26 



WYNNE : TRANS-INDUS SALT REGION, KOHAT DISTRICT. 



salt and the adjacent gypsum smelling strongly of petroleum. The bitu- 

 minous salt prevails, however, only for a few feet from the upper surface 

 of the deposit, though layers of bituminous or foetid clay may be found 

 apparently in the body of the salt-rock, through large portions of which, 

 even when seemingly pure and crystalline, freshly broken samples have 

 still a faint odour of naphtha or petroleum, specially observable at 

 Jatta.* 



Composition. — Specimens of the salt sent to the Laboratory of the 

 Geological Survey of India have been examined by Mr. Tween with the 

 following results. It appears that the better portion of the Bahadur 

 Khel salt contains less sulphate of lime (gypsum) than the purer look- 

 ing salt from Malgin, while there is but little petroleum present in any, 

 that little being, however, often very perceptible to the senses. 



Clean salt from Bahadur Khel had this composition — 



Chlorine 



Sulphuric acid ... 

 Lime 

 Sodium 

 Insoluble 



59'52 

 1-5 



106 y i 



3747 



•45 J 



The relative characters of other salt specimens from the district 

 may be seen from the following table : — 





1 



2 



3 



4 



5 





Eartby salt 



from Bahadur 



Kbel. 



Good salt, 



bituminous, 



Jatta. 



Upper black 

 salt, Jatta. 



Another 



specimen, 



Jatta. 



Good salt, 

 Margin. 



Loss on heating ... 

 Soluble matter 

 Insoluble 



22 



87'8 

 100 



0-4 



97-8 

 1-8 



0-8 



98-2 



10 



0-2 



99-2 



•6 



9975 

 •25 





100 100 



100 



100 



100 



* Rock-salt frequently contains admixtures of bitumen, clay, &c. : Cotta, " Rocks classi- 

 fied and described," p. 352. 



( 130 ) 



