Now and then Thor would stop and sniff over the edge of them.

He was hunting for something, and yet he never seemed to find it; and each time that he started on afresh Muskwa was so much nearer to the end of his endurance.
They were fully seven miles north of the point from which Bruce and Langdon were scanning the valley through their glasses when they came to a lake.

It was a dark and unfriendly looking lake to Muskwa, who had never seen anything but sunlit pools in the dips.

The forest grew close down to its shore.

In places it was almost black.