The park superintendent or another person designated by the legislative body shall cause at least three notices of the adoption of the resolution to be posted conspicuously not more than three hundred feet apart along the exterior boundaries of the area proposed to be discontinued and abandoned as a public park. Posting shall be completed at least twenty days before the time set for the hearing. Failure to post the notices does not invalidate the proceedings or prevent the legislative body from acquiring jurisdiction to proceed with the discontinuance and abandonment.