Geological Papers. ^ 67 



clay is derived from shales, slates, granites and lavas; quartz 

 sand comes from disintegrated sandstones and granites and 

 from pulverized quartzites; potash is taken from the feldspar 

 of granite, and soda and lime from the feldspar of lava. 



Potash, soda and lime were taken away by carbonic acid 

 and exist in the waters as carbonates or bicarbonates ; but the 

 carbonic acid will vacate in favor of almost any other acid. 

 Carbonate of potash becomes nitrate of potash in the presence 

 of nitric acid generated by bacteria or by flashes of lightning 

 in thunderstorms. The carbonate of soda, so abundant in 

 lakes in the craters of volcanoes, may be changed to a nitrate 

 on encountering nitric acid, or to chloride (common salt) in 

 the presence of hydrochloric acid. In a similar way potash 

 carbonate may become a chloride. 



The bicarbonate of lime in rivers, lakes and ocean is used 

 in skeleton-making by myriads of animals, which, however, 

 reject half of the carbonic acid. Great quantities of the bi- 

 carbonate of lime are precipitated as a carbonate by sea weeds 

 which rob it of half of its carbonic acid. 



The sulphates are among our most abundant minerals. The 

 plants and animals of Kansas will never sufl"er from lack of 

 sulphur so long as gypsum (lime sulphate plus water) is such 

 a common mineral, and epsom salts (magnesium sulphate) is 

 so generally present in spring water. 



Phosphatic minerals are fortunately widely distributed in 

 the crust of the earth, especially the mineral apatite (in tri- 

 calcium phosphate). Chemists say that nine one-hundredths 

 of one per cent of the crust of the earth is phosphorus. 

 From the first, life has found phosphorus indispensable 

 as an ingredient of its protoplasm, and no soil will pro- 

 duce crops without it. All sedimentary rocks in Kansas con- 

 tain small amounts of this element and on disintegration yield 

 it to the soils and subsoils. The amounts are very small and 

 must be expressed in hundredths of one per cent. Sandstone 

 has about seven, shale about seventeen, and limestone, not 

 weathered, forty-two. As an argument in favor of deep plow- 

 ing it must be remembered that the subsoils are richer in 

 phosphorus than the soils because of leaching. 



Potash is necessary, in some way not well understood, to 

 plants in their work of food-making, and where lost to soils 

 by leaching must be supplied in a fertilizer. The other min- 

 erals listed above are necessary to the work of plants but are 



