“The mochilla [sic] system developed out of necessity—an adaptation made to problems encountered in the daily operation of the Pony Express. There is no indication that these special pouches were ordered and used before the first run of the Pony Express in April 1860. Evidently, they were not put in use until after late 1860, for when the English traveller Richard Burton passed along the route at that time, he mentioned that letters were carried in leathern bags, and that they were “thrown about carelessly” when the saddle was changed between horses.39 Given the Spanish nomenclature, it may have been adapted from similar pouches in use in California.”
