14 
DIENER : TRIAS OF THE HIMALAYAS. 
III.— GENERAL DEVELOPMENT OF THE HIMALAYAN TRIAS. 
A broad sedimentary belt extends from Kashmir through Spiti, 
G-arhwal and Kumaon to the N.-W. boundary of Nepal. 
In this sedimentary zone of fossiliferous deposits, which range from 
Middle Cambrian to Cretaceous, the Trias is developed in a facies of 
dark shales and limestones of exclusively marine origin. No igneous 
rocks have been noticed within the Triassic or Jurassic series. The 
limestones are of dark or grey colour, well bedded as a rule, and in some 
horizons either concretionary or dolomitic. In the majority of sections 
there is a remarkable contrast between the light grey dolomitic lime- 
stones of the upper and the dark coloured shales and limestones of the 
lower portion of the Triassic rocks, the total thickness of which amounts 
to more than 4,000 feet in Spiti. 
This normal development of the Himalayan Trias is chiefly charac- 
terised by the regular distribution of each single horizon over a com- 
paratively large area, and by the absence of a facies of red marble. 
In the region of the exotic blocks in Malla J ohar and near Chitichun 
No. I, the Triassic strata show a development differing considerably 
from that observed in the normal sections of the main region of the 
Himalayas. In this region the Triassic system is of only comparatively 
small thickness, and most of the Triassic horizons are developed 
in a facies of red limestone and marble exhibiting a striking resemblance 
to the Hallstatt limestone of the Eastern Alps. Esj)ecially in the beds 
of the carnic stage are there remarkable agreements with their homo- 
taxial equivalents in the Mediterranean region, the agreement being 
faunistic as well as lithological. 
Thus two regions of different development can be distinguished 
within the area of Triassic rocks in the Central Himalayas, one of them 
representing the normal facies of the Mesozoic belt, and the other 
representing the facies of exotic blocks connected intimately with 
igneous intrusions. 
The former A. v. Krafft termed the Himalayan and the latter the 
Tibetan facies of the marine Trias, 
( 215 ) 
