The notice of sale so published shall contain a description sufficient to identify each lot or parcel of land delinquent, and opposite each description the name of its owner, if known, otherwise designating him as unknown, and the amount of the assessment and costs due, including the cost of advertisement, which cost of advertisement shall not exceed the sum of fifty cents ($0.50) for each lot or parcel of land separately assessed. The tax collector shall append to and publish with the notice of sale a notice that unless each delinquent assessment, together with the penalties and costs thereon, is paid, the land upon which the assessment is a lien will be sold at public auction, at a time and place to be specified in the notice.