At last the canoes grounded on some yielding surface and refused to budge. Ned staggered forward and found their prows imbedded in what he judged to be a bar of sand and gravel stretching across the channel. He walked on a few steps to ascertain its width, and was amazed and frightened by coming in contact with a solid wall of rock.
"Come here, quick, Nugget!" he called hoarsely.
Nugget waded alongside the canoes, and was soon on the bar.
"What is it?" he cried. "Anything wrong?"
For answer Ned took the last match from the little metal box, and lighted it.
As the little blaze flared up the boys looked curiously about them. One brief glimpse revealed the awful truth. The sandy bar was in reality the end of the passage. Beyond it rose a smooth, slimy wall, and overhead was a low jagged roof dripping with moisture. The canoes lay in a quiet pool of water that was as dead and void of current as a mill pond.