10 
HAYDEN : GEOLOGY OF SPITI. 
careful search, neither the late Dr. von Krafft nor the present writer 
succeeded in finding this among the lowest beds, but a conglomerate, 
very similar to that dpscribed by Mr. Griesbach, was found overlying 
the Cambrian beds, and invariably defining the boundary between them 
and the silurian rocks. Numerous blocks of the conglomerate are 
found along the route traversed by Mr. Griesbach, and since he states^ 
that he did not examine the beds in any detail, it is possible that on 
meeting with a rock bearing so close a resemblance to the lower 
haimanta conglomerate of Niti, he came to the natural conclusion 
that it was the same. A fuller description of this rock will be found 
below (see p. 22). 
The oldest sedimentary rocks, therefore, with which we have to 
Oldest sedimentary slates and quartzites belonging to 
rocks of Spiti. Mr. Griesbach's middle haimantas. They consist 
chiefly of soft, ferruginous clay slates, — thinly foliated and often 
crushed and micaceous (phyllite) — interbedded with bands of grey and 
purple quartzite. Thin beds of grit ranging from a few inches to a foot 
in thickness are not uncommon, especially near the upper boundary of 
the series. These rocks extend from the north-western end of Spiti, 
throughout the whole length of the chain of snowy peaks separating 
Spiti from Kulu and the Wangar valley, into the valleys of the Teti 
(Taite) and Thanam rivers in Bashahr, continuing eastwards from 
Sungnam, and forming most of the hills on either side of the Sutlej 
and Spiti rivers below Lio and Chango in Kanaur. At either end, 
they appear to run on in the direction of Garhw51 and Kumaon on 
the south-east and of Lahaul on the north-west, and extend for many 
miles down the valley of the Sutlej, below its confluence with the Spiti 
river. Along their southern boundary they are found, in Spiti and 
Altered by contact- Bashahr, in contact with great masses of intru- 
metamorphism, gjyg granite. Near the line of junction, they 
have been highly altered, chiefly into garnetiferous mica schist, biotite 
schist, biotite-kyanite schist and biotite-staurolite schist. 
' Op. cit., p. 120. 
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