On the voyage up the Missouri, a party was detached from the steam-boat at Fort Osage, with instructions to proceed across the country by land, to the Konzas village, and thence to the villages of the Pawnees, on the river Platte, and to return on board again at the Council Bluffs. This excursion was undertaken with a view of prosecuting the business of the expedition. The party had accomplished part of the duties assigned them, when they were met near the Konzas village by a war-party of the Republican Pawnees, and robbed of their horses, baggage, &c., which compelled them to give up the further prosecution of their enterprize. This misfortune rendered it necessary for them to change their route, and shape their course for the Missouri, which they reached at Cow Island, having obtained much useful information concerning the country through which they passed, and the natives inhabiting it. On my return to the wintering post of the expedition, to which we had given the name of Engineer Cantonment, I pursued a course north of the Missouri, from near its mouth to that place, taking sketches of the country, preparatory to a topographical delineation. The observance of courses, distances, magnetic variations, &c. were objects of our particular care and attention in all the movements of the expedition. On my arrival at the cantonment, which I reached on the 27th of May last, preparations were made, with all convenient despatch, for reconnoitring the country {192} westward to the Rocky Mountains, in conformity to your order of the 28th of February, 1820. The steam-boat was ordered on topographical duties under the command of Lieut. Graham, who proceeded with her down the Missouri to St. Louis, thence up the Mississippi to the De Moyen rapids, and thence down the river to Cape Girardeau, taking such observations and sketches on the voyage as are requisite in constructing a chart of that part of the river and the adjacent country. Having made the necessary arrangements, and rendered our outfit, for the western tour, as complete as circumstances would permit, we commenced our march on the 6th of June, all in good health, except Mr. Say, the zoologist for the expedition. It may not be improper here to give a list, exhibiting the names of the persons composing the party, and the several capacities in which they served.