#A VERY FINE EXAMPLE OF THE "SOUTHERN LETTER UNPAID" MARKING, WHICH IS RARELY FOUND ON COVERS ORIGINATING IN CONFEDERATE NEW ORLEANS
Reviewing our records of Southern Letter Unpaid covers, there is a pattern suggesting that the earliest mail processed at the Louisville post office was not marked with the double-circle datestamp (earliest known date is June 26th) and that the use of the blue grid to cancel U.S. stamps was soon abandoned in favor of using the "Southn. Letter Unpaid" marking as a cancel. When Louisville Postmaster J. J. Speed received a directive from the U.S. Post Office Department on June 24th, instructing him to forward mail of Confederate origin to destinations in Federal territory, there were 4,000 to 5,000 pieces of mail being held at Louisville (Schenfield book, p. 7). Speed was instructed to remove U.S. stamps affixed to Confederate letters; however, the impracticality of physically removing stamps resulted in the creation of the "Southn. Letter Unpaid" handstamp. If clerks began the task of processing mail on June 25th by 1) cancelling U.S. postage with the blue grid, 2) applying the blue "Southn. Letter Unpaid" and 3) applying the "Due" marking, the use of the blue grid could have been abandoned when the double-circle datestamp was introduced to the process on the following day, June 26th. An additional step in marking covers - the application of the datestamp - would slow down the process. Our hypothesis is that the clerks discarded the blue grid on June 26th and began using the "Southn. Letter Unpaid" marking to cancel any U.S. stamps present. If correct, the cover offered here is quite possibly a June 25th "first day use" of the "Southn. Letter Unpaid" marking.
A fascinating and extremely rare cover