PAINKANDA SECTIONS. 133 



in situ, and as the streams all run nearly at right angles to the strike, 

 they have exposed good sections. 



The track from the Marchauk to the Bara Hoti grazing grounds 

 leads along the ridge of one of the great fans which descends from 

 the pass eastwards, A ravine cuts through this fan north of the 

 path and finally rims into tire Shal-Shal river. It exposes a good 

 section through the middle and upper trias. I found in descending 

 order: 



Concretionary brown limestones of great thickness, which rest 

 conformably on — 



■d. Grey lime'toTse in thick beds, with fossil traces weathered out on the 

 surface ; Monotis sp. 



^. Dark grey limestone beds filled with small Bivalves, which a<e closely 

 united with the matrix. 



h. Several hundred feet of flaggy black litnestone beds, alternating with 

 splintery black shales. The latter yielded a few traces of fossils, Tervbra- 

 tula sp. and Ammonites. This division is of 'most striking aspect, with 

 the limestone weathering a dirty white, in strong contrast to the black 

 shales ; the latter Increase in thickness towards the top of the series. 



a. Thick beds of very hard dark grey limestone, traversed by numerous 

 calcspar veins. The upper beds especially are very massive, and \ 

 measured one more than 30' in thickness. Fossils, chiefly Cephal poda, 

 are numerous, but almost impossible to chisel out of the rock, with which 

 they are closely united. Ceratites sp. 



The base of this section is hidden under masses of debris, but I 

 observed above the brown limestone beds which overlie this section, 

 the nearly vertical cliff of dark limestone and dolomites of the rhae- 

 tic system rise towards the Silakank pass. 



North-eastwards of the head of the Shal-Shal ravine one passes 

 through an ascending section of the rhaetic and trias beds, overlaid 

 conformably by the black Spiti shales which, owing to the very un- 

 even and rolling dip, swell out here to a band of considerable width 

 and form part of the low ridge of the watershed in which the Ting 

 Jung La and Ma Rhi La (passes) are situated ; the higher parts of 

 this ridge is formed by the greenish brown sandstones and shales of 

 the lower cretaceous, which overlie the Spiti shales conformably. 



( *33 ) 



