THE INDIAN PENINSULA 137

time they leave the hills, So does the Indus itself
at first, for it spreads into a network of channels as it
crosses the Peshawur Valley. But its channel is constricted
 again to one main stream after receiving the
Kabul River at Attok, and the river thenceforward flows in
a rocky bed (which narrows to a gorge below Attok) for
some 70 miles, until it emerges from the defiles between
the cliffs of the Kohat district on its western bank and
the abutment of the Salt range of Rawal Pindi on the east,
and passes the salt-built town of Kalabagh.
Throughout these enclosed reaches of the river the
narrow rock passages are magnificent in the wildness and
‘he weirdness of their scenery.
The road connecting our frontier post of Kohat with
the railway system of the Punjab crosses the river by
a bridge of boats about half-way between Attok and
Kalabagh. South of Kalabagh the river again opens out
into countless channels, which are constantly shifting and
changing their position under the influence of the yearly
floods. The general tendency of the main branch of the
civer is to shift westward, and it is this process which so
nearly demolished the town of Dera Ismail Khan. From
Dera Ismail Khan, southwards, the river is navigable for
the flat-bottomed steamers of the Indus flotilla. The
character of the Indus remains unchanged till it crosses
the Sind frontier on leaving the Punjab, some 60 miles
below the junction of the Punjab rivers, now united in
the Chenab. Here, at Kasmur, a great engineering
scheme has arranged for the storage of the yearly overflow
 for distribution in the form of irrigation through
that part of Sind which lies between the river and the
Baluch Mountains. At Sukkur the channel is so enclosed
and narrowed that, with the assistance of a rocky island in
‘ts midst, the river has been spanned by a magnificent
bridge in two spans. This bridge carries the line of the
North-Western Railway from the left, or eastern, to the
right bank of the river, which it follows till it reaches
Karachi.
From Sukkur southward the river again pursues an