GEOLOGICAL SURVEY OF THE TERRITORIES. 109 



vegetation on their sides, especially the u Yuccas, or Spanish Needles," 

 which seem to grow luxuriantly in these almost soilless regions. No 

 portion of the country is so barren or soilless as to be destitute of its 

 peculiar vegetation, and even those portions that appear most sterile 



Fig. 5. 



HI 



Sand Hills on the Niobrara River. 



have some forms which flourish there best, and would perhaps perish 

 if transported to a richer district. In the "Bad Lands" the soft, suc- 

 culent cactus, which draws most of its nourishment from the atmos- 

 phere, often covers the bald, dome-like hills as if it would conceal their 

 nakedness and sterility. These large moving bodies of sand are not 

 uncommon in the West ; in the North Parle there is quite a large area 

 completely covered with them, and as the surface reflects the light of 

 the sun's rays, they appear in the distance like some extensive lake. 

 Near the Mosca Pass in the San Luis Valley is another group of sand 

 hills which is quite conspicuous. The winds seem to delight in playing 

 their antics in these places, throwing up the sand in the most beautiful 

 wave-like furrows. Sometimes the strong winds that sweep over these 

 vast plains will fill the air with a storm of sand so as to impede the 

 traveler's progress for the time, and again they whirl it in circular col- 

 umns far out of sight. 



We shall now continue our way up the valley of the Platte with a 

 good deal of rapidity. The country is monotonous, and yet now and 

 then a fact of some interest might be gathered. We soon pass into what 

 is called the alkali district, where the ground is covered in places with a 

 white efflorescence, which looks in the distance like snow. If the traveler 

 were to ascend the high hills that border the valley and cast his eyes 

 in every direction, he would see nothing but a gently rolling prairie, 

 without a tree or shrub as far as they could reach. No cozy farm-houses, 

 with all the signs of cultivated fields, greet the eye ; no groves of timber 

 dot the landscape. For more than two hundred miles along the valley 

 of the Platte it would be difficult to find wood enough to kindle a fire. 

 Fuel for the supply of Fort Sedgwick and the city of Julesburg, during 

 the winter of 1865-'6, when it was in its glory, was hauled from the moun- 

 tains near Denver, Colorado, a distance of more than two hundred miles, 

 at a cost from one to two hundred dollars per cord. 



