RECORDS 
OF THE 
GEOLOGICAL SURVEY OE INDIA. 
No. 4.] 1870 [November. 
On the Geology of Mount Tilla in the Punjab, by A. B. Wynne, P. G. S., 
Geologica] Survey of India. 
The fine liill which forms the subject of this brief memoir rises between the eastern 
termination of the Salt -Range proper and the outworks of the Western Himalaya where 
the river Jhelum emerges from them to traverse the vast plain of the Five Fivers which 
united in the Lower Indus (or Sind) reach the sea near Kurraehi. 
It is one of three or four minor ranges, all of which form links more or less between 
the Himalaya and the 8alt, Range. Of these the parallel chain of the Bukrala Hills 
to the north seems to form the most continuous connexion ; but Mount Tilla exceeds them 
all in height, reaching an elevation of 3,242 feet above the sea. It runs generally north¬ 
easterly by east, commences abruptly at its western end, and continues thence lofty for 
about ten miles, when it sinks rather suddenly into high ravine ground, with elevations 
of over 1,200 and 1,300 feet, for about twelve miles further, past the extensive ruined fortress 
of Rhotas. It terminates in low rounded hills a few miles beyond this point, projecting 
into the commencement of the alluvial plains of the. river Jhelum. It is widest where 
most lofty, having a base of three miles, but the extension of the range to the eastward is 
on an average not less than two and half miles in width. 
Neither the Mount Tilla. range nor that of Bukrala to the north appear to have 
any strong relation to the drainage depressions of the country in their immediate vicinity, 
both of these ridges and the valiev between being crossed by the usually dry or nearly 
dry courses of streams, occasionally powerful, as indicated by the depths of their gorges 
and great width of their sandy beds when the currents become slack. With the Jhelum, 
however, ordinary relations seem to exist after it has left the Himalaya ; the direction of 
the Tilla range coinciding more or less with that of the river, and the ground failin'' 
generally towards the latter—except where one of the other chains or groups of hills inter¬ 
venes—on the southern side of the ridge. 
The existence of Mount Tilla as a striking feature of the country—that of Chamlial 
to the south, of the Bukrala range to the north, and indeed perhaps of the wholoSalt 
Range itself—is, through denudation, directly due to huge' dislocation of the stratified 
rocks, placing certain of the beds of greater or less strength in abnormal contact with 
others possessing different degrees of resistance to disintegrating forces. The chief line of 
dislocation affecting Mount Tilla passes along its southern base, obliquely separating the 
lofty portion from the lower extension to the east, and is perhaps continuous westward, 
though concealed, to the great fracture lying in the bed of the Boon liar river, which 
separates the adjacent portion of the Ohambal range from the western termination of 
Tilla, completely discordant dips occurring on each side of the hero constricted channel. 
As results of the forces, or of similar forces to those, which caused this and other 
fractures, the whole strata of the country have been subjected to violent contortion, one 
of the finest‘curves being the interrupted anticlinal formed by the strata of Mount Tilla 
itself and traceable round its western end nearly to the line of dislocation occupying the 
lower gorge of the Boonhar.* 
* On one of the early days of last April a somewhat singular occurrence was observed from the higher parts 
of Mount Tilla. The day was warm and bright, and a very strong breeze blowing, so much so that traversing 
