18. Power to enter upon, examine and clear obstruction on lands-

(1) For the purpose of any survey, enquiry or other proceedings under this Act, the Survey Officer or the Collector or any of the subordinates of such officer shall have power to enter upon, examine and measure any land under survey and to clear, by cutting down or removing any trees, jungle, fences, standing crops or other material obstructions, the boundaries or other lines, the clearance of which may be necessary for the purposes of the survey. (2) An authorized officer or a licensed Surveyor referred to in section 17A shall have the power to enter upon, examine and measure any lands adjacent to the land respecting which he is required to prepare a survey map, if necessary, for the purpose of preparation of such map by him: Provided that, he shall give due notice to the owner or occupier of the adjacent land before entering such land.