166 GUIDEBOOK OF THE WESTERN UNITED STATES. 
The railroad cut at the summit of the pass is in a volcanic breccia 
made up of bombs and other fragments thrown out by a volcano and 
afterward consolidated and cemented into a bed of rock. The source 
of this volcanic material is not known, but it probably came from the 
south, where the eruptions were many and violent, though they did 
not extend into this region. This breccia is much younger than the 
rocks of Ouray Peak, and it therefore does not indicate that that 
mountain is a voleano. 
The steepest railroad grade on the east side of the summit is 4 per 
cent, or 211 feet to the mile, a grade that is maintained from a point 
not far above Mears Junction to the summit, a distance of 14 miles. 
The grade on the west side is the same from the summit of the pass 
to a point about a mile below Chester, a distance of 9 miles. As the 
maximum grade on the standard-gage main line is only 3 per cent, 
or 158 feet to the mile, a change in gage here would probably mean 
an entirely new location, so as to avoid the steep grades and short 
curves. 
On emerging from the snowsheds at the summit the traveler has 
spread before him on the left the long slope down which the rail- 
road winds with many loops and turns. This side of the mountain 
is more nearly treeless than the east side, because it is much drier, for 
it is swept by dry winds that have passed over the arid plateaus of 
southern Utah and Arizona. There are no indications that glaciers 
ever existed on this side, for the entire slope is exposed to view and 
nothing resembling a terminal moraine can be seen. This fact also 
is due to the strong west winds and the drier atmosphere on the west 
side and to the greater heat of the sun’s rays, which aided the melting 
of the snow on the south and west sides. After the train loops back 
directly under the pass there is little of interest to be seen; the slopes 
are generally smooth, and the valley is without scenic attractions. 
A short distance west of Marshall Pass the railroad goes from 
voleanic breccia to granite and then onto quartzite and shale similar 
to those seen below the Ouray or Leadville limestone in both Eagle 
River canyon and the canyon of Colorado River above Glenwood 
Springs. These rocks are not strikingly exposed and probably will 
be detected only by those who look specially for them. 
from a toothache! Such a trip would | Truly the “winning of the West” 
be bad enough to make under present | called for courage and endurance of 
conditions, but what must it have been | which the traveler of to-day, with all 
through an unbroken wilderness and | the comforts and even luxuries of 
across the backbone of the continent! | travel, can have little comprehension. 
