of ninety-six yards over the low ground, where the wall recommences and crosses the plain in a course N. 81 degrees W. for eighteen hundred and thirty yards to the bank of the Missouri.  In this course its height is about eight feet, till it enters, at the distance of five hundred and thirty-three yards, a deep circular pond of seventy-three yards diameter; after which it is gradually lower, towards the river:  it touches the river at a muddy bar, which bears every mark of being an encroachment of the water, for a considerable distance; and a little above the junction, is a small circular redoubt.  Along the bank of the river, and at eleven hundred yards distance, in a straight line from this wall, is a second, about six feet high, and of considerable width:  it rises abruptly from the bank of the Missouri, at a point where the river bends, and goes straight forward, forming an acute angle with the last wall, till it enters the river again, not far from the mounds just described, towards which it is obviously tending.  At the bend the Missouri is five hundred yards wide; the ground on the opposite side highlands, or low hills on the bank; and where the river passes between this fort and Bonhomme island, all the distance from the bend, it is constantly washing the banks into the stream, a large sandbank being already taken from the shore near the wall.  During the whole course of this wall, or glacis, it is covered with trees, among which are many large cotton trees, two or three feet in diameter.  Immediately opposite the citadel, or the part most strongly fortified, on Bonhomme island, is a small work in a circular form, with a wall surrounding it, about six feet in height.  The young willows along the water, joined to the general appearance of the two shores, induce a belief that the bank of the island is encroaching, and the Missouri indemnifies itself by washing away the base of the fortification.  The citadel contains about twenty acres, but the parts between the long walls must embrace nearly five hundred acres.

These are the first remains of the kind which we have had an opportunity of examining; but our French interpreters assure us, that there are great numbers of them on the Platte, the Kanzas, the Jacques, &c. and some of our party say, that they observed two of those fortresses on the upper side of the Petit Arc creek, not far from its mouth; that the wall was about six feet high, and the sides of the angles one hundred yards in length.

September 3.  The morning was cold, and the wind from the northwest.  We passed at sunrise, three large sandbars, and at the distance of ten miles reached a small creek, about twelve yards wide, coming in from the north, above a white bluff:  this creek has obtained the name of Plum creek, from the number of that fruit which are in the neighbourhood, and of a delightful quality.  Five miles further, we encamped on the south near the edge of a plain; the river is wide, and covered with sandbars to-day:  the banks are high and of a whitish colour; the timber scarce, but an abundance of grapes.  Beaver houses too have been observed in great numbers on the river, but none of the animals themselves.