The water-system of the south-western feeders of the Ganges is more complex.
The water-system in question forms the centre of the great Athabaskan area—the centre, but not the whole.
No great family has its distribution so closely coincident with a water-system as the one in question.
When it was planned to furnish a water-system for the city of Tunis, all that had to be done was to repair a Roman aqueduct.
It is the great southern artery of a water-system that lies almost wholly beyond the jurisdiction of the United States.