Two Expeditions into the Interior of Southern Australia — Volume I

by Charles Sturt

"Dumaresq's river falling 2970 feet from granite mountains, in 28 1/4 degrees under the meridian of 152 degrees, would have to pursue its course for 2969 miles, its average fall being eighteen inches to a mile."

As I have never been upon the banks either of the Gwydir or the Dumaresq, I cannot speak of those two rivers; but in estimating the sources of the Macquarie at 3500 feet above the level of the sea, Mr. Cunningham has lost sight of, or overlooked the fact, that the fall of its bed in the first two hundred miles, is more than 2800 feet, since the cataract, which is midway between Wellington Valley and the marshes, was ascertained by barometrical admeasurement, to be 680 feet only above the ocean. The country, therefore, through which the Macquarie would have to flow during the remainder of its course of 1700 miles, in order to gain the N.W. coast, would not be a gradually inclined plain, but for the most part a dead level, and the fact of its failure is a sufficient proof in itself how short the course of a river so circumstanced must necessarily be.

MR. OXLEY'S OPINIONS.

Having conversed frequently with Mr. Oxley on the subject of his expeditions, I went into the interior prepossessed in favour of his opinions, nor do I think he could have drawn any other conclusion than that which he did, from his experience of the terminations of the rivers whose courses he explored. Had Mr. Oxley advanced forty, or even thirty miles, farther than he did, to the westward of Mount Harris; nay, had he proceeded eight miles in the above direction beyond the actual spot from which he turned back, he would have formed other and very different opinions of the probable character of the distant interior. But I am aware that Mr. Oxley performed all that enterprise, and perseverance, and talent could have performed, and that it would have been impracticable in him to have attempted to force its marshes in the state in which he found them. It was from his want of knowledge of their nature and extent, that he inferred the swampy and inhospitable character of the more remote country, a state in which subsequent investigation has found it not to be. The marsh of the Macquarie is nothing more than an ordinary marsh or swamp in another country. However large a space it covers, it is no more than a concavity or basin for the reception of the waters of the river itself, nor has it any influence whatever on the country to the westward of it, in respect to inundation; the general features of the latter being a regular alternation of plain and brush. These facts are in themselves sufficient to give a fresh interest to the interior of the Australian continent, and to increase its importance.

CAPT. KING'S OPINIONS.

With respect to that part of its coast at which the rivers falling from the eastern mountains, discharge themselves, it is a question of very great doubt. It seems that Capt. King, in consequence of some peculiarities in the currents at its N.W. angle, supports Mr. Cunningham's opinion as to their probable discharge in that quarter. But I fear the internal structure of the continent is so low, as to preclude the hopes of any river reaching from one extremity of it to the other. A variety of local circumstances, as the contraction of a channel, a shoal sea, or numerous islands, influence currents generally, but more especially round so extensive a continent as that of which we are treating; nor does it strike me that any observations made by Capt. King during his survey, can be held to bear any connection with the eastern ranges, or their western waters. It may, however, be said, that as the course of the Darling is still involved in uncertainty, the question remains undecided; but it appears to me, the discovery of that river has set aside every conjecture (founded on previous observation) respecting the main features of the interior lying to the westward of the Blue Mountains. Both Mr. Oxley and Mr. Cunningham drew their conclusions from the appearances of the country they severally explored. The ground on which those theories were built, has been travelled over, and has not been found to realise them, but subsequent investigation has discovered to us a river, the dip of whose bed is to the S.W. We have every reason to believe that the sources of this river must be far to the northward of the most distant northerly point to which any survey has been made, as we are certain that it is far beyond the stretch of vision from the loftiest and most westerly of the barrier ranges; from which circumstance, it is evident that whatever disposition the streams descending from those ranges to the westward may show to hold a N.W. course more immediately at the base, the whole of the interior streams, from the Macquarie to the Dumaresq, are tributaries to the principal channel which conveys their united waters at right angles, if not still more opposite to the direction they were supposed to take, as far as is yet known.

COURSE OF THE DARLING.

The Darling River must be considered as the boundary line to all inland discoveries from the eastward. Any judgment or opinion of the interior to the westward of that stream, would be extremely premature and uncertain. There is not a single feature over it to guide or to strengthen either the one or the other.

CHARACTER OF THE WESTERN INTERIOR.

My impression, when travelling the country to the west and N.W. of the marshes of the Macquarie, was, that I was traversing a country of comparatively recent formation. The sandy nature of its soil, the great want of vegetable decay, the salsolaceous character of its plants, the appearance of its isolated hills and flooded tracts, and its trifling elevations above the sea, severally contributed to strengthen these impressions on my mind. My knowledge of the interior is, however, too limited to justify me in any conclusion with regard to the central parts of Australia. An ample field is open to enterprise and to ambition, and it is to be hoped that some more decisive measures will be carried into effect, both for the sake of the colony and of geography, to fill up the blank upon the face of the chart of Australia, and remove from us the reproach of indifference and inaction.