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John Wesley Powell was an explorer and geologist who led the Powell Geographic Expedition of 1869. This was the first major scientific investigation of long segments of the Green and Colorado rivers in the southwestern United States. Part of this journey included the first ever passage of white men through the entire Grand Canyon. The expedition lasted about three months during the summer of 1869. The party embarked from Green River Station, which was in Wyoming Territory, and then went down the river through parts of what is now the states of Colorado, Utah, and Arizona before reaching the intersection of the Colorado and Virgin rivers (in now Nevada). They faced many difficulties, including losing boats/supplies and some near-drownings. In the end, his voyage created the first detailed description of the previously unexplored canyon country of the Colorado Plateau.
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