The descriptions of the rivers, valleys and mountains got a bit repetitive after a while, and didn't come close to describing the scenery adequately. The book was best when Marshall was writing about the details of hiking and camping in the wilderness or telling stories about interesting events that happened. Because of the competence of the men, there was little danger except for one time when their boat capsized in a flood. It would have been better if Marshall could have identified the birds he saw.