Baltimore, Md., 1857, 1¢ black, top right corner margin gutter block of 10 with left vertical pair tête-bêche to adjacent pair, full o.g., the block consisting of three impression from the plate of 10, two blocks of 4 at right being positions 1-2/34 and the left pair positions 7/9, with position 7 the "Sent" error variety, slight gum creasing in selvage and tiny nick in bottom left stamp which is not mentioned in certificate, Very Fine, ex Caspary & Middendorf; with 1991 P.F. certificate. Scott No. 1LB8  Estimate $7,500 - 10,000. THE UNIQUE TETE-BECHE BLOCK OF THE BALTIMORE HORSE & RIDER CARRIER STAMP. Only one other tete-beche example is known which is in a strip of five. $0 (Image)