Many of the low valleys of all the western streams (Red River as well as Arkansas and its branches), are impregnated with salinous qualities, and, during wet weather, ooze saltish exudations, which efflorescence in a thin scum. This is sometimes pure salt, but more frequently compounded of different salts — not only of the muriate, but of the sulphate of soda, and perhaps magnesia; often strongly tinctured with nitre. Some of the waters of these sections (particularly when stagnant) are so saturated with this compound during dry weather, that they are insupportable even for brutes — much to the consternation of a forlorn traveler. In these saline flats nothing grows but hard wiry grass, which a famished beast will scarcely eat.

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