Last night the tide rose up the shore And washed about old logs long dried. Fresh weeds came in; the sea wind bore Loud threats of doom; a curlew cried.
And now at daybreak mists inspire Live fancies round each sudden form, For well I know that bars may tire Of toys they took that last, great storm!
A night of rising tide, and in the morning the shore looks different. Old logs, long dry, have been soaked again; fresh weeds are strewn about; the wind carried what sounded like threats of doom, and a curlew cried somewhere in the dark. The first stanza is simply the aftermath of a storm night, told in quiet, orderly lines.
The second stanza turns inward. At daybreak, mist hangs over the beach and makes ordinary shapes look alive, so the speaker half sees creatures or figures in every odd lump of driftwood. But there's a knowing undertone: the speaker says he understands that sandbars can "tire" of the objects they collected in the last great storm, and so let them go. The sea, in other words, is imagined as something like a child dropping old playthings.
The mood is hushed and slightly eerie, a mix of dawn calm and leftover unease, with a playful, imaginative streak running underneath.