Upon the filing with the Clerk of any initiatory or referendum petition, the Clerk shall canvass the signatures thereon to determine whether said petition contains a sufficient number of signatures of registered electors of the City. Any signatures obtained more than thirty (30) days before the filing of such petition with the Clerk shall not be counted. The Clerk shall complete said canvass within fifteen (15) days from the filing of said petition. If the petition does not contain a sufficient number of signatures of registered electors of the City, the Clerk shall notify forthwith the person filing such petition and ten (10) days from such notification shall be allowed for filing of supplemental petition papers. When a petition with sufficient signatures is filed within the time allowed and is in compliance with the provisions of this Charter, the Clerk shall present the petition to the City Commission at its next regular meeting.