SILURIAN SYSTEM. 
In spite of repeated and careful search, no trace of this limestone 
was found below the red silurian quartzite in normal sections either 
by the late Dr. von Krafft or by the present writer. The section on 
which Mr. Griesbach's description was based is presumably that near 
Muth, where the beds have been somewhat disturbed, and without 
the assistance of the sections seen on the opposite side of the Pin 
river and in other parts of Spiti the true sequence might be some- 
what difficult to determine. 
The following may be taken as a type of the sequence of beds 
between the cambrlan (upper) quartzites and the silurian quartzite : — 
ig. Red, gritty quartzite, about .... 1,500 feet. 
/. Grit and quartzite, passing down into coarse conglo- 
merate, which alternates with quartzite . . 100 „ 
e. Conglomerate, composed of fragments of white 
quartz (often angular) in fine-grained slaty matrix 2 „ 
d. Coarse, reddish and purple conglomerate . • 73 » 
( c. Purple quartzite, with slate . . . . . 50 „ 
Cambrian ^' quartzite, passing down into greenish 
slates 32 „ 
Purple quartzite, and slate. 
This section is seen near Shidn, in the Pin valley, a few miles south 
of the village of Muth. 
The slates (c) contain fragments of trilobites resembling those found 
in the lowest beds of the fossiliferous series of the Parahio valley. 
1 he above series represents the alternating beds of " conglomerate 
and sandstone " described by Stoliczka as underlying the lowest sub- 
division (" purple rocks ") of his " Muth series." Beds (c) and (d) are 
separated here by a fault (PI. VIII) which continues across the Pin 
valley and is seen again near Muth : it does not, however, affect the sec- 
tion to any appreciable extent, for the sequence is almost identical with 
that seen in the unfaulted sections high up among the hills to the west- 
south-west of Muth. 
On account of the unconformity which has been shown to exist ■ 
between the upper cambrian beds with trilobites and the conglomerates, 
it has been, for reasons stated in the last chapter, considered advisable 
to adopt the latter as the basal bed of the silurian system. As might 
( 21 ) 
