The location and boundaries of the zoning districts established by this chapter are as indicated on a map entitled "Official Zoning Map, Mathews County, Virginia," identified by the signature of the Chairman of the Mathews County Board of Supervisors, attested to by the clerk of the Circuit Court of Mathews County, and bearing the seal of Mathews County, Virginia, together with the date of adoption of this chapter. Said map shall be deemed to be a part of this chapter as if it were fully set forth herein.