Underlying the great flat plain of the Yucatan is a limestone shelf.

The limestone shelf acts as a natural filter for water that passes over it.

The island is basically a sand bar over a limestone shelf.

There, against a limestone shelf, I moored the punt to an iron ring.

He broke into a run across the flat, gritty limestone shelf.

Here are scattered numerous slate boulders which have been carried by glacier action and dumped on a limestone shelf.

Aherla is built on a limestone shelf typical of the Cork ridges and valleys.

It is a limestone shelf never much more than a mile wide that begins at Dijon, 30 miles to the north.

There's a limestone shelf big enough for both of us to sit upon and look across the camp and the bay to the open sea.

The fire burned high and bright, set on the edge of one of the many limestone shelves layered throughout our woods.