Whenever it shall be determined by the return of the sheriff of the county in which said cemetery is located, that the owner or owners of said lot or lots is not a resident of said county and cannot be found therein, then said board of directors may cause such notice to be published in a legal newspaper within said county for the period of three (3) weeks, and shall cause a copy of such notice to be served on the owner or owners thereof by registered mail addressed to their last known address, which said notice shall specify a time for payment, at least thirty (30) days after the completed service of such notice by publication thereof.