From Ruth Tongue's Forgotten Folk-Tales of the English Counties, told by a woman "in a Watchet teashop on a wet day in about 1916".
here was a fisherman come down in the owl-light into St Audries Bay. He'd heard someone singing down there in the dark and he were curious. So he come down by all a tip-toe. But he couldn't be quiet enough if he tried and the sea-morgans was all away off the rocks and into the tide, but in their hurry they left a baby-morgan a-kicking and chuckling under the cliff waterfall and the fisherman found her.
His heart was sore for a little daughter he'd just left in Watchet churchyard and his wife's heart were abroke. So he takes the baby morgan whoame up over to the farm and puts her in the empty cradle, and his wife took to her at once though she couldn't ever get the little creature's hair dry--not properly dry even in sun and hill wind and it smelled of the sea.
The baby grew up like they all do, and, except that she would be forever paddling and dabbling in the spring-pond and the trout stream, she made 'en a real good daughter till a neighbour came pushing her nose in.
"Dear, dear, how wet your hair be. Go and dry it like a Christian!" But the girl just laughed. Then she had to go and say, "A girt girl like you a-paddling in the spring-pond an't Christian at all. You go down to the sea and have a swim there."
The old couple bustled her out and as she went she heart a queer song coming from the far-away sea. "What ever be that?" she asked, but they wouldn't say and she heard it again behind her and it was the girl singing. "That's my song," she say. "Someone wants me. There will be a storm tonight."
Well, that meddler ran and roused the Doniford and Staple men to chase away this witch--but the girl ran away from them all, laughing. They couldn't catch up with her, and then they heard the song and the waves was thundering on the rocks and they bided where they was up on the cart-track. They heard her singing as she ran out along the rocks and then a great wave took her and no one ever saw her again.