Mexico, (Monterrey) Monterrey. Boxed date stamp (Schatzkes 860) on 1864 folded letter to French held town San Luis Potosi, reverse with Catorce transit boxed date stamp, matching "Franco" & "2" (Schatzkes 1472-1473) with additional "2" handstamp applied in Monterrey, file fold, Very Fine, a rare "Thru-The-Lines" usage taking 16 days to get through. Estimate  $150 - 200. $0 (Image)