(7)Whenever the [State Government] sanctions a plan of a proposed public street [or a proposed public park], it shall announce the fact by notification, and the publication of such notification shall be conclusive evidence that the plan has been duly made and sanctioned;and the proposed public street [or a proposed public park] to which such notification refers shall be deemed to be a projected public street [or a projected public park], and shall be so deemed until -(a)such street [or park] has been declared, under section 65 or section 66, as the case may be, to be a public street [or park], or(b)the said notification has been cancelled by another notification:Provided that such cancellation shall not affect the validity of any action taken by the Board in pursuance of the said notification.
