28 
[No. 1 
On the Sab-Himalayan rocks. 
stratigraphical and mineral affinities of the Subatlioo group are with 
the Siwalik type rather than with that of the Salt-range Nummulitic 
strata. These latter appeared to be more probably the represen- 
tatives of the great limestone deposits which were found all along 
unconformably subjacent to the Subatlioo group. These on the main 
range of hills have been more developed than on the salt range : 
they have also been much more indurated, and very much more 
disturbed, but are supposed to be one and the same. 
While, therefore, in deference to its fossils, the Subatlioo group 
has been classed as upper Nummulitic, it must be remembered that 
considered stratigraphically, it should be considered as the com- 
mencement of the Siwalik conditions of deposition. 
The northern extension in the outer Himalayas of this lower Num- 
mulitic series, the Krol group and the subjacent slaty schists, has 
not been as yet worked out. The section through Simla to Kotgurh 
(forty miles N. E. of the Krol) presents no contrasting junctions like 
those already described in the outermost zone : there are several lines 
of special crushing and contortion, but they do not introduce new 
rocks. The degree of disturbance is not on the whole increased, and 
the increase of metamorphism is very gradual and strangely capri- 
cious. Thus at Simla highly schistose rocks overlie smooth slaty 
grits. Indeed, it seems highly probable that the rocks of this section 
will be identified with, or found closely connected with, the Krol series. 
Simla stands on the northern rise of a great synclinal bend, of which 
the Tara-Devi hill is the southern rise ; at Jatog, the western spur of 
the Simla ridge, there are some hard cherty limestones that may well 
be the Krol limestone ; the thin-bedded slaty grits in the glen 
below Simla are very similar to the series subjacent to the Krol 
group ; among all these are frequent re-appearances of the carbo- 
naceous (graphitic) ingredient that is so well developed on the S. W. 
base of the Krol hill. 
Besides their greater induration, these lower Nummulitic rocks 
differ from the Subathoo group in the presence of trap rocks. Towards 
the east these are very abundant : west of the Jumna, trap rocks 
are scarce. 
Siwaliks . — Little has been added to our knowledge of these rocks 
since Capt. (now Col. Sir Proby) Cautley described them in 1836. 
