Mexico, (Saltillo) Saltillo/Certification al. Straight line registry postmark with manuscript date (Yag-Bash ST 12) on 1841 official front to Mexico City, matching small ray cancels at edges, bold Coahuila official eagle cachet handstamp and San Luis Potosi postmark with matching boxed "Franco" handstamp (SL6, SL15A), Extremely Fine, ex Backal. Estimate  $500 - 750. $0 (Image)