THE SANTA FE ROUTE. 135 
consists in part of the lower red shale of the Supai formation and in 
part of the upper surface of the Redwall limestone. The railway 
follows the boundary line between these two formations, in some 
places on the red shale and in others on the limestone. The Aubrey 
Cliffs are prominent in the landscape to the east as the train bears 
away northwestward by rising on the gentle slope of the eastward- 
dipping beds to the summit of the plateau of Redwall limestone. 
This plateau is the next ‘‘step”’ in the descent from the great plateau 
of Arizona, a descent which is begun a short distance west of Williams 
and continues nearly to Colorado River. 
At Pica (see sheet 20, p. 138) there are wells 1,100 
Pica. oe 
feet deep sunk on the recommendation of a Govern- 
Elevation 5,247 feet. : . j 
Kansas City 1,367miles, ent geologist. They furnish water for locomotives 
and also for a large number of cattle and sheep. 
The summit of the slope of Redwall limestone is reached at Yampai, 
where there are cuts in this limestone. At the summit is a wide 
pass, west of which the train enters Yampai Canyon, 
cut in the Redwall limestone to Peach Springs, 
> sania a distance of about 14 miles. Below Fields siding the 
walls of the canyon show extensive ledges of the lime- 
stone, and at Nelson this rock is quarried to a moderate extent for 
burning into lime. 
Massive beds of hard limestone, weathering to a light dove-gray 
color, are highly characteristic of the Redwall in this region, as also 
in places in the Grand Canyon where the rock is not 
Yampai. 
Nelson. stained red by wash from the overlying red shale. 
Elevation 5,106 feet. On some of these limestone walls there may be seen 
Population 300.* = ah-cay’ 
ya the peculiar mescal plant, or maguey (mah-gay’, 
Agave americana) shown in Plate XXXV, A. After 
several years of growth the plant sends up a tall flower stalk which 
develops from a cabbage-like heart greatly prized by the Indians, 
who roast it in small pits in the ground. Its juice is sweet and when 
fermented and distilled yields the mescal brandy so extensively used 
in Mexico and the Southwest. 
Near Peach Springs the Yampai Canyon widens into a valley 
known as Truxton Wash, which for some distance westward is 
occupied by a lava flow (basalt) that is well exposed 
for half a mile or more beyond Cherokee siding. - The 
ridge north of the valley consists of Redwall lime- 
: stone. On its north side there are canyons descend- 
ing into the Grand Canyon of the Colorado at a point only 18 
miles north of the Peach Springs station. These smaller canyons 
are cut mainly in sandstone and shales of the Tonto group (see 
Pl. XXXVI) lying on granite, which is deeply trenched in turn as 
Orado River is approached. A fairly good road extends from 
Peach Springs. 
Elevation 4,739 feet. 
Kansas City 1,387 miles. 
