Official, 1873-79 Official Covers, group of 7 legal-size covers including O17 on pension office cover, O18 on two different pension office cover, O75 tied by Washington D.C. duplex on Office of the Auditor of the Treasury for the Post Office cover, O85 on Surgeon General's Office cover, O86 on Adjutant General's Office cover to Rogersville Tenn., 1882 penalty envelope with Washington D.C. Leavitt machine cancel. Estimate  $200 - 300. $0 (Image)