On April 22, 1859, James Hutton was appointed as topographer at a salary of $120 a month with the Raynolds Expedition led by Captain William F. Raynolds of the Army Corps of Topographical Engineers to explore the northern Rocky Mountains from Fort Pierre in the soon-to-be Dakota Territory to the headwaters of the Yellowstone River. His charter was to report on the climate, natural resources and Native American tribes he found. He was also directed to map wagon roads from Fort Laramie to Fort Union and Fort Benton, and from the Yellowstone River to South Pass on the Oregon Trail and between the headwaters of the Missouri and Wind Rivers. Hutton doubled as an assistant artist and photographer with the expedition, making pen-and-ink sketches and taking photographs of Wyoming's Big Horn and Wind River Mountains and Montana's Yellowstone and Missouri River valleys. He is known to have made ethnographic photographs of members of the Crow, Sioux, Cheyenne, and Arapaho Nations. In 1862, seven engravings after Hutton's photographs of Native Americans were published in Contributions to the Ethnology and Philology of the Indian Tribes of the Missouri Valley (Transactions of the American Philosophical Society, Volume 12), by Ferdinand V. Hayden, the expedition's geologist. During July 1859 while on the Raynolds Expedition, Hutton and Zephyr Recontre, the expedition's Sioux interpreter, took a side trip to locate an isolated rock formation that had been seen from great distance in 1857 by a previous expedition. Hutton and Recontre became the first caucasians to reach the rock formation, later known as Devils Tower; Raynolds never elaborated on this event in great detail, mentioning it only in passing.