306 Saline Incrustations. paet ii. 



analysis by Mr. A. Hayes, of an average specimen, 



gave — 



Nitrate of Soda 61-98 



Sulphate of Soda 3-00 



Chloride of Soda 28-69 



Iodic Salts 0-63 



Shells and Marl 2-60 



99-90 



The ' mother water ' at some of the refineries is very 

 rich in iodic salts, and is supposed l to contain much 

 muriate of lime. In an unrefined specimen brought 

 home by myself, Mr. T. Reeks has ascertained that the 

 muriate of lime is very abundant. With respect to the 

 origin of this saline mass, from the manner in which 

 the gently inclined, compact bed follows for so many 

 miles the sinuous margin of the plain, there can be no 

 doubt that it was deposited from a sheet of water : from 

 the fragments of embedded shells, from the abundant 

 iodic salts, from the superficial saliferous crust occur- 

 ring at a higher level and being probably of marine 

 origin, and from the plain resembling in form those of 

 Chile and that of Uspallata, there can be little doubt 

 that this sheet of water was, at least originally, con- 

 nected with the sea. 2 



Thin, superficial, saline Incrustations. — These 

 saline incrustations are common in many parts of 

 x\merica : Humboldt met with them on the table-land 



1 'Literary Gazette,' 1841, p. 475. 



2 From an official document, shown me by Mr. Belford Wilson, 

 it appears that the first export of nitrate of soda to Europe was in 

 July 1830, on French account, in a British ship : — 



In 1S30, the entire export was 



1831, ,, ,, 



1832, „ „ 



1833, ,, ,, 



1834, „ „ 



The Spanish quintal nearly equals 100 English pounds. 



Quintals. 

 . 17,300 

 . 40,885 

 . 51,400 

 . 91,335 

 . 149,538 



