4 PHYSICAL GEOGRAPHY. 



empire, and yet as we shall see hereafter, few states have really so 

 little waste land as Nebraska. It lies in the same path in which the 

 currents of emigration have been flowing in the line of the great 

 States of the Union, and must in the nature of things receive their 

 overflow of population. 



SURFACE OF THE STATE. 



The surface of Nebraska is exceedingly varied. There are in- 

 deed no elevations that can be dignified with the name of mountains, 

 but in the northern and western parts of the State there are lofty 

 hills of very varied character. Generally the ascent is gentle, 

 though occasionally it is precipitous. Unlike the ridges of the east 

 which are so generally the result of elevations and subsidences of 

 the earth's crust modified by subsequent aqueous agencies, the hills 

 and rolling lands of Nebraska are mostly wholly caused by erosion. 

 In the east the body of hills is mainly made up of massive rocks, 

 here it is partly composed of loosely compacted drift materials, but 

 mainly of Loess. In fact, Nebraska emerged so recently geologically 

 from the waters of the Loess age, that it still exhibits as a whole 

 many of the phenomena of a recently drained lake bed. The gen- 

 tly rolling lands of three-fourths of the State appear very much like 

 the suddenly petrified waves and billows of the ocean. Sometimes 

 extensive stretches of surface are met with that appear to be level, 

 but closer observation shows even these to be gently undulating. 

 From these last mentioned forms to the few isolated sections of lim- 

 ited extent,broken by canyons with precipitous sides, the transition is 

 gradual. Every shade of form and surface connects the two varieties 



of relief. The 



BOTTOM LANDS 



are the most conspicuous modifying feature of the landscape of the 

 State. In crossing the State at rf'ght angles to the direction of the 

 streams, the bottom lands are met with every few miles. They are 

 huge, generally shallow troughs, in breadth proportionate common- 

 ly, to the size of the streams. They range in width from a quarter 

 of a mile on the smaller streams to twenty-three miles on the Platte 

 and the Missouri. They are frequently terraced, and the terraces like 

 broad steps gradually lead to the bordering bluffs which in turn are 

 very varied in height and form. Frequently the low terraces on 

 the bottoms have had their edges so worn away that their charac- 

 ter is concealed. What was once a terrace has become a gentle slope. 



