If the rock sank, the spirit would stay in the world below and there would be death.
The rock sank, and the people knew then that the twin was dead, and First Man remembered the agreement they had made with the sun.
Where the ice started, in the uplands, much weathered rock - boulders, clay and sand - sunk into it.
That water would weigh less than the rock, so the rock can sink.
The rock sank abruptly, and every building and living thing on the island tumbled to the ground.
The captain said: 'When the rocks sink - first one, then t'other.'
One rock is sinking first because it's smaller.
And the rock was slowly sinking through the air like a stone through water, pitching this way and that as it fell.
That is, either the flat rock had sunk or the volcano had been thrown upwards.
Meanwhile, the old rock at the other end of the plate sinks back down into the earth's interior, where it melts away.