TOPOGRAPHY OF NEBRASKA. 13 



entire surface of the State is made up of bottom lands. This is a 

 higher estimate than I formerly made, but I have come to it by in- 

 creased study of the physical features of the State. 



Exceptional Features of the Niobrara River Region. 



The Niobrara River is the least known of all the drainage sys- 

 tems of the State. It deserves to be better known, and in the near 

 future will be visited and studied by the geologist and the artist. 

 It holds concealed many unrevealed wonders for the student of na- 

 ture and of art. 



For the first ninety miles from its mouth the Niobrara is not 

 greatly different from other Nebraska rivers, save in the exception- 

 al rapidity of its current, and its sandy flats and numerous islands. 

 Its bottom is also narrower in proportion to the size of the river 

 than other streams of the State. 



In going up the valley it is observed to change rapidly at about 

 longitude 99 20'. The bluffs contract and become lofty. In fact, 

 the river here flows through a deep canyon. It retains this charac- 

 ter for the next 1S0 miles or to about longitude 102 . The sides of 

 the canyon are often three hundred and sometimes four hundred feet 

 high. The walls are mostly composed of silicious, and yellowish, 

 whitish and calcareous rocks. They are often capped with a hard 

 grit which preserves their vertical character, and often causes them 

 to be undermined and assume an umbrella form. In this canyon re- 

 gion it is next to impossible to follow along the immediate banks of 

 the river, owing to the numerous isolated buttes and walls that 

 rise perpendicularly from near the water's edge, making walls 

 across the line of travel hundreds of feet high. No indication of 

 the river's existence is here given in approaching it from either side, 

 except by the trees that sometimes rear their tops above the canyon, 

 and which grow near the water's edge. The sides of the canyon are 

 worn into innumerable labyrinths by the numberless springs that 

 have been, like the main river, chiseling the rocks for ages. These 

 lateral canyons are exceedingly mazy in their windings. Nowhere 

 else have I ever seen such cool, clear, strong and sparkling springs 

 as here abound. Their number is astonishing. They are met with 

 in places for miles every few hundred feet or yards. 



At the lower end of this canyon region the rocks are of cretaceous 

 age. Towards the west end the cretaceous becomes covered with 

 tertiary rocks. Vegetation in the canyons of the Niobrara is 



