ECONOMICAL GEOLOGY. 309 



duction of varying climates is correct, the extremes of temperature 

 will also gradually become less, and continually milder conditions 

 will prevail. All the changes that may occur hereafter, therefore, 

 for a long period will be favorable, and the globe as a whole be- 

 come more and more fitted for a theatre for the development of 

 mind and morals. 



Even if this explanation of the causes of climatic changes is not 

 the correct one, there can be little doubt that some cosmical influ- 

 ences will in the end be found to furnish the key to unlock the 

 mysteries of these changing phenomena. 



CHAPTER X, 



ECONOMICAL GEOLOGY. 



Coal, Bituminous and Lignite. — Peat, its Quantity, Quality, and Where 

 and How Formed.— Building Stone, Where and How Found; their Charac- 

 ter at South Bend. — Building Stone in the Cretaceous and Tertiary. — Lime 

 and Hydraulic Cement. — Its Manufacture at Beatrice. Brick Clay. — Fire 

 Clay.— Potters' Clay; Sections and Character of at Louisville — Kaolin. — 

 Gypsum, Where Found and How it Occurs. — Silica, its Great Extent and 

 •Character. — Iron Ores. — Zinc and Lead. — Gold. — Marl Beds. — Salt, Where 

 and How it Occurs. — Artesian Well in Lincoln and its Medicinal Character. 

 Artesian Wells over the State; their Future Value and Importance. 



Coal. — Bituminous coal has already been discussed in the chap- 

 ter on the Carboniferous measures; and lignite coal in the chapter 

 on the Cretnceous deposits. 



Peat. — There is no question about the great quantity of peat in 

 Nebraska. Hayden mentions many localities where it is found. 

 (Report for 1S67, 1S6S, and 1S69.) It is also found on the tributar- 

 ies and head-waters of the Logan, the Elkhorn, the Blue, and on 

 Stinking River, and other tributaries of the Republican. Great 

 quantities are also found in Boone County, on the Loups, and on 

 their tributaries. In fact, there is hardly a township in some sec- 

 tions of the State that does not contain some peat-bogs. When 

 people once learn its value, and more attention is directed to it, it 

 •will be found where now it is not expected. One peat-bog on the 



