One permanent monument shall be placed at each corner and at each change of direction in the boundary lines of the subdivision. Permanent monuments shall be of concrete, reinforced over its full length with a inch reinforcement bar which shall be clearly visible at the top. Such monuments shall be 36 inches long and shall be not less than six inches in least dimension at the bottom and four inches in least dimension at the top, set flush with the established adjoining grade.
(1984 Code, § 16.32.350)