352 



Journal of Agricultural Research 



Vol. X. No. 7 



caused a local concentration by seepage through the rock and deposi- 

 tion by evaporation. There is a marked variation in the amount of 

 salts occurring in the country rock in any given geological series. But 

 uniformly high results have been obtained at widely separated sections 

 of the country, such as those found at Grand Junction, Colo., Emery 

 and Vernal, Utah, and Lyman, Wyo. There is a marked concentra- 

 tion of nitrates and alkali in the ashlike and alkali deposits in the uncul- 

 tivated areas. 



The following summary (Table XVII) shows the average alkali ma- 

 terial found in the country rock. 



Table XVII. — Average alkali tnaterial in country rock 



CRETACEOUS MATERIAL 



[Results expressed as pounds per 2,000,000] 



Material. 



Calcium. 



Bicar- 

 bonate. 



Sul- 

 phate. 



Haenesiuxn. 



Sul- 

 phate. 



Chlo- 

 rid. 



Ni- 

 trate. 



Sodium. 



Sul- 

 phate. 



Chlo- 

 rid. 



Ni- 

 trate. 



Total. 



Sandstone. 



Shale 



Clay 



Ash 



AlkaU 



983 



993 



1,021 

 1,073 

 3;419 



16,469 



IS- 738 



18,091 

 21,743 

 3S, 666 



3.92i 

 10, 780 



7,780 

 14.03s 

 127,23s 



98s 



1,961 



13.036 



9,411 



99.910 



152,682 



1,148 

 1.999 



2,380 

 17,665 



2,079 



775 



3.623 



5.492 



Per cent. 

 I. 21 

 2. 19 

 1-75 

 7- 13 



" Also 1,156 pounds of calcium chlorid present. 



The summary brings clearly to mind the fact that in a widely dis- 

 seminated form there is in the shales and sandstones of the Cretaceous 

 and Tertiary of Utah, Colorado, and Wyoming enormous deposits of 

 soluble salts consisting of the sulphates, chlorids, nitrates, and bicar- 

 bonates of calcium, magnesium, and sodium. In certain local areas 

 these salts become concentrated so as to produce native alkali, or " niter 

 spots," by the movement of the underground water without the instru- 

 mentality of the irrigation ditch. Wherever the shale is highly impreg- 

 nated with the salts the evaporation of the water deposits the alkali 

 salts on the surface in the form of an ashlike powder. 



