An Act authorizing the town of Nantucket conservation commission to convey a certain parcel of land situated in the town for purposes of conveyance to the town of Nantucket under the care, custody, management and control of the select board and the town of Nantucket to convey certain land in the town of Nantucket held for open space, passive recreation or conservation purposes to the Nantucket Islands Land Bank for the purposes pursuant to its enabling legislation for open space, conservation and passive recreation purposes