Whenever the Planning Commission has adopted a Master Plan relating to the major street system of the territory within its subdivision, jurisdiction or part thereof, and has filed a certified copy of such Plan in the office of the County Register of Deeds of the county in which such territory or part is located, then no plat of a subdivision of land within such territory or part shall be filed or recorded until it has been approved by the Planning Commission and such approval entered in writing on the plat by the Chairman or Secretary of the Commission.