54 PHYSICAL GEOGRAPHY. 



mah, in the bluffs, called sometimes, from the color of the rocks, 

 Yellow Springs. The former has the rock above the spring cov- 

 ered with Indian hierogliphics. Occasionally springs proceed from 

 or near the line of junction between these rocks and the next below. 

 Some impervious layers of clayey, brownish shale in the Fort Ben- 

 ton Group, also arrest the downward course of water and leads it to 

 the next break or valley of erosion to appear as a spring. 



The se ond class of springs are those that proceed from between 

 different kinds of layers of the drift and loess. The drift is 

 specially remarkable for the number of clayey layers that are inter- 

 posed between layers of sand and pebbles. These layers of clay 

 carry the water to the nearest cut, where they form springs. 

 Where these layers of clay do not exist, the water is carried along 

 the top of the underlying rocks, if these happen to be hard or com- 

 pact, and springs as in the former case appear on the edges of the 

 valley. Many of the springs that emerge from the bluffs of all the 

 river valleys owe their origin to these causes. This explains, too, 

 why in many sections of the State, springs are found (often several 

 of them on every quarter section of land), and why in other por- 

 tions of the State they are found only at long intervals. The more 

 broken or rolling, other things being equal, the more abundant 

 they are. On the long reaches of nearly level land springs occur 

 at much longer intervals. On and near the top of the level water 

 sheds springs occur still more rarely. 



Water, however, is abundant even here. Wells or borings 

 always obtain it. Over the greater portion of the State, shafts or 

 holes sunk down from fifteen to fifty feet are sure to obtain it in 

 abundance. The exceptions to this rule are some portions of wide 

 divides in such counties as Fillmore, Clay, Adams and Phelps, 

 where there is a great thickness of loess and drift to be penetrated 

 before impervious strata, capable of holding water are reached. 

 Many farmers prefer land with no springs or running water on it. 

 There is less waste, they claim. A well with a wind mill attached 

 supplies water to man and beast in whatever quantity needed. A 

 wind mill and reservoir attached to a well not unfrequently is made 

 to water a thousand head of cattle daily, besides supplying the wants 

 of a household. 



Artesian Wells have been bored in a few places. The one in the 

 public square in Lincoln is one thousand and fifty feet deep. It was 

 put down in the hope that fresh water would be found. This effort 



