80 WYNNE : GEOLOGY OF THE SALT EANGE IN THE PUNJAB. 



in some of the old drifts, which are now neither safe nor easy of access. 

 In fissures of the salt* he has met with scattered crystals of selenite 

 and crystalline nests of a mineral with the composition of Glauberite 

 (sulphate of calcium and sulphate of sodium without water) . 



While a collection of the Salt Range minerals was being- made for the 



- Vienna Exhibition of 1873, a greenish or reddish- 



Potassium salts. •Till ii 



white glassy mmeral, harder than common salt, 



was found by Dr. Warth extensively mixed with the material of the 



Icallar band, separating the Sujewal and Purwalla salt seams of the Mayo 



mines. It predominated throughout a thickness of 6 feet in the hallar 



bed, and was largely mixed with sulphate of magnesium, which also pre- 



vailed through 7 feet of the same band immediately beneath. On a 



rough examination by Dr. Warth this was found to be potassium salt. 



In composition it varied, and two of the specimens for the Vienna 



Exhibition examined by Mr. Tween gave the following results : — 



Chloride of potassium 

 Do. of sodium 



Sulphate of magnesium 

 Do. of potassium 



Water 



No. 1. No. 2. 



Colourless salt. Pink-coloured salt. 



3-8 61 '43 

 29-82 



58-02 7-78 

 38 



•62 2-1 



100-44 100-63 



This potassium salt is referred to in a translation from the Jahrbuch 

 der h. k. Qeologisehen Reichsanstalt, xxiii, No. 2, p. 136,t as a white or 

 reddish granular mixture of sylvine (chloride of potassium) and kieserite 

 (sulphate of magnesium) , the kieserite possessing the same hardness and 

 cleavage as the Hallstadt mineral and also appearing to be compact. It 



* In Sujewal and PurwaUa mines, where the salt crystals sometimes assume unusual 

 forms, the margins of the cube-faces being replaced so that the solid angles have 6 bevelled 



3S. 



t Records, Geol. Surv. Ind., Vol. VII, p. 64. 

 ( 80 ) 



