(a)   The City Planning Commission shall consist of the Mayor, one member of the Council to be appointed by the Council, and three electors of the City, not holding other municipal office, to be appointed by the Mayor. The terms of the present members of the Planning Commission shall terminate on December 31, 1955, and their successors shall be appointed by the Mayor for a term of six years except that, of the three appointed for the terms beginning January 1, 1956, one shall be appointed for a term of two years, one for a term of four years and one for a term of six years. A vacancy occurring during the term of any member of the City Planning Commission shall be filled for the unexpired term in the manner authorized for an original appointment.
   (b)   The City Planning Commission shall have such powers and duties as shall be conferred upon it by the Council concerning (a) the plan, design, location, removal, relocation and alteration of any buildings or structures owned by the public or located on public streets or public property; (b) the location, relocation, widening, extension and vacation of streets, parkways, playgrounds and other public places; (c) the approval of plats for the subdivision of land; and (d) the zoning of the City for any lawful purpose or purposes.