Colo. Rev. Stat. § 34-49-103
Such owners shall cause the same to be surveyed and a plat thereof to be made by the county surveyor or some other competent surveyor, which plat shall particularly describe each fraction as blocks and lots, describing by appropriate lines each fraction or parcel of land so platted. Reference shall also be made upon the plat to some known and permanent monument from which surveys may be made. If no such monument exists within convenient distance, the surveyor shall, at the time of making his survey, plant and fix at least three feet below the surface, at a corner most convenient for reference, a good and sufficient stone, the total expense of which shall not exceed the sum of fifteen dollars, and the surveyor shall designate upon the plat the point where the same may be found.
C.R.S. § 34-49-103