each other on both sides of the Platte river, and which, after passing under the Black Hills, disappear at the base of the Rocky Mountains, the whole plain which we traversed for i,5oo miles after we had left Westport might be called the Prairie Ocean. In fact, nearly the whole of this territory is of an undulating form and the undulations resemble the billows of the sea when agitated by the storm. On the tops of some of these elevations we have seen shells and petrifactions, such as are found on several mountains in E=urope. No doubt some impartial geologists may discover here, as they have done elsewhere, incontestible proofs of the deluge. A petrified fragment which I have in my possession, seems to contain a number of these shells.
In proportion as one removes from the banks of the Missouri or penetrates into the western regions, the forests lose much in height, density and depth, in consequence of the scarcity of water. Soon after only the rivers are lined with narrow skirts of wood, in which are seldom seen any lofty trees. In the neighborhood of creeks and rivulets we generally find willow bushes, and where there is no water it would be vain to look for anything but grass, and even this grass is only found in the fertile plains that lie between Westport and the Platte River.
This intimate connection between rivers and forests is so striking to the eye that our beasts of burden had not journeyed more than eight days through this desert when we saw them in some manner exult and quicken their pace at the sight of trees that appeared at a distance. This was chiefly observable when the day's journey had been rather long. This scarcity of wood in the western regions, so much at variance with what is seen in other parts of North America, proceeds from two principal causes: In the plains on this side [south of] the Platte River, from the custom which the Indians who live here have adopted, of firing their prairies toward the end of autumn, in order to have better pasture at the return of spring; but in the Far West, where the Indians do not follow this practice (because they fear to