Next Felix felt the canoe heave up, and he was aware that a large roller had passed under him.

A second and a third followed.

They were without crests, and were not raised by the wind; they obviously started from the scene of the disturbance.

Soon afterwards the canoe moved quicker, and he detected a strong current setting in the direction he was sailing.
The noise did not recur, nor did any more rollers pass under.

Felix felt better and less dazed, but his weariness and sleepiness increased every moment.