City council may, by ordinance, create, change and abolish offices, departments or agencies of the municipal government in addition to those created by this chapter and may prescribe the functions of all departments, offices and agencies, except that no function assigned by law to a particular department, office or agency may be discontinued or assigned to any other agency. The head of each department shall be designated director thereof and shall have supervision and control over his department, subject, however, to the direction of the city administrator. (Prior code § 1-4-1)