Imperforate Horizontally (319d). Block of four containing two pairs of the error, deep rich color
According to Johl, a block of 25, imperforate horizontally, was found at the Washington D.C. post office. Eight were used for postage, leaving two blocks of four, a strip of three and a pair.
This error differs from the more famous so-called “San Francisco roulette”, where a small quantity of sheets was found imperforate between the top two rows only and was rouletted locally.
With 1959 and 1998 P.F. certificates. Scott Retail as two pairs