INTRODUCTION. 200 



are always present in the soil. Their ashes are rich in sodium 



chloride, and many species were formerly and are still here and 



there employed to make an impure carbonate of soda (Barilla, 

 Sajji)" 



In Sind and in the Kachhi district of Kalat, which is geographi- 

 cally a continuation of the Sind plain, small quantities of this crude 

 carbonate (barilla or sajji) are manufactured by burning and 

 lixiviating the ashes of these chenopodiacious plants, locally known 

 as lani. Doubtless a certain amount of reduction takes place 

 during the process of burning, in a manner crudely similar to that 

 of the Leblanc process. I mean that the roots of these plants which 

 contain various sodium salts, carbon in the woody tissue, and a 

 certain amount of calcium carbonate in the calcareous soil mixed 

 with the roots, react under the influence of heat, so that the total 

 amount of carbonate after burning is considerably greater than 

 that originally present. 



The soda produced in this manner is small in quantity, and lies 

 outside the scope of my enquiry. I need not therefore allude to 

 it again. 



Another tree of common occurrence, especially near the saline 

 dhands, is the tamarisk. I shall allude subsequently to the curious 

 apparent connection between the rounded mounds of chiroli 

 (gypsum) seen so frequently on the shores of saline dhands, and 

 this tree. 



Several other halophytes are found, but they do not appear to 

 be of interest in my present enquiry. 



The alluvial country is fairly free from large sand-dunes, but 

 small incipient crescent-shape dunes, technically known to science 

 as barkhans, are of common occurrence throughout this area. Near 

 Karachi they have received a special description from 

 Mr. R. D. Oldham. 1 



The second tract, comprising the country east of the Nara and 

 north of the Jamrao, is entirely covered with wind-blown sand. 

 East of the Nara and in the south of Thar and Parkar, the sand- 

 hills are aligned in long parallel ridges, called in Sind hi bhits, the 

 direction being parallel to that of the prevailing monsoon winds. 

 In the south of Thar and Parkar near Diplo, Mithi, Nagar, and 



1 R. D. Oldham, Mem. Gcol. Sur. Ind. f Vol XXXIV, pt. 3. 



