6o GRIESBACH : GEOLOGY OF THE CENTRAL HIMALAYAS. 



Thickness and distri- 7™ feet in the sections of the Niti district, but 

 bution. both in the Milam and Dharma valleys it swells 



out to very much larger proportions. In the palaeozoic series of the 

 Lipd Lek and other localities of the Byans district, these dark Crinoid 

 and Coral limestones play an important part and are developed in 

 great thickness, but the beds have suffered such crushing and folding 

 that to measure their thickness correctly would have been a hopeless 

 task. Nevertheless I think that there this concretionary Coral lime- 

 stone can hardly be less than 1,000 feet in thickness. It yielded 

 better fossils also, and these await determination. 



I also met with it in great thickness in the Spiti area, south of 

 Muth, and on both sides of the valley. Stoliczka has quite overlooked 

 this limestone formation I believe. On pages 21 to 24 of his memoir 

 he describes certain rocks of the u Muth series," of which the second 

 only is silurian, which according to him is overlaid by the white 

 quartzite, a horizon which is undoubtedly upper carboniferous. Had 

 he moved along, or near the crest of the mountain range, which forms 

 the left side of the valley south of Muth, he would easily have been 

 able to make out tjie succession of the entire series which constitute 

 the palaeozoic group in Spiti. 



The Coral limestone (6) may also be seen in great force in the 

 area between Nilang and the Sutlej, especially well in the valley of 

 the Hop Gcidh, or rather as forming the steep sides to it which lead 

 to the Tsang-Tsok Lst (pass) (see pi. 11). 



All the strata which rest conformably on the dark Coral lime- 

 stone (6) and are overlaid by the Productus 



Carboniferous. 



shales (9) must be* considered carboniferous. 



This system forms one of the most important features in all Central 

 Himalayan sections, alike on account of its thickness and uniform 

 distribution, and by reason of its characteristic lithological develop- 

 ment. 



Of the full original development of the system I have no certain 



Divisions of the carbo- data; the Productus shales (g) rest on a par- 

 niferous system. tially eroded surface of the carboniferous, and 



until it is possible to compare the sections of the Central Himalayas 

 ( 60 ) 



