THE SANTA FE ROUTER. 119 
in trees show marked changes in climate in alternating long cycles of 
drier and more rainy periods. 
On the edge of the high mesa in the western part of Flagstaff is the 
Lowell Observatory, which is equipped with an especially fine tele- 
scope through which Dr. Percival Lowell and his assistants have 
made their famous observations on the planet Mars. The clear, 
steady air of this high altitude is particularly favorable for astronom- 
ical work. 
The peaks of the San Francisco Mountains! are prominent from 
Flagstaff, and the trip to their summit can easily be made on horse- 
back from that place. The region from these mountains to Gila 
River was the domain of the Apaches (Pinal cgi until their 
final surrender through the efforts of Gen. Crook and Gen. Miles 
in 1886. At one time the San Francisco Mountains were the refuge 
of the Havasupai Indians, who fled there when driven from their 
home on the Little Colorado. These Indians are the only ones 
among the Yuman tribes who had a culture similar to that of the 
Pueblo people farther east. A number of ruins are ascribed to them 
as far south as the Rio Verde, in central Arizona, and the early name 
Cosnino, by which this tribe was known, has been applied to many 
features in this region. They now live in Cataract Canyon, 60 miles 
northwest of Williams. 
West of Flagstaff the train continues to climb up the plateau slope. 
In this vicinity the Kaibab limestone is mostly covered by lavas of 
various kinds, but its surface appears for a short distance in a de- 
pression just west of Flagstaff. For the first 5 miles west the railroad 
passes along the southern foot of a mesa consisting of a sa of 
a (latite), poured out over the surface in a thick mass during t 
second period of volcanic activity. 
''The structure of these mountains is.| These rocks appear to lie on the limestone 
shown in figure 26. They consist of a | platform of the plateau, but the beds may 
Agassiz baer 
frm oy mittiin nh apa ninty 
ft Re 2 limestone + 
J 
Early basalt vent?7; 
Dacite vent-+ 
Latite vent 
FiguRE 26.—Generalized section through the San Francisco heast of Flagstaff, Ariz., 
looking north. Dotted portion eroded; broken line hypothetical. 
possibly some Moen- 
ed, and 
thick pile of latite lying on a sheet of | be upturn the central 
earlier basalt and overlain by flows of | copie sandstone may underlie 
_ other lava, mainly dacite and andesite. | mass of latite 
