SALINOUS EXUDATIONS. 191 
streams (Red River as well as Arkansas and 
its branches), are impregnated with salinous 
qualities, and, during wet weather, ooze saltish 
exudations, which effloresce in a thin scum. 
This is sometimes pure salt, but more fre- 
quently 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 for- 
lorn traveller. In these saline flats nothing 
grows but hard wiry grass, which a famished 
beast will scarcely eat. 
It is from these exudations, as well as from 
the salines or salt plains before mentioned, 
that our western waters, especially from Ar- 
kansas to Red River, acquire their brackish- 
ness during the low seasons; and not from 
the mountains, as some have presumed. Such 
as issue from thence are there as pure, fresh 
and crystalline as art line rills and icy foun- 
tains can make t 
It will now Konalsty be inferred that the 
Great Prairies from Red River to the western 
sources of the Missouri, are, as has before 
been intimated, chiefly uninhabitable—not so 
much for want of wood (though the plains 
are altogether naked), as of soil and of water; 
for though some of the plains appear of suffi- 
ciently fertile soil, they are mostly of a sterile 
character, and all too dry to be cultivated. 
