After all criticisms have been urged to the utmost, the work of the expedition was, and is, of considerable value. The exploration of the Canadian River was an important contribution to American geography. It was thenceforth evident that the sources of the Red must be looked for farther south than had previously been supposed, although a generation was to elapse before their discovery. Otherwise, the exploration added greatly to the knowledge of a portion of the country but imperfectly known through hunters and traders. Especially is this true as regards details relative to natural history and ethnology; for the work was done in the spirit of modern scientific investigation, and in this respect anticipated later expeditions, for which American public sentiment in 1820 was hardly ripe. The collections included more than sixty skins of new or rare animals, several thousand insects, of which many hundreds were new, nearly five hundred undescribed plants, mineral specimens, many new species of shells, numerous fossils, a hundred and twenty-two animal sketches, and a hundred and fifty landscape views. While not primarily designed as a scientific report on these collections, James's _Account_ gives in the form of notes[11] much of the more important information derived from them. Perhaps no other portions of the work, however equal in value those devoted to the aborigines; as an authoritative source of knowledge of the sociology of the Kansa and Omaha tribes, the _Account_ has no rival. Soon after his return from the Rockies, Major Long was sent upon another expedition, this time to the sources of the St. Peter's (now Minnesota) River. This enterprise was contemplated by the original instructions issued to Long at the time of the Yellowstone project; but the subsequent abandonment of the latter compelled alterations in the programme of the scientific division. As in the case of the first journey, the report of the St. Peter's exploration is the work of another person--William H. Keating, author of _Long's Expedition to the Source of St. Peter's River, Lake of the Woods, etc._ (Philadelphia, 2 vols., 1824). For these several explorations, Long was breveted lieutenant-colonel. In 1827 he assumed charge of the survey of the Baltimore & Ohio Railroad, and for many years thereafter was much engaged in railroad engineering. His _Railroad Manual_ (1829) was the first original treatise on railroad building published in this country. Upon the organization of the Topographical Engineers as a separate corps (1838), he became a major; later (1861) he was made chief of the corps, with the rank of colonel. He was retired from active service in 1863, still being entrusted with important duties, which were interrupted by his death, occurring at Alton, Illinois, the following year.