CARBONIFEROUS SYSTEM. 49 
Higher up on the same ridge another bed of shale contains 
immense numbers of Bryozoa, with a few badly 
preserved brachiopods ; the collections made 
from this horizon were sent to Europe for description, and are not 
therefore available for examination, but the present writer is greatly 
indebted to Professor Diener, to whom the specimens were sent, for 
the information that "the Bryozoa appear to be identical with the 
leading species from the Zewdn beds of Kashmir." Dr. Diener also 
adds that " among the Brachiopoda there is a species of Productus 
which is either identical with, or very nearly allied to, P. scabrtculus, 
Mart." 1 
Owing to the innumerable alternations of exactly similar beds 
of shale and quartzite, it has been found advisable to take advantage 
of any peculiarities in order to distinguish the various beds, and in con- 
sequence of the large numbers of Bryozoa— c\iit^y belonging to the 
genus Fenestella — found in this band, it has been named the " Fenes- 
tella shales." 
The same bed crops out again about half way between Po and 
Thabo (PI. XII), at Lanjarse E. G., on the left bank of the Spiti river, 
where the path leaves the level of ihe stream and turns suddenly up a 
steep ascent of shale : at the top of the slope the path passes over the 
same black shales full of impressions of Bryozoa, and there is little 
doubt that the horizon is the same as that seen above Po where, how- 
ever, the beds have been greatly disturbed by faults and the relative 
positions of the two fossiliferous horizons there exposed are somewhat 
doubtful, it being uncertain whether the shale with concretions is in 
reality older than the Fenestella shales, although the latter appear to 
occupy a considerably higher horizon. 
^ Since writing the above, the author has had access to Professor Diener's 
description of the fossils from this horizon ; they include — 
Productus undatus, Defr. 
„ scab ri cuius. Mart. 
„ nystianus var. lopinginsis, Keyset. 
Fenestella sp. ind. aff. F. plebeia, M'Coy. 
Proioretepora ampla, Lnsd. 
e ( 49 ) 
