THE NITER DEPOSITS OF CALIFORNIA 295 



This geologist is of the opinion that the nitrate deposits are the 

 result of the decomposition of feldspathic rocks; the bases thus 

 produced gradually becoming united with the nitric acid pro- 

 vided from the air. 57 



According to the theory of Nollner, the deposits are of more 

 modern origin and due to the decomposition of marine vegeta- 

 tion. 58 Continuous solution of soils gives rise to the formation 

 of great lakes of saturated water, in which occur the develop- 

 ment of much marine vegetation. On the evaporation of this 

 water, due to geologic isolation, the decomposition of nitrogen- 

 ous organic matter causes generation of nitric acid, which, coming 

 in contact with the calcareous rocks, attacks them, forming nitrate 

 of calcium, which, in presence of sulfate of sodium, gives rise to 

 a double decomposition into nitrate of sodium and sulfate of 

 calcium. 



The fact that iodin is found in greater or less quantity in 

 Chile saltpeter, is one of the chief supports of this hypothesis of 

 marine origin, inasmuch as iodin is always found in sea and not 

 in terrestrial plants. Further than this, it must be taken into 

 consideration that these deposits of nitrate of soda contain neither 

 shells nor fossils, nor do they contain any phosphate of lime. 

 The theory, therefore, that they are due to animal origin, is 

 scarcely tenable. 



Extensive nitrate deposits have been discovered in the U. S. 

 of Columbia. 59 These deposits have been found extending 

 over 30 square miles and vary in thickness from one to 10 feet. 

 The deposits consist of a mixture of sodium nitrate, sodium 

 chlorid, calcium sulfate, aluminum sulfate and insoluble silica, 

 and contain from one to 13.5 per cent, of nitrate. 



259. The Niter Deposits of California. Many of the condi- 

 tions which favor the deposition of niter in the soil are found in 

 Southern California and Arizona, and it has been confidently 

 predicted that niter deposits of value and of great extent would 

 bo found in these localities. The California State Mining Bureau 



57 Fuchs and de Launay, Traitd des Giles mine'raux, 1893, 1 : 425. 



58 Le Feuvre and Dagnino, El Salitre de Chile, 1893 : 12. 



59 Wiley, Presidential Address, Journal of the American Chemical 

 Society, 1894, 16 : 20. 



