mystery solved: the 10ctBRCL1A

The small batch of the 10c Rivadavia Browns issued during late 1939 and early 1940 are 1E4s by watermark, but the paper is clearly the CL1A. A comparison with a large selection of the 5c stamp on the same paper from the same era is all that is needed.



I have previously shown this stamp on a June 1939 cover.