Trying to remember name of an eerie story about a seemingly uninhabited Greek island

"Island of Fear", a short story by William Sambrot.

The story can be found on pp. 298–306 of the anthology Alfred Hitchcock Presents: My Favorites in Suspense, Random House, 1959 which can be borrowed from the Internet Archive (registration required).

I read this in an old anthology years ago.

Any of these covers ring a bell?

A traveler is staying at a Greek seaside town when he notices a wooded island off the coast.

He's in a tiny village on an obscure Greek island, and the place of interest is the walled-off end of the island, approachable only from the sea:

After he'd settled in the primitive little inn, he'd immediately set out for the wall, surveying it from the low knoll, surprised again to note how much of this small island it encompassed.

He'd walked all around it, hoping to find a gate or a break in the smooth, unscalable wall that towered up. There had been none. The grounds within sprawled on a sort of peninsula that jutted out to where rock, barnacled, fanged, resisted the restless surf.

And coming back along the great wall, utterly baffled, he'd heard the faint musical sound of water dropping within, and, peering carefully at the wall, had seen the small aperture, no bigger than a walnut, just above his head.

[. . . .]

Beyond, in the garden beyond the wall, was a fountain, plashing gently. And in the center of that fountain, two nudes, a mother and child.

A mother and child, marvelously intertwined, intricately wrought of some stone that almost might have been heliotrope, jasper or one of the other semiprecious chalcedonies—although that would have been manifestly impossible.

He took a small object like a pencil from his pocket and extended it. A miniature telescope. He gasped, looking once more through the chink. Heavens, the detail of that woman! Head slightly turned, eyes just widening with the infinitesimal beginning of an expression of surprise as she looked at—what?

He asks some of the local fishermen if they will give him a ride over to this island but no one will even talk about it.

"That wall," Kyle said to the spectators, singling out one old man. "I am interested in meeting the people who own that property."

The old man muttered something and walked away.

Kyle mentally kicked himself for the psychological error. In Greece, money talks first. "I will pay fifty—one hundred drachmas," he said loudly, "to anyone who will take me in his boat around to the seaward side of that wall."

It was a lot of money, he knew, to a poor people eking out a precarious existence on this rocky island, with their goats and scanty gardens. Most of them wouldn't see that much in a year's hard work. A lot of money—but they looked at one another, then turned and without a backward glance they walked away from him. All of them.

Later a young man with a noticeable scar surreptitously offers to take him across.

He was standing on the outskirts of the darkened village, gazing unhappily out to sea, when he heard a soft scuffling. He turned quickly. A small boy was approaching. It was the shoeshine boy, eyes gleaming in the starshine, shivering slightly, though the night was balmy.

The boy clutched his arm. "The others—tonight, I will take you in my boat," he whispered.

The boy's scar was described earlier:

A boy, eyes snapping, popped out of the inn with a rag in one hand and some primitive shoe blacking in the other, and began cleaning Kyle's shoes.

Kyle sat down on a bench and examined the boy. He was about fifteen, wiry and strong, but small for his age. He might have, in an earlier era, been a model for one of Praxiteles' masterpieces: the same perfectly molded head, the right curls, two ringlets falling over the brows, like Pan's snubbed horns, the classic Grecian profile. But no, a ridged scar ran from the boy's nose to the corner of the upper lip, lifting it ever so slightly, revealing a glimmer of white teeth.

The traveller, really concerned, returns to the boat, where he finds a sculpture of the scarred young man. Just as he realizes whose island this is, he hears someone behind him. Will he turn to look?

Not an English family named the Gordons. A much more ancient family, named—the Gorgons. Perseus had slain Medusa, but her two hideous sisters, Euryale and Stheno, were immortal.

Immortal. Oh, God! It was impossible! A myth! And yet—

His connoisseur's eyes, even through the sweat of fear, noted the utter perfection of the small statue that leaned against the rock, head turned slightly, an expression of surprise on the face as it peered over one shoulder in the direction of the trees. The two tight ringlets, like stubbed horns above the brow, the perfect molding of the head, the classic Grecian profile. Salt water still flecked the smoothly gleaming shoulders, still dripped from the torn shirt that flapped above the stone waist.

Pan in chalcedony. But Pan had a flaw. From the nose to the corner of the upper lip ran a ridge, an onyx scar that lifted the edge of the onyx lip slightly, so that, faintly, a glimmer of onyx teeth showed. A flawed masterpiece.

He heard the rustle behind him, as of robes, smelled an indescribable scent, heard a sound that could only have been a multiple hissing—and though he knew he mustn't, he turned slowly. And looked.