Boston, Massachusetts. Union Bank. 1860s. $500. PMG Choice Uncirculated 64. Proof.(MA-385 G264a) ABNC. India paper only. A fascinating high denomination proof in the Perkins Patented Steel Plate style though this design type was used on occasion by the bank into the 1860s as evidenced by the ABNCo monogram seen near center. Dark inks and bright paper are featured throughout.