Mich. Comp. Laws § 54.210

Sec. 10. (1) When set, a monument shall possess a magnetic field, be at least 1/2 inch in diameter and a minimum of 18 inches in length, and be legibly capped showing the license number of the surveyor. (2) Unless it is to be set in a public roadway, a monument shall be set with not less than 2/3 of its length below the surface of the surrounding ground. (3) If a corner is located in a public roadway and the roadway is not hard-surfaced at the corner, the monument shall be placed at least 6 inches below the surface of the roadway. (4) If a corner is located in a public roadway and the roadway is hard-surfaced at the corner, whether by concrete, asphalt, or otherwise, the monument, including, but not limited to, a monument set before the effective date of the 2000 amendatory act that amended this section, shall be visible or contained within a visible protected enclosure and shall comply with any requirements of the agency having jurisdiction over the roadway. (5) If a corner to be monumented is located on a rock outcropping, the monument shall be an iron bar at least 1/2 inch in diameter, drilled and grouted into solid rock to a depth of at least 8 inches.