On the sixteenth the party again broke camp, and moved southwest to the Arkansas, which they reached twelve or fifteen miles above the present city of Pueblo. The following day Captain Bell, Dr. James, and two of the men ascended the river to the site of Cañon City, at the entrance of Royal Gorge, where they turned back, again baffled by what seemed to them impassable barriers.
The expedition began the descent of the Arkansas on the nineteenth. After two days' march a camp was made a few miles above the future site of La Junta, Colorado; here a division into two parties was effected, for the purpose of carrying out the instructions of the War Department to explore the courses of both the Arkansas and the Red. The division assigned to the exploration of Red River, consisting of James, Peale, and seven men, was commanded by Major Long himself, for this was one of the principal objects of the expedition; the other division, charged with the less important task of descending the Arkansas, the entire course of which had already been examined by Pike and his assistants, was led by Captain Bell.
Leaving the Arkansas on the twenty-fourth, Long's party crossed Purgatory Creek and the upper waters of Cimarron River, and after six days reached a small tributary of Canadian River, which, after five days' still further travel, brought them to the latter near the present Texas-New Mexico boundary line. As the region in which they had encountered the waters of the Canadian was that wherein the sources of the Red had, previous to that time, been universally supposed to lie, they naturally at first believed that they were upon the latter stream. Their suspicions were soon aroused by the deviation of the river's course from that which they expected the Red to pursue; but it was not until they arrived at the confluence of this waterway with the Arkansas that they became certain of their error. During their descent of the Canadian they encountered parties of Kaskaia and Comanche Indians, whose conduct was not uniformly friendly. Few incidents of interest, however, broke the painful monotony of a journey accompanied by almost constant suffering from exposure to violent storms and intense heat, lack of food and water, and the attacks of wood ticks. On the thirteenth of September the explorers arrived at Fort Smith, the appointed rendezvous, where they found Bell's party awaiting them.