If any member of the system is separated from the service of the county before retirement for any cause other than for death or permanent disability, any contributions made by him shall become part of the retirement fund. If the separation is caused by death or disability, there shall be paid to him or his heirs all his contributions to the fund and one-half of all interest credited to his account.

Any contributions paid into the system by a member prior to the ninety-first day after the final adjournment of the 1947 Regular Session of the Legislature shall be returned to any member upon his separation from service of the county in

the same manner as provided in this section for payment upon separation caused by death or disability.