THE SANTA FE ROUTE. 131 
guardian and lord high steward of Dofia Juana, the daughter of King 
Ferdinand and Queen Isabella, who married Philip the Second. On 
no other exploration were there so many distinguished men as accom- 
panied Coronado on his dangerous journey from Mexico into this 
unknown land. 
MAIN LINE WEST OF WILLIAMS. 
From Williams (see sheet 19, p. 122) westward for some distance 
Bill Williams Mountain is a prominent feature south of the railway. 
Cinder cones are in view to the north, and one of considerable size also 
lies at the foot of Bill Williams Mountain a short distance south of the 
tracks. After passing Supai siding, 3 miles west of Williams, the 
train begins the long descent from the high plateau of lava and Kaibab 
limestone. From Supai to Corva a new line with an easier grade 
has been built for the eastbound trains. The lava (basalt) extends to 
the edge of the plateau and for a considerable distance down its west- 
ern slope, but the deeper canyons in the slope cut through into the 
Kaibab limestone. 
There are deep cuts in the basalt at the entrance to Johnson Can- 
yon. This gorge affords an advantageous line of descent for the 
westbound trains and exhibits many features of interesting geology 
and attractive scenery. 
Halfway between mileposts 388 and 389 the Kaibab limestone 
appears under the lava, and the train passes through a tunnel in the 
limestone with the lava cap not far above. On leaving the tunnel it 
goes over a long trestle, below which are many cliffs of the limestone, 
most of them with a capping of lava. In the deep canyon to the 
south are some sink holes in the limestone, known as the Bottomless 
Pits, into which the water disappears when there has been sufficient 
rain to develop a stream in the canyon. They are similar in char- 
acter and origin to the pits described on page 117. 
A short distance beyond milepost 390 the lava descends over the 
limestone ledges to a level somewhat below that of the bottom of 
Johnson Canyon, and for several miles west from this place it consti- 
tutes a broad bench that extends for some distance north and south 
of the canyon. From these relations it appears that the outflow of 
lava, probably issuing from a vent on top of the plateau west of Wil- 
liams, flowed westward over the plateau surface and down its western 
slope. The canyons have been eroded by streams since the time of 
this eruption, and some of the deeper ones have been cut through the 
lava into the underlying limestone. In part of the slope a few miles 
south of Johnson Canyon the grade down which the lava flowed was 
very steep, and at this place the igneous rock is very much broken 
where it cascaded over the limestone ledges. This outflow occurred 
n..1y thousand years ago, as much erosion has taken place since; but 
