SALINE GROUP. 



73 



forms a hill of some 427 feet* above the plains at Marl on the Indus. 

 On the north side of the range it is found in a small glen at Vasnal, and 

 obliquely traversing the slope from Kalar Kahar lake to west-by-south. 



The only non-constituent minerals which the marl is known to con- 

 tain besides the gypseous and saline ones are bi- 

 pyramidal quartz crystals in the gypsum of Mari 

 (said also to be found at Sardi), scattered crystals or nests of iron pyrites 

 in the gypsum also, here and there, and earth-oil intercalated with the 

 gypsum of Khewra gorge. 



As to age, the salt marl has been referred to Triassic, New Red 

 Sandstone or Permian, Miocene or Pliocene, but it 

 is now known, from the way in which it passes 

 beneath the overlying beds, to be not newer than Silurian — a fact de- 

 pending upon the discovery of Obolus or Siphonotreta in the group 

 No. 4. Beyond this its place cannot be as yet more definitely fixed. 



Besides the disseminated gypsum, the red marl contains extensive 



beds and masses of this mineral, often largely 

 Gypsum. 



developed in its upper part, but also more doubt- 

 fully present in lower situations. As a rule, the gypsum overlies the salt. 

 Sometimes it is interstratified with the marl, and sometimes it appears as if 

 former beds had been broken up, or partially dissolved, leaving large frag- 

 mentary masses embedded in the softer rock. Contorted or even distorted 

 lines of stratification are found in the gypsum, but it has never been found 

 to contain any detrital pebbles or foreign fragments. According to 

 Dr. Fleming, it is nearly pure sulphate of lime, free from carbonate of 

 lime. Its texture varies from compact and sub-crystalline to saccharine, 

 and plates of clear selenite are also foundo Its colour is white, or white 

 mottled with grey or bluish grey, or it is sometimes pink or red ; 

 the more compact varieties are used for turning into ornamental 

 utensils. 



* From comparison of heights on map and that given by Fleming, p. 449, 2ud Report. 

 K ( ^3 ) 



