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GUIDEBOOK OF THE WESTERN UNITED STATES. 



the mouth of Elk Creek the traveler, by looking back on the 

 west (left) may see high rugged peaks coming one by one into view. 

 Mount Jackson may be seen by looking up Cross Creek, but the one 

 peak which he desires to see more than all others is hidden for a long 

 time by the high plateau on the south side of the canyon. Finally, 

 however, after crossing Elk Creek, which comes in from the 

 east, when the train is near milepost 300 and just before it passes be- 

 hind a ridge on the left, the traveler may catch a glimpse up the creek 

 valley of the Mount of the Holy Cross (see PI. LUI), but even 

 here the cross itself is not well shown. Very few persons who have 

 passed over this road have been able to identify this famous peak, 

 but if the traveler will look as directed he can certainly see it unless 

 the atmospheric conditions prevent a view of 

 any of the high mountains. 



Just after milepost 300 is passed the moraine 

 that marks the other limit of the Cross Creek 

 glacier appears across the river as a sharp and 

 distinct ridge which curves parallel with the 

 railroad, and a good view of its tree-covered 

 slopes may be had from the train. This moraine 

 is composed of sand, clay, gravel, and boulders 

 brought down by the ice from the high moun- 

 tains on the west, and the glacier that brought 

 this great mass of material marked the last 

 stage of glaciation (AVisconsin) that affected 

 North America ; but half a mile beyond mile- 

 jDOst 300 there is on the west (left) another ridge 

 or moraine that is rudely parallel to the other 

 ridge just described, but sharply distinct from 

 it. This outer moraine was evidently formed 

 long before the last glacier occupied the valley, for its slopes are 

 more aifected by the weather, and as it is outside of the other moraine 

 it must have been formed earlier or else the ice would have de- 

 molished the inner ridge, which now is the more conspicuous of the 

 two. The relative position of the two moraines is shown in figure 

 30. The existence of this older moraine shows clearly that glaciers 

 were formed in these mountains in at least two distinct epochs of 

 time, one of which was much earlier than the other. 



The rocks that are so well shown in the mountain slope on the east 

 (right) are supposed to belong to the lower part of the upper Car- 

 boniferous or, in other words, to have been formed at the same time 

 as the earliest of the great coal beds in the Appalachian region and 

 the Mississippi Valley. In the Rocky Mountains some coal beds have 

 been found in these rocks, but most of them are too small or too im- 



FiGURE 30. — Sketch map 

 showing old and new 

 moraines above Min- 

 turn. 



