The long stretch of waterless desert between Jauf and J.
The karez is a system of underground channelling which usually taps a sub-surface water supply at the foot of some of the many rugged and apparently waterless hills which cover the face of the country.
2 Including waterless tracts naturally belonging to the river-basin.
As the plains on the Rolling Downs formation are mostly waterless, the discovery of this deep reservoir of water has been of great aid in the development of central Australia.
The migrations must have always been dependent upon physical difficulties, such as waterless tracts or mountain barriers.