3-’ 
Records of the Geoloykal Survey of India. 
[vOL. XIII. 
Tankse range, to tlie nortli-east of Tankse, we have a regular ascending series 
of gneissic rocks . The higher beds become gradually interstratified with unalter¬ 
ed slates and sandstones, with some banded jaspideous rocks; till finally all 
gneiss disappears, and the series consists solely of slaty and sandstone rocks, 
corrcsjionding exactly in mineralogical character with the slaty series to the 
south of Tankse. The transition from the crystalline to the slate series is, how¬ 
ever, hero so very gradual that only an arbitrary boundary can bo drawn, but 
the higher gneissic rocks are probably altered Silurians. 
The slaty series I have traced to the north-west to the Shyok river, and to 
the south-east, along the whole length of the Pangong and Pangiir lakes: its 
north-eastern boundary I shall refer to subsequently. Near Bapi Station to the 
south-east of the Pangiir lake, the slates are underlaid by a core of granitoid 
gneiss. We have already seen that to the north-east of Tankse there is a 
regular sequence from the crystalline to the slate series ; along the south-western 
shore of the Pangong lake, on the other hand, the junction between the two 
series seems to be a faulted one, the black slates and gi’een shales and sand¬ 
stones which form a narrow band along this shore of the lake dippiing towards 
the gneiss. S till further to the south-east the junction again apipears to be a 
normal one. In the mineralogical composition of the rocks surrounding the 
Pangong lake, there is very groat variety, but with one exception they consist 
mainly of colored slates, shales and sandstones. I have already mentioned the 
composition of these rocks on the south-western shore of the lake, and need not, 
therefore, refer to them again. On the ojiposite shore, in addition to the rocks 
of the south-western shore, thei’e also occur banded jaspideous rocks, together 
with the slaty-sandy rock of the Dras river, and true slates which weather to a 
rusty red color like those in the neighbourhood of Dras, already noticed. The 
minoi'alogical composition of these Pangong rocks affords by itself alone abund¬ 
antly sufficient evidence to show that they are the equivalents of the slate series 
of Dras and of the country to the south of Tankse. 
At the north-western extremity of the Pangong lake, where the original rela¬ 
tions of the rocks have been greatly disturbed by faulting and inversion, there 
occurs a great local development of a glistening white saccharoid quartzitic sand, 
stone or quartzite, which superiorly gradually becomes calcareous, and passes 
by imperceptible degrees into a piale blue limestone. This rock overlies the slate 
series of the Pangong lake, and is apparently faulted against the ridge of gneiss 
to the south. This very characteristic saccharoid sandstone and limestone is 
precisely similar in mineralogical composition to the rocks underlying the 
Triassic series in South Eupsu, which we shall subsequently show to be probably 
of Carboniferous age. This identification confirms our conclusion as to the Silu¬ 
rian age of the slaty rocks of Pangong and Dras, the former of which underlie 
the sandstone and limestone. 
Some miles to the south-east of the village of Sbushal, at the Saki La, and 
elsewhere in the neighbourhood, there occur other outlying masses of blue 
limestones and wliite sandstones, which seem undoubtedly to be the same as 
those at the north-western end of the Pangong lake. 
