Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 84, § 3

If any town does not comply with any orders passed by the county commissioners under the preceding section, within the time and in the manner prescribed in such orders and to the acceptance of the commissioners, the commissioners shall forthwith cause such bridge to be completed in accordance with such orders and shall direct the expenses and charges of completing the same to be paid in the first instance by the county, and shall order notice thereof to be given to the delinquent town, stating the proportion which it is to pay.