2 DIEMER : GEOLOGICAL STRUCTURE OF CHITICHUN. 



of the Austrian geologists) and the Jurassic Spiti shales, the dark 

 brown or Indian-red pisolites of the Kelloway are exposed in most 

 of the sections which we were able to examine during our visit to this 

 part of the Himalayas. The best exposures of these pisolites have 

 been met with on the western slope of Chanambaniali. For these 

 beds the name "Sulcacutus beds " has been recently proposed on 

 account of their leading fossil, Belemnites sulcacutus, Suess, of the 

 bisulcati group. They were regarded as lias by Griesbach in his preli- 

 minary notes, but the fossils, which have meanwhile been examined 

 by Dr. F. Suess, are all dogger forms. According to Dr. Suess, the 

 Sulcacutus beds are most probably representative of the European 

 Kelloway. Of the Spiti shales and Gieumal sandstones Griesbach has 

 given an excellent description, to which I have but little to add. The 

 three divisions, which, according to Griesbach, can be distinguished 

 among the Spiti shales, are not equally well respresented in the 

 Chitichun area. The upper horizon, for which the name Lochambel 

 beds has been introduced, is most typically developed. It is near 

 Locbambelkichak encamping ground (south-east of Chitichun No. I), 

 that the beds of this horizon are richest in fossils of the youngest 

 Jurassic type (stage of Berrias). 



Gieumal sandstones, Flysch. — The overlying Gieumal sandstones 

 are connected with the Spiti shales by a gradual passage. In the 

 vicinity of the Kungribingri Pass (18,300 feet) their lowest beds 

 actually alternate with Spiti shales, from which it results that the 

 main bulk of the Gieumal sandstones must be cretaceous, although 

 Stoliczka considered them to be of upper Jurassic age. Lithologi- 

 cally this mighty formation represents a typical Flysch development, 

 strongly recalling in its chief characters the Alpine or Carpathian 

 flysch. A few traces which might be crushed belemnites, are the only 

 organic remains which have been hitherto found in this system 

 along the Kumaon-Tibet frontier. 



Diabase porphyrite. — Both the Spiti shales and the Gieumal 

 sandstones are intimately associated with intrusive igneous rocks in 



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