(a) Deposit for safekeeping in the vaults of any of the state or national banks located within this state which are members of the Federal Deposit Insurance Corporation and which have appropriate safekeeping facilities which have been approved by the State Depository Commission, any Federal Reserve bank, any Federal Reserve branch bank, or any bank which is a member of the Federal Reserve system and is located in a city where there is a Federal Reserve branch bank, the securities placed with him by insurance companies; or
(b) Accept, in lieu of the securities themselves, safekeeping trust receipts issued to the State Treasurer by the authorized safekeeping banks located within this state which are members of the Federal Deposit Insurance Corporation and which have appropriate safekeeping facilities which have been approved by the State Depository Commission, such safekeeping trust receipts to describe the securities and show that such securities are held for safekeeping for the account of the State Treasurer. The securities so deposited shall not be commingled in any manner with the assets of the safekeeping bank.