It shall be the duty of the Assessor to ascertain the tangibles and property within said Town subject to taxation and make returns thereof to the Council at such time as may be prescribed, substantially in manner and form as in the case of assessments by County assessors; and to this end he shall have access to the most recent books and record of the County of Hancock upon payment of reasonable fees and charges to be arranged and provided for by the Council. The latest accessible assessments, for State and County purposes, including value, shall be used and adopted by him; but as to property not included in such assessment, he shall ascertain the same, fix the value thereof, and include the same in his assessment; but the Council may correct any error on his part in this regard, upon the application of any person aggrieved. In the discharge of his duty he shall have the same powers as are conferred by law upon County Assessors.