32 
DIENER : TRIAS OF THE HIMALAYAS. 
main layer of Otoceras Woodwardi in the Shalshal cliff agrees with the 
rusty-brown, ferruginous layer at the base of the Triassic series in the 
Lilang section, to which the genus Otoceras is restricted in Spiti. The 
place of the hard, dark clay with Episagecems Dalailamce is taken by 
the unfossiliferous sandy limestone (bed 2) of Lilang. The main layer 
of Ophiceras in Spiti corresponds to the bed containing Ophiceras 
tibeticum in the Painkhanda sections. 
The vertical distribution of Otoceras is smaller in Spiti than in 
Painkhanda. The absence of this genus in the second fossiliferous 
horizon of the sections near Lilang justifies the distinction of an Otoceras 
bed and an Ophiceras bed, as advocated by A. v. Krafit,^ but it is no 
vaUd reason for dividing the fauna of the Otoceras stage into two 
separate palaeontological zones, since the predominating types of 
Ophiceras persist throughout the two horizons and impart to the fauna 
a uniform aspect. 
Thus the fauna of the Otoceras stage represents one single palaeon- 
tological zone only, which, from its most conspicuous types, should be 
called zone of Otoceras Woodwardi and Ophiceras Sakuntala. 
The second fauna of Lower Triassic age, which represents a special 
stratigraphical horizon, is the fauna of the Meekoceras beds. 
In the section of Lilang it follows immediately above the Ophiceras 
bed and is only three feet in thickness. In Painkhanda it is separated 
from the bed with Ophiceras tibeticum by a large mass of unfossili- 
ferous rock. 
The following detailed section has been published by Noetling 
(Asiatische Trias, 1. c, pp. 129, 130) :— 
5. Dark, concretionary limestone, with Meekoceras 
Markhami Dien. ..... 
cm. 20 
4e. Dark blue shales ...... 
2m. 80 
id. Hard, grey limestone ..... 
17 
4c. Dark blue shales ...... 
25 
46. Hard, grey limestone ..... 
30 
4a. Dark blue shales ...... 
2m. 50 
3. Hard, blue, very tough limestone, with Ophiceras 
tibeticum Griesb. ..... 
12 
In the section of the Shalshal cliff the Meekoceras fauna makes its 
appearance only nineteen feet above the top of the Otoceras beds, but it 
1 A. V. Krafft : Gen. Report, Geol. Svrv. o / India, 1900-01 , p. 4. 
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