Kelly & Co., 4¢ Black, Experimental Silk Paper, showing plate crack at left of "A" in "Cabin Bitters" and extending slightly into left margin, large even margins, rich bold color, faint crease and margin edge thin at top well away from design, Extremely Fine appearance, a very rare Kelly & Co. 4¢ Black on Experimental Silk Paper with an unrecorded plate crack and quite possibly unique as such, only 19 are recorded in the Aldrich census (of which 9 are reported to be faulty); with 2012 P.F. certificate. Scott No. RS153e  $2,500. $0 (Image)