A few yards down stream the wall of rock jutted out slightly and then receded. As the canoes rounded this a great heaving wave--the vanguard of the flood--tossed them high on its crest and cast them, like a stone from a catapult, straight toward a black, semi-circular hole in the base of the cliff. A furious current swept in the same direction, and even had the boys realized the nature of this new peril they could have done nothing to help themselves.