120 GUIDEBOOK OF THE WESTERN UNITED STATES. 
Just east of Riordan siding, eight-tenths of a mile beyond milepost 
350, the Arizona Divide is crossed at an altitude of 7,311 feet, the 
highest point reached by the railway on the plateau. 
Reem: At this place and westward to and beyond Williams 
reece re ails the surface is dark lava (basalt) of somewhat irreg- 
ular configuration, with many large cinder cones 
on every side. 
Bellemont is in a wide ‘‘park” or open space in the forest, near the 
southern edge of one of the large lava flows. <A short distance to the 
south, where the lava lies on limestone, there are 
Bellemont. copious springs of exceptionally good water. This 
Elevation 7,132 feet. water is derived from rain and melting snow on the 
eae teradie: surface of the lava. It percolates through the porous 
rock to the underlying limestone and flows along the 
surface of the limestone to its outcrop. It is pumped to the station 
and used on the railway. On a well-watered flat north of this 
station is probably the heaviest stand of timber in Arizona or New 
Mexico. 
At Nevin siding, 2 miles west of Bellemont, a small cinder cone has 
afforded the railway company a supply of ballast which has been 
used on the tracks for many miles to the east and west. The pit, 
which is north of the siding, is large and presents an especially fine 
section through the cone. The principal working face, nearly 100 feet 
high, shows thick beds of cinders with large numbers of scattered 
bombs of various sizes and flattened masses of lava which have been 
thrown out bodily. The vent from which all this material was ejected 
has not been exposed by the excavations. As in many other cones, 
much of the material is red, owing to the oxidation of the iron which 
the lava contains. This oxidation develops more extensively in the 
cinder or bombs than in the solid basalt, for air and water, which 
facilitate the oxidation, have more complete access to material that 
is in the porous form. 
South of Nevin is Volunteer Mountain, a very large pile of cinders 
including some hard layers which appear to have been mud flows and 
consist of cinders that evidently flowed out mixed with more or less 
water and are now cemented into a porous rock. There are other 
thick piles of cinders to the north and northwest of Nevin and Maine. 
From Bellemont westward at intervals to and beyond Maine (see 
sheet 19, p. 122) there are excellent views of Kendrick Peak, which is 
: 12 miles north of Bellemont, and of Mount Sitgreaves, 
Maine. which is 8 miles northwest of Maine. These peaks 
emetic; aeaia _are due to thick masses of lavas of the viscous type 
ae se poured out during the second period of eruption and 
rising high above the plain of older basalt. The mass culminating in 
Mount Sitgreaves consists mainly of rhyolite; the principal rocks in 
