From the Grand Canyon of the Colorado a great plateau extends southeastward through Arizona nearly to the line of New Mexico, where this elevated land merges into the Sierra Madre. The general surface of this plateau is from 6,000 to 8,000 feet above the level of the sea. It is sharply defined from the lowlands of Arizona by the Mogollon Escarpment. On the northeast it gradually falls off into the valley of the Little Colorado, and on the north it terminates abruptly in the Grand Canyon.

Various tributaries of the Gila have their sources in this escarpment, and before entering the desolate valley below they run in beautiful canyons which they have carved for themselves in the margin of the plateau. Sometimes these canyons are in the sandstones and limestones which constitute the platform of the great elevated region called the San Francisco Plateau. The escarpment is caused by a fault, the great block of the upper side being lifted several thousand feet above the valley region. Through the fissure lavas poured out, and in many places the escarpment is concealed by sheets of lava. The canyons in these lava beds are often of great interest.

On the plateau a number of volcanic mountains are found, and black cinder cones are scattered in profusion. Through the forest lands are many beautiful prairies and glades that in midsummer are decked with gorgeous wild flowers. The rains of the region give source to few perennial streams, but intermittent streams have carved deep gorges in the plateau, so that it is divided into many blocks. The upper surface, although forest-clad and covered with beautiful grasses, is almost destitute of water. A few springs are found, but they are far apart, and some of the volcanic craters hold lakelets. The limestone and basaltic rocks sometimes hold pools of water; and where the basins are deep the waters are perennial. Such pools are known as "water pockets."

This is the great timber region of Arizona. Not many years ago it was a vast park for elk, deer, and antelope, and bears and mountain lions were abundant. This is the last home of the wild turkey in the United States, for they are still found here in great numbers. San Francisco Peak is the highest of these volcanic mountains, and about it are grouped in an irregular way many volcanic cones, one of which presents some remarkable characteristics. A portion of the cone is of bright reddish cinders, while the adjacent rocks are of black basalt. The contrast in the colors is so great that on viewing the mountain from a distance the red cinders seem to be on fire. From this circumstance the cone has been named Sunset Peak. When distant from it ten or twenty miles it is hard to believe that the effect is produced by contrasting colors, for the peak seems to glow with a light of its own.

In centuries past the San Francisco Plateau was the home of pueblo-building tribes, and the ruins of their habitations are widely scattered over this elevated region. Thousands of little dwellings are found, usually built of blocks of basalt. In some cases they were clustered in little towns, and three of these deserve further mention.

A few miles south of San Francisco Peak there is an intermittent stream known as Walnut Creek. This stream runs in a deep gorge 600 to 800 feet below the general surface. The stream has cut its way through the limestone and through series of sandstones, and bold walls of rock are presented on either side. In some places the softer sandstones lying between the harder limestones and sandstones have yielded to weathering agencies, so that there are caves running along the face of the wall, sometimes for hundreds or thousands of feet, but not very deep. These natural shelves in the rock were utilized by an ancient tribe of Indians for their homes. They built stairways to the waters below and to the hunting grounds above, and lived in the caves. They walled the fronts of the caves with rock, which they covered with plaster, and divided them into compartments or rooms; and now many hundreds of these dwellings are found. Such is the cliff village of Walnut Canyon. In the ruins of these cliff houses mortars and pestles are found in great profusion, and when first discovered many articles of pottery were found, and still many potsherds are seen. The people were very skillful in the manufacture of stone implements, especially spears, knives, and arrows.

East of San Francisco Peak there is another low volcanic cone, composed of ashes which have been slightly cemented by the processes of time, but which can be worked with great ease. On this cone another tribe of Indians made its village, and for the purpose they sunk shafts into the easily worked but partially consolidated ashes, and after penetrating from the surface three or four feet they enlarged the chambers so as to make them ten or twelve feet in diameter. In such a chamber they made a little fireplace, its chimney running up on one side of the wellhole by which the chamber was entered. Often they excavated smaller chambers connected with the larger, so that sometimes two, three, four, or even five smaller connecting chambers are grouped about a large central room. The arts of these people resembled those of the people who dwelt in Walnut Canyon. One thing more is worthy of special notice. On the very top of the cone they cleared oif a space for a courtyard, or assembly square, and about it they erected booths, and within the square a space of ground was prepared with a smooth floor, on which they performed the ceremonies of their religion and danced to the gods in prayer and praise.