144 GUIDEBOOK OF THE WESTERN UNITED STATES. 



The soft Tertiary and Cretaceous formations have been eroded 

 very rapidly, and vast quantities of clay, gravel, and sand have been 

 washed into the basin-like valley below the narrow canyon which 

 the river has cut through the Grand Hogback. This loose material 

 once filled the valley to a considerable depth, and the streams then 

 removed part of it, leaving the remainder as great sloping terraces, 

 which come down from the sides of the valley and would meet in 

 the middle were it not for the trench which the river has cut. The 



presence of this fine material has given to one of 

 Silt. the villages the appropriate name of Silt. On the 



Elevation 5,441 feet, old maps of this region this broad valley was called 

 Denver 380 miles. Cactus Valley, on account of the barrenness of the 



region and the presence of many forms of cacti. To- 

 day the parts on which water has been taken bear little resem- 

 blance to a cactus valley, but the unreclaimed part is extremely 

 barren. Here for the first time on this journey the traveler is coming 

 into the real semiarid region, where precipitation is so slight that 

 crops can not be raised without irrigation and where the unreclaimed 

 tracts are either barren of vegetation or have the kind that is char- 

 acteristic of the more nearly desert regions. On the south (left) 

 the traveler may see the east front of Battlement Mesa, which is 

 capped by a layer of basalt that has preserved the even surface over 

 which it flowed as lava. Its east front, which is seamed and scarred, 

 presenting a very rugged face, is one of the highest points in the 

 vicinity, having an altitude of over 10,000 feet. The even surface 

 upon which this flood of lava was poured is probably a part of the 

 peneplain of which the White River Plateau is another remnant. 

 Those who have made no study of geology may think that all pla- 

 teaus are formed by the uplift of parts of the country to a greater 

 altitude than that of the surrounding regions — in other words, that 

 they are on anticlines or upfolds of the rocks, but this is not uni- 

 formly true. The White River Plateau is on such an upfold, but 

 Battlement Mesa is in a downfold, and generally upfolds and down- 

 folds have no necessary connection with the formation and preser- 

 vation of plateaus. 



Rifle, on Colorado River at the mouth of Rifle Creek, although not a 

 large town, is one of the most important points on the railroad. 



The irrigated land along the river near Rifle yields 

 Rifle. abundant crops, but they are somewhat different 



Elevation 5,310 feet, from those that are raised about Glenwood Springs, 



Denver*38°7mi^ies ^^^ *^^® ^^^^ ^^^'^ stands at a lower altitude and the 

 summer temperature is consequently higher. Po- 

 tatoes and grains are not large crops about Rifle ; sugar beets, alfalfa, 

 and fruits are more common. From Rifle a stage line, 42 miles long, 

 leads northward to Meeker, the largest town in the irrigated valley 



