DENVER & RIO GRANDE WESTERN ROUTE. 119 
result is that the quartzite steadily approaches railroad level down- 
stream. About half a mile below milepost 297 the quartzite reaches 
railroad grade, and a short distance below it passes beneath the 
stream and is lost to view. 
Just before reaching Rex siding the traveler may see on the west 
(left) a ridge of loose boulders, which seems almost like a dam 
thrown across the valley of Eagle River. Doubtless he has already 
learned to recognize such an accumulation of boulders as a moraine 
that was pushed out by a glacier from some side valley. This moraine 
was built by a large body of ice which descended Cross Creek from 
the high peaks of the Holy Cross group of mountains. The boulders 
were carried entirely across the valley of Eagle River, showing that 
the ice filled the valley to the foot of the slope on the east side. The 
glacier expanded when it reached Eagle River, so that its extremity 
must have resembled a fan, and it covered the area on which the rail- 
road has been built for a distance of 24 miles. One of the great blocks 
of gneiss which it carried to the foot of the slope on the farther side 
may be seen on the east (right) of the track near Elk Creek. It 
is 40 feet long and 25 or 30 feet wide, and its top stands 12 feet above 
the ground. 
Cross Creek is noted for the peculiar forms that were produced 
along it by the passage of the glacier over its granite bed. As the 
glacier found the floor of the granite canyon somewhat irregular its 
principal work was to round off and polish the projecting knobs. 
The rounded masses of granite in this canyon, called “ roches mouton- 
nées ” (rdsh moo-ton-nay’), are shown in Plate LV, A. This name 
has been applied by French geologists to such rounded rocks on 
account of their fancied resemblance, when seen at a distance, to the 
backs of sheep. 
' At Rex siding the top of the quartzite is at railroad level, and the 
Leadville limestone may be seen on the left, where it forms 
knobs. Its color is light blue, and it is easily distinguishable from 
the quartzite, which has a yellowish tone. As the railroad swings 
to the east and the rocks dip in the same direction the Leadville 
limestone soon disappears below the bottom of the valley, and the 
only hard rocks in sight are the Carboniferous sandstones and shales, 
which give to the slopes on the east (right) their banded appearance. 
One of the most noteworthy features of this part of the Denver & 
Rio Grande Western Railroad is the Mount of the Holy Cross 
(Pl. LIT). This peak stands near the head of Cross Creek, but 
unfortunately no good view of it can be obtained from the train. 
Near the mouth of Elk Creek, however, a fleeting glimpse of 
the mountain may be had, if the traveler is on the alert and looks in 
the right direction. As the train swings eastward and approaches 
