The registrars shall complete the records of their respective towns by adding thereto a record of all the births, marriages, deaths and fetal deaths that have occurred in such towns since the date of incorporation of such towns, of which no certificate has been returned to their office, provided the facts upon which such record is made have been obtained from the record of a public official, a church society or under section 7-42, 7-48 or 7-62b, and such record shall indicate the source from which such facts were obtained.