4.  Whenever it appears to the Collector that any land held under a State lease or grant has been subdivided and no notification of the subdivision in respect of the land has been given under section 3, the Collector may determine the rent payable in respect of each subdivision and shall thereafter proceed to make an order of apportionment in accordance with the provisions of this Act which shall apply, with the necessary modifications, as if the determination has been made by the Collector under section 3(2).