88 GUIDEBOOK OF THE WESTEBX UNITED STATES. 



this section (see fior. 19) the syncline has been so squeezed by pres- 

 sure from the east that its sides have been pressed close together 

 or overturned, and consequently all the rocks dip toward the east. 

 The lava is prominent in this part of the valley, but it is limited 

 to the hills on the opposite side of the river. These hills at first 

 appear to be composed entirely of lava, but close scrutiny will show 

 that the red sandstone crops out here and there near the river level. 

 This low place in the sandstone evidently marked the middle of the 

 valley at the time the lava was poured out and filled the valley 

 to a depth of 300 or 400 feet. TTest of milepost 205 the railroad 

 crosses Badger Creek, which drains a large territory between the 

 Arkansas Valley and South Park. The red sandstones are well 

 exposed in the bend of the river a little farther on and in the ap- 



Hunts Peak 





5 Miles 



FiGUEE 19. — Section of the San^e de Ciisto Ran^e and the valley on its east side, through 



Hunts Peak and Howard. 



proaches to the tunnel beyond milepost 206. They are fairly con- 

 spicuous in the river bluffs near milepost 207, but west of this point 

 the red color disappears from both sides of the valley. The last 

 lava-capped hill is nearly opposite milepost 207, and this hill marks 

 the western limit of the old valley, which is now so deeply filled with 

 the volcanic material that it constitutes hills rather than a valley. 



At Swissvale the railroad is built upon a broad gravel-covered 

 flat. The absence of exposures of hard rock is due largely to this 

 fact and to the fact that the flat, or rather terrace, is composed of 

 the Weber shale and sandstone, which underlie the 

 Swissvale. pg^j sandstone that is so conspicuous farther east. 



This relation is due largely to the effect of a cross 

 anticline, which trends in the direction followed by 

 the railroad. This anticline brings the Leadville limestone near 

 the surface, but it can not be seen from the railroad until the train 

 passes Wellsville Springs. Its position is marked on the river bank, 

 however, by numerous springs, which carry so much lime in solution 

 that as soon as they emerge from the bank they deposit the lime 



Elevation 6,868 feel. 

 Denver 208 miles. 



