The Official Zoning Map shall be identified by the signature of the Chairman of the Board of Supervisors, attested by the Secretary, and bearing the seal of the Township under the following words: "This is to certify that this is the Official Zoning Map referred to in Article II, § 250-3 of Chapter 250, Zoning, of the Township of East Hanover, Lebanon County, Pennsylvania," together with the date of the adoption of this chapter.