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GRIESBACH : GEOLOGY OF THE CENTRAL HIMALAYAS. 



Himalayas. This sandstone, very silicious near the Takht-i-Sulaim£n, 

 is overlaid again by Hippuritic and Coral limestone of the cretaceous 

 system. This sandstone is not only very similar in lithological charac- 

 ter to the greenish-grey sandstone of Hundes, but it also corresponds 

 with it in its stratigraphical position, and, I believe, will be found to 

 represent the exact horizon of the Upper Gieumal sandstone. 



All along the north-flank of the Hindu Kush, and further west- 

 wards, north of the Great Central Asian watershed, I found the upper 

 Jurassic alum shales overlaid by a sandstone, mostly reddish brown, 

 often gritty and even conglomeratic. I traced this formation into 

 Eastern Khorass^n, and I believe it extends through Northern Persia 

 into Armenia. The formation underlies the Hippuritic limestone, has 

 yielded neocomian fossils, and occupies precisely the same stratigra- 

 phical position as does the sandstone (a) of Hundes. 



The overlying light-coloured limestone with upper cretaceous 

 fossils has a still greater distribution in Central Asia and the Perso- 

 Afghan area. It may be said to overlap the entire mesozoic form- 

 ations and is therefore generally in marked unconformable position 

 as regards the older rocks. Fragments of Rudistes in the Himalayan 

 development of this limestone, and numerous remains of Hippurites 

 in the cretaceous limestone of the Perso-Afghan area enable us to 

 say with considerable certainty that this horizon must be placed into 

 the upper cretaceous system. 



jo. Tertiary formations of Hundes. 



The high plateau of Hundes is formed by a great synclinal of 

 Lower and middle ter- mesozoic and older rocks, which is filled to a 

 Varies, large extent by deposits of tertiary age. 



The latter form vast plains in which the Sutlej with its tributaries 

 has eroded deep V-shaped valleys. Some of them are so deep as to 

 have cut entirely through the horizontal upper tertiary deposits, and 

 have thus exposed some strata which rest on the upper cretaceous 



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