The canyon is narrow, and seen from a height resembles, as previously mentioned, a dark serpent lying across a plain.

As the formation down to the Little Colorado is mainly a fine-grained grey marble, Powell concluded to call this division by a separate name, and gave it the title it now bears, Marble Canyon.

There is no separation between Marble Canyon and the following one, the Grand Canyon, except the narrow gorge of the Little Colorado, so that topographically the chasm which begins at the Paria, ends at the Grand Wash, a distance of 283 miles, as the river runs, the longest, deepest, and altogether most magnificent example of the canyon formation to be found on the globe.

With an average depth of about four thousand feet, it reaches for long stretches between five thousand and six thousand.

At the Paria (Lee's Ferry) the altitude above the sea is 3170 feet, while at the end of the canyon, the Grand Wash, the elevation is only 840 feet.