Mexico, 1859-61 "Sello Negro" Covers. 19 covers; with towns including Guichapa (Schatzkes 259+259C), San Luis Potosi, Alamos (543A), Zacatecas (1849C), blue Parral (161), Sierra Hermosa (1911), Silao (525), Matamoros (1583), San Fernando (1374AA+1374AB), Nieves (1894A+1896), etc.; clear full strikes throughout, few cover flaws, overall Very Fine. Estimate  $750 - 1,000. $0 (Image)