It was shut in by hills whose rocky sides were seamed by ravines and covered with banks of stones and short brush, through which it was almost impossible to force a passage.
After making several attempts to get out of the valley, the men plodded on through the muskeg, tramping down the wiry grass, often stumbling over a partly submerged tree-trunk.
Then one day Blake felt his head reel.

He staggered, and dropped down heavily.
"Sorry!" he mumbled.

"Malaria!" His companions gazed at him in dismay.

His face was flushed; his eyes glittered; and he lay limply among the grass.

He looked seriously ill.
Harding, realizing that the situation must be grappled with, resolutely pulled himself together.
"You can't lie there; the ground's too wet," he said.