134 GUIDEBOOK OF THE WESTERN UNITED STATES. 
at a height of 1,200 feet, as to the north and south, there would have 
been great difficulty in building the railway down them. The break 
in their continuity was developed by erosion or faulting prior to the 
time of the volcanic eruptions, and now the sloping surface is covered 
by the extensive sheet of lava extending from Crookton to Seligman 
and beyond. 
Seligman, being a railway division point, is sustained largely by the 
railway interests, together with trade from scattered ranches in some 
of the adjoining valleys. The railway time changes 
Seligman. here from mountain to Pacific time, one hour earlier. 
Elevation 5,242 feet. Formerly the branch line to Phoenix jomed the main 
hiasth Lathe: line at this place, following a relatively easy grade 
up Chino Valley. It was changed to shorten the 
distance from Phoenix to the East. There is a road from Seligman 
north 67 miles to Cataract Canyon, a branch of Grand Canyon, which 
has high red walls and several picturesque waterfalls. Here live the 
~ Aubrey Cliffs . 
Aubrey Valley 
ar ap 
. a, Limestone 
pre tieg b, red sandstone and shale (Supai); c, gray sandstone (Coconino); d, limestone (Kaibab); 
e, lava, 
FIGURE 32.—Section through Aubrey Cliffs, northwest of Seligman, Ariz., looking north 
Havasu (Supai) Indians, who cultivate a few acres of rich land by the 
water from the great springs that form Cataract Creek, 
Railway cuts a short distance west of Seligman show the red sand- 
railway. They extend along the lower slope of the Aubrey Cliffs, 
which continue as a long, high wall far to the north. Above the red 
which is softer and less conspicuous here than in the walls of the 
Grand Canyon. At the top of the cliff are light-colored ledges of the 
cherty Kaibab limestone, forming a plateau that slopes somewhat to 
the east. The relations in this cliff are shown in figure 32. 
The Aubrey Cliffs extend for many miles across the plateau region 
on both sides of the Grand Canyon. As explained above, they are 
caused by the western edge of the great sheet of limestone that caps 
the Arizona Plateau. The depression at their foot, here known as 
Aubrey Valley, is followed by the railway for some distance to the 
northwest, past Audley and Pica sidings. The floor of the valley 
