Cal. Gov. Code § 25100.5
The board of supervisors of any county may provide by ordinance that the clerk of the board of supervisors may be appointed by the board in the same manner as other county officers are appointed. In such counties, the county clerk is not ex officio clerk of the board of supervisors.
The clerk of the board of supervisors shall perform those duties prescribed by law for the county clerk as ex officio clerk of the board of supervisors or for the clerk of the board of supervisors and such additional duties as the board of supervisors shall prescribe by ordinance. Such person may perform all the duties vested in the county clerk other than those vested in the county clerk as registrar of voters and may take acknowledgments and administer and certify oaths in the performance of such person's official duties.
Ca. Gov. Code § 25100.5