For the purpose of ready reference to the local indexes in counties adopting local indexes, and the discovery of errors of entry therein, every deed, mortgage or other instrument so entered shall have the block number or numbers under which the same is indexed noted on the margin at the commencement of the record or registry thereof. The book and page of the record of every assignment of mortgage, and all releases, satisfactions and agreements respecting mortgages shall be noted on the margin of the record of the mortgage to which the same shall refer, and such release, assignment or other instrument shall thereupon be considered as fully entered in the local indexes. Every satisfaction or cancellation of a mortgage, however, shall, in addition to the entry required by law on the record thereof, be also noted in red ink on the local index entry of such mortgage.