MUSCIIELKALK OF BYANS. 
66 
shaly partings. This is evident from the notes left by Smith and A. v. 
Krafft, which have been published in my memoir on the fauna of the 
Himalayan Muschelkalk. 
This eastern facies of the Himalayan Muschelkalk consists of pure 
limestones of a light grey colour, which overlie the chocolate limestone 
of Lower Triassic age. The dark, concretionary limestone with shaly 
partings, which is characteristic of the Muschelkalk in the north- 
western districts of the Central Himalayas, is entirely absent. In this 
development of light grey, pure limestones even the zone of Rhynchonella 
Griesbachi is included, as is proved by a large number of examples of 
this species in Smith's collections from Kalapani. 
Noetling proposed to group the bed with Rhynchonella Griesbachi 
with the Hedenstroemia stage, because in the section of the Shalshal 
clift he found it to agree lithologically with this stage. Any geologist 
starting from an examination of the sections in Byans will be inclined to 
draw the boundary between the Lower end Middle Trias at the base, not 
at the top of the bed with Rhynchonella Griesbachi, which is united with 
the Muschelkalk into one uniform mass of light grey limestone. 
The presence of the zone of Spiriferina Stracheyi is indicated by 
several species of brachiopods, characteristic of that zone, in Smith's 
collections from Jolinka and Kalapani, namely : — 
Spiriferina Stracheyi Salt. 
Spirigera Stoliczkai Salt. 
Dielasma himalayanum Bittn. 
It cannot be decided whether the two specimens of Rhynchonella 
trinodosi Bittn., one of the most characteristic species of the Alpine 
Muschelkalk, which I discovered among Smith's collections from Kala- 
pani, have their habitat in this zone (group No. 3) or in the Upper 
Muschelkalk. The Indian group of Ceratites subrobusti {Keyserlingites 
Hyatt, Durgaites Dien.) is not yet known to us from Byans. 
The layer of brachiopods, representing the zone of Spiriferina 
Stracheyi in the uniform mass of the Muschelkalk in Byans, occurs about 
50 feet above the top of the chocolate limestone, according to A. v. 
Krafft. Thus the lower part of the Muschelkalk might be considered as 
an equivalent of the Niti^ limestone in Painkhanda and Spiti. A bed of 
1 See footnote to p. 59. — Ed. 
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