I am searching for some books on the mail system in mexico in the mid 1800's. My grandfather told my parents that as a young man he delivered mail on horseback and on his route he had to cross three rivers. Not sure why he made this statement without any other information but if I can find some related info I might be able to find where his family came from. It might have been in Tampico, Nuevo Leon or Tamaulipas, not sure. Any help would be appreciated. Thanks Maria Elena