28 
HAYDEN : GEOLOGY OF SPITI. 
" Muth series " have now been dealt with and their age determined 
with a fair degree of certainty. The uppermost 
ut quartzite. member of that series is a hard, white quartzite, 
frequently containing brown specks of ferruginous matter. About half 
a mile to the west-south-west of Muth it forms a great wall of rock, 
nearly five hundred feet high, dipping at about 50° to the north-east. 
In its lower beds it is brownish and thin-bedded, and passes down 
very gradually into the grey, calcareous quartzites and siliceous lime- 
stones with Pentamerus oblongus» 
No trace of fossils has been found in the quartzite, and its age can 
only be inferred from that of the rocks above and below it. There is 
little doubt that it is immediately underlain by upper silurian beds ; 
above, it passes up gradually into a series of hard, siliceous limestones, 
the age of which is doubtful, jput which, as will be seen in the following 
chapter, may belong to the devonian system. Hitherto, Stoliczka has 
stood alone in including the Muth quartzite in the silurian system, and 
it might seem undesirable, in view of the opinions expressed by subse- 
quent observers, to adopt his classification in the present memoir, but 
since internal evidence of its age is entirely wanting, it has been deemed 
advisable to describe it with the rest of the series in which it was ori- 
ginally included. At present it is only possible to assert that its age is 
either upper silurian or devonian, and until more detailed researches 
shall have fixed definite horizons above or below it, the question must 
remain open. 
In the " Manual of the Geology of India," the Muth quartzite has 
been included in the carboniferous system. This is mainly in con- 
sequence of the observations of Mr. Griesbach in the Kumaon and 
Garhwdl Himalayas, and subsequently in Spiti. By Mr. Oldham, also, it 
was correlated with a certain white quartzite found in Kashmir among 
beds yielding a carboniferous fauna. This correlation was apparently 
based on its lithological resemblance to the Kashmir rock and also on its 
position at the base of Stoliczka's carboniferous " Kuling series." The 
only sections found along the route traversed by Mr. Oldham, viz., those 
at Muth and Kuling, would seem to support this view, but subsequent 
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