210 GUIDEBOOK OF THE WESTERN UNITED STATES. 



The railroad rises steadily until it reaches a local summit at Cliff 

 siding, betAveen mileposts 574 and 575, and then begins a rapid de- 

 scent to Price River, the master stream in the north 

 end of Castle Valley. This stream heads on the 

 Denve'r^Ts mne?'*" ^asatch Platcau, far to the northwest, and flows 

 across the north end of the San Rafael Swell, be- 

 yond which it joins Green River through a deep canyon cut in the 

 Book Cliffs just north of the Beckwith Plateau. The traveler may 

 see the entrance to this canyon by looking ahead on the east (right) 

 after passing Cliff siding. 



The line of cottonwood trees that marks the course of Price River 

 may be seen long before the train has reached the bottom of the valley, 

 and their soft green color is very refreshing to the eye that has been 

 gazing on the barren expanse of desert just crossed. At Woodside 

 the railroad crosses Price River, which the traveler 

 Woodside. unaccustomed to this region may not be willing to 



Elevation 4,645 feet, call a river uuless he remembers that most of the 

 Denve^*58i mites "^^ter it normally carries is withdrawn for irri- 

 gation farther upstream, and then he may wonder 

 that any water at all is left in it at Woodside. 



For a distance of about 3 miles the railroad follows the east bank 

 of the river through groves of cottonwood trees and small irrigated 

 farms. Its course here lies near the west margin of the belt of shale, and 

 the underlying sandstone (Dakota) and the red and green rocks of the 

 McElmo may be seen at many places across the river on the left. 

 Xear milepost 583 the river ceases to follow the shale and swings in 

 from the west, where it has cut a deep and narrow canyon in the 

 hard rocks across the north end of the San Rafael Swell. The rail- 

 road engineers sought to avoid this canyon by following the broad 

 valley that Grassy Creek has cut in the shale. This valley is the 

 extension of the one that the train has followed ever since it left 

 Green River. 



The valley was not formed by a downfold in the rocks but simply 

 by the erosion of the soft Mancos shale. The traveler may under- 

 stand this easily by looking at the higher rocks in the face of the 

 Book Cliffs on the east and the lower rocks in the San Rafael Swell 

 on the west and noticing that they dip in the same direction — toward 

 the northeast. From time to time as the traveler may be able to 

 look ahead he can see that apparently the valley is filled and cut off 

 by terraces that rise 100 feet or more above the level of the track, 

 as shown in figure 56. These terraces appear to bar the further pas- 

 sage of the railroad, so it turns to the left a short distance beyond 

 Grassy siding and climbs out of the shale valley. In making this 

 climb the road turns and twists about some of the barren shale hills, 



