through.  At the mouth of the Kanab the altitude of the river-bed is 1800 feet above the sea, showing a fall in the interval of 890 feet.  The greatest declivity is about 210 feet in 10 miles, in what is termed the Kaibab division, extending from a point 10 miles below the Little Colorado to a point 58 miles farther down.  Here the smooth stretches of river are long, the rapids short and violent.  Here, also, is the “granite,” making the walls sombre, as the colour is slaty to black.  At the mouth of Diamond Creek the river is still 1300 feet higher than the sea, giving a fall of 500 feet from the Kanab.  There is another descent of 460 feet to the Grand Wash, and then 149 to the mouth of the Virgen.  Next to the Kaibab division of the Grand Canyon, the greatest declivity occurs in the Uinta region, in the Canyon of Lodore.  The profile of the river in these two districts is approximately given on page 57.  The average depth of the Grand Canyon is about 4000 feet.  Its width at the top varies from 4 1/2 to 12 miles.  This is the extreme outer cliff-line.  The inner gorge is much narrower, at the Toroweap being only about 3500 feet.  The river varies in width from 500 or 600 feet to 75 or 100.  In this canyon is water-power enough to run the machinery of the world, and there is as much more in the canyons above.

Joining Marble Canyon on the north is Glen, 149 miles long, from the Paria to Fremont River.  It has but one rapid of consequence.  At high water, with the exception of this rapid, the tide sweeps smoothly and swiftly down with a majestic flow.  The walls are homogeneous sandstone, in places absolutely perpendicular for about a thousand feet.  I have stood on the brink and dropped a stone into the river.  The highest walls are 1600 feet.  Next is Narrow Canyon, about 9 miles long, 1300 feet deep, and no rapids.  It is hardly more than the finish of Cataract, a superb gorge about 40 miles long with a depth of 2700 feet, often nearly vertical.  The rapids here are many and violent, the total fall being about 450 feet.  At its head is the mouth of the Grand River.  The altitude of the junction is 3860 feet.* Following up the Green, we have first Stillwater, then Labyrinth Canyon, much alike, the first 42 3/4 and the second 62 1/2 miles in length.  The walls of sandstone are 1300 feet.  Their names well describe them, though the stillwater of the first is very swift and straight.  There are no rapids in either.  All these canyon names, from Green River Valley to the Grand Wash, were applied by Powell.  Between Labyrinth and the next canyon, Gray, so called from the colour of its walls, 2000 feet high, is Gunnison Valley, where the river may first be easily crossed.  Here the unfortunate Captain Gunnison, in 1853, passed over on his way to his doom, and here, too, the Old Spanish Trail led the traveller in former days toward Los Angeles.  The Denver and Rio Grande Western Railway has taken advantage of the same place to cross.  The 36 miles of Gray are hardly more than a continuation