Naturalists Thomas Nuttall (1786–1859) and John Bradbury (1768–1823) travel up the Missouri River with the Astor expedition in 1811, documenting and drawing plant and animal life.

Later, Nuthall will explore the Indian Territory (Oklahoma), the Oregon Trail, and (in 1834-35) even Hawaii.

His book A Journal of Travels into the Arkansas Territory is an important account of frontier life.

Although Nuthall is the most traveled Western naturalist before 1840, unfortunately most of his documentation and specimens are lost.