Lot 306 o
Special Delivery, 1917, 10¢ ultramarine, with red "61516" control number, light cancel in left margin, strong color, Fine, an unusual and possibly unique issue with control number.Scott No. E11 Estimate $750 - 1,000.
This control is very reminiscent of the red control numbers applied to the 1861-66 issues which was applied by a bond-numbering mechanical device.