Section 612. Clerks of the Orphans' Court to Collect Tax on Marriage Licenses.--Clerks of the orphans' courts shall continue to be the agents of the Commonwealth for the collection of the fees payable to the Commonwealth for the issuance of marriage licenses as provided by law, but they shall make their returns to the Department of Revenue, and pay the fees collected to the State Treasurer, through the Department of Revenue, as provided in this act.