John Wesley Powell and Crew’s 1869 River Mapping: What Did They Know and When Did They Know It? – Video Recording

The intent of the 1869 river expedition of Major John Wesley Powell was to map the course of the Green River to its junction with the Colorado River, and then through the Grand Canyon, ending at Callville, Nevada, filling in somewhat terra incognita of the plateau country of the southwestern United States. Starting at Green River Station, Wyoming Territory, one of the four boats wrecked in the Cañon of Lodore, resulting in one crew member leaving the trip at the Uinta River. Weather, rapids, hard work portaging and lining boats and supplies, and other time-consuming activities curtailed much of the needed survey and mapping work. Loss of the maps due to wetting caused the need for them to be recreated. Even with that, plus broken barometers and wet chronometers and watches, at least one map remained so that Powell’s return river trip of 1871-72 could carry it with them, compare it with their longer-term surveying, and update the 1869 results. However, by the time they reached about river mile 240 in the Grand Canyon, Powell still could not tell how far west they had boated or how close they were to Callville. Because of that and other reasons, three men left the party at what has been named Separation Rapid and up Separation Canyon on the north rim. Powell and the remaining men exited Grand Canyon soon thereafter at the mouth of the Virgin River, not far above Callville; the three men perished somewhere on the Arizona Strip. This talk will cover how the men used their scientific instruments to survey and map, and speculate about what they knew of their location along their trip, focusing specifically on Grand Canyon.