COLORADO PLATEAU— SAN FRANCISCO MOUNTAINS. 
15 
usually clad with an ample growth of pine, pinon and cedar ; broad and 
shallow valleys, yellow with sand or gray with sage, repeat themselves over 
the entire area. The altitude is greater than the plateaus north of the chasm 
except the Kaibab, being on an average not far from 7,000 to 7,500 feet. 
From such commanding points as give an overlook of this region one lonely 
butte is always visible and even conspicuous by reason of its isolation. It 
stands about twenty miles south of the Kaibab division of the Grand Canon 
and is named the Red Butte. It consists of Permian strata lying like a cameo 
upon the general platform of Carboniferous beds. The nearest remnant of 
similar beds is many miles away. The butte owes its preservation to a mantle 
of basalt which came to the surface near the center of its summit. It is an 
important factor in the evidence upon which rest the deductions concerning 
the great erosion of this country. 
Fifty or sixty miles south of the river rise the San Francisco Mountains. 
They are all volcanoes, and four of them are of large dimensions. The 
largest, San Francisco Mountain, nearly 13,000 feet high, might be classed 
among the largest volcanic piles of the west. Around these four masses 
are scattered many cones, and the lavas which emanated from them have 
sheeted over a large area. The foundation upon which they are planted is 
still the same platform of level Carboniferous strata which stretches calmly 
and evenly from the base of the Vermilion Cliffs for more than one hun- 
dred and fifty miles southward, patched over here and there with the lin- 
gering remnants of lower Permian sti'ata and isolated sheets of basalt. 
South of the San Francisco Mountains the level Carboniferous platform 
extends for twenty or thirty miles, and at last ends abruptly in the Aubrey 
Cliffs, which face southward and southwestward, overlooking the sierra 
country of central Arizona. 
Recapitulating now in regular order from west to east the several pla- 
teaus which lie immediately north of the Grand Canon, we note: 1. The 
Sheavwits; 2. The Uinkaret; 3. The Kanab; 4. The Kaibab. East of 
these, and draining into the Marble Canon from the north, is the Paria 
Plateau. South of the Grand Canon is the great expanse of the Colorado 
Plateau. The limits of the district must also be extended to include the 
