Exploration of the Valley of the Amazon

''Exploration of the Valley of the Amazon'' is a two-volume work by William Lewis Herndon and Lardner A. Gibbon, who were lieutenants in the United States Navy. Volume I was written by Herndon, and Volume II was written by Gibbon. The publication was originally a report about their exploration, consisting of 442 pages. During the exploration, Herndon divided the main party into two groups so that he and Gibbon could explore different regions of the area. Provided by Wikipedia