MUSCIIELKALK OF SPITI AND TAINKnANnA. 
61 
the rocks in situ in a section of the Shalshal cliff, not locally identical 
with the section where the large species of brachiopods from the zone 
of Spiriferina Stracheiji have been found. ^ In Spiti, however, several 
examples of this species have been collected in bed 36 of the section 
near Lilang by A. v. Krafft.^ Now the question arises, whether 
Sibirites Prahlada is restricted to bed 3 or ranges from the layer with 
Rhynckonella Griesbachi into a horizon of undoubted Muschelkalk age. 
No second specimen has been found in Painkhanda, neither in bed 1, 
nor in bed 3 of the Bambanag and Shalshal cliffs. 
Provided the species could be proved to have its habitat in bed 
No. 1 of the Shalshal cliff, this might be accepted as a strong reason 
for including the horizon of Rhynckonella Griesbachi with the Muschel- 
kalk. 
On the other hand two ammonites, which have been discovered in 
the Niti ^ limestone of Spiti by H. Hayden, were identified with species 
from the Hedenstroemia beds of Muth by A. v. Krafft.* He therefore 
proposes to draw the boundary line between the Lower and Middle Trias 
at or above the middle of the Niti limestone. But Diener, on the 
strength of a re-examination of the specimens collected by Hayden, 
refuses to admit their identity with Lower Triassic species declaring 
them to be altogether indeterminable owing to their unfavourable state 
of preservation.^ 
In the absence of more convincing evidence, the age of the bed con- 
taining Rhynchonella Griesbachi and of the overlying Niti limestone 
must still remain an open question. For the present I prefer to leave 
them with the Muschelkalk, both from respect for historical priority— 
Griesbach having included them in the Upper Trias — and because from 
a geological point of view the Niti limestone certainly belongs to this 
group, not to the Lower Trias. 
1 C. Diener : The fauna of the Himalayan Muschelkalk, Palceont. Ind., Ser. XV 
Vol. V, Pt. 2, p. 130. 
~ The name ' zone of Sibirites Prahlada,^ in the sense in which it was used by 
Diener must be discarded, since this species has in Spiti its inain layer above, not 
below the Niti limestone. 
3 See footnote to p. 59. — Ed. 
* H. Hayden, Geology of Spiti, 1. c, p. 67. 
5 In General Report, Geol. Surv. of India, 1899-1900, p. 192, H. Hayden men- 
tions'one species of Nautilidce, Grypoceras sp. ind. ex. aff. Palladii Mojs. from the 
Niti limestone of Spiti. 
( 262 ) 
