Mexico, (San Luis Potosí) Penon Blanco. 4 covers; 1840-48 two-line postmark (SL135) on two matching official cachet (SL136) covers with "3" & "4" rate handstamps, another 1849 postmark use with different "4" rate handstamps, 1853 boxed date stamp (SL138) with "2" rate and additional blue "2" handstamp, Very Fine. Estimate  $200 - 300. $0 (Image)