RECENT DEPOSITS. 43 



Pachp-cdra, Sambhar, and other places, the drainage from the sur- 

 rounding higher ground concentrates the salt, until in course of time 

 the accumulation has become so great as to be commercially 

 valuable. 



It is perhaps not improbable that as particles of carbonate of lime 

 are distributed over the desert by winds blowing from the south-west, 

 and in time form beds of kunkur, so also particles of salt may be 

 blown up from the sea shore and help to increase the amount of salt 

 contained in the sand. 



4. Gypsum. 



In several places in the desert, on low lying ground surrounded by 

 sandhills, beds of impure gypsum of considerable extent are found. 

 A large deposit of this kind occurs on the plains about half way 

 between Barmer and Madpura, on the Balotra-Barmer railway. It 

 probably owes its origin to a process similar to that which has resulted 

 in the accumulation of the salt, being gradually leached out from 

 the sand and deposited when the water dissolving it evaporates. 

 The gypsum is locally known as " Kuddi " and is extensively used 

 as a cement for lining the interior of wells. 



( 43 ) 



