RECENT VOLCANOES. 279 



dyes of various colours as is described by Major Brazier-Creagh, 1 

 who collected a similar material near the K6h-i-Tafdcin. The bright- 

 red clay called " Gilik " is used for marking sheep. These soft clays 

 with their associated minerals have been formed by the action of 

 mineral vapours. They are full of large plates of gypsum and occasion- 

 ally contain sulphur, which is also extracted. The ore is placed in 

 large cauldrons built over a fireplace in which brambles are burnt \ a 

 man stirs the sulphur, while it melts ; the lighter 



Extraction of Sulphur. 



impurities are skimmed off the top with a flat 

 Sadie, the heavier ones sink to the bottom, and the sulphur is finally 

 decanted into basin-shaped moulds. This industry has been carried 

 on for ages by a family living in the Afghin Province of Garm Sel. 

 The K6h-i-Sult£n and all the minerals which it contains are looked 

 upon as the special property of the mythical Pfr Sultdn who is 

 supposed to reside there. None of this land can become private 

 property. One-tenth of the value of the sulphur and sulphate of 

 alumina is given away in charities as a right of work (the same rule is 

 followed by the people who collect asafcetida, the plant being com- 

 mon in some parts of the mountain). 



In addition to chlorinizing and sulphurizing actions, silicification 

 has also taken place in some localities. Super- 



Silicificatiort. . 



heated vapours charged with silica have found 

 their way through vertical cracks and little by little the substance 

 of the rock has been replaced by silica, causing the altered portion 

 to resist weathering better than the unaltered rock, so that 

 it stands out resembling a dyke. These silicified rocks occur 

 often at quite a distance from the main regions of solfataric action 

 (specimens ^ r , ^), Sometimes the silicified rock is surrounded on 

 either side by a narrow zone transformed into clay and gypsum. 

 Sometimes the vapours have followed a plane of stratification making 

 one stratum quite hard. The substance of the rock has been 

 replaced so gradually that the shapes of the fragments in an 



1 Rec. Geol. Surv. Ind., Vol. XXX, p. 253. 



( toi ) 



