Ibant Obscur?

To-night I saw three maidens on the beach,
Dark-robed descending to the sea,
So slow, so silent of all speech,
And visible to me
Only by that strange drift-light, dim, forlorn,
Of the sun's wreck and clashing surges born.

Each after other went,
And they were gathered to his breast--
It seemed to me a sacrament
Of some stern creed unblest:
As when to rocks, that cheerless girt the bay,
They bound thy holy limbs, Andromeda.