An Entry from the Journal
of John Wesley Powell

We are ready to start our way down the great unknown... We are three-quarters of a mile in the depths of the earth and the great river shrinks into insignificance as it dashes its angry waves against the walls and cliffs that rise to the world above... We have an unknown distance yet to run, an unknown river to explore. What falls there are, we know not. What rocks beset the channel, we know not. What walls rise over the river, we know not.