July 5.--Independently of the nature of the country rendering it altogether uninhabitable, the noxious vapours that must naturally arise during the heats of summer from these marshes (should the present surface of land on which we are now travelling be then free from water), would render the whole tract peculiarly unhealthy. Even during the short space of a fortnight, when it might be presumed that the winter's cold had in a great degree rendered the effluvia innoxious, every person in the expedition was more or less affected by dysenterical complaints; and the putrid sour smell that constantly attended us was symptomatic of what would be its effects when rendered active by the powerful heats of summer. Although there was no grass out of the marshes for the horses to feed upon, yet they appeared to live very tolerably upon a species of atriplex which covered the plains, and being extremely succulent was eaten with avidity by them; they certainly preferred it to the grasses which the swamps produced. Our route lay over the same unvarying plain surface as on the preceding days, and after travelling about five miles, we again saw the line of trees growing on the banks of the stream; and having performed about ten miles more, we halted on the immediate banks of it. These were considerably lower, being about six feet above the water; the current was almost imperceptible, and the depth did not exceed four feet, and was extremely muddy; the trees growing on the banks were neither so large nor so numerous as before, and a new species of eucalyptus prevailed over the old blue gum. The north-east side was precisely of the same description of country as the south-east. A very large sheet of water or lake lay on the north-west side, opposite to the place where we made the river. The horizon was clear and distinct round the whole circle, the line of trees on the river alone excepted. From the marks on these trees, the waters appear to rise about three feet above the level of the bank; a height more than sufficient to inundate the whole country. This stream is certainly in the summer season, or in the long absence of rain, nothing more than a mere chain of ponds, serving as a channel to convey the waters from the eastward over this low tract. It is certain that no waters join this river from its source to this point; and passing, as it does, for the most part, through a line of country so low as to be frequently overflowed, and to an extent north and south perfectly unknown. but certainly at this place exceeding forty miles, it must cause the country to remain for ever uninhabitable, and useless for all the purposes of civilized man.