19. Se-tenant Bureau precancels: Some precanceling was done by the Bureau for small cities by using adjoining precancel mats with different city names. Shifting of the mats caused different city names to be printed on adjoining stamps. These are rare, with examples ranging from $200 per pair.
Type 19: Only known error of this Type is the 1 1/2¢ Liberty (Mount Vernon), plate no. 25366LL, on which 90 of the stamps are Bureau precanceled "Duluth, Minn.", and 10 other "Green Bay, Wis."