The creek which Thor was following was a tributary of the Babine, and he was headed pretty nearly straight for the Skeena.

As he was travelling upstream the country was becoming higher and rougher.

He had come perhaps seven or eight miles from the summit of the divide when he found Muskwa.
From this point the slopes began to assume a different aspect.

They were cut up by dark, narrow gullies, and broken by enormous masses of rocks, jagged cuffs, and steep slides of shale.

The creek became noisier and more difficult to follow.
Thor was now entering one of his strongholds: a region which contained a thousand hiding-places, if he had wanted to hide; a wild, uptorn country where it was not difficult for him to kill big game, and where he was certain that the man-smell would not follow him.
For half an hour after leaving the mass of rocks where he had encountered Muskwa, Thor lumbered on as if utterly oblivious of the fact that the cub was following.