The Washita, tributary to Red river, is navigable many miles. That part of it particularly situated within the valley of the Mississippi, and denominated Black river, admits of constant navigation for boats of considerable burden. The Little river, which is also tributary to Red river, together with its forks, heretofore enumerated, is navigable in high water. White river is navigable in a moderate stage of water between three and four hundred miles. Also the Big Black, its principal tributary, and several branches of the river last mentioned, viz. the Strawberry, Currant, {222} Eleven Point, and Spring rivers. The navigation of the St. Francis is blocked up near its mouth, and rendered impassable for boats of every description, by rafts of logs and drift-wood, completely choking the channel of the river, and in many places occupying the whole of its bed for the distance of several miles together. The Merameg is also navigable in a moderate stage of water for many miles. The Gasconade, Osage, and Konzas rivers are navigable in the spring season, but their navigation seldom extends far inland from their mouths, being obstructed by shoals or rapids. Of the rivers tributary to the Missouri, it is remarkable that their mouths are generally blocked up with mud, consequent to the subsidence of the summer freshet of that river, which usually takes place in the month of July. The reason is obvious; the freshets of the more southerly tributaries are discharged early in the season, and wash from their mouths the sand and mud previously deposited therein, leaving them free from obstructions. These freshets having subsided, the more northerly branches discharge their floods, formed by the melting of the snow at a later period. The Missouri being swollen thereby, backs its waters, charged with mud, considerable distances up the mouths of the tributaries before alluded to. The water here becoming stagnant, deposits its mud; and the tributaries, having no more freshets to expel it, remain with their mouths thus obstructed till the ensuing spring. The lower part of the Canadian river, although it is included within the section under consideration, will be described in the sequel of the report, in connexion with the rest of that river. Of the animals found in the several sections of country above described, there are a great variety in almost every department of zoology. But as most of them are common in other parts of the United States, they need not to be enumerated here. {223} _Of the country situated between the meridian of the Council Bluff and the Rocky Mountains_ We next proceed to a description of the country westward of the assumed meridian, and extending to the Rocky Mountains, which are its western boundary. This section embraces an extent of about four hundred miles square, lying between 96 and 105 degrees of west longitude, and between 35 and 42 degrees of north latitude.