Shulamith Levey Oppenheim is a published author of many Children's Books. Some of her writtings are Lily Cupboard, Hundredth Name, I Love You, Bunny Rabbit & Fish Prince and Other Stories: Mermen Folk Tales among many others.
It’s a wistful and winsome tale of love and longing between young 15 year old Marion and the white whale who appears in the voe with a torn flipper. Her father, Edward Sinclare, and brother, Graeme, fear for her, but her mother, Ursula, a woman of the Clan MacCodrun of the Hebrides, recognizes the whale whose flipper she salves and is instantly healed as being a Finn, magical kin of the Children of the Sealfolk. Her father rails against such pagan beliefs and denies that his beloved daughter, born with the slightest webbing between her fingers and toes, bears the Selchie’s seed, and longs to return to her kind. Desperate to save his daughter, the father begs his wife to allow him to destroy the trunk she had brought with her as a bride twenty years before, including the soft, leather belt. Ursula realizes it won’t change what must be, agrees and the lingering whale swims away to the north. Marion pines until the whale returns to give her the soft belt that has been dumped into the deep waters with her mother’s trunk. The belt allows her to transform into a mermaid, but also to return and take it off to visit her family.
I've been trying to locate a book by this name that was a favorite of mine when I was young. This could very well be it; just a different cover now. Good telling of the legend of the selchie/selkie and beautiful black and white illustrations.