When any plan of consolidation has been approved by the assistant judges, the selectboard of each of the towns involved shall publish such plan by posting a copy of the same in at least three public places in each town for three consecutive weeks and causing the same to be published once a week for three consecutive weeks in a newspaper in general circulation in such town. Within 30 days after such publication the selectboard shall call a town meeting of each town to be held on the same day for the purpose of voting on the proposed consolidation. The voting shall be by ballot and shall be held at the usual polling place in each town and the polls shall be open from 6:00 A.M. to 6:00 P.M. (Added 1963, No. 146, § 5.)