In case the territory formerly embraced within such vacated city shall consist of territory of two or more townships in the same county, it shall be the duty of the board of supervisors to apportion, among the several townships, the amount of such indebtedness which each township shall bear; and in case such city was comprised of territory from 2 different counties, it shall be the duty of the boards of supervisors of the 2 counties to determine what portion of such indebtedness each county shall bear, using as a basis the last preceding assessment roll of such city prior to its vacation. Such indebtedness when so apportioned, shall be assessed, levied and collected as provided in the preceding section.