Auction Series 257-264 in Zurich Day 4

T.B. Morton & Co. / Danube & Black Sea Line Steamers 1870 (Oct): 3rd issue, 2 pi. second printing in grey-blue, an unused block of four on white wove paper, perf. 12½, an unused block of four from the lower left corner of the sheet (positions 41-42/46-47), imperforate at left and at base with vertical and horizontal outer framelines, large part og. A rare positional multiple Mi = € 600+.
Catalogue 261: Stamp Issuing Steamship Companies