ECONOMICAL GEOLOGY. 313 



some of their largest brick blocks. The best quarry of it that I 

 have examined is that of Hon. J. Warner in Dakota County. This 

 group also furnishes building stones in portions of Dixon, Burt, 

 Dodge, Washington, Saunders, Lancaster and Gage Counties. 

 The rocks of the Niobrara Group which occur above those last 

 mentioned are mostly limestone more or less pure. One of its beds 

 called from the abundance of its fossils the Inoceramus bed, often 

 breaks up into flagging stone. It forms good building materials, 

 is easily worked, and is capable of resisting great pressure. Along 

 the Missouri it is first seen on the hill tops in Dakota County, and 

 increases in thickness northward and westward. It extends in a 

 southwestern direction across the State into Kansas. Over the In- 

 oceramus beds in Cedar and Knox counties, there is an immense 

 thickness of massive chalk rock. In a few places it is almost as 

 pure as the chalk of commerce. It varies in color from light blue, 

 and the various shades of yellow, to almost white. It can be easily 

 sawed and planed into any shape. Though soft, it does not disin- 

 tegrate on exposure, but appears when exposed to grow harder 

 with age. Some houses built of it on the Santee Agency in Knox 

 County, twenty years ago, show no sign of crumbling. Some 

 equally old houses, built of this chalk rock, in Yankton, D. T., are 

 still intact. The various rocks of the Niobrara Group furnish build- 

 ing materials in Cedar, Knox, Wayne, Cuming, Colfax, Stanton, 

 Butter, Saunders, Seward, Jefferson, Nuckolls, Webster, Franklin, 

 and some other counties. 



West of the Cretaceous deposits the Tertiary beds occupy the 

 State to its very borders. The superficial deposits here generally 

 conceal the rocks, but as already observed where they are exposed, 

 there are some silicious beds, and silicates of lime that answer for 

 foundation stone. This is notably the case along the Republican 

 River and its tributaries, and on some of the tributaries of the Loup 

 and the Niobrara. But this section of the State has not yet been 

 sufficiently explored to indicate sharply where building stones may 

 be found. 



LIME AND HYDRAULIC CEMENT. 



As already stated, limestone is abundant in the Carboniferous 

 and Permo-Carboniferous measures of the State. The Niobrara 

 Group also furnishes an unlimited supply of it. A curious phenom- 

 enon of the limestone of the Carboniferous and Permo-Carbonifer- 

 ous, is that nearly all of it is more or less hydraulic. This is proba- 



