contour line

The scenery is quietly pleasant, the hills away to the southwest exceeding, here and there, the 500 feet contour line.

Who gave the 1,000 feet contour line that arbitrary nomenclature is unknown.

The contour-line of 0, or datum level, is the coastal boundary of any land form.

It follows the 600-feet contour-line and winds 211 therefore exactly round the outline of the hill.

It ran straight along the 300-feet contour-line, and took the southern edge of a wood called Brockham Warren.