62 
Records of tie Geological Survey of India. 
[VOL. vi. 
traceable at intervals in the position first described. The outer limestone rib expands and is 
flanked by another similar band, the alternation of limestones and Murree bed being apparently 
produced by faults ; at least it has entirely this aspect in the neighbourhood of Shah Durah. 
Further west a strongly marked line, also bearing the strongest resemblance to a fault, 
diverges north of Rawul Pindi from the main line of junction in the direction of the 
Margulla pass, on the Peshawur road. Along it the Murree beds are brought, against the 
hill limestones, here including both nummulitic and Jurassic rocks (with perhaps an inter¬ 
vening cretaeeons band). The jurassic beds contain a very marked layer made up of large 
Trigonire resembling Trigonia Ventricosa, Kraus, with some smaller forms; while beyond 
Margulla Ammonites and Belemnites are also to be found. As usual along the contact of 
the limestones and finely detrital rocks, the red Murree beds are often either vertical or 
highly inclined towards the limestones. The actual junction surface, from being situated 
at the foot of the hills, is concealed; and the branch line disappears beyond Margulla, the low 
ground in that direction being heavily covered with detrital deposits, and the small hills in 
which the spur from Mochpoora terminates being formed of the nummulitic and jurassic 
limestones, shales, &c. 
The main line of boundary between the limestones and the Murree group continues from 
the place of divergence north of Rawul Pindi westwards, marked at first by low limestone 
hills at the foot of the Mochpoora ridge or spur, which gradually increase in height and 
width, till they form the chain of the Chita Pahar mountains, abutting on the Indus several 
miles southward of Attock, near Nilab Gash. Beyond this the same feature continues 
westward along the Afireedi hills passing just north of Kohat; on this line also the gypseous 
zone seen at Murree and more largely developed at Tret, as well as lower down in the plains, 
may be recognised at intervals. In connexion with this gypseous zone, and sometimes in the 
gypsum itself, are sulphurous springs, which bring petroleum or mineral oil to the surface; 
this also frequently occurs slightly impregnating the adjacent limestones. 
Along the whole of this line of junction within British territory, from near the Jhelam* 
to the Indus and beyond it, the ■positions of the two sets of rooks furnish nothing decisive 
iu the way of evidence to prove which is the older: and in many places the inference from 
dips would he directly contrary to fact. The nummulitic limestones of the hills being, 
however, found in some spots close to the boundary passing downwards into jurassic rocks 
(with or without a thin intervening band which may be, but is not here proved cretaceous), 
all doubt of the true position of the red rocks is removed; and their close association with 
certain layers containing nnmmulites on the south side of the junction fixes their age with 
certainty. 
It will then appear that on one side of the general boundary there are red Murree beds 
containing layers of nummulitic, calcareous, or earthy rock, while on the other there is a 
mass of limestones and shales of nummulitic, jurassic, and perhaps some of cretaceous age. 
The junction itself presents all the features of a fault or band of several faults, and the 
only reason why it should not he unreservedly accepted as such is that, in the Simla Outer- 
Himalaya examined by Mr. Medlicott, the same tertiary sandstones and clays as occur 
in this country have been divided by that gentleman into groups, the boundaries of which, 
having the same general resemblance to lines of fault, are in most cases believed and in 
some are proved by him to be lines of unconformable contact and not of faulting (see 
Memoirs, Geological Survey, Vol. 111). 
* The continuation of this line in the valley of the .ihelam has been recently seen. It makes a sharp bend 
northwards near Kohala, and runs along the foot of the Mochpoora aud lluzar lulls on the right bank of that 
river, crossing the bend of the stream near Mosufferabad in Cashmere. Here it bends to south-east, following the 
course of the .Ihelam still on the right bauk, but far up on the Hunks of the Kyj Nag range to Ooree, where it crosses 
the river and takes a course along the outer flank of the Peer Punjal chain. Slates, metamorphic rocks, and 
occasionally limestones, are seen injunction with the red Murree rocks, the line still resembling one of faulting. 
