34 HAYDEN : GEOLOGY OF SPITl. 
contain lower, and probably also upper, silurian fossils. It is evident, 
therefore, that the Himalayan equivalent of the devonian system must 
be sought for at a higher horizon, which, as already shown, must be 
situated at least above the base of the Muth quartzite. 
In the valleys of the Lipak and Yulang rivers in Kanaur, this 
Devonian in quartzite passes up, through shaly beds and nar- 
Bashahr. row bands of quartzite, into a series of siliceous 
and shaly limestone, with hard, nodular, coral-bearing bands. At about 
So feet above the Muth quartzite is a bed of grey limestone contain- 
ing corals, crinoids and brachiopods. The matrix is very hard and 
siliceous, and the fossils are most clearly seen on the reddish-brown 
weathered surface of the rock. They are unfortunately all badly 
crushed and cannot be determined with any degree of certainty, but 
the brachiopods include large numbers of a form very closely resem- 
bling Streptorhynchus umbraculum, Schloth., with species of Orthis, 
Atrypa aspera, Schloth., and Cyathophyllum sp. These beds form 
the base of a series of dark, splintery limestones, about 300 feet thick, 
in which, with the exception of four bands of coral limestone, no other 
fossiliferous horizons have been found. 
The coral bands occur at intervals through the limestone, and 
vary in thickness from i to 3 feet. They appear to be composed 
entirely of a species of Cyathophyllum, but the original fossils have 
been almost entirely replaced by crystalline calcite and silica, and 
their internal structure to a great extent obliterated. It is possible that 
this series may represent the whole or a part of the devonian system, 
but in all the localities visited, the fossils are too badly preserved for 
reliable determinations. 
It has already been stated that the palaeozoic beds have undergone 
erosion, which took place between carboniferous and permian times ; 
owing to this, the limestone just described is frequently wanting in the 
palaeozoic sections. In Spiti, however, it is found at Trdkse, near 
Losar, where it is greatly crushed, but contains brachiopods similar to 
those found in the Yulang valley. The same beds probably occur at 
Muth also, but no determinable fossils have been found. 
• ( 34 ) 
