18th. The creek was rapidly subsiding, so that a bridge constructed by the Omawhaws, which we had passed almost unobserved, was now two feet above the surface of the water, and rendered it necessary to unload the boat in order to drag her over. This structure is very simple; a double series of stout forked pieces of wood are driven into the bottom of the creek, upon these, poles are laid transversely, crossed by numerous smaller pieces, which form a support for dried grass covered by a proper quantity of earth. What necessity gave rise to the building of this bridge we know not, and we are inclined to believe, that bridge-building is a rare effort in our aboriginal architecture. On the 20th, Major O'Fallon set out on a visit to the Pawnee villages, accompanied by Captain Riley, Adjutant Pentland, Lieutenants Talcott and Graham, Mr. Dougherty and myself, together with a guard of twenty-seven men, and with seventeen pack and riding horses.[38] In recording the events of this journey, it would be superfluous to note the appearance of the country over which we passed, or to describe the magnitude and direction of the water courses that intersect the route, as this will be detailed in another part of the work; our attention in the few following pages will be more particularly directed to our transactions and interviews with the natives. In the course of the two following days, we met with several Oto and Omawhaw Indians, who were occupied with hunting and trapping. On the 23d we halted a short time with a party of the latter nation, headed by a man of much note, known to the traders by the name of the _Voleur_,[39] the relics of whose former village, we had previously observed on Shell Creek.[40] {71} Near this stream of water we examined a great excavation in the brow of a bluff, to which the name of _Pawnee Medicine_ has been applied, in consequence of its being an object of superstitious reverence to the people of that nation. It is evidently an artificial work, and the product of much labour, being about two hundred feet long, one hundred and thirty feet wide, and thirty feet deep. The origin and object of this effort of savage labour is involved in mystery, and the Pawnees cannot, at this day, give any rational history of it; the only advantage which we can suppose people to have derived from such a work, is security from the attack of a powerful enemy. An entire nation may have here defied the efforts of some allied army of an extensive coalition. We are inclined to conjecture, that the nation that has left us this monument of a primitive military art, is no other than the Rickarees,[41] who now reside on the banks of the Missouri, between the Sioux (Dacota) and Mandan nations, and who are, beyond a doubt, a branch of the Pawnee stock, and probably are more immediately descended from that branch of it, now known as Pawnee Loups. We are led to this conjecture, however, only from the fact, that ruins of their former