John Wesley Powell made a great contribution to American History. Throughout his adult life, he had been fascinated by natural phenomena. In 1869, he and nine other men set out to explore the Southwest. He and some of his men finally made it to the Virgin River (now under Lake Meade) on the far side of the Grand Canyon. His trip through the Grand Canyon allowed Powell to establish what he set out to show: the Colorado River preceded the Grand Canyon, carving the course of the canyon into the rock. Until that tiime, it was not known exactly how the Grand Canyon had been created.
After his experience exploring the Grand Canyon, Powell wrote of his experiences in The Canyons of the Colorado (1895). In addition to the contributions stemming from his exploration, Powell also served as the second director of the United States Geological Survey (USGS).
Powell's overall contribution to American History lies primarily in his attitude toward the practice of geology, particularly his discovery concerning the relationship between the Colorado River and the Grand Canyon. By extension, Powell's observations established a great deal of our knowledge about the nature of erosion.