"Of the probable character of the distant unexplored interior, into which it has been ascertained ALL the rivers falling westerly from the dividing ranges flow, some inference may be drawn from the following data.
"Viewing, between the parallels of 34 degrees and 27 degrees, a vast area of depressed interior, subjected in seasons of prolonged rains to partial inundation, by a dispersion of the several waters that flow upon it from the eastern mountains whence they originate; and bearing in mind at the same time, that the declension of the country within the above parallels, as most decidedly shown by the dip of its several rivers, is uniformly to the N.N.W. and N.W., it would appear very conclusive, that either a portion of our distant interior is occupied by a lake of considerable magnitude, or that the confluence of those large streams, the Macquarie, Castlereagh, Gwydir, and the Dumaresq, with the many minor interfluent waters, which doubtless takes place upon those low levels, forms one or more n.o.ble rivers, which may flow across the continent by an almost imperceptible declivity of country to the north of north-west coasts, on certain parts of which, recent surveys have discovered to us extensive openings, by which the largest acc.u.mulations of waters might escape to the sea."
CHARACTER OF THE RIVERS.
It is the characteristic of the streams falling westerly from the eastern, or coast ranges, to maintain a breadth of channel and a rapidity of current more immediately near their sources, that ill accords with their diminished size, and the sluggish flow of their waters in the more depressed interior. In truth, neither the Macquarie nor the Castlereagh can strictly be considered as permanent rivers. The last particularly is nothing more than a mountain torrent. The Macquarie, although it at length ceased to run, kept up the appearance of a river to the very marshes; but the bed of the Castlereagh might have been crossed in many places without being noticed, nor did its channel contain so much water as was to be found on the neighbouring plains.
There are two circ.u.mstances upon which the magnitude, and velocity of a river, more immediately depend. The first is the abundance of its sources, the other the dip of its bed. If a stream has constant fountains at its head, and numerous tributaries joining it in its course, and flows withal through a country of gradual descent, such a stream will never fail; but if the supplies do not exceed the evaporation and absorption, to which every river is subject, if a river dependant on its head alone, falls rapidly into a level country, without receiving a single addition to its waters to a.s.sist the first impulse acquired in their descent, it must necessarily cease to flow at one point or other. Such is the case with the Lachlan, the Macquarie, the Castlereagh, and the Darling. Whence the latter originates, still remains to be ascertained; but most undoubtedly its sources have been influenced by the same drought that has exhausted the fountains of the three first mentioned streams.
In supporting his opinion of the probable discharge of the interior waters of Australia upon its north-west coast, Mr. Cunningham thus remarks in the publication from which I have already made an extract.
"To those remarkable parts of the north-west coast above referred to in the parallel of 16 degrees south, the Macquarie river, which rises in lat. 33 degrees, and under the meridian of 150 degrees east, would have a course of 2045 statute miles throughout, while the elevation of its source, being 3500 feet above the level of the sea as shown by the barometer, would give its waters an average descent of twenty inches to the mile, supposing the bed of the river to be an inclined plane.
"The Gwydir originating in elevated land, lying in 31 degrees south, and long. 151 degrees east, at a mean height of 3000 feet, would have to flow 2020 miles, its elevated sources giving to each a mean fall of seventeen inches.
"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 circ.u.mstanced 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 s.p.a.ce 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 circ.u.mstances, 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 circ.u.mstance, 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 princ.i.p.al 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.
BARBER"S STATEMENT.
Since the above pages were written, an expedition was undertaken by Major Mitch.e.l.l, the Surveyor-General, to ascertain the truth of a report brought in by a runaway convict of the name of Barber, or Clarke, who had been at large for five years, at different times, among the natives to the northward of Port Macquarie. This man stated that a large river, originating in the high lands near Liverpool Plains, and the mountains to the north of them, pursued a N.W. course to the sea. His story ran thus: Having learnt from the natives the existence of this river, he determined to follow it down, in hopes that he might ultimately be enabled to make his escape from the colony. He accordingly started from Liverpool Plains, and kept on a river called the Gnamoi, for some time, which took him N.W.
After a few days" journey, he left this river, traversed the country northwards, and crossed some lofty ranges. Descending to the N.E. he came to another large river, the Keindur, which again took him N.W. He travelled 400 miles down it, when he observed a large stream joining it upon its left bank, which he supposed to be the Gnamoi. The river he was upon was broad and navigable. It flowed through a level country with a dead current and muddy water, and spread into frequent lakes. He found that it ultimately discharged itself into the sea, but was uncertain at what distance from its sources. He was positive he never travelled to the SOUTHWARD OF WEST. He ascended a hill near the sea, and observed an island in the distance, from which, the natives informed him, a race of light-coloured men came in large canoes for a scented wood; but having failed in the immediate object of his journey, he was eventually obliged to return.
MAJOR MITCh.e.l.l"S REPORT.
The following official report of Major Mitch.e.l.l will sufficiently point out the incorrectness of the preceding statement. It is most probable that Barber merely told that which he had heard from the natives, and that having a more than ordinary share of cunning, he made up a story upon their vague and uncertain accounts, in hopes that it would benefit him, as in truth it did.
Bullabalakit, on the River Nammoy, in lat. 30 degrees 38 minutes 21 seconds S., long. 149 degrees 30 minutes 20 seconds E.
23d December, 1831.
SIR,
I have the honour to state, for the information of His Excellency the Governor, the progress I have made in exploring the course of the interior waters to the northward of the Colony, with reference to the letter which I had the honour to address to Col. Lindesay, on this subject, on the 19th ult.
On crossing Liverpool Range my object was to proceed northward, so as to avoid the plains and head the streams which water them, and avoiding also the mountain ranges on the east.
I arrived accordingly, by a tolerably straight and level line, at Walamoul, on Peel"s River; this place (a cattle station of Mr. Brown) being nearly due north from the common pa.s.s across Liverpool Range, and about a mile-and-a-half above the spot where Mr. Oxley crossed this river.
PEEL"S RIVER.
I found the general course of the Peel below Walamoul to be nearly west; and after tracing this river downwards twenty-two miles (in direct distance), I crossed it at an excellent ford, named Wallamburra. I then traversed the extensive plain of Mulluba; and leaving that of c.o.o.nil on the right, extending far to the north-east, we pa.s.sed through a favourable interval of what I considered Hardwicke"s Range, the general direction of this range being two points west of north.
On pa.s.sing through this gorge, which, from the name of a hill on the south side, may be named Ydire, I crossed a very extensive tract of flat country, on which the wood consisted of iron-bark and acacia pendula; this tract being part of a valley evidently declining to the north-west, which is bounded on the south by the Liverpool Range, and on the south-west by the extremities from the same. On the west, at a distance of twenty-two miles from Hardwicke"s Range, there stands a remarkable isolated hill named Bounalla; and towards the lowest part of the country, and in the direction in which all the waters tend, there is a rocky peak named Tangulda. On the north, a low range (named Wowa), branching westerly from Hardwicke"s Range, bounds on that side this extensive basin, which includes Liverpool Plains. Peel"s River is the princ.i.p.al stream, and receives, in its course, all the waters of these plains below the junction of Connadilly,--which I take to be York"s River, of Oxley.
THE RIVER NAMMOY.
The stream is well known to the natives by the name Nammoy; and six miles below Tangulda, the low extremities from the surrounding ranges close on the river, and separate this extensive vale from the unexplored country which extends beyond to an horizon which is unbroken between W.N.W.
and N.N.W.
The impracticable appearance of the mountains to the northward, induced me to proceed thus far to the west; and on examining the country thirty miles N.E. by N. from Tangulda, I ascended a lofty range extending westward from the coast chain, and on which the perpendicular sides of ma.s.ses of trachyte (a volcanic rock) were opposed to my further progress even with horses: it was therefore evident that the river supposed to rise about the lat.i.tude of 28 degrees would not be accessible, or at least available to the Colony, in that direction, and that in the event of the discovery of a river beyond that range flowing to the northern or north-western sh.o.r.es, it would become of importance to ascertain whether it was joined by the Nammoy, the head of this river being so accessible that I have brought my heavily laden drays to where it is navigable for boats, my present encampment being on its banks six miles below Tangulda. From this station I can perceive the western termination of the Trachytic range, and I am now about to explore the country between it and the Nammoy, and the further course of this river; and in the event of its continuance in a favourable direction, I shall fix my depot on its right bank, whence I now write, and descend the stream in the portable boats.
I have the honour to be, Sir, Your most obedient servant, T. L. MITCh.e.l.l, SURVEYOR-GENERAL
The Hon. The Colonial Secretary.
Peel"s River, 29th February, 1832.
SIR,
I have the honour to inform you, for the information of His Excellency the Governor, that I have reached the left bank of this River with my whole party on my return from the northern interior, having explored the course of the river referred to in my letter of 22nd December last, and others within the 29th parallel of lat.i.tude.
There was so much fallen timber in the Nammoy, and its waters were so low, that the portable boats could not be used on that river with advantage, and I proceeded by land in a north-west direction, until convinced by its course turning more to the westward that this river joined the river Darling. I therefore quitted its banks with the intention of exploring the country further northward, by moving round the western extremities of the mountains mentioned in my former letter, and which I have since distinguished in my map by the name of the Lindesay Range. These mountains terminate abruptly on the west, and I entered a fine open country at their base, from whence plains (or rather open ground of gentle undulation) extended westward as far as could be seen. On turning these mountains I directed my course northward, and to the eastward of north, into the country beyond them, in search of the river KINDUR; and I reached a river flowing westward, the bed of which was deep, broad, and permanent, but in which there was not then much water.
THE RIVER KARAULA.
The marks of inundation on trees, and on the adjoining high ground, proved that its floods rose to an extraordinary height; and from the lat.i.tude, and also from the general direction of its course, I considered this to be the river which Mr. Cunningham named the Gwydir, on crossing it sixty miles higher, on his route to Moreton Bay. I descended this river, and explored the country on its left bank for about eighty miles to the westward, when I found that its general course was somewhat to the southward of west. This river received no addition from the mountains over that part of its left bank traversed by me; and the heat being intense, the stream was at length so reduced that I could step across it. The banks had become low, and the bed much contracted, being no longer gravelly, but muddy. I therefore crossed this river and travelled northward, on a meridian line, until, in the lat.i.tude of 29 degrees 2 minutes, I came upon the largest river I had yet seen. The banks were earthy and broken, the soil being loose, and the water of a white muddy colour. Trees, washed out by the roots from the soft soil, filled the bed of this river in many places. There was abundance of cod-fish of a small size, as well as of the two other kinds of fish which we had caught in the Peel, the Nammoy, and the Gwydir. The name of this river, as well as we could make it out from the natives, was Karaula. Having made fast one tree to top of another tall tree, I obtained a view of the horizon, which appeared perfectly level, and I was in hopes that we had at length found a river which would flow to the northward and avoid the Darling. I accordingly ordered the boat to be put together, and sent Mr. White with a party some miles down to clear away any trees in the way. Mr. White came upon a rocky fall, and found besides the channel so much obstructed by trees, and the course so tortuous, that I determined to ascertain before embarking upon it, whether the general course was in the desired direction. Leaving Mr. White with half the party, I accordingly traced the Karaula downwards, and found that its course changed to south, a few miles below where I had made it, and that it was joined by the Gwydir only eight miles below where I had crossed that river. Immediately below the junction of the Gwydir (which is in lat.i.tude 29 degrees 30 minutes 27 seconds, longitude 148 degrees 13 minutes 20 seconds) the course of the river continues southward of west, directly towards where Captain Sturt discovered the River Darling; and I could no longer doubt that this was the same river. I therefore returned to the party, determined to explore the country further northward.
The results of my progress thus far were sufficient, I considered, to prove that the division of the waters falling towards the northern and southern sh.o.r.es of Australia is not, as has been supposed, in the direction of the Liverpool and Warrabangle range, but extends between Cape Byron on the eastern sh.o.r.e, towards d.i.c.k Hartog"s Island on the west; the greater elongation of this country being between these points, and intermediate between the lines of its northern and southern coasts. The basin of the streams I have been upon must be bounded on the north by this dividing ground or water-shed, and although no rise was perceptible in the northern horizon, the river was traversed by several rocky d.y.k.es, over which it fell southward; their direction being oblique to the course, and nearly parallel to this division of the waters. I beg leave to state, that I should not feel certain on this point without having seen more, were it not evident from Mr. Cunningham"s observations, made on crossing this division on his way to Moreton Bay. Mr. Cunningham, on crossing the head of this river, nearly in the same lat.i.tude, but much nearer its sources, found the height of its bed above the sea to be 840 feet; at about forty-five miles further northward the ground rose to upwards of 1700 feet, but immediately beyond, he reached a river flowing north-west, the height of which was only 1400 feet above the sea. He had thus crossed this dividing higher ground, between the parallels of 29 degrees and 28 degrees. It appears, therefore, that all the interior rivers we know of to the northward of the Morumbidgee, belong to the basin of the Karaula; this stream flowing southward, and hence the disappearance of the Macquarie and other lower rivers may be understood, for all along the banks of the Karaula, the Gwydir, and the Nammoy, the country, though not swampy, bears marks of frequent inundation; thus the floods occasioned by these rivers united, cover the low country, and receive the Macquarie so that no channel marks its further course.