The boundaries of said districts shall be shown upon the map attached to and made a part of this Chapter, which shall be designated “Official Zoning Map” of Cornwall Borough. Said map, together with all explanatory matter thereon, is hereby adopted by reference and declared to be part of this Chapter. The Official Zoning Map shall be identified by the signature of the President of the Borough Council, attested by the Borough Secretary, and bearing the seal of the Borough under the following words: “This is to certify that this is the Official Zoning Map referre; d to in Article 3, §302 of Ordinance Number ________ of the Borough of Cornwall, Lebanon County, Pennsylvania,” together with the date of the adoption of this Ordinance.