210 GRIESBACH : GEOLOGY OF THE CENTRAL HIMALAYAS 



the Central Himalayas. The term " Babeh" system might have 

 stood with some modification of its meaning, but as under that name 

 some members of the silurian have also been included, I prefer to 

 retain the term haimanta system. 



This rock system consists, in the Spiti area, of a succession of 

 chiefly quartzitic rocks ; I did not study it in detail, but found simi- 

 larly as in the Garhw^l sections, a purple semi-metamorphic quartzite 

 predominant. Associated with it are silicious shales, and a strongly 

 developed conglomerate or rather boulder-bed which is a most charac- 

 teristic rock, and is traceable from Spiti to the Nepa*l frontier. It is 

 such a constant factor in this system, that once seen it will always 

 easily be recognized. In its constancy it reminds me of the ever- 

 recurring boulder-bed near the base of the Talchirs. These dark 

 purplish quartzites and conglomerates form usually thick beds, and 

 are associated with greenish talcose slates and semi-metamorphic 

 schists which I found near the boundary of the gneissose series south 

 of the Babeh Pass, and again near the upper boundary of the system. 

 In these same greenish schists, fossil traces {Bellerophonl) were 

 found in the Niti sections. Strata of thinner-bedded purple and 

 brown silicious rocks are not absent, which also here show exten- 

 sive and often very typical ripple-marking quite distinct from the 

 wrinkling into which the beds have been contorted. 



The system shares in the extensive plication which has crumpled 



Extensive folding of tne en ti re succession of marine sedimentary 



strata - rocks of this and the neighbouring sections of 



the Himalayas. The folds are generally very close, reserved flexures 



with their longer shoulders falling to the north and north-east. 



The thickness of the system I have not been able to ascertain, but 

 Thickness of haim- ** w1 ^ probably be found to be not less than 



that of the haimantas of the north-eastern and 

 eastern sections, where I estimate it as from 3,000 to 4,000 feet. 



Near the camping-ground of Buldur (of the map), the beds form a 



deep synclinal, strike nearly east and west 

 enclosing a portion of the silurian system 

 ( 210 ) 



Buldur synclinal. 



