112 
Records of the Geological Survey of India. 
[VOL. X, 
northward extension of these rooks, however, in the direction of the dip is interrupted by 
faulting; most of the lower ground and hills towards Kohat being occupied by older parts 
of the series. 
Drainage .—Crossing this whole tract of tertiary rocks, the Jhelum river is a racing, rapid 
torrent, hemmed in by mountains; the Indus (or Abba Sin), larger and more powerful, flows 
from among lofty and picturesque ranges, across an expanding and highly cultivated plain, 
till it receives the Lunda or Kabul river at Attock. It then cuts its way through every one 
of three intervening ranges, and has formed for itself a deep narrow gulch through the rocks 
of the plateau, running swiftly, with occasional rapids, until it reaches and escapes into the 
lower plains at Kalabagh. The minor drainage of the district mainly seeks the Indus, some 
smaller portion reaching the Jhelum. It is everywhere distinguished by its cross-country 
character, preferring, in many cases, to intersect the hilly or mountainous ranges rather than 
to follow the larger depressions of the surface. Even the Soan, the most considerable local 
stream, rises in the hills at Murree, not very far from the Jhelum, yet wanders away west¬ 
wards to the Indus, by a part of the plateau-land which itself sends affluents to the Jhelum river 
through ridges of the Salt Range. The Haro, too, in the Hazara valley to the north, does not 
take all that drainage to the Indus, for the Dore, which would otherwise form one of its upper 
tributaries, turns aside, crosses through part of the lofty Gandgarh range, and finds thus a 
shorter way to join the groat river at Turbela. The Tiri (Teeree) Towey, another tributary of 
the Indus, from the Kohat district, changes its course from one depression to another, inter¬ 
secting the ridge between. 
These peculiarities of the drainage tend to show that its course was initiated more directly 
by agencies of elevation than by the results of atmospheric denudation acting, at different 
rates, upon rocks of varying texture. The valleys of the grouud are not always those of 
the rivers; both are now valleys of denudation, but the directions of the streams were decided 
by much older contours of the surface than now exist. The rivers have maintained their 
courses, even though the wasting agencies in carving out prominent features have at the same 
time lowered the “ divides,” in some localities to hardly noticeable undulations. 
The antiquity of the courses of the larger rivers Jhelum, Indus, and Kurram is proved 
by the Himalayan transported detritus, brought to form late tertiary (Siwalik) boulder beds 
and conglomerates, being thickest near their hanks.* A later phase in their history is marked 
by the occurrence of the same hard detrital and stream-worn blocks lying upon the adjacent 
mountains at heights of about 2,000 feet above the present bed of the Indus ;f and a still 
later period of the river action is indicated by the same pebbles and boulders interstratified 
with the superficial deposits of the country along this river. Such hard boulders now 
form its bed at Attock, and are doubtless still travelling downwards from the Hima¬ 
layan regions. 
Classification 
The rocks found in the district may he classified as follows :— 
POST-T ERTIAET— 
Unconformity. 
Upper Siwalik— Pliocene (Lydekker),} 
about 4,000 feet- 
Natural order. 
j- Conglomerates, pebble beds, silt and alluvium. 
Brown, drab, and reddish clays, mammalian and reptilian remains. 
{ Soft grey sandstones, conglomerates, and orange or grey clays. Mammalian 
remains, &c., not abundant. 
* This feature was pointed out for the Mid-Himalayan rivers long since by Mr. Medlicott. 
t Over Kalabagh, and again on the Chita Pah&r (Mountain) near their highest elevations above Bag and 
Choi. 
% Records, Geol. Surv. Ind., Voi. IX, p. 87. 
