All that area generally south and west of a line beginning at the intersection of the Northern State Parkway and the Nassau-Suffolk county line; thence westerly along the Northern State Parkway to the Oyster Bay-North Hempstead town line; thence northwesterly along the town line to Glen Cove Road; thence northerly along Glen Cove Road to Cedar Swamp Road; thence northerly along Cedar Swamp Road to the Glen Cove city line; thence counterclockwise along the Glen Cove city line to the shore of Long Island Sound; except that area delineated as Level IV.