Cover franked with 1959 20p carmine (SG 477) with large 'S.O.S.' handstamp in black and small red 'H.B.' boxed control marking tied by VALDIVIA cds dated 11 JUL 1960. Addressed to VALDIVIA. These overprints were privately produced by the Valdivian Philatelic Society to publicise the need for aid after the earthquake of May 22nd. Very scarce. Three page article on the issue accompanies.