It shall be the duty of the engineer in charge, or the owner, or owners, or the agent of the owner or owners, of any subdivision of land in this state to have permanent cornerstone monuments, of stone or concrete, not less than twenty-four inches in length by six inches square at the top, or not less than six inches in diameter, with proper centers, placed at the most important corners (where permanent corners do not already exist) so that there shall be not less than two permanent corners to each lot or block of any subdivision thereafter made, and the position of the same shall be indicated on the plan or map when finally filed for record. No certificate of acknowledgment, or other proof thereof, shall be necessary or prerequisite to the recordation of such plat, map or plan.