Mochila

A mochila (pronounced mo-chee-lah is Spanish for knapsack, pack or pouch) is a removable lightweight leather cover put over a horse's saddle. It was used for carrying mail by the Pony Express in the nineteenth century - a type of mail bag. The eighth of an inch leather cover draped over the saddle on a horse. There were slits cut into the leather which allowed the saddle horn and cantle to protrude through.