The sur­vey­or must at the time of mak­ing the sur­vey, set in such man­ner that they will not be moved by frost, good and suf­fi­cient mon­u­ments mark­ing the exter­nal bound­aries of the tract to be divid­ed and must des­ig­nate upon the plat the points where they may be found. These mon­u­ments must be placed at all cor­ners, at each end of all curves, at the point where a curve changes its radius, at all angle points in any line and at all angle points along a mean­der line, the points to be not less than twen­ty (20) feet back from the nor­mal water ele­va­tion of a lake or from the bank of a stream, except that when such cor­ners or points fall with­in a street, or pro­posed future street, the mon­u­ments must be placed in the right of way line of the street. These mon­u­ments, two of which must be of rein­forced con­crete and set at oppo­site extrem­i­ties of the prop­er­ty plat­ted. All lot cor­ners shall be mon­u­ment­ed in a like man­ner with iron pins or pipe.

Con­crete mon­u­ments shall be in accor­dance with State Plat Act.