country is of such an absorbent nature that any water falling in torrents from the hills is imbibed by the soft earth, or is received in the deep broad cracks which sear the hollow parts, and in wet seasons must take up much water and retain it, until either evaporated or sunk to lower levels.  The water may thus be absorbed and retained for a considerable time, or until it is carried by slow drainage into the river, especially where the lower parts of such plains are shut in by hills approaching the channel.  Thus, where the extremity of Dunlop’s range shot forward into the wide level margin, we found that the water had lost all taste of salt, a circumstance most easily accounted for by supposing that springs, being more abundant there from the near vicinity of the hills, had diluted the water which we had found salt higher up.  That some tributary or branch joins the river from the opposite bank, at or near the sweep it describes round the hill, is not unlikely.  I could not conveniently examine that part from our side, and hence it remains doubtful whether the problem admits of such easy solution.

TRACES OF FLOODS.

The marks of high floods were apparent on the surface, frequently to the extent of two miles back from the ordinary channel.  Within such a space the waters appear to overflow and then to lodge in hollows (covered with Polygonum junceum) and which were at the time of our visit full of yawning cracks.  Such parts of the surface would naturally be the first saturated in times of flood, and the last to part with moisture in seasons of drought.  I observed that there was less of that kind of low ground where the water was saltest, which was to the westward of D’Urban’s group.

EXTENT OF THE BASIN OF THIS RIVER.

The basin of the Darling, which may be considered to extend, in parts, at least, to the coast ranges on the east, appears to be very limited on the opposite or western side; a desert country from which it did not receive, as far as I could discover, a single tributary of any importance.  A succession of low ridges seemed there to mark the extent of its basin, nor did I perceive in the country beyond any ranges of a more decidedly fluviatile character.

ITS BREADTH.

The average breadth of the river at the surface of the water, when low, is about fifty yards, but oftener less than this, and seldom more.  Judging from the slight fall of the country and the softness and evenness of the banks (commonly inclined to an angle with the horizon of about 40 degrees) I cannot think that the velocity of the floods in the river ever exceeds one mile per hour, but that it is in general much less.  At this time the water actually flowing, as seen at one or two shallow places, did not exceed in quantity that which would be necessary to turn a mill.  The banks everywhere displayed one peculiar feature, namely the effect of floods in parallel lines, marking on the smooth sloping earth the various heights to which the waters had in different floods arisen.