Biorn is said to have had a horse which was splendid and of exceeding speed, so that when all the rest were powerless to cross the river it alone stemmed the roaring eddy without weariness.

This rapid comes down in so swift and sheer a volume that animals often lose all power of swimming in it, and perish.

For, trickling from the topmost crests of the hills, it comes down the steep sides, catches on the rocks, and is shattered, falling into the deep valleys with a manifold clamour of waters; but, being straightway rebuffed by the rocks that bar the way, it keeps the speed of its current ever at the same even pace.

And so, along the whole length of the channel, the waves are one turbid mass, and the white foam brims over everywhere.

But, after rolling out of the narrows between the rocks, it spreads abroad in a slacker and stiller flood, and turns into an island a rock that lies in its course.