The department shall proceed forthwith to examine the returns made by all persons, firms, and corporations required by law to make the same and also such information as the department may have obtained in addition thereto, shall determine the valuation of the different items of property required to be returned to it and shall assess such property for taxation at 30 percent of its reasonable value; and, in case no return has been made by or on behalf of such person, firm, or corporation on or before March 1 in each year, the department may add to the assessment which it makes against such person, firm, or corporation a penalty not exceeding 10 percent of the assessment as made therefor. The assessment herein required to be made shall be completed on or before July 1, or as soon thereafter as practicable, and reported to the tax assessor of every county in which any part of said tangible personal property is taxable under the provisions of this title. The report to the tax assessor shall contain a description of all property included in the assessment, the assessed value thereof, and an apportionment of the assessed value of such property to the county, to each municipality, to each special school district, and other districts levying a district tax within said county, with the name and residence or place of business of the owner thereof and all other information necessary to enable the tax assessor to set up such tax assessment upon the assessment books.