Commissioners appointed pursuant to § 15.2-3100, before proceeding to ascertain a boundary, shall employ a competent surveyor to run the boundary. The commissioners shall, with the best evidence which they can procure, direct the surveyor where to run the line and shall have him mark the boundary. After the boundary line has been run and marked, the commissioners shall require the surveyor to make two plats of the courses and distances of the line and to note thereon particularly such well-known places or prominent objects through or by which it passes as, in the opinion of the commissioners, will best designate the line.