Cape Saknussemm
They name the beach with the cave "Cape Saknussemm" and return to Hans to tell him the news. By now he has repaired the raft. They decide to sail round to the new Cape and anchor the raft there.
Having done that, Harry is anxious to proceed through the tunnel. He is furious to find it is blocked by a huge rock, reaching from left to right, floor to ceiling, after only twenty yards. The rock must have fallen after Saknussemm passed underneath. It is too tough and too big to be destroyed by pickaxe or crowbar. They will have to blast it away.
It is midnight by the time the charge is in place. They decide to wait until morning before detonating the powder.
The next day is the twenty-nineth of August. Harry lights the fuse and the three men immediately push off from the beach on the raft, so that they can watch the explosion from the saftey of the water.
There is a terrific roar and the shape of the coastline in front of them changes completely. The rocks seem to be drawn aside like a curtain to reveal a fathomless, bottomless abyss. The sea around them goes mad and drops down into the blackness as a single block. The raft and its occupants go straight down with it.