Section 12B. Two or more contiguous cities or towns may, in a city by vote of the city council thereof, and in a town by vote of the town at an annual meeting, form a district for the purpose of acquiring, whether by gift or otherwise, developing, maintaining and operating, within their territorial limits, beaches for public and recreational uses, and may pay over to the district treasurer, as provided in section twelve E, appropriations made for such purpose. Each of such districts shall be under the control of a commission which shall be appointed by, and the number and the terms of office of the members of which shall be determined by, a joint committee composed of the mayor and president of the city council, in each of such cities, and the chairman of the selectmen in each of such towns. In cities having both a city council and board of aldermen the president of the board of aldermen shall also be a member of such committee.

The director of accounts in the department of revenue shall cause an audit to be made annually of the accounts of all districts organized under the authority of this section, and for such purpose he and his duly accredited agents shall have access to all necessary papers, books and records. Said director shall apportion the cost of each audit among the several municipalities comprising the district on the basis of the taxable valuation of said municipalities as last established by the general court for state and county taxes, and submit the amounts of each apportionment to the state treasurer, who shall issue his warrant requiring the assessors of the cities and towns which comprise the district to assess a tax to the amount so apportioned, and such amount shall be collected and paid to the state treasurer as provided by section twenty of chapter fifty-nine.