 In 1835 George William <unk> conducted a geological survey of the Minnesota River valley and wrote an account entitled A <unk> Voyage up the <unk> <unk> . Joseph <unk> scouted the area in the late 1830s accompanied by John C. <unk> , exploring and mapping the Upper Mississippi River basin , the Saint Croix River , and the land between the Mississippi and Missouri Rivers . 
