance on a shallow sandy shore, especially if there is some bar or barrier which prevents heavy ice being stranded on the beach at high water during the short summer season.

On the land, plant life may be represented by more than diatoms and other algæ. But, be it noted, land plants have a better chance