Lieutenant James William Abert (1820 97) of the United States Army Topographical Engineers received orders in 1845 to explore the Canadian River region of the southern plains an area covering present-day Colorado, New Mexico, Texas, and Oklahoma. Although this land was still in Mexican territory, the United States had gradually abandoned most of the diplomatic niceties regarding its boundaries with Mexico by that time.Abert set out from Bent s Fort to conduct a detailed reconnaissance. He possessed a great eye for detail, providing in his journal graphic descriptions of the birds, plants, and...