An exception to the general rule is found in the Mulla, which carries the floods of the Kalat highlands into the Gandava basin and forms one of the most important of the ancient highways from the Indus plains to Kandahar.
The fortress of Kalat is situated about midway between the sources of the Bolan and the Mulla, near a small tributary of the Lora (the river of Pishin and Quetta), about 6800 ft.
East and south are the rugged bands of Jalawan, amongst which the Mulla rises, and through which it breaks in a series of magnificent defiles in order to reach the Gandava plain.
Kalat is the " hub " or centre, from which radiate the Bolan, the Mulla and the southern Lora affluents; but the Lora drains also the Pishin valley on the north; the two systems uniting in Shorawak, to lose themselves in the desert and swamps to the west of Nushki, on the road to Seistan.
Sixty miles south of Kalat, and beyond the Mulla sources, commences another remarkable hydrographic system which includes all southern and south-western Baluchistan.