The clerk shall, within 10 days from the filing of the supplemental petition, make a like examination of the supplemental petition and certify to the result of the examination as provided in Section 2936. If the certificate of the clerk shows any petition, or any petition together with a supplemental petition, to be insufficient, it shall be retained by him and kept as a public record, without prejudice, however, to the filing of a new petition to the same effect. But if, by the certificate of the clerk, any petition, or any petition together with a supplemental petition, is shown to be sufficient, the clerk shall forthwith present the petition to the legislative body of the municipal corporation.