Overlay zoning districts are hereby established to regulate areas and structures of historical significance, provide for development plan review, agricultural/residential clusters, and village overlay districts. These regulations are necessary to meet the purposes set forth in Section 1-1 of this Ordinance. The boundaries of the overlay zoning districts are as shown on the Overlay Zoning District Map of the Cumberland Plats, the official zoning map of the Town. These boundaries may be amended in accordance with Article 9 of this Ordinance.