quaking bog

They pressed forward, and in another moment stood on the edge of the quaking bog.

Lying flat, she began slowly and cautiously to wriggle out across the surface of the quaking bog.

They left the strange island in the heart of the quaking bog in the same way they had reached it.

First Aunt: There is a good dyke around about the marshes, and a sort of quaking bog.

It was evidently a quaking bog, a hidden lake, and only the fear behind us drove us on.