With such inexhaustible mines of salt within two or three days' journey of the Arkansas river, and again within the same distance of the Missouri, which would cost no further labor than the digging it up and the transporting of it to boats for freighting it down those streams, it seems strange that they should lie idle, while we are receiving much of our supplies of this indispensable commodity from abroad. Besides the salines already mentioned, there is one high on the Canadian river, some two hundred miles east of Santa Fé. Also, it is said, there are some to be found on the waters of Red River; and numerous others are no doubt scattered throughout the same regions, which have never been discovered.

Commerce of the Prairies (1831–1839), Chapter 26 Geography of the Prairies