The pilot boat ran up into this stream, and as the water of the Colorado had been particularly muddy, the men were eager to discover clear, sparkling affluents and springs.

One behind shouted, "How is she, Jack ?" and Jack sententiously replied, "Oh, she's a dirty devil!" and by this title the river was long called, and probably is still so known in that region, though on the maps it was afterwards changed by Powell to Fremont River, in honour of the Pathfinder.
They were now in the beginning of what has since been called Glen Canyon.

Powell at first gave the name of Mound to the upper half, and Monument to the lower, but after 1871 Glen was substituted for the whole.

On July 31st they passed the mouth of the San Juan, which enters through a canyon similar to that of the main river, about a thousand feet deep.

They tried to climb out near this point, but failed to accomplish it.