1861.] 
On the Sul- Himalayan rocks. 
25 
does not even reach the Jumna, on the east ; while on the west also, 
its continuity is interrupted, though not permanently. 
Thus the connection suggested in Capt. Strachey’s paper and map 
between the lignite sandstone, 1ST. of the Kotah Dun, and the fossi- 
liferous sandstone of Subathoo, is not established. The Kotah Dun 
rocks really correspond to the Siwalik-like sandstone, 1ST. of Pinjore 
Dun, in Major Yicary’s section.* 
Between the two groups, the most decided physical separation 
exists, a fault of enormous throw, amounting to the entire thickness of 
the two sei'ies, cutting off the Siwalik group from all to the north of 
it. To the east of the river Jumna, this great fault runs at a variable 
elevation along the flank of the hills lying to the north of the Duns ; 
the rocks, in junction on the north, being the limestones, slates, 
and grits of the lower Nummulitics and of the undetermined subja- 
cent rocks — (the Masuri or Nainee Tal series) : while to the west 
of the Jumna, the rocks injunction are generally these same schistose 
rocks, but often, especially at higher levels, the upper Nummu- 
litic series. 
North of this fault, there is no so decided a boundary ; the junc- 
tion of the upper Nummulitic series with the slaty series, lying to 
the north of it, is not (though so represented) a great fault. There 
is, undoubtedly, considerable local faulting ; but, generally, the junc- 
tion appears to be the original contact of deposition between uncon- 
formable strata. The upper Nummulitics in fact, seem to rest upon a 
ledge of the slaty rocks, upon a denuded surface of which they had 
been deposited. 
There is a most marked geological separation to be made in the 
series spoken of as Nummulitic, upper and lower. Of the lower 
group, the best and least disturbed section is at the Krol mountain 
on the new roaSd to Simla. At this locality there is a well defined 
series (from 500 to 800 feet) of hard limestones with variegated slaty 
shales and grits, which may be called the Krdl group. It rests, uneon- 
formably, upon a great thickness of very thin bedded slaty shales and 
gritty flags, often highly carbonaceous and black ; which may or may 
not prove to be a member of the lower Nummulitic series. 
* All are confounded under one colour in Mr. GreenougU’s map. 
E 
