The waters compassed me about, even to the soul: the depth closed me round about, the weeds were wrapped about my head.
The waters compassed me about, even to the soul - i:e., threatening to extinguish the animal life.
The weeds were wrapped about my head - he felt as if the seaweeds through which he was dragged were wrapped about his head. Or, rather, Jonah was not swallowed at once, but sank to the bottom of the sea, God keeping him alive there, as he did subsequently in the fish's belly. Then it was that the seaweed was wrapped round his head, as though it were his grave napkin.