Sound of screaming was a premonition of a drowning.
The six crew of a salmon coble, five from Melvich and one from Portskerra, tied up for Sunday and decided to meet at 3 a.m. on Monday to start fishing again. The Portskerra man took the path to Melvich to meet up with the rest, who were late. He had to pass a big stone with iron rings set into it for tying up boats. He put his hand on the stone and repeatedly heard a scream like someone drowning in the sea. When the rest of the crew arrived he tackled them about being late, but when they checked their watches it was just three o'clock. They went to the nets, then came ashore for breakfast, and soon the story was being told around both villages. The following Monday they made an early start again. This time the crew from Melvich found the body of a woman under the stone, drowned. She had been with them the previous night. A week had passed since the Portskerra crewman had heard the drowning noises.
The woman's son is still  alive, so Donald Grant mentions no names. She was a woman who was fascinated by the sea and would sit on the rocks watching it at night. She evidently gave herself to it.