CSA 3, 2¢ green, Left Top Knot variety, position 31R, two huge margins, right side ample and barely touched at top right, tied by bold RICHMOND VA. MAR 16 (1863) circular datestamp on linen-lined blue envelope (usually used for money letters) with manuscript "Treasy. Dept. C.S., 2nd Auditors Office, Official" endorsement, addressed to Maj. William Leigh, Richmond, Virginia. Lovely drop-rate use with left top knot variety and a Treasury Department official endorsement. Ex Brugh, Birkinbine, and Hill. With 1979 PF certificate. SCV $3,500 as an ordinary stamp on an ordinary cover which this is anything but. $4,500. Listed in both CSA 3 covers and Official & Semi-Officials, Section 1.