Section 11. If there is necessity for a new cemetery in a town, or for the enlargement of an existing cemetery in and belonging to a town, and the owner or any person interested in the land needed for either purpose refuses to sell the same, or demands therefor a price which the selectmen consider unreasonable, or is unable to convey it, the selectmen may, with the approval of the town, make application therefor by written petition to the county commissioners of the county where the land lies.