SALINE GROUP. 71 



Its brilliant scarlet colour, together with the arid aspect of the ground 



it forms, distinguish this rock from all the other 

 Colour. 



groups. Under vertical sunshine it pales consid- 

 erably, owing to the slope of the ground, and to the associated whiter 

 gypsum being more visible ; but when the sun is low the marl glows vividly 

 in the slanting rays, reflections of one surface upon another producing the 

 softest and most velvet-like transparent shadows, while parts of a dull 

 purple colour vary its monotony, and, at a sufficient distance to be in- 

 fluenced by the blue of the atmosphere, this gives rise to many harmo- 

 nious effects. 



The marl forms the most noticeable portion of the saline group, but 

 in close association with it are thick beds of gypsum and thicker ones 

 of rock-salt. It is tough rather than hard, but when very dry, possesses 

 much the consistence of sun-dried brick. 



According to Dr. Warth's examination, it contains a quantity of 

 gypsum, and from Dr. Fleming's account I extract 



Composition. 



the followmg : " It does not disintegrate when 

 treated with hydrochloric acid, but in powder effervesces strongly, the 

 greater part remaining undissolved as a red mud composed of clay and 

 sulphate of lime ; the portion soluble in acid consists of carbonate of 

 lime and carbonate of magnesia in about equal proportions with a 

 little alumina and peroxide of iron, to which it owes its colour.''' "^ With 

 this composition the name of "gypseous marP' is not inapplicable. 



Beyond the gjrpseous, saline, and dolomitic layers the red marl bears 

 stratification andtWck- ^^^ original traces .of stratification, or inter-strati- 

 ^^^^^" fication, generally none at all ; hence it is difficult 



to form any correct idea of its thickness. Supposing it to have, where 

 most largely developed, the same nearly horizontal stratification as other 

 groups in its vicinity, and reckoning from the height of the mountain 

 slopes which it forms (near Kusuk), it would appear to be at least 1,500 

 feet in thickness. It may be doubted whether another example could be 



* Fleming's 2nd Report, p. 240. 



( 71 ) 



