CAMBRIAN SYSTEM. 
ri 
In the valley of the Chandra river, between Kulu and Spiti, the 
commonest product of alteration is a dark bio- 
Biotite schist. , . i r u- i. r i 
tite schist, composed of biotite, quartz, felspar 
(orthoclase, albite and microperthite) , with some rutiie and zircon. 
In the valley of the Sutlej, the products of contact-metamorphism 
are similar to those in the Chandra valley, but to the other component 
minerals are added kyanite and staurolite, the former occurrmg in large 
crystals, often of a beautiful blue colour, which 
Biotite-kyanite schist ■' .... . , , , . 
and biotite-staurolite has led to their being mistaken tor sapphires. 
Fine specimens of this biotite-kyanite schist are 
found between Naku and Chango on the left side of the lower Spiti 
river, and also on the left side of the Kozhang river on the old road 
from Pangi to Asrang. At the latter locality, staurolite occurs in 
great quantity, locally replacing most of the kyanite, the rock thus 
becoming a biotite-staurolite-kyanite schist: it contains also quartz, 
orthoclase, albite, zircon and large quantities of rutiie ; an iron ore, 
probably ilmenite, is found in small grains scattered through the 
staurolite, to which it appears to be entirely confined. 
In the neighbourhood of Lio, in the valley of the Lipak river, 
Autoclastic con ^lo. the effects both of contact- and of dynamo- 
merate of Lipak river, metamorphism are very pronounced, and on 
the right bank of the river, at about two miles above its junction 
with the Sutlej, the lower slates and quartzites contain the only rock, 
which, having regard to its appearance and position, could be supposed 
to belong to Mr. Griesbach's lower haimanta conglomerates. The rock 
is a conglomerate forming abed of varying thickness, and composed of 
more or less rounded and lenticular fragments of white quartz, scat- 
tered through a matrix of fine-grained biotite schist. The band is usually 
tenor twelve feet in thickness, and in places contains the white pebbles 
throughout its whole extent ; in other places, however, only narrow 
strings of pebbles, separated by bands of schist, run both parallel and 
obliquely to the original direction of stratification of the rock. When 
first seen in the bed of the river, the conglomerate was taken for the 
one which occurs throughout Spiti at the base of the silurian system 
( II ) 
