Outline Sketch of the Grand Canyon from Point Sublime.
Drawn by W.H. HOLMES.
There are six chief topographical features, canyons, cliffs, valleys, mesa plateaus, high plateaus, mountains. There are two grand divisions: the lowland or desert, below the Virgen, and the plateau, but the topography of the immediate river course separates itself into four parts, the Green River Valley, the canyon, the valley-canyon, and the alluvial. The canyon part is the longest, occupying about two-thirds of the whole, or about 1200 miles. It is cut mainly through the plateaus. The last of these southward is the Colorado, a vast upheaval reaching from the lower end of the Grand Canyon south-east to about where the 34th parallel crosses the western line of New Mexico. Lieutenant Wheeler several times claims the honour of naming it (1868-71), but the name occurs on Lieutenant Ives’s map of 1858. This plateau breaks sharply along its south-west line to the lowland district, and on its north-westerly edge slopes to the Little Colorado. It bears a noble pine forest, and from its summit rise to over 12,000 feet the volcanic peaks of the San Francisco Mountains. Its northern edge is the Grand Canyon, which separates it from its kindred on the other side. These and the Colorado Plateau rise to from 6000 to 8000 feet above sea-level, and it is through this huge mass that the river has ground out the Grand Canyon, by corrading its bed down tremendously, the bottom at the end being only 840 feet above the sea, whereas the start at the mouth of the Little Colorado is 2690. Yet here it is already 3500 feet below the surface at the end of Marble Canyon, which, separated only by the deep canyon of the Little Colorado, is practically a northward continuation of the Grand Canyon itself. As the river runs, the Grand Canyon is 217½ miles long. To this may be added the 65½ miles of Marble, giving a continuous chasm of 283 miles, the longest, deepest, and most difficult of passage in every direction of any canyon in the world. The depth begins with a couple of hundred feet at Lee’s Ferry (mouth of the Paria), the head of Marble Canyon, and steadily deepens to some 3500 feet near the Little Colorado, where the sudden uplift of the Kaibab lends about 2000 feet more to the already magnificent gorge. Along the end of the Kaibab the walls, for a long distance, reach their greatest height, about 6000 feet, but the other side is considerably lower than the north all the way 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 4½ 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.
Character of the Mountains and High Plateau Regions of the Basin of the Colorado.
Photograph by J.K. HILLERS.
Profile of the Colorado through the Grand Canyon.
Horizontal Scale: One Inch = 40 miles—Vertical: One Inch = 2000 feet.
The altitude of Grand Wash is given about 60 feet too high.